* [PATCH net-next v3 2/2] net: pse-pd: Add LTC4266 PSE controller driver
2026-09-27 21:29 [PATCH net-next v3 0/2] net: pse-pd: Add LTC4266 PSE controller driver Kyle Swenson
2026-09-27 21:29 ` [PATCH net-next v3 1/2] dt-bindings: net: pse-pd: Add bindings for LTC4266 PSE Controller Kyle Swenson
@ 2026-09-27 21:29 ` Kyle Swenson
1 sibling, 0 replies; 3+ messages in thread
From: Kyle Swenson @ 2026-09-27 21:29 UTC (permalink / raw)
To: o.rempel, kory.maincent, andrew+netdev, davem, edumazet, kuba,
pabeni, robh, krzk+dt, conor+dt
Cc: Kyle Swenson, netdev, devicetree, linux-kernel,
Roland Kovács, David Nyström
Add a new driver for the Linear Technology LTC4266 I2C Power Sourcing
Equipment controller and integrate with the PSE controller core. The
LTC4266 supports Type 1 and Type 2 Powered Devices.
Signed-off-by: Kyle Swenson <kyle.swenson@est.tech>
---
MAINTAINERS | 7 +
drivers/net/pse-pd/Kconfig | 11 +
drivers/net/pse-pd/Makefile | 1 +
drivers/net/pse-pd/ltc4266.c | 1386 ++++++++++++++++++++++++++++++++++
4 files changed, 1405 insertions(+)
create mode 100644 drivers/net/pse-pd/ltc4266.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 6de1ff058db6..3f7226d04983 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15531,10 +15531,17 @@ L: linux-leds@vger.kernel.org
S: Maintained
W: https://ez.analog.com/linux-software-drivers
F: Documentation/devicetree/bindings/leds/adi,ltc3220.yaml
F: drivers/leds/leds-ltc3220.c
+LTC4266 PSE CONTROLLER DRIVER
+M: Kyle Swenson <kyle.swenson@est.tech>
+L: netdev@vger.kernel.org
+S: Maintained
+F: Documentation/devicetree/bindings/net/pse-pd/lltc,ltc4266.yaml
+F: drivers/net/pse-pd/ltc4266.c
+
LTC4282 HARDWARE MONITOR DRIVER
M: Nuno Sa <nuno.sa@analog.com>
L: linux-hwmon@vger.kernel.org
S: Supported
F: Documentation/devicetree/bindings/hwmon/adi,ltc4282.yaml
diff --git a/drivers/net/pse-pd/Kconfig b/drivers/net/pse-pd/Kconfig
index a0f2ae668c67..844c1b237df7 100644
--- a/drivers/net/pse-pd/Kconfig
+++ b/drivers/net/pse-pd/Kconfig
@@ -46,10 +46,21 @@ config PSE_REGULATOR
help
This module provides support for simple regulator based Ethernet Power
Sourcing Equipment without automatic classification support. For
example for basic implementation of PoDL (802.3bu) specification.
+config PSE_LTC4266
+ tristate "LTC4266 PSE controller"
+ depends on I2C
+ select REGMAP_I2C
+ help
+ This module provides support for LTC4266 regulator based Ethernet
+ Power Sourcing Equipment.
+
+ To compile this driver as a module, choose M here: the
+ module will be called ltc4266.
+
config PSE_PD692X0
tristate "PD692X0 PSE controller"
depends on I2C
select FW_LOADER
select FW_UPLOAD
diff --git a/drivers/net/pse-pd/Makefile b/drivers/net/pse-pd/Makefile
index 9cca5900fe34..c3fe4efcf1de 100644
--- a/drivers/net/pse-pd/Makefile
+++ b/drivers/net/pse-pd/Makefile
@@ -1,10 +1,11 @@
# SPDX-License-Identifier: GPL-2.0-only
# Makefile for Linux PSE drivers
obj-$(CONFIG_PSE_CONTROLLER) += pse_core.o
+obj-$(CONFIG_PSE_LTC4266) += ltc4266.o
obj-$(CONFIG_PSE_REALTEK_MCU) += realtek-pse-mcu-core.o
obj-$(CONFIG_PSE_REALTEK_MCU_I2C) += realtek-pse-mcu-i2c.o
obj-$(CONFIG_PSE_REALTEK_MCU_UART) += realtek-pse-mcu-uart.o
obj-$(CONFIG_PSE_REGULATOR) += pse_regulator.o
obj-$(CONFIG_PSE_PD692X0) += pd692x0.o
diff --git a/drivers/net/pse-pd/ltc4266.c b/drivers/net/pse-pd/ltc4266.c
new file mode 100644
index 000000000000..37dea467811a
--- /dev/null
+++ b/drivers/net/pse-pd/ltc4266.c
@@ -0,0 +1,1386 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Linear LTC4266 PoE PSE Controller
+ *
+ * Original work:
+ * Copyright 2019 Cradlepoint Technology, Inc.
+ * Cradlepoint Technology, Inc. <source@cradlepoint.com>
+ *
+ * Re-written in 2026:
+ * Copyright 2026 Ericsson Software Technology
+ * Kyle Swenson <kyle.swenson@est.tech>
+ *
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/ethtool.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pse-pd/pse.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+#define LTC4266_MAX_PORTS 4
+
+/* The minimum and maximum here depend on the resolution of the I_CUT field,
+ * which is 18.75mA. To get 1000mW with a 50V port voltage, we need 20mA; but
+ * with 18.75 mA steps we end up with a current limit of 37.5 mA resulting in
+ * an actual power limit of 1875mW.
+ */
+#define LTC4266_PW_LIMIT_MAX 30000
+#define LTC4266_PW_LIMIT_MIN 1000
+
+/* Nominal PI voltage reported when the port is not delivering power and no
+ * "vpwr-supply" is described in the device tree: V_Port_PSE min for a Type 2
+ * PSE. IEEE 802.3-2022 Table 33-11 item 1 specifies the POWER_ON state output
+ * voltage as 50.0 V to 57.0 V for a Type 2 PSE, 44.0 V to 57.0 V for Type 1.
+ */
+#define LTC4266_VPORT_NOMINAL_UV 50000000
+
+/* Register definitions */
+#define LTC4266_REG_INTSTAT 0x00
+#define LTC4266_REG_INTMASK 0x01
+#define LTC4266_REG_PWREVN_COR 0x03
+#define LTC4266_REG_DETEVN_COR 0x05
+#define LTC4266_REG_FLTEVN_COR 0x07
+#define LTC4266_REG_TSEVN_COR 0x09
+#define LTC4266_REG_SUPEVN_COR 0x0B
+#define LTC4266_REG_STAT(_p) (0x0C + (_p))
+#define LTC4266_REG_STATPWR 0x10
+#define LTC4266_REG_OPMD 0x12
+#define LTC4266_REG_DISENA 0x13 /* Disconnect detect enable */
+#define LTC4266_REG_MCONF 0x17
+#define LTC4266_REG_DETPB 0x18 /*PB means "push button" */
+#define LTC4266_REG_PWRPB 0x19
+#define LTC4266_REG_RSTPB 0x1A
+#define LTC4266_REG_ID 0x1B
+#define LTC4266_REG_TLIM12 0x1E
+#define LTC4266_REG_TLIM34 0x1F
+#define LTC4266_REG_IPLSB(_p) (0x30 | ((_p) << 2))
+#define LTC4266_REG_VPLSB(_p) (LTC4266_REG_IPLSB(_p) + 2)
+#define LTC4266_REG_HPEN 0x44
+#define LTC4266_REG_HPMD(_p) (0x46 + (5 * (_p)))
+#define LTC4266_REG_ICUT_HP(_p) (LTC4266_REG_HPMD(_p) + 1)
+#define LTC4266_REG_ILIM(_p) (LTC4266_REG_HPMD(_p) + 2)
+
+/* Register field definitions */
+
+/* LTC4266_REG_INTSTAT and LTC4266_REG_INTMASK */
+#define LTC4266_INT_TSTART BIT(6)
+#define LTC4266_INT_TCUT BIT(5)
+#define LTC4266_INT_CLASS BIT(4)
+#define LTC4266_INT_DETECT BIT(3)
+#define LTC4266_INT_DIS BIT(2)
+#define LTC4266_INT_PWRGD BIT(1)
+
+/* Per-port event bits within the CoR event registers. Every per-port event
+ * register splits its 8 bits into a per-port low nibble and a per-port high
+ * nibble:
+ * pwrevn (03h): LO = power on/off change, HI = power good change
+ * detevn (05h): LO = detection complete, HI = classification complete
+ * fltevn (07h): LO = tCUT overcurrent, HI = tDIS DC disconnect
+ * tsevn (09h): LO = tSTART overcurrent, HI = tLIM current-limit timeout
+ */
+#define LTC4266_EVN_HI(_p) BIT((_p) + 4) /* ports 0-3 */
+#define LTC4266_EVN_LO(_p) BIT(_p) /* ports 0-3 */
+
+/* statp<n> (0Ch-0Fh) detection result, and the "Signature Good" value */
+#define LTC4266_PORT_CLASS(_stat) FIELD_GET(GENMASK(6, 4), (_stat))
+#define LTC4266_PORT_DETECT(_stat) FIELD_GET(GENMASK(2, 0), (_stat))
+#define LTC4266_DETECT_GOOD 0x4
+
+/* LTC4266_REG_STATPWR */
+#define LTC4266_STATPWR_PG(_p) BIT((_p) + 4)
+#define LTC4266_STATPWR_PE(_p) BIT(_p)
+
+/* LTC4266_REG_OPMD
+ * There are three other operation modes possible this
+ * driver doesn't support and so aren't defined. The one supported mode,
+ * OPMD_SEMI, means that a port will continuously detect and classify devices,
+ * but will not power the device until instructed to do so.
+ */
+#define LTC4266_OPMD_SEMI 2
+#define LTC4266_TWO_BIT_WORD_OFFSET(_v, _p) ((_v) << ((_p) * 2))
+#define LTC4266_TWO_BIT_WORD_MASK(_p) LTC4266_TWO_BIT_WORD_OFFSET(0x03, (_p))
+
+/* LTC4266_REG_MCONF */
+#define LTC4266_MCONF_INTERRUPT_ENABLE BIT(7)
+/* Only report a detect event when the result changes, not every cycle */
+#define LTC4266_MCONF_DETCHG BIT(6)
+
+/* LTC4266_REG_DETPB */
+#define LTC4266_DETPB_CLASS_ENABLE(_p) BIT((_p) + 4)
+#define LTC4266_DETPB_DETECT_ENABLE(_p) BIT(_p)
+
+/* LTC4266_REG_RSTPB */
+#define LTC4266_RSTPB_INTCLR BIT(7)
+#define LTC4266_RSTPB_PINCLR BIT(6)
+#define LTC4266_RSTPB_RSTALL BIT(4)
+#define LTC4266_RSTPB_RSTPORTS GENMASK(3, 0)
+
+/* LTC4266_REG_ID */
+#define LTC4266_ID 0x64
+
+/* LTC4266_REG_TLIM* */
+#define LTC4266_TLIM_VALUE 0x01
+
+/* Current-sense scaling, in nA per LSB, dependent on the sense resistor. */
+#define LTC4266_IP_NA_PER_LSB_RSENSE_025 122070 /* 122.07 uA/LSB */
+#define LTC4266_IP_NA_PER_LSB_RSENSE_050 61035 /* 61.035 uA/LSB */
+
+/* Voltage-sense scaling: 5.835 mV == 5835 uV per LSB. */
+#define LTC4266_VP_UV_PER_LSB 5835
+
+/* LTC4266_REG_HPEN, enable "High Power" mode (Type 2, Class 4) */
+#define LTC4266_HPEN(_p) BIT(_p)
+
+/* LTC4266_REG_HPMD */
+#define LTC4266_HPMD_PONGEN 0x01
+
+/* LTC4266_REG_ICUT_HP.
+ * Set if the sense resistor specified in DT is 0.25 Ohm to have accurately
+ * scaled ICUT thresholds.
+ */
+#define LTC4266_ICUT_RSENSE_025_OHM BIT(7)
+
+/* To keep the ICUT resolution at a constant 18.75 mA, for the 0.25 Ohm sense
+ * case we should also set this ICUT_RANGE
+ */
+#define LTC4266_ICUT_RANGE BIT(6)
+
+/* I_CUT is programmed in a 6-bit field; each step is 18.75 mA (18750 uA). */
+#define LTC4266_ICUT_STEP_UA 18750
+#define LTC4266_ICUT_MASK GENMASK(5, 0)
+
+/* Cap I_CUT at the suggested value for a Type 2 PD at 638mA */
+#define LTC4266_ICUT_MAX_MA 638
+#define LTC4266_ICUT_MAX_STEPS 34
+
+/* Recommended lim<n> settings from datasheet Table 5.
+ *
+ * I_LIM (mA) RSENSE = 0.5 Ohm RSENSE = 0.25 Ohm
+ * 425 (Type 1) 0x00 0x80
+ * 850 (Type 2) 0x40 0xC0
+ */
+#define LTC4266_ILIM_TYPE1_RSENSE_050 0x00
+#define LTC4266_ILIM_TYPE1_RSENSE_025 0x80
+#define LTC4266_ILIM_TYPE2_RSENSE_050 0x40
+#define LTC4266_ILIM_TYPE2_RSENSE_025 0xC0
+
+enum {
+ LTC4266_READ_CURRENT = 0,
+ LTC4266_READ_VOLTAGE = 2
+};
+
+/* Map LTC4266 Classification result to PD class. Note for a PD that has a
+ * valid detect signature, but doesn't produce a classification signature is
+ * still a valid PD. The LTC4266 indicates this with 0x06 in the statp<n>
+ * register and calls it "Class 0". This is a different state than when
+ * statp<n> indicates 0, which means classification isn't complete. This maps
+ * the result to either an errno or classification value suitable for use up
+ * the stack.
+ */
+static const int ltc4266_class_map[] = {
+ -EAGAIN, /* Classification is incomplete */
+ 1,
+ 2,
+ 3,
+ 4,
+ -EINVAL,
+ 0,
+ -ERANGE
+};
+
+/* Map a PD Class to I_CUT thresholds from the LTC4266 datasheet Table 2 */
+static const int ltc4266_class_to_icut[] = {
+ 375,
+ 112,
+ 206,
+ 375,
+ 638
+};
+
+/* Per-class power budget at the PSE PI in mW, indexed by class (0-4).
+ * Classes 0-3 are the P_Class values from Table 33-7 in the IEEE802.3
+ * standard, which Note 1 defines as the minimum power a PSE must supply at the
+ * PI for that class (the PD input power maxima are in Table 33-18). Class 4 is
+ * P_Type, which Table 33-11 item 12 defines as I_Cable x V_Port_PSE min:
+ * 0.600 A x 50.0 V for a Type 2 PSE, with I_Cable from Table 33-1.
+ *
+ * Class 0 and Class 3 have the same value because a device without a classification
+ * signature (Class 0) has to be assumed to consume up to the maximum power for
+ * a Type 1 PD (Class 3).
+ */
+static const int ltc4266_class_pw[] = {
+ 15400, /* Class 0 */
+ 4000, /* Class 1 */
+ 7000, /* Class 2 */
+ 15400, /* Class 3 */
+ 30000, /* Class 4 (Type 2) */
+};
+
+enum sense_resistor {
+ LTC4266_RSENSE_500, /* Rsense 0.5 Ohm */
+ LTC4266_RSENSE_250 /* Rsense 0.25 Ohm */
+};
+
+struct ltc4266;
+
+/**
+ * struct ltc4266_port - per-PSE-PI context
+ *
+ * @ltc4266: the controller owning this port
+ * @chan: index of the LTC4266 delivery channel backing this PI, established
+ * from the PI pairset phandle by ltc4266_map_pis(). All register
+ * addressing uses this member.
+ * @rsense: sense resistor on @chan, used to scale current readings and
+ * to pick the I_CUT and I_LIM encodings.
+ * @pw_limit: Admin-configured power limit in mW, always valid: it defaults to
+ * LTC4266_PW_LIMIT_MAX, the most this controller can deliver, until
+ * pi_set_pw_limit() lowers it.
+ * @vpwr_uv: nominal PI voltage in uV, read once from the PI's "vpwr-supply" at
+ * probe, or LTC4266_VPORT_NOMINAL_UV when the PI does not describe
+ * one. Reported while the port is not delivering power, when the
+ * controller has nothing to measure.
+ */
+struct ltc4266_port {
+ struct ltc4266 *ltc4266;
+ u8 chan;
+ enum sense_resistor rsense;
+ int pw_limit;
+ int vpwr_uv;
+};
+
+/**
+ * struct ltc4266 - LTC4266 controller context
+ *
+ * @client: the I2C client
+ * @regmap: register map of @client
+ * @ports: table of PSE PI contexts, indexed by PSE PI id. A NULL entry is a PI
+ * that is not described in the device tree and therefore has no
+ * channel mapped.
+ * @dev: the underlying device
+ * @np: device node of @dev
+ * @pcdev: the PSE controller registered with the PSE core
+ */
+struct ltc4266 {
+ struct i2c_client *client;
+ struct regmap *regmap;
+ struct ltc4266_port *ports[LTC4266_MAX_PORTS];
+ struct device *dev;
+ struct device_node *np;
+ struct pse_controller_dev pcdev;
+};
+
+static struct ltc4266_port *ltc4266_pi_port(struct pse_controller_dev *pcdev,
+ int id)
+{
+ struct ltc4266 *ltc4266 = container_of(pcdev, struct ltc4266, pcdev);
+
+ return ltc4266->ports[id];
+}
+
+static int ltc4266_read_iv(struct ltc4266_port *port, u8 iv)
+{
+ struct ltc4266 *ltc4266 = port->ltc4266;
+ unsigned int lsb, msb;
+ unsigned int statpwr;
+ int lsb_reg;
+ int result;
+ u64 ivbits;
+
+ result = regmap_read(ltc4266->regmap, LTC4266_REG_STATPWR, &statpwr);
+ if (result < 0)
+ return result;
+
+ /* LTC4266 IV readings are only meaningful while the port is delivering
+ * power. When the PG (power good) bit is not set, the port is
+ * delivering nothing, so report 0 rather than an error: returning an
+ * errno here would abort pse_ethtool_get_status() and fail the whole
+ * "ethtool --show-pse" query for an otherwise perfectly readable port.
+ * Callers that must not report 0 (ltc4266_port_voltage_uv()) substitute
+ * a nominal value.
+ */
+ if (!(statpwr & LTC4266_STATPWR_PG(port->chan)))
+ return 0;
+
+ /* Since iv is either 0 (to read current) or 2 to (read voltage), we
+ * can get the LSB reg by adding
+ */
+ lsb_reg = LTC4266_REG_IPLSB(port->chan) + iv;
+
+ result = regmap_read(ltc4266->regmap, lsb_reg, &lsb);
+ if (result < 0)
+ return result;
+
+ result = regmap_read(ltc4266->regmap, lsb_reg + 1, &msb);
+ if (result < 0)
+ return result;
+
+ ivbits = (msb << 8) | lsb;
+
+ if (iv == LTC4266_READ_CURRENT)
+ if (port->rsense == LTC4266_RSENSE_250)
+ result = DIV_ROUND_CLOSEST_ULL(ivbits * LTC4266_IP_NA_PER_LSB_RSENSE_025,
+ 1000);
+ else
+ result = DIV_ROUND_CLOSEST_ULL(ivbits * LTC4266_IP_NA_PER_LSB_RSENSE_050,
+ 1000);
+ else
+ result = ivbits * LTC4266_VP_UV_PER_LSB;
+
+ return result;
+}
+
+/* Voltage at the PI in uV, if the PI is currently powering a device;
+ * otherwise, return the nominal voltage
+ */
+static int ltc4266_port_voltage_uv(struct ltc4266_port *port)
+{
+ int uv = ltc4266_read_iv(port, LTC4266_READ_VOLTAGE);
+
+ if (uv < 0)
+ return uv;
+
+ return uv ? uv : port->vpwr_uv;
+}
+
+/**
+ * ltc4266_port_set_ilim - Set the active current limit (ILIM) for a port
+ * @port: the port to configure
+ * @class: the detected PD class (0-4)
+ *
+ * Given the PD class, configure the active current limit for a particular
+ * channel. The LTC4266 will actively enforce this current limit using the
+ * sense resistor for the channel. The values written are from the LTC4266
+ * Datasheet, Table 5, and correspond to 425mA for Type I PDs, and 850mA for
+ * Type 2 PDs (per the datasheet requirement for IEEE compliance).
+ *
+ * IEEE Std 802.3-2022, Table 33-11 specifies ILIM parameter ranges:
+ * - For Type 1 PSE operation (PD Classes 0-3):
+ * The minimum ILIM is 0.400A. This driver uses 425mA. This value fits
+ * within typical Type 1 ILIM specifications (e.g., 0.400A min to
+ * around 0.440A-0.500A max for the programmed steady-state limit).
+ *
+ * - For Type 2 PSE operation (typically PD Class 4):
+ * The minimum ILIM is 1.14 * ICable (or ~1.05 * IPort_max from other
+ * interpretations, e.g., ~0.630A to ~0.684A). This driver uses 850mA.
+ * This value meets the minimum requirement and is a supported operational
+ * current limit for high power modes in the LTC4266.
+ *
+ * The overall PSE current output must not exceed the time-dependent PSE
+ * upperbound template, IPSEUT(t), described in IEEE Std 802.3-2022,
+ * Equation (33-6). The programmed ILIM values (425mA/850mA) serve as the
+ * long-term current limit (Ilimmin segment of IPSEUT(t)) and are well
+ * within the higher short-term current allowances of that template (e.g., 1.75A).
+ *
+ * Returns: 0 on success or a negative errno.
+ */
+static int ltc4266_port_set_ilim(struct ltc4266_port *port, int class)
+{
+ bool rsense_250 = port->rsense == LTC4266_RSENSE_250;
+ u8 ilim;
+
+ if (class > 4 || class < 0)
+ return -EINVAL;
+
+ if (class < 4)
+ ilim = rsense_250 ? LTC4266_ILIM_TYPE1_RSENSE_025 :
+ LTC4266_ILIM_TYPE1_RSENSE_050;
+ else
+ ilim = rsense_250 ? LTC4266_ILIM_TYPE2_RSENSE_025 :
+ LTC4266_ILIM_TYPE2_RSENSE_050;
+
+ return regmap_write(port->ltc4266->regmap,
+ LTC4266_REG_ILIM(port->chan), ilim);
+}
+
+static int ltc4266_port_set_icut(struct ltc4266_port *port, int icut)
+{
+ u8 val;
+
+ if (icut > LTC4266_ICUT_MAX_MA)
+ return -ERANGE;
+
+ val = min(DIV_ROUND_UP(icut * 1000, LTC4266_ICUT_STEP_UA),
+ LTC4266_ICUT_MAX_STEPS) & LTC4266_ICUT_MASK;
+
+ if (port->rsense == LTC4266_RSENSE_250)
+ val |= LTC4266_ICUT_RSENSE_025_OHM | LTC4266_ICUT_RANGE;
+
+ return regmap_write(port->ltc4266->regmap,
+ LTC4266_REG_ICUT_HP(port->chan), val);
+}
+
+/**
+ * ltc4266_pw_limit_to_icut - Convert an admin power limit to an I_CUT threshold
+ * @port: the port to convert for
+ * @max_mw: the power limit in mW
+ * @class: the detected PD class (0-4)
+ *
+ * The LTC4266 only enforces a current threshold, so a power limit has to be
+ * divided by the port voltage.
+ *
+ * Lowering I_CUT below the class threshold is legitimate: IEEE 802.3-2022
+ * 33.2.7.10 defines P_Class as either the class power or "PSE allocated power
+ * ... added to the channel power loss", and an administrative limit is that
+ * allocated power.
+ *
+ * Raising it above the class threshold is not. Table 33-11 item 7 bounds I_CUT
+ * at I_LIM, and ltc4266_port_set_ilim() picks I_LIM from the class: 425 mA for
+ * Type 1, 850 mA for Type 2. An administrative limit of LTC4266_PW_LIMIT_MAX
+ * asks for 600 mA at the nominal port voltage, which would exceed I_LIM on a
+ * Type 1 class. Capping at the class threshold from datasheet Table 2 keeps
+ * I_CUT under I_LIM for every class; the LTC4266_ICUT_MAX_MA check in
+ * ltc4266_port_set_icut() only covers Type 2.
+ *
+ * Return: the threshold in mA, or a negative errno if the voltage read failed.
+ */
+static int ltc4266_pw_limit_to_icut(struct ltc4266_port *port, int max_mw,
+ int class)
+{
+ int uv = ltc4266_port_voltage_uv(port);
+ int icut_mA;
+
+ if (uv < 0)
+ return uv;
+
+ /* 30000 mW x 1000000 overflows an int */
+ icut_mA = DIV_ROUND_UP_ULL((u64)max_mw * 1000000, uv);
+
+ return min(ltc4266_class_to_icut[class], icut_mA);
+}
+
+static int ltc4266_port_delivering(struct ltc4266_port *port)
+{
+ unsigned int result;
+ int ret;
+
+ ret = regmap_read(port->ltc4266->regmap, LTC4266_REG_STATPWR, &result);
+ if (ret < 0)
+ return ret;
+
+ return !!((result & LTC4266_STATPWR_PG(port->chan)) &&
+ (result & LTC4266_STATPWR_PE(port->chan)));
+}
+
+static int ltc4266_port_init(struct ltc4266_port *port)
+{
+ struct ltc4266 *ltc4266 = port->ltc4266;
+ u8 chan = port->chan;
+ u8 tlim_shift;
+ u8 tlim_mask;
+ u8 tlim_reg;
+ int ret;
+
+ /* Reset the port */
+ ret = regmap_write(ltc4266->regmap, LTC4266_REG_RSTPB, BIT(chan));
+ if (ret < 0)
+ return ret;
+
+ /* Set Semi-auto mode */
+ ret = regmap_update_bits(port->ltc4266->regmap, LTC4266_REG_OPMD,
+ LTC4266_TWO_BIT_WORD_MASK(port->chan),
+ LTC4266_TWO_BIT_WORD_OFFSET(LTC4266_OPMD_SEMI,
+ port->chan));
+ if (ret < 0)
+ return ret;
+
+ /* Enable high power mode on the port (for Type 2 PD support) */
+ ret = regmap_update_bits(ltc4266->regmap, LTC4266_REG_HPEN,
+ LTC4266_HPEN(chan), LTC4266_HPEN(chan));
+ if (ret < 0)
+ return ret;
+
+ /* Enable 2-event classification (IEEE 802.3-2022, Clause 33), which the
+ * datasheet refers to as "Ping-Pong" classification.
+ */
+ ret = regmap_update_bits(ltc4266->regmap, LTC4266_REG_HPMD(chan),
+ LTC4266_HPMD_PONGEN, LTC4266_HPMD_PONGEN);
+ if (ret < 0)
+ return ret;
+
+ if (chan <= 1)
+ tlim_reg = LTC4266_REG_TLIM12;
+ else
+ tlim_reg = LTC4266_REG_TLIM34;
+
+ /* Each tlim register packs two ports: the even port in the low nibble
+ * and the odd port in the high nibble. Shift both the value and the
+ * mask into the correct nibble.
+ */
+ if (chan & BIT(0))
+ tlim_shift = 4;
+ else
+ tlim_shift = 0;
+
+ tlim_mask = GENMASK(3, 0) << tlim_shift;
+
+ ret = regmap_update_bits(ltc4266->regmap, tlim_reg,
+ tlim_mask, LTC4266_TLIM_VALUE << tlim_shift);
+ if (ret < 0)
+ return ret;
+
+ /* Enable disconnect detect. */
+ ret = regmap_update_bits(ltc4266->regmap, LTC4266_REG_DISENA,
+ BIT(chan), BIT(chan));
+ if (ret < 0)
+ return ret;
+
+ /* Enable detection (low nibble), classification (high nibble) on the port */
+ ret = regmap_write(ltc4266->regmap, LTC4266_REG_DETPB,
+ LTC4266_DETPB_CLASS_ENABLE(chan) |
+ LTC4266_DETPB_DETECT_ENABLE(chan));
+
+ if (ret < 0)
+ return ret;
+
+ dev_dbg(ltc4266->dev, "Channel %d has been initialized\n", chan);
+ return 0;
+}
+
+/* Read the port's classification result and return a class 0-4 or an error if
+ * the result isn't valid.
+ */
+static int ltc4266_port_get_class(struct ltc4266_port *port)
+{
+ struct ltc4266 *ltc4266 = port->ltc4266;
+ unsigned int val;
+ int ret;
+
+ ret = regmap_read(ltc4266->regmap, LTC4266_REG_STAT(port->chan), &val);
+ if (ret < 0) {
+ dev_warn(ltc4266->dev, "Failed to read status register, err=%d\n", ret);
+ return ret;
+ }
+
+ /* Can't have a valid classification result if we've not yet had a good
+ * detection result.
+ */
+ if (LTC4266_PORT_DETECT(val) != LTC4266_DETECT_GOOD)
+ return -EINVAL;
+
+ ret = ltc4266_class_map[LTC4266_PORT_CLASS(val)];
+ return ret;
+}
+
+/* Maximum power the classified PD is allowed. It does not depend on the port
+ * being powered, but it does depend on the port having a PD attached and being
+ * enabled to the point of running classification and detection cycles.
+ */
+static int ltc4266_port_max_pw(struct ltc4266_port *port)
+{
+ int class = ltc4266_port_get_class(port);
+
+ if (class < 0)
+ return class;
+
+ return ltc4266_class_pw[class];
+}
+
+static int ltc4266_pi_get_pw_status(struct pse_controller_dev *pcdev, int id,
+ struct pse_pw_status *pw_status)
+{
+ struct ltc4266_port *port = ltc4266_pi_port(pcdev, id);
+ int ret;
+
+ ret = ltc4266_port_delivering(port);
+ if (ret < 0)
+ return ret;
+
+ if (ret)
+ pw_status->c33_pw_status = ETHTOOL_C33_PSE_PW_D_STATUS_DELIVERING;
+ else
+ pw_status->c33_pw_status = ETHTOOL_C33_PSE_PW_D_STATUS_SEARCHING;
+
+ return 0;
+}
+
+/* With the static budget evaluation strategy the PSE core calls this only
+ * after a PD has been classified and the power budget has been allocated.
+ * Program the current limit for the classified PD, reduced if an admin power
+ * limit asks for less than the class is entitled to, and apply power.
+ */
+static int ltc4266_pi_enable(struct pse_controller_dev *pcdev, int id)
+{
+ struct ltc4266_port *port = ltc4266_pi_port(pcdev, id);
+ int class, icut, ret;
+
+ class = ltc4266_port_get_class(port);
+ if (class < 0)
+ return class;
+
+ ret = ltc4266_port_set_ilim(port, class);
+ if (ret < 0)
+ return ret;
+
+ /* Derive the threshold from the admin limit against the class in front of
+ * us now, since a different PD may have been plugged in since the limit
+ * was set.
+ */
+ icut = ltc4266_pw_limit_to_icut(port, port->pw_limit, class);
+ if (icut < 0)
+ return icut;
+
+ ret = ltc4266_port_set_icut(port, icut);
+ if (ret < 0)
+ return ret;
+
+ /* Apply power to the port. */
+ return regmap_write(port->ltc4266->regmap, LTC4266_REG_PWRPB,
+ BIT(port->chan));
+}
+
+static int ltc4266_pi_disable(struct pse_controller_dev *pcdev, int id)
+{
+ struct ltc4266_port *port = ltc4266_pi_port(pcdev, id);
+
+ /* Resetting the port (RSTPB, issued at the start of ltc4266_port_init)
+ * removes power, disables detection and classification, and clears the
+ * port's status register. Re-init the port so that detection and
+ * classification can happen again.
+ */
+ return ltc4266_port_init(port);
+}
+
+static int ltc4266_pi_get_voltage(struct pse_controller_dev *pcdev, int id)
+{
+ return ltc4266_port_voltage_uv(ltc4266_pi_port(pcdev, id));
+}
+
+static int ltc4266_pi_get_admin_state(struct pse_controller_dev *pcdev, int id,
+ struct pse_admin_state *admin_state)
+{
+ struct ltc4266_port *port = ltc4266_pi_port(pcdev, id);
+ unsigned int val;
+ int ret;
+
+ /* The PSE core uses this as the hardware admin state: whether power has
+ * been commanded on, not whether it has finished coming up.
+ * pse_pi_is_hw_enabled() decides from it which software-enabled PIs
+ * still need power delivery attempted, so report the power-enable
+ * nibble (peN), which the controller sets as soon as it applies power to
+ * the port. The power-good nibble only sets once OUT has pulled down to
+ * VEE, up to a tSTART later, and a port reported as not enabled for that
+ * whole ramp is one the core will allocate power domain budget for a
+ * second time. Actual delivery is reported by pi_get_pw_status().
+ */
+ ret = regmap_read(port->ltc4266->regmap, LTC4266_REG_STATPWR, &val);
+ if (ret < 0)
+ return ret;
+
+ if (val & LTC4266_STATPWR_PE(port->chan))
+ admin_state->c33_admin_state =
+ ETHTOOL_C33_PSE_ADMIN_STATE_ENABLED;
+ else
+ admin_state->c33_admin_state =
+ ETHTOOL_C33_PSE_ADMIN_STATE_DISABLED;
+
+ return 0;
+}
+
+static int ltc4266_pi_get_pw_class(struct pse_controller_dev *pcdev, int id)
+{
+ int ret = ltc4266_port_get_class(ltc4266_pi_port(pcdev, id));
+
+ /* ltc4266_port_get_class will return either the class, or an errno.
+ * Returning an errno from this function will mean the ethtool command
+ * will abort with the error and not emit later useful information.
+ * Additionally, returning 0 to indicate no classification signature
+ * will cause the ethtool output to omit the "Power Class" attribute
+ * entirely. Since the "Power Class" is expected to be returned here,
+ * and class 0 and class 3 are equivalent in terms of power allocation,
+ * we'll return 3.
+ */
+
+ if (ret == 0)
+ ret = 3;
+ if (ret < 0)
+ ret = 0;
+ return ret;
+}
+
+/* Get the power requested by the PD before enabling the port: its
+ * classification power.
+ */
+static int ltc4266_pi_get_pw_req(struct pse_controller_dev *pcdev, int id)
+{
+ return ltc4266_port_max_pw(ltc4266_pi_port(pcdev, id));
+}
+
+static int ltc4266_pi_get_actual_pw(struct pse_controller_dev *pcdev, int id)
+{
+ struct ltc4266_port *port = ltc4266_pi_port(pcdev, id);
+ int uA, uV;
+
+ uA = ltc4266_read_iv(port, LTC4266_READ_CURRENT);
+ if (uA < 0)
+ return uA;
+
+ uV = ltc4266_read_iv(port, LTC4266_READ_VOLTAGE);
+ if (uV < 0)
+ return uV;
+
+ /* mW = uA * uV / 1000000000 */
+ return DIV_ROUND_CLOSEST_ULL((u64)uA * uV, 1000000000);
+}
+
+/* The range of administrative power limits this controller supports. It does
+ * not depend on the detected class: the class only bounds the I_CUT threshold
+ * that ltc4266_pw_limit_to_icut() programs.
+ */
+static int ltc4266_pi_get_pw_limit_ranges(struct pse_controller_dev *pcdev, int id,
+ struct pse_pw_limit_ranges *pw_limit_ranges)
+{
+ struct ethtool_c33_pse_pw_limit_range *c33_pw_limit_ranges;
+
+ c33_pw_limit_ranges = kzalloc_obj(*c33_pw_limit_ranges);
+ if (!c33_pw_limit_ranges)
+ return -ENOMEM;
+
+ c33_pw_limit_ranges[0].min = LTC4266_PW_LIMIT_MIN;
+ c33_pw_limit_ranges[0].max = LTC4266_PW_LIMIT_MAX;
+
+ pw_limit_ranges->c33_pw_limit_ranges = c33_pw_limit_ranges;
+
+ /* Return the number of ranges */
+ return 1;
+}
+
+/* Store the administrative power limit. The limit is independent of any PD in
+ * front of us, so accept it whether or not the port has classified anything;
+ * program I_CUT immediately when it has, so a change on a live port takes
+ * effect, and leave it to ltc4266_pi_enable() otherwise.
+ */
+static int ltc4266_pi_set_pw_limit(struct pse_controller_dev *pcdev,
+ int id, int max_mw)
+{
+ struct ltc4266_port *port = ltc4266_pi_port(pcdev, id);
+ int class;
+ int icut;
+ int ret;
+
+ if (max_mw < LTC4266_PW_LIMIT_MIN || max_mw > LTC4266_PW_LIMIT_MAX) {
+ dev_err(port->ltc4266->dev, "power limit %d is out of range [%d, %d]\n",
+ max_mw, LTC4266_PW_LIMIT_MIN, LTC4266_PW_LIMIT_MAX);
+ return -ERANGE;
+ }
+
+ class = ltc4266_port_get_class(port);
+ if (class >= 0) {
+ icut = ltc4266_pw_limit_to_icut(port, max_mw, class);
+ if (icut < 0)
+ return icut;
+
+ ret = ltc4266_port_set_icut(port, icut);
+ if (ret < 0)
+ return ret;
+ }
+
+ port->pw_limit = max_mw;
+
+ return 0;
+}
+
+static int ltc4266_pi_get_pw_limit(struct pse_controller_dev *pcdev, int id)
+{
+ return ltc4266_pi_port(pcdev, id)->pw_limit;
+}
+
+/* Description of one delivery channel parsed out of the "channels" node. Used
+ * locally only during ltc4266_setup_pi_matrix()
+ */
+struct ltc4266_chan_desc {
+ struct device_node *np;
+ enum sense_resistor rsense;
+};
+
+static int ltc4266_get_of_channels(struct ltc4266 *ltc4266,
+ struct ltc4266_chan_desc *chans)
+{
+ struct device_node *channels_node __free(device_node) =
+ of_get_child_by_name(ltc4266->np, "channels");
+ u32 chan_id, sense;
+ int ret;
+
+ if (!channels_node)
+ return dev_err_probe(ltc4266->dev, -EINVAL,
+ "missing \"channels\" node\n");
+
+ for_each_child_of_node_scoped(channels_node, chan_node) {
+ if (!of_node_name_eq(chan_node, "channel"))
+ continue;
+
+ ret = of_property_read_u32(chan_node, "reg", &chan_id);
+ if (ret)
+ return dev_err_probe(ltc4266->dev, ret,
+ "missing reg property in node %pOF\n",
+ chan_node);
+
+ if (chan_id >= LTC4266_MAX_PORTS)
+ return dev_err_probe(ltc4266->dev, -EINVAL,
+ "channel id %u is out of range in node %pOF\n",
+ chan_id, chan_node);
+
+ if (chans[chan_id].np)
+ return dev_err_probe(ltc4266->dev, -EINVAL,
+ "channel id %u is already used, please check the reg property in node %pOF\n",
+ chan_id, chan_node);
+
+ ret = of_property_read_u32(chan_node, "sense-resistor-micro-ohms", &sense);
+ if (ret)
+ return dev_err_probe(ltc4266->dev, ret,
+ "missing sense-resistor-micro-ohms property in node %pOF\n",
+ chan_node);
+
+ if (sense == 250000)
+ chans[chan_id].rsense = LTC4266_RSENSE_250;
+ else if (sense == 500000)
+ chans[chan_id].rsense = LTC4266_RSENSE_500;
+ else
+ return dev_err_probe(ltc4266->dev, -EINVAL,
+ "invalid sense resistor value %u in node %pOF\n",
+ sense, chan_node);
+
+ chans[chan_id].np = of_node_get(chan_node);
+ }
+
+ return 0;
+}
+
+/* Find the channel a PI pairset phandle points at. */
+static int ltc4266_match_channel(const struct pse_pi_pairset *pairset,
+ struct ltc4266_chan_desc *chans)
+{
+ int i;
+
+ for (i = 0; i < LTC4266_MAX_PORTS; i++)
+ if (pairset->np == chans[i].np)
+ return i;
+
+ return -ENODEV;
+}
+
+/*
+ * Nominal voltage of the rail feeding a PSE PI, taken from its "vpwr-supply".
+ * This is intended to work around the limitation on the LTC4266 where the port
+ * voltage is not valid until _after_ the port is powered. Since the PSE core
+ * expects to read the port voltage when the port is not powered we need
+ * something non-zero to return to the core.
+ *
+ * In the event the regulator isn't present, or if the regulator doesn't have a
+ * nominal voltage available, we'll fall back and use 50V, which is the minimum
+ * allowed for a Type 2 PSE.
+ *
+ * Finally, we read this regulator voltage here instead of during
+ * ltc4266_pi_get_voltage to avoid deadlock.
+ *
+ * Return: the nominal voltage in uV, or LTC4266_VPORT_NOMINAL_UV if the PI
+ * describes no supply, its supply has not registered yet, or its voltage
+ * cannot be determined.
+ */
+static int ltc4266_pi_nominal_uv(struct ltc4266 *ltc4266, struct device_node *np)
+{
+ struct regulator *vpwr;
+ int uv;
+
+ vpwr = of_regulator_get_optional(ltc4266->dev, np, "vpwr");
+ if (IS_ERR(vpwr)) {
+ /* -ENODEV means the PI describes no vpwr-supply at all, which
+ * is the case the fallback exists for. -EPROBE_DEFER means the
+ * rail _is_ described but has not registered yet, so the
+ * fallback is wrong for it. Asking for a probe retry is not an
+ * option from here: we run from setup_pi_matrix(), and
+ * pse_controller_register() unwinds neither its notification
+ * fifo nor its pse_pi array when that fails, so every retry
+ * would leak. Warn instead so the assumed voltage is visible.
+ */
+ if (PTR_ERR(vpwr) == -EPROBE_DEFER)
+ dev_warn(ltc4266->dev,
+ "%pOF: vpwr-supply is not registered yet, assuming %d uV\n",
+ np, LTC4266_VPORT_NOMINAL_UV);
+
+ return LTC4266_VPORT_NOMINAL_UV;
+ }
+
+ uv = regulator_get_voltage(vpwr);
+ regulator_put(vpwr);
+
+ if (uv <= 0)
+ return LTC4266_VPORT_NOMINAL_UV;
+
+ return uv;
+}
+
+/* Build a port context for every PSE PI described in the device tree, bound to
+ * the channel its pairset references. A PI with no node is left NULL; the PSE
+ * core does not register a regulator for it and so never calls back for it.
+ */
+static int ltc4266_map_pis(struct ltc4266 *ltc4266,
+ struct ltc4266_chan_desc *chans)
+{
+ struct pse_controller_dev *pcdev = <c4266->pcdev;
+ struct ltc4266_port *port;
+ int i, j, chan, uv;
+
+ for (i = 0; i < LTC4266_MAX_PORTS; i++) {
+ struct pse_pi *pi = &pcdev->pi[i];
+
+ if (!pi->np)
+ continue;
+
+ if (!pi->pairset[0].np)
+ return dev_err_probe(ltc4266->dev, -EINVAL,
+ "%pOF has no pairsets\n", pi->np);
+
+ /* The LTC4266 delivers over a single pairset per channel, so
+ * there is no 4-pair mode to spread a PI over two channels.
+ */
+ if (pi->pairset[1].np)
+ return dev_err_probe(ltc4266->dev, -EOPNOTSUPP,
+ "%pOF: 4-pair PSE PIs are not supported\n",
+ pi->np);
+
+ chan = ltc4266_match_channel(&pi->pairset[0], chans);
+ if (chan < 0)
+ return dev_err_probe(ltc4266->dev, chan,
+ "%pOF: pairset %pOF is not a channel of this controller\n",
+ pi->np, pi->pairset[0].np);
+
+ for (j = 0; j < i; j++)
+ if (ltc4266->ports[j] && ltc4266->ports[j]->chan == chan)
+ return dev_err_probe(ltc4266->dev, -EINVAL,
+ "%pOF: channel %d is already used by %pOF\n",
+ pi->np, chan, pcdev->pi[j].np);
+
+ uv = ltc4266_pi_nominal_uv(ltc4266, pi->np);
+
+ port = devm_kzalloc(ltc4266->dev, sizeof(*port), GFP_KERNEL);
+ if (!port)
+ return -ENOMEM;
+
+ port->ltc4266 = ltc4266;
+ port->chan = chan;
+ port->rsense = chans[chan].rsense;
+ port->vpwr_uv = uv;
+ port->pw_limit = LTC4266_PW_LIMIT_MAX;
+ ltc4266->ports[i] = port;
+
+ dev_dbg(ltc4266->dev, "PI %d is backed by channel %d, nominal %d uV\n",
+ i, chan, uv);
+ }
+
+ return 0;
+}
+
+static int ltc4266_setup_pi_matrix(struct pse_controller_dev *pcdev)
+{
+ struct ltc4266 *ltc4266 = container_of(pcdev, struct ltc4266, pcdev);
+ struct ltc4266_chan_desc chans[LTC4266_MAX_PORTS] = { };
+ int i, ret;
+
+ if (pcdev->no_of_pse_pi)
+ return dev_err_probe(ltc4266->dev, -EINVAL,
+ "a \"pse-pis\" node is required\n");
+
+ ret = ltc4266_get_of_channels(ltc4266, chans);
+ if (!ret)
+ ret = ltc4266_map_pis(ltc4266, chans);
+
+ for (i = 0; i < LTC4266_MAX_PORTS; i++)
+ of_node_put(chans[i].np);
+
+ if (ret)
+ return ret;
+
+ for (i = 0; i < LTC4266_MAX_PORTS; i++) {
+ if (!ltc4266->ports[i])
+ continue;
+
+ ret = ltc4266_port_init(ltc4266->ports[i]);
+ if (ret < 0)
+ return dev_err_probe(ltc4266->dev, ret,
+ "Failed to initialize PI %d\n", i);
+ }
+
+ return 0;
+}
+
+static const struct pse_controller_ops ltc4266_ops = {
+ .setup_pi_matrix = ltc4266_setup_pi_matrix,
+ .pi_get_admin_state = ltc4266_pi_get_admin_state,
+ .pi_get_pw_status = ltc4266_pi_get_pw_status,
+ .pi_get_pw_class = ltc4266_pi_get_pw_class,
+ .pi_get_actual_pw = ltc4266_pi_get_actual_pw,
+ .pi_enable = ltc4266_pi_enable,
+ .pi_disable = ltc4266_pi_disable,
+ .pi_get_voltage = ltc4266_pi_get_voltage,
+ .pi_get_pw_limit = ltc4266_pi_get_pw_limit,
+ .pi_set_pw_limit = ltc4266_pi_set_pw_limit,
+ .pi_get_pw_limit_ranges = ltc4266_pi_get_pw_limit_ranges,
+ .pi_get_pw_req = ltc4266_pi_get_pw_req,
+};
+
+#define LTC4266_INTERRUPT_SOURCES (LTC4266_INT_TSTART | LTC4266_INT_TCUT | \
+ LTC4266_INT_CLASS | LTC4266_INT_DETECT | \
+ LTC4266_INT_DIS | LTC4266_INT_PWRGD)
+
+static int ltc4266_enable_interrupts(struct ltc4266 *ltc4266)
+{
+ /* Unmask interrupts */
+ return regmap_write(ltc4266->regmap, LTC4266_REG_INTMASK,
+ LTC4266_INTERRUPT_SOURCES);
+}
+
+static int ltc4266_disable_interrupts(struct ltc4266 *ltc4266)
+{
+ int ret;
+
+ ret = regmap_write(ltc4266->regmap, LTC4266_REG_INTMASK, 0x00);
+ if (ret < 0)
+ return ret;
+
+ /* Reset the (SMBus Alert) interrupt pin */
+ return regmap_write(ltc4266->regmap, LTC4266_REG_RSTPB, LTC4266_RSTPB_PINCLR);
+}
+
+static int ltc4266_map_event(int irq, struct pse_controller_dev *pcdev,
+ unsigned long *notifs, unsigned long *notifs_mask)
+{
+ struct ltc4266 *ltc4266 = container_of(pcdev, struct ltc4266, pcdev);
+ unsigned int detevn = 0, fltevn = 0, tsevn = 0, pwrevn = 0;
+ unsigned int statpwr = 0;
+ unsigned int intstat;
+ int ret;
+ int i;
+
+ ret = ltc4266_disable_interrupts(ltc4266);
+ if (ret < 0)
+ goto err;
+
+ ret = regmap_read(ltc4266->regmap, LTC4266_REG_INTSTAT, &intstat);
+ if (ret < 0)
+ goto err;
+
+ if (!intstat)
+ goto done;
+
+ if (intstat & LTC4266_INT_PWRGD) {
+ ret = regmap_read(ltc4266->regmap, LTC4266_REG_PWREVN_COR, &pwrevn);
+ if (ret < 0) {
+ dev_err(<c4266->client->dev, "Failed to read pwrevn, err=%d\n", ret);
+ goto err;
+ }
+
+ ret = regmap_read(ltc4266->regmap, LTC4266_REG_STATPWR, &statpwr);
+ if (ret < 0) {
+ dev_err(<c4266->client->dev, "Failed to read statpwr, err=%d\n", ret);
+ goto err;
+ }
+ }
+
+ if (intstat & (LTC4266_INT_DIS | LTC4266_INT_TCUT)) {
+ ret = regmap_read(ltc4266->regmap, LTC4266_REG_FLTEVN_COR, &fltevn);
+ if (ret < 0) {
+ dev_err(<c4266->client->dev, "Failed to read fltevn err=%d\n", ret);
+ goto err;
+ }
+ }
+
+ if (intstat & (LTC4266_INT_TSTART | LTC4266_INT_TCUT)) {
+ ret = regmap_read(ltc4266->regmap, LTC4266_REG_TSEVN_COR, &tsevn);
+ if (ret < 0) {
+ dev_err(<c4266->client->dev, "Failed to read tsevn, err=%d\n", ret);
+ goto err;
+ }
+ }
+
+ if (intstat & (LTC4266_INT_CLASS | LTC4266_INT_DETECT)) {
+ ret = regmap_read(ltc4266->regmap, LTC4266_REG_DETEVN_COR, &detevn);
+ if (ret < 0) {
+ dev_err(<c4266->client->dev, "Failed to read detevn, err=%d\n", ret);
+ goto err;
+ }
+ }
+
+ /* The event registers are indexed by delivery channel while notifs[] is
+ * indexed by PSE PI id, so walk the PIs and use each one's channel to
+ * select the event bits.
+ */
+ for (i = 0; i < LTC4266_MAX_PORTS; i++) {
+ struct ltc4266_port *port = ltc4266->ports[i];
+ unsigned int fault;
+ bool pg_lost;
+ u8 chan;
+
+ if (!port)
+ continue;
+
+ chan = port->chan;
+
+ fault = (tsevn | fltevn) &
+ (LTC4266_EVN_HI(chan) | LTC4266_EVN_LO(chan));
+
+ /* The controller also drops a port without reporting any
+ * per-port fault event, for instance on an over-temperature
+ * shutdown or when it finds a failed external MOSFET. Both of
+ * those clear the port's detection and classification enables,
+ * so the port stays dark until it is re-initialised. A power
+ * good change that leaves statpwr[pg] clear catches them, and
+ * ignores the rising edge of a port that has just been powered
+ * on.
+ */
+ pg_lost = (pwrevn & LTC4266_EVN_HI(chan)) &&
+ !(statpwr & LTC4266_STATPWR_PG(chan));
+
+ if (fault || pg_lost) {
+ /* The port has gone down; if we see this, then we don't
+ * care if any of the remaining events are set. If the
+ * device did disconnect briefly, it'll redetect and
+ * reclassify accordingly
+ */
+ notifs[i] |= ETHTOOL_C33_PSE_EVENT_DISCONNECTION;
+ *notifs_mask |= BIT(i);
+
+ /* Report over-current if the port went down for any
+ * overcurrent reason: tSTART (tsevn low nibble, startup
+ * inrush), tLIM (tsevn high nibble, current-limit
+ * timeout) or tCUT (fltevn low nibble, I_CUT timeout).
+ */
+ if ((tsevn & (LTC4266_EVN_LO(chan) | LTC4266_EVN_HI(chan))) ||
+ (fltevn & LTC4266_EVN_LO(chan)))
+ notifs[i] |= ETHTOOL_PSE_EVENT_OVER_CURRENT;
+
+ dev_dbg(<c4266->client->dev,
+ "tsevn=0x%02X fltevn=0x%02X pwrevn=0x%02X statpwr=0x%02X\n",
+ tsevn, fltevn, pwrevn, statpwr);
+ continue;
+ }
+ if (detevn & LTC4266_EVN_LO(chan)) {
+ /* Read the detect result, and if it isn't detect good,
+ * call it a disconnect
+ */
+ unsigned int detval;
+
+ ret = regmap_read(ltc4266->regmap, LTC4266_REG_STAT(chan), &detval);
+ if (ret < 0) {
+ dev_warn(ltc4266->dev, "Failed to read status register, err=%d\n",
+ ret);
+ continue;
+ }
+
+ if (LTC4266_PORT_DETECT(detval) != LTC4266_DETECT_GOOD) {
+ notifs[i] |= ETHTOOL_C33_PSE_EVENT_DISCONNECTION;
+ *notifs_mask |= BIT(i);
+ continue;
+ }
+ }
+
+ if (detevn & LTC4266_EVN_HI(chan)) {
+ int class = ltc4266_port_get_class(port);
+
+ if (class >= 0) {
+ notifs[i] |= ETHTOOL_C33_PSE_EVENT_CLASSIFICATION;
+ *notifs_mask |= BIT(i);
+ }
+ }
+ }
+
+done:
+ return ltc4266_enable_interrupts(ltc4266);
+
+err:
+ /* (Attempt to) clear any remaining event registers that we might've
+ * missed in the event a previous read has failed.
+ */
+ ret = regmap_write(ltc4266->regmap, LTC4266_REG_RSTPB, LTC4266_RSTPB_INTCLR);
+ if (ret)
+ dev_warn(<c4266->client->dev, "Failed to clear pending interrupts, err=%d\n",
+ ret);
+
+ return ltc4266_enable_interrupts(ltc4266);
+}
+
+static const struct regmap_config ltc4266_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = 0x5F,
+};
+
+static void ltc4266_teardown(void *data)
+{
+ struct ltc4266 *ltc4266 = data;
+
+ ltc4266_disable_interrupts(ltc4266);
+
+ /* Prevent the chip from asserting interrupts */
+ regmap_update_bits(ltc4266->regmap, LTC4266_REG_MCONF,
+ LTC4266_MCONF_INTERRUPT_ENABLE, 0);
+
+ /* Reset all the ports and do not re-init: a port reset removes power and
+ * clears the port's detection and classification enables, leaving it in
+ * semi-auto mode, which never powers a port without a host request.
+ */
+ regmap_write(ltc4266->regmap, LTC4266_REG_RSTPB, LTC4266_RSTPB_RSTPORTS);
+}
+
+static int ltc4266_probe(struct i2c_client *client)
+{
+ struct ltc4266 *ltc4266;
+ struct regmap *regmap;
+ unsigned int id_reg;
+ int ret;
+
+ struct pse_irq_desc irq_desc = {
+ .name = "ltc4266-irq",
+ .map_event = ltc4266_map_event,
+ };
+
+ /* We need IRQ for static power budgeting and if don't have it, fail
+ * probe early
+ */
+ if (!client->irq)
+ return dev_err_probe(&client->dev, -EINVAL,
+ "Interrupt is required for power budget management\n");
+
+ regmap = devm_regmap_init_i2c(client, <c4266_regmap_config);
+ if (IS_ERR(regmap))
+ return dev_err_probe(&client->dev, PTR_ERR(regmap),
+ "Failed to allocate regmap\n");
+
+ /* Confirm we are talking to an LTC4266: the id register (0x1B) should
+ * read back its documented reset value of 0x64.
+ */
+ ret = regmap_read(regmap, LTC4266_REG_ID, &id_reg);
+ if (ret < 0)
+ return dev_err_probe(&client->dev, ret, "Failed to read ID register\n");
+
+ if (id_reg != LTC4266_ID)
+ return dev_err_probe(&client->dev, -ENODEV,
+ "Expected an ID of 0x64, saw 0x%02X\n", id_reg);
+
+ /* Reset the chip */
+ ret = regmap_write(regmap, LTC4266_REG_RSTPB, LTC4266_RSTPB_INTCLR | LTC4266_RSTPB_RSTALL);
+ if (ret < 0)
+ return dev_err_probe(&client->dev, ret, "Failed to reset\n");
+
+ /* LTC4266 requires approximately 10 ms after reset to be stable; if it
+ * isn't, then there is typically an undervoltage lockout/something pretty bad
+ * going on. We give it 50 ms here so we don't need to poll the chip and use I2C bandwidth
+ */
+ msleep(50);
+
+ /* Let's make sure the chip came out of reset (if not, the chip is probably
+ * either (no longer?) present, in thermal shutdown, or watchdogged....either
+ * way, there's nothing we can do in software to fix it)
+ */
+ ret = regmap_read(regmap, LTC4266_REG_ID, &id_reg);
+ if (ret < 0)
+ return dev_err_probe(&client->dev, ret,
+ "Failed to re-read ID register after reset\n");
+
+ if (id_reg != LTC4266_ID)
+ return dev_err_probe(&client->dev, -ENODEV,
+ "Failed to re-read device ID after reset 0x%02X\n",
+ id_reg);
+
+ ltc4266 = devm_kzalloc(&client->dev, sizeof(struct ltc4266), GFP_KERNEL);
+ if (!ltc4266)
+ return -ENOMEM;
+
+ ltc4266->client = client;
+ ltc4266->regmap = regmap;
+ ltc4266->np = client->dev.of_node;
+ ltc4266->dev = &client->dev;
+
+ /* After reset, the LTC4266 will interrupt with a (single) supply fault.
+ * Clear it here and discard the result
+ */
+ regmap_read(ltc4266->regmap, LTC4266_REG_SUPEVN_COR, &id_reg);
+
+ ret = ltc4266_disable_interrupts(ltc4266);
+ if (ret)
+ return dev_err_probe(&client->dev, ret,
+ "Failed to disable interrupts\n");
+
+ /* Registered before the controller and the IRQ so devres ordering runs
+ * it after free_irq() and pse_controller_unregister(), and so a failed
+ * probe cannot leave ports running detection with no driver bound.
+ */
+ ret = devm_add_action_or_reset(&client->dev, ltc4266_teardown, ltc4266);
+ if (ret)
+ return ret;
+
+ ltc4266->pcdev.owner = THIS_MODULE;
+ ltc4266->pcdev.ops = <c4266_ops;
+ ltc4266->pcdev.dev = &client->dev;
+ ltc4266->pcdev.types = ETHTOOL_PSE_C33;
+ ltc4266->pcdev.nr_lines = LTC4266_MAX_PORTS;
+ ltc4266->pcdev.supp_budget_eval_strategies = PSE_BUDGET_EVAL_STRAT_STATIC;
+
+ ret = devm_pse_controller_register(ltc4266->dev, <c4266->pcdev);
+ if (ret)
+ return dev_err_probe(&client->dev, ret,
+ "Failed to register PSE controller\n");
+
+ /* Enable the interrupt pin, and only report detect events on
+ * change (detchg) so idle ports continuously re-running
+ * detection in semi-auto mode don't flood the host with a
+ * detect event every cycle.
+ */
+ ret = regmap_update_bits(ltc4266->regmap, LTC4266_REG_MCONF,
+ LTC4266_MCONF_INTERRUPT_ENABLE | LTC4266_MCONF_DETCHG,
+ LTC4266_MCONF_INTERRUPT_ENABLE | LTC4266_MCONF_DETCHG);
+ if (ret)
+ return dev_err_probe(&client->dev, ret,
+ "Failed to configure interrupts\n");
+
+ ret = devm_pse_irq_helper(<c4266->pcdev, client->irq,
+ 0, &irq_desc);
+ if (ret)
+ return dev_err_probe(&client->dev, ret,
+ "Failed to register PSE IRQ\n");
+
+ /* Unmask the chip interrupt sources now the handler is ready. */
+ ret = ltc4266_enable_interrupts(ltc4266);
+ if (ret)
+ return dev_err_probe(&client->dev, ret,
+ "Failed to enable interrupts\n");
+
+ return 0;
+}
+
+static const struct i2c_device_id ltc4266_id[] = {
+ {.name = "ltc4266"},
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ltc4266_id);
+
+static const struct of_device_id ltc4266_of_match[] = {
+ { .compatible = "lltc,ltc4266" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ltc4266_of_match);
+
+static struct i2c_driver ltc4266_driver = {
+ .driver = {
+ .name = "ltc4266",
+ .of_match_table = ltc4266_of_match,
+ },
+ .probe = ltc4266_probe,
+ .id_table = ltc4266_id,
+};
+module_i2c_driver(ltc4266_driver);
+
+MODULE_AUTHOR("Kyle Swenson <kyle.swenson@est.tech>");
+MODULE_DESCRIPTION("LTC4266 PoE PSE Controller Driver");
+MODULE_LICENSE("GPL");
--
2.55.0
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