* [PATCH 1/2] i2c: smbus: add core function handling SMBus host-notify
2020-07-02 14:47 [PATCH 0/2] i2c: stm32: add host-notify support via i2c slave Alain Volmat
@ 2020-07-02 14:47 ` Alain Volmat
2020-07-02 14:47 ` [PATCH 2/2] i2c: stm32f7: Add SMBus Host-Notify protocol support Alain Volmat
1 sibling, 0 replies; 3+ messages in thread
From: Alain Volmat @ 2020-07-02 14:47 UTC (permalink / raw)
To: wsa, pierre-yves.mordret
Cc: alexandre.torgue, linux-i2c, linux-stm32, linux-arm-kernel,
linux-kernel, fabrice.gasnier, alain.volmat
SMBus Host-Notify protocol, from the adapter point of view
consist of receiving a message from a client, including the
client address and some other data.
It can be simply handled by creating a new slave device
and registering a callback performing the parsing of the
message received from the client.
This commit introduces two new core functions
* i2c_new_slave_host_notify_device
* i2c_free_slave_host_notify_device
that take care of registration of the new slave device and
callback and will call i2c_handle_smbus_host_notify once a
Host-Notify event is received.
Signed-off-by: Alain Volmat <alain.volmat@st.com>
---
drivers/i2c/i2c-core-smbus.c | 114 +++++++++++++++++++++++++++++++++++++++++++
include/linux/i2c-smbus.h | 12 +++++
2 files changed, 126 insertions(+)
diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
index f5c9787992e9..23ab9dc5ac85 100644
--- a/drivers/i2c/i2c-core-smbus.c
+++ b/drivers/i2c/i2c-core-smbus.c
@@ -715,3 +715,117 @@ int of_i2c_setup_smbus_alert(struct i2c_adapter *adapter)
}
EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert);
#endif
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+#define SMBUS_HOST_NOTIFY_LEN 3
+struct i2c_slave_host_notify_status {
+ u8 index;
+ u8 addr;
+};
+
+static int i2c_slave_host_notify_cb(struct i2c_client *client,
+ enum i2c_slave_event event, u8 *val)
+{
+ struct i2c_slave_host_notify_status *status = client->dev.platform_data;
+ int ret;
+
+ switch (event) {
+ case I2C_SLAVE_WRITE_REQUESTED:
+ status->index = 0;
+ break;
+ case I2C_SLAVE_WRITE_RECEIVED:
+ /* We only retrieve the first byte received (addr)
+ * since there is currently no support to retrieve the data
+ * parameter from the client.
+ */
+ if (status->index == 0)
+ status->addr = *val;
+ if (status->index < U8_MAX)
+ status->index++;
+ break;
+ case I2C_SLAVE_STOP:
+ /* Handle host-notify if whole message received only */
+ if (status->index != SMBUS_HOST_NOTIFY_LEN) {
+ status->index = U8_MAX;
+ break;
+ }
+
+ ret = i2c_handle_smbus_host_notify(client->adapter,
+ status->addr);
+ if (ret < 0)
+ return ret;
+ status->index = U8_MAX;
+ break;
+ case I2C_SLAVE_READ_REQUESTED:
+ case I2C_SLAVE_READ_PROCESSED:
+ *val = 0xff;
+ break;
+ }
+
+ return 0;
+}
+
+/**
+ * i2c_new_slave_host_notify_device - get a client for SMBus host-notify support
+ * @adapter: the target adapter
+ * Context: can sleep
+ *
+ * Setup handling of the SMBus host-notify protocol on a given I2C bus segment.
+ *
+ * Handling is done by creating a device and its callback and handling data
+ * received via the SMBus host-notify address (0x8)
+ *
+ * This returns the client, which should be ultimately freed using
+ * i2c_free_slave_host_notify_device(); or an ERRPTR to indicate an error.
+ */
+struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter)
+{
+ struct i2c_board_info host_notify_board_info = {
+ I2C_BOARD_INFO("smbus_host_notify", 0x08),
+ .flags = I2C_CLIENT_SLAVE,
+ };
+ struct i2c_slave_host_notify_status *status;
+ struct i2c_client *client;
+ int ret;
+
+ status = kzalloc(sizeof(struct i2c_slave_host_notify_status),
+ GFP_KERNEL);
+ if (!status)
+ return ERR_PTR(-ENOMEM);
+ status->index = U8_MAX;
+
+ host_notify_board_info.platform_data = status;
+
+ client = i2c_new_client_device(adapter, &host_notify_board_info);
+ if (IS_ERR(client)) {
+ kfree(status);
+ return client;
+ }
+
+ ret = i2c_slave_register(client, i2c_slave_host_notify_cb);
+ if (ret) {
+ i2c_unregister_device(client);
+ kfree(status);
+ return ERR_PTR(ret);
+ }
+
+ return client;
+}
+EXPORT_SYMBOL_GPL(i2c_new_slave_host_notify_device);
+
+/**
+ * i2c_free_slave_host_notify_device - free the client for SMBus host-notify
+ * support
+ * @client: the client to free
+ * Context: can sleep
+ *
+ * Free the i2c_client allocated via i2c_new_slave_host_notify_device
+ */
+void i2c_free_slave_host_notify_device(struct i2c_client *client)
+{
+ i2c_slave_unregister(client);
+ kfree(client->dev.platform_data);
+ i2c_unregister_device(client);
+}
+EXPORT_SYMBOL_GPL(i2c_free_slave_host_notify_device);
+#endif
diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h
index 1e4e0de4ef8b..52e62f398f1c 100644
--- a/include/linux/i2c-smbus.h
+++ b/include/linux/i2c-smbus.h
@@ -38,6 +38,18 @@ static inline int of_i2c_setup_smbus_alert(struct i2c_adapter *adap)
return 0;
}
#endif
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter);
+void i2c_free_slave_host_notify_device(struct i2c_client *client);
+#else
+static inline struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter)
+{
+ return NULL;
+}
+static inline void i2c_free_slave_host_notify_device(struct i2c_client *client)
+{
+}
+#endif
#if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_DMI)
void i2c_register_spd(struct i2c_adapter *adap);
--
2.7.4
^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH 2/2] i2c: stm32f7: Add SMBus Host-Notify protocol support
2020-07-02 14:47 [PATCH 0/2] i2c: stm32: add host-notify support via i2c slave Alain Volmat
2020-07-02 14:47 ` [PATCH 1/2] i2c: smbus: add core function handling SMBus host-notify Alain Volmat
@ 2020-07-02 14:47 ` Alain Volmat
1 sibling, 0 replies; 3+ messages in thread
From: Alain Volmat @ 2020-07-02 14:47 UTC (permalink / raw)
To: wsa, pierre-yves.mordret
Cc: alexandre.torgue, linux-i2c, linux-stm32, linux-arm-kernel,
linux-kernel, fabrice.gasnier, alain.volmat
Rely on the core functions to implement the host-notify
protocol via the a I2C slave device.
Signed-off-by: Alain Volmat <alain.volmat@st.com>
---
drivers/i2c/busses/Kconfig | 1 +
drivers/i2c/busses/i2c-stm32f7.c | 110 +++++++++++++++++++++++++++++++++------
2 files changed, 96 insertions(+), 15 deletions(-)
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 735bf31a3fdf..ae8671727a4c 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1036,6 +1036,7 @@ config I2C_STM32F7
tristate "STMicroelectronics STM32F7 I2C support"
depends on ARCH_STM32 || COMPILE_TEST
select I2C_SLAVE
+ select I2C_SMBUS
help
Enable this option to add support for STM32 I2C controller embedded
in STM32F7 SoCs.
diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index bff3479fe122..09d07376e70a 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -18,6 +18,7 @@
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
@@ -50,6 +51,7 @@
/* STM32F7 I2C control 1 */
#define STM32F7_I2C_CR1_PECEN BIT(23)
+#define STM32F7_I2C_CR1_SMBHEN BIT(20)
#define STM32F7_I2C_CR1_WUPEN BIT(18)
#define STM32F7_I2C_CR1_SBC BIT(16)
#define STM32F7_I2C_CR1_RXDMAEN BIT(15)
@@ -150,7 +152,7 @@
#define STM32F7_I2C_MAX_LEN 0xff
#define STM32F7_I2C_DMA_LEN_MIN 0x16
-#define STM32F7_I2C_MAX_SLAVE 0x2
+#define STM32F7_I2C_MAX_SLAVE 0x3
#define STM32F7_I2C_DNF_DEFAULT 0
#define STM32F7_I2C_DNF_MAX 16
@@ -301,6 +303,8 @@ struct stm32f7_i2c_msg {
* @fmp_creg: register address for clearing Fast Mode Plus bits
* @fmp_mask: mask for Fast Mode Plus bits in set register
* @wakeup_src: boolean to know if the device is a wakeup source
+ * @smbus_mode: states that the controller is configured in SMBus mode
+ * @host_notify_client: SMBus host-notify client
*/
struct stm32f7_i2c_dev {
struct i2c_adapter adap;
@@ -327,6 +331,8 @@ struct stm32f7_i2c_dev {
u32 fmp_creg;
u32 fmp_mask;
bool wakeup_src;
+ bool smbus_mode;
+ struct i2c_client *host_notify_client;
};
/*
@@ -1321,10 +1327,18 @@ static int stm32f7_i2c_get_free_slave_id(struct stm32f7_i2c_dev *i2c_dev,
int i;
/*
- * slave[0] supports 7-bit and 10-bit slave address
- * slave[1] supports 7-bit slave address only
+ * slave[0] support only SMBus Host address (0x8)
+ * slave[1] supports 7-bit and 10-bit slave address
+ * slave[2] supports 7-bit slave address only
*/
- for (i = STM32F7_I2C_MAX_SLAVE - 1; i >= 0; i--) {
+ if (i2c_dev->host_notify_client && (slave->addr == 0x08)) {
+ if (i2c_dev->slave[0])
+ goto fail;
+ *id = 0;
+ return 0;
+ }
+
+ for (i = STM32F7_I2C_MAX_SLAVE - 1; i > 0; i--) {
if (i == 1 && (slave->flags & I2C_CLIENT_TEN))
continue;
if (!i2c_dev->slave[i]) {
@@ -1333,6 +1347,7 @@ static int stm32f7_i2c_get_free_slave_id(struct stm32f7_i2c_dev *i2c_dev,
}
}
+fail:
dev_err(dev, "Slave 0x%x could not be registered\n", slave->addr);
return -EINVAL;
@@ -1776,7 +1791,13 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
if (!stm32f7_i2c_is_slave_registered(i2c_dev))
stm32f7_i2c_enable_wakeup(i2c_dev, true);
- if (id == 0) {
+ switch (id) {
+ case 0:
+ /* Slave SMBus Host */
+ i2c_dev->slave[id] = slave;
+ break;
+
+ case 1:
/* Configure Own Address 1 */
oar1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_OAR1);
oar1 &= ~STM32F7_I2C_OAR1_MASK;
@@ -1789,7 +1810,9 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
oar1 |= STM32F7_I2C_OAR1_OA1EN;
i2c_dev->slave[id] = slave;
writel_relaxed(oar1, i2c_dev->base + STM32F7_I2C_OAR1);
- } else if (id == 1) {
+ break;
+
+ case 2:
/* Configure Own Address 2 */
oar2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_OAR2);
oar2 &= ~STM32F7_I2C_OAR2_MASK;
@@ -1802,7 +1825,10 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
oar2 |= STM32F7_I2C_OAR2_OA2EN;
i2c_dev->slave[id] = slave;
writel_relaxed(oar2, i2c_dev->base + STM32F7_I2C_OAR2);
- } else {
+ break;
+
+ default:
+ dev_err(dev, "I2C slave id not supported\n");
ret = -ENODEV;
goto pm_free;
}
@@ -1843,10 +1869,10 @@ static int stm32f7_i2c_unreg_slave(struct i2c_client *slave)
if (ret < 0)
return ret;
- if (id == 0) {
+ if (id == 1) {
mask = STM32F7_I2C_OAR1_OA1EN;
stm32f7_i2c_clr_bits(base + STM32F7_I2C_OAR1, mask);
- } else {
+ } else if (id == 2) {
mask = STM32F7_I2C_OAR2_OA2EN;
stm32f7_i2c_clr_bits(base + STM32F7_I2C_OAR2, mask);
}
@@ -1911,14 +1937,51 @@ static int stm32f7_i2c_setup_fm_plus_bits(struct platform_device *pdev,
&i2c_dev->fmp_mask);
}
+static int stm32f7_i2c_enable_smbus_host(struct stm32f7_i2c_dev *i2c_dev)
+{
+ struct i2c_adapter *adap = &i2c_dev->adap;
+ void __iomem *base = i2c_dev->base;
+ struct i2c_client *client;
+
+ client = i2c_new_slave_host_notify_device(adap);
+ if (IS_ERR(client))
+ return PTR_ERR(client);
+
+ i2c_dev->host_notify_client = client;
+
+ /* Enable SMBus Host address */
+ stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, STM32F7_I2C_CR1_SMBHEN);
+
+ return 0;
+}
+
+static void stm32f7_i2c_disable_smbus_host(struct stm32f7_i2c_dev *i2c_dev)
+{
+ void __iomem *base = i2c_dev->base;
+
+ if (i2c_dev->host_notify_client) {
+ /* Disable SMBus Host address */
+ stm32f7_i2c_clr_bits(base + STM32F7_I2C_CR1,
+ STM32F7_I2C_CR1_SMBHEN);
+ i2c_free_slave_host_notify_device(i2c_dev->host_notify_client);
+ }
+}
+
static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
{
- return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SLAVE |
- I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
- I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
- I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
- I2C_FUNC_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_PEC |
- I2C_FUNC_SMBUS_I2C_BLOCK;
+ struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
+
+ u32 func = I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SLAVE |
+ I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
+ I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+ I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
+ I2C_FUNC_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_PEC |
+ I2C_FUNC_SMBUS_I2C_BLOCK;
+
+ if (i2c_dev->smbus_mode)
+ func |= I2C_FUNC_SMBUS_HOST_NOTIFY;
+
+ return func;
}
static const struct i2c_algorithm stm32f7_i2c_algo = {
@@ -2084,10 +2147,22 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
stm32f7_i2c_hw_config(i2c_dev);
+ i2c_dev->smbus_mode = of_property_read_bool(pdev->dev.of_node, "smbus");
+
ret = i2c_add_adapter(adap);
if (ret)
goto pm_disable;
+ if (i2c_dev->smbus_mode) {
+ ret = stm32f7_i2c_enable_smbus_host(i2c_dev);
+ if (ret) {
+ dev_err(i2c_dev->dev,
+ "failed to enable SMBus Host-Notify protocol (%d)\n",
+ ret);
+ goto i2c_adapter_remove;
+ }
+ }
+
dev_info(i2c_dev->dev, "STM32F7 I2C-%d bus adapter\n", adap->nr);
pm_runtime_mark_last_busy(i2c_dev->dev);
@@ -2095,6 +2170,9 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
return 0;
+i2c_adapter_remove:
+ i2c_del_adapter(adap);
+
pm_disable:
pm_runtime_put_noidle(i2c_dev->dev);
pm_runtime_disable(i2c_dev->dev);
@@ -2126,6 +2204,8 @@ static int stm32f7_i2c_remove(struct platform_device *pdev)
{
struct stm32f7_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+ stm32f7_i2c_disable_smbus_host(i2c_dev);
+
i2c_del_adapter(&i2c_dev->adap);
pm_runtime_get_sync(i2c_dev->dev);
--
2.7.4
^ permalink raw reply [flat|nested] 3+ messages in thread