[PATCH v3 0/2] phy: intel: Add Keem Bay eMMC PHY support

[PATCH v3 0/2] phy: intel: Add Keem Bay eMMC PHY support

[Wan Ahmad Zainie]

Hi.

The first part is to document DT bindings for Keem Bay eMMC PHY.

The second is the driver file, loosely based on phy-rockchip-emmc.c
and phy-intel-emmc.c. The latter is not being reused as there are
quite a number of differences i.e. registers offset, supported clock
rates, bitfield to set.

The patch was tested with Keem Bay evaluation module board.

Thank you.

Best regards,
Zainie

Changes since v2:
- Modify DT example to use single cell for address and size.

Changes since v1:
- Rework phy-keembay-emmc.c to make it similar to phy-intel-emmc.c.
- Use regmap_mmio, and remove reference to intel,syscon.
- Use node name phy@....
- Update license i.e. use dual license.


Wan Ahmad Zainie (2):
  dt-bindings: phy: intel: Add Keem Bay eMMC PHY bindings
  phy: intel: Add Keem Bay eMMC PHY support

 .../bindings/phy/intel,keembay-emmc-phy.yaml  |  45 +++
 drivers/phy/intel/Kconfig                     |   8 +
 drivers/phy/intel/Makefile                    |   1 +
 drivers/phy/intel/phy-keembay-emmc.c          | 321 ++++++++++++++++++
 4 files changed, 375 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/phy/intel,keembay-emmc-phy.yaml
 create mode 100644 drivers/phy/intel/phy-keembay-emmc.c

-- 
2.17.1

[PATCH v3 1/2] dt-bindings: phy: intel: Add Keem Bay eMMC PHY bindings

[Wan Ahmad Zainie]

Binding description for Intel Keem Bay eMMC PHY.

Signed-off-by: Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>
---
 .../bindings/phy/intel,keembay-emmc-phy.yaml  | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/phy/intel,keembay-emmc-phy.yaml

diff --git a/Documentation/devicetree/bindings/phy/intel,keembay-emmc-phy.yaml b/Documentation/devicetree/bindings/phy/intel,keembay-emmc-phy.yaml
new file mode 100644
index 000000000000..639f2b2d8950
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/intel,keembay-emmc-phy.yaml
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2020 Intel Corporation
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/phy/intel,keembay-emmc-phy.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Intel Keem Bay eMMC PHY bindings
+
+maintainers:
+  - Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>
+
+properties:
+  compatible:
+    const: intel,keembay-emmc-phy
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: emmcclk
+
+  "#phy-cells":
+    const: 0
+
+required:
+  - compatible
+  - reg
+  - "#phy-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    phy@20290000 {
+          compatible = "intel,keembay-emmc-phy";
+          reg = <0x20290000 0x54>;
+          clocks = <&emmc>;
+          clock-names = "emmcclk";
+          #phy-cells = <0>;
+    };
-- 
2.17.1

[PATCH v3 2/2] phy: intel: Add Keem Bay eMMC PHY support

[Wan Ahmad Zainie]

Add support for eMMC PHY on Intel Keem Bay SoC.

Signed-off-by: Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>
---
 drivers/phy/intel/Kconfig            |   8 +
 drivers/phy/intel/Makefile           |   1 +
 drivers/phy/intel/phy-keembay-emmc.c | 321 +++++++++++++++++++++++++++
 3 files changed, 330 insertions(+)
 create mode 100644 drivers/phy/intel/phy-keembay-emmc.c

diff --git a/drivers/phy/intel/Kconfig b/drivers/phy/intel/Kconfig
index 7b47682a4e0e..5f5497d1624a 100644
--- a/drivers/phy/intel/Kconfig
+++ b/drivers/phy/intel/Kconfig
@@ -22,3 +22,11 @@ config PHY_INTEL_EMMC
 	select GENERIC_PHY
 	help
 	  Enable this to support the Intel EMMC PHY
+
+config PHY_KEEMBAY_EMMC
+	tristate "Intel Keem Bay EMMC PHY Driver"
+	depends on OF
+	select GENERIC_PHY
+	select REGMAP_MMIO
+	help
+	  Enable this to support the Keem Bay EMMC PHY.
diff --git a/drivers/phy/intel/Makefile b/drivers/phy/intel/Makefile
index 233d530dadde..6566334e7b77 100644
--- a/drivers/phy/intel/Makefile
+++ b/drivers/phy/intel/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_PHY_INTEL_COMBO)		+= phy-intel-combo.o
 obj-$(CONFIG_PHY_INTEL_EMMC)            += phy-intel-emmc.o
+obj-$(CONFIG_PHY_KEEMBAY_EMMC)		+= phy-keembay-emmc.o
diff --git a/drivers/phy/intel/phy-keembay-emmc.c b/drivers/phy/intel/phy-keembay-emmc.c
new file mode 100644
index 000000000000..546854cdbb0c
--- /dev/null
+++ b/drivers/phy/intel/phy-keembay-emmc.c
@@ -0,0 +1,321 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel Keem Bay eMMC PHY driver
+ * Copyright (C) 2020 Intel Corporation
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* eMMC/SD/SDIO core/phy configuration registers */
+#define PHY_CFG_0		0x24
+#define  SEL_DLY_TXCLK_MASK	BIT(29)
+#define  SEL_DLY_TXCLK(x)	(((x) << 29) & SEL_DLY_TXCLK_MASK)
+#define  OTAP_DLY_ENA_MASK	BIT(27)
+#define  OTAP_DLY_ENA(x)	(((x) << 27) & OTAP_DLY_ENA_MASK)
+#define  OTAP_DLY_SEL_MASK	GENMASK(26, 23)
+#define  OTAP_DLY_SEL(x)	(((x) << 23) & OTAP_DLY_SEL_MASK)
+#define  DLL_EN_MASK		BIT(10)
+#define  DLL_EN(x)		(((x) << 10) & DLL_EN_MASK)
+#define  PWR_DOWN_MASK		BIT(0)
+#define  PWR_DOWN(x)		(((x) << 0) & PWR_DOWN_MASK)
+
+#define PHY_CFG_2		0x2c
+#define  SEL_FREQ_MASK		GENMASK(12, 10)
+#define  SEL_FREQ(x)		(((x) << 10) & SEL_FREQ_MASK)
+
+#define PHY_STAT		0x40
+#define  CAL_DONE_MASK		BIT(6)
+#define  IS_CALDONE(x)		((x) & CAL_DONE_MASK)
+#define  DLL_RDY_MASK		BIT(5)
+#define  IS_DLLRDY(x)		((x) & DLL_RDY_MASK)
+
+/* From ACS_eMMC51_16nFFC_RO1100_Userguide_v1p0.pdf p17 */
+#define FREQSEL_200M_170M	0x0
+#define FREQSEL_170M_140M	0x1
+#define FREQSEL_140M_110M	0x2
+#define FREQSEL_110M_80M	0x3
+#define FREQSEL_80M_50M		0x4
+
+struct keembay_emmc_phy {
+	struct regmap *syscfg;
+	struct clk *emmcclk;
+};
+
+static const struct regmap_config keembay_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
+static int keembay_emmc_phy_power(struct phy *phy, bool on_off)
+{
+	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
+	unsigned int caldone;
+	unsigned int dllrdy;
+	unsigned int freqsel;
+	unsigned int mhz;
+	int ret;
+
+	/*
+	 * Keep phyctrl_pdb and phyctrl_endll low to allow
+	 * initialization of CALIO state M/C DFFs
+	 */
+	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, PWR_DOWN_MASK,
+				 PWR_DOWN(0));
+	if (ret) {
+		dev_err(&phy->dev, "CALIO power down bar failed: %d\n", ret);
+		return ret;
+	}
+
+	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, DLL_EN_MASK,
+				 DLL_EN(0));
+	if (ret) {
+		dev_err(&phy->dev, "turn off the dll failed: %d\n", ret);
+		return ret;
+	}
+
+	/* Already finish power off above */
+	if (!on_off)
+		return 0;
+
+	mhz = DIV_ROUND_CLOSEST(clk_get_rate(priv->emmcclk), 1000000);
+	if (mhz <= 200 && mhz >= 170)
+		freqsel = FREQSEL_200M_170M;
+	else if (mhz <= 170 && mhz >= 140)
+		freqsel = FREQSEL_170M_140M;
+	else if (mhz <= 140 && mhz >= 110)
+		freqsel = FREQSEL_140M_110M;
+	else if (mhz <= 110 && mhz >= 80)
+		freqsel = FREQSEL_110M_80M;
+	else if (mhz <= 80 && mhz >= 50)
+		freqsel = FREQSEL_80M_50M;
+	else
+		freqsel = 0x0;
+
+	if (mhz < 50 || mhz > 200)
+		dev_warn(&phy->dev, "Unsupported rate: %d MHz\n", mhz);
+
+	/*
+	 * According to the user manual, calpad calibration
+	 * cycle takes more than 2us without the minimal recommended
+	 * value, so we may need a little margin here
+	 */
+	udelay(5);
+
+	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, PWR_DOWN_MASK,
+				 PWR_DOWN(1));
+	if (ret) {
+		dev_err(&phy->dev, "CALIO power down bar failed: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * According to the user manual, it asks driver to wait 5us for
+	 * calpad busy trimming. However it is documented that this value is
+	 * PVT(A.K.A. process, voltage and temperature) relevant, so some
+	 * failure cases are found which indicates we should be more tolerant
+	 * to calpad busy trimming.
+	 */
+	ret = regmap_read_poll_timeout(priv->syscfg, PHY_STAT,
+				       caldone, IS_CALDONE(caldone),
+				       0, 50);
+	if (ret) {
+		dev_err(&phy->dev, "caldone failed, ret=%d\n", ret);
+		return ret;
+	}
+
+	/* Set the frequency of the DLL operation */
+	ret = regmap_update_bits(priv->syscfg, PHY_CFG_2, SEL_FREQ_MASK,
+				 SEL_FREQ(freqsel));
+	if (ret) {
+		dev_err(&phy->dev, "set the frequency of dll failed:%d\n", ret);
+		return ret;
+	}
+
+	/* Turn on the DLL */
+	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, DLL_EN_MASK,
+				 DLL_EN(1));
+	if (ret) {
+		dev_err(&phy->dev, "turn on the dll failed: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * We turned on the DLL even though the rate was 0 because we the
+	 * clock might be turned on later.  ...but we can't wait for the DLL
+	 * to lock when the rate is 0 because it will never lock with no
+	 * input clock.
+	 *
+	 * Technically we should be checking the lock later when the clock
+	 * is turned on, but for now we won't.
+	 */
+	if (mhz == 0)
+		return 0;
+
+	/*
+	 * After enabling analog DLL circuits docs say that we need 10.2 us if
+	 * our source clock is at 50 MHz and that lock time scales linearly
+	 * with clock speed. If we are powering on the PHY and the card clock
+	 * is super slow (like 100kHz) this could take as long as 5.1 ms as
+	 * per the math: 10.2 us * (50000000 Hz / 100000 Hz) => 5.1 ms
+	 * hopefully we won't be running at 100 kHz, but we should still make
+	 * sure we wait long enough.
+	 *
+	 * NOTE: There appear to be corner cases where the DLL seems to take
+	 * extra long to lock for reasons that aren't understood. In some
+	 * extreme cases we've seen it take up to over 10ms (!). We'll be
+	 * generous and give it 50ms.
+	 */
+	ret = regmap_read_poll_timeout(priv->syscfg, PHY_STAT,
+				       dllrdy, IS_DLLRDY(dllrdy),
+				       0, 50 * USEC_PER_MSEC);
+	if (ret) {
+		dev_err(&phy->dev, "dllrdy failed, ret=%d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int keembay_emmc_phy_init(struct phy *phy)
+{
+	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
+
+	/*
+	 * We purposely get the clock here and not in probe to avoid the
+	 * circular dependency problem. We expect:
+	 * - PHY driver to probe
+	 * - SDHCI driver to start probe
+	 * - SDHCI driver to register it's clock
+	 * - SDHCI driver to get the PHY
+	 * - SDHCI driver to init the PHY
+	 *
+	 * The clock is optional, so upon any error just return it like
+	 * any other error to user.
+	 */
+	priv->emmcclk = clk_get_optional(&phy->dev, "emmcclk");
+	if (IS_ERR(priv->emmcclk)) {
+		dev_err(&phy->dev, "ERROR: getting emmcclk\n");
+		return PTR_ERR(priv->emmcclk);
+	}
+
+	return 0;
+}
+
+static int keembay_emmc_phy_exit(struct phy *phy)
+{
+	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
+
+	clk_put(priv->emmcclk);
+
+	return 0;
+};
+
+static int keembay_emmc_phy_power_on(struct phy *phy)
+{
+	struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
+	int ret;
+
+	/* Delay chain based txclk: enable */
+	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, SEL_DLY_TXCLK_MASK,
+				 SEL_DLY_TXCLK(1));
+	if (ret) {
+		dev_err(&phy->dev, "ERROR: delay chain txclk set: %d\n", ret);
+		return ret;
+	}
+
+	/* Output tap delay: enable */
+	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, OTAP_DLY_ENA_MASK,
+				 OTAP_DLY_ENA(1));
+	if (ret) {
+		dev_err(&phy->dev, "ERROR: output tap delay set: %d\n", ret);
+		return ret;
+	}
+
+	/* Output tap delay */
+	ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, OTAP_DLY_SEL_MASK,
+				 OTAP_DLY_SEL(2));
+	if (ret) {
+		dev_err(&phy->dev, "ERROR: output tap delay select: %d\n", ret);
+		return ret;
+	}
+
+	/* Power up eMMC phy analog blocks */
+	return keembay_emmc_phy_power(phy, true);
+}
+
+static int keembay_emmc_phy_power_off(struct phy *phy)
+{
+	/* Power down eMMC phy analog blocks */
+	return keembay_emmc_phy_power(phy, false);
+}
+
+static const struct phy_ops ops = {
+	.init		= keembay_emmc_phy_init,
+	.exit		= keembay_emmc_phy_exit,
+	.power_on	= keembay_emmc_phy_power_on,
+	.power_off	= keembay_emmc_phy_power_off,
+	.owner		= THIS_MODULE,
+};
+
+static int keembay_emmc_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct keembay_emmc_phy *priv;
+	struct phy *generic_phy;
+	struct phy_provider *phy_provider;
+	void __iomem *base;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	priv->syscfg = devm_regmap_init_mmio(dev, base,
+					     &keembay_regmap_config);
+	if (IS_ERR(priv->syscfg))
+		return PTR_ERR(priv->syscfg);
+
+	generic_phy = devm_phy_create(dev, np, &ops);
+	if (IS_ERR(generic_phy)) {
+		dev_err(dev, "failed to create PHY\n");
+		return PTR_ERR(generic_phy);
+	}
+
+	phy_set_drvdata(generic_phy, priv);
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct of_device_id keembay_emmc_phy_dt_ids[] = {
+	{ .compatible = "intel,keembay-emmc-phy" },
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, keembay_emmc_phy_dt_ids);
+
+static struct platform_driver keembay_emmc_phy_driver = {
+	.probe		= keembay_emmc_phy_probe,
+	.driver		= {
+		.name	= "keembay-emmc-phy",
+		.of_match_table = keembay_emmc_phy_dt_ids,
+	},
+};
+module_platform_driver(keembay_emmc_phy_driver);
+
+MODULE_AUTHOR("Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>");
+MODULE_DESCRIPTION("Intel Keem Bay eMMC PHY driver");
+MODULE_LICENSE("GPL v2");
-- 
2.17.1

Re: [PATCH v3 2/2] phy: intel: Add Keem Bay eMMC PHY support

[Andy Shevchenko]

On Mon, Jun 08, 2020 at 04:15:01PM +0800, Wan Ahmad Zainie wrote:
> Add support for eMMC PHY on Intel Keem Bay SoC.

I think I commented on something already.

...

> +	if (ret) {
> +		dev_err(&phy->dev, "dllrdy failed, ret=%d\n", ret);

> +		return ret;
> +	}
> +
> +	return 0;

return ret;

...

> +	if (IS_ERR(priv->emmcclk)) {
> +		dev_err(&phy->dev, "ERROR: getting emmcclk\n");

> +		return PTR_ERR(priv->emmcclk);
> +	}
> +
> +	return 0;

return PTR_ERR_OR_ZERO(...);

...

> +	priv->syscfg = devm_regmap_init_mmio(dev, base,
> +					     &keembay_regmap_config);

One line.

-- 
With Best Regards,
Andy Shevchenko

RE: [PATCH v3 2/2] phy: intel: Add Keem Bay eMMC PHY support

[Wan Mohamad, Wan Ahmad Zainie]

> -----Original Message-----
> From: Shevchenko, Andriy <andriy.shevchenko@intel.com>
> Sent: Monday, June 8, 2020 6:08 PM
> To: Wan Mohamad, Wan Ahmad Zainie
> <wan.ahmad.zainie.wan.mohamad@intel.com>
> Cc: kishon@ti.com; vkoul@kernel.org; robh+dt@kernel.org; linux-
> kernel@vger.kernel.org; devicetree@vger.kernel.org; Hunter, Adrian
> <adrian.hunter@intel.com>
> Subject: Re: [PATCH v3 2/2] phy: intel: Add Keem Bay eMMC PHY support
> 
> On Mon, Jun 08, 2020 at 04:15:01PM +0800, Wan Ahmad Zainie wrote:
> > Add support for eMMC PHY on Intel Keem Bay SoC.
> 
> I think I commented on something already.

I don't recall any. May be on other similar patches.
I will wait for few days before sending next revision, if it is okay with you.

> 
> ...
> 
> > +	if (ret) {
> > +		dev_err(&phy->dev, "dllrdy failed, ret=%d\n", ret);
> 
> > +		return ret;
> > +	}
> > +
> > +	return 0;
> 
> return ret;

I will change in next revision.

> 
> ...
> 
> > +	if (IS_ERR(priv->emmcclk)) {
> > +		dev_err(&phy->dev, "ERROR: getting emmcclk\n");
> 
> > +		return PTR_ERR(priv->emmcclk);
> > +	}
> > +
> > +	return 0;
> 
> return PTR_ERR_OR_ZERO(...);

To clarify, I should replace the block above with,
return PTR_ERR_OR_ZERO(priv->emmcclk);

> 
> ...
> 
> > +	priv->syscfg = devm_regmap_init_mmio(dev, base,
> > +					     &keembay_regmap_config);
> 
> One line.

I will change in next revision.

> 
> --
> With Best Regards,
> Andy Shevchenko
> 

Re: [PATCH v3 2/2] phy: intel: Add Keem Bay eMMC PHY support

[Shevchenko, Andriy]

On Mon, Jun 08, 2020 at 01:37:25PM +0300, Wan Mohamad, Wan Ahmad Zainie wrote:
> > -----Original Message-----
> > From: Shevchenko, Andriy <andriy.shevchenko@intel.com>
> > On Mon, Jun 08, 2020 at 04:15:01PM +0800, Wan Ahmad Zainie wrote:

...

> > > +return PTR_ERR(priv->emmcclk);
> > > +}
> > > +
> > > +return 0;
> >
> > return PTR_ERR_OR_ZERO(...);
> 
> To clarify, I should replace the block above with,
> return PTR_ERR_OR_ZERO(priv->emmcclk);

I left the context.

-- 
With Best Regards,
Andy Shevchenko