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Subject[PATCH 5/6] i2c: i2c-stm32f7: allow controller to be wakeup-source
Date
Allow the i2c-stm32f7 controller to become a wakeup-source
of the system. In such case, when a slave is registered to the
I2C controller, receiving a I2C message targeting that registered
slave address wakes up the suspended system.

In order to be able to wake-up, the I2C controller DT node
must have the property wakeup-source defined and a slave
must be registered.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
---
drivers/i2c/busses/i2c-stm32f7.c | 98 ++++++++++++++++++++++++++++++++++------
1 file changed, 83 insertions(+), 15 deletions(-)

diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 5c3e8ac6ad92..844a22d64aa8 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -29,6 +29,7 @@
#include <linux/platform_device.h>
#include <linux/pinctrl/consumer.h>
#include <linux/pm_runtime.h>
+#include <linux/pm_wakeirq.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#include <linux/slab.h>
@@ -49,6 +50,7 @@

/* STM32F7 I2C control 1 */
#define STM32F7_I2C_CR1_PECEN BIT(23)
+#define STM32F7_I2C_CR1_WUPEN BIT(18)
#define STM32F7_I2C_CR1_SBC BIT(16)
#define STM32F7_I2C_CR1_RXDMAEN BIT(15)
#define STM32F7_I2C_CR1_TXDMAEN BIT(14)
@@ -301,6 +303,7 @@ struct stm32f7_i2c_msg {
* @dma: dma data
* @use_dma: boolean to know if dma is used in the current transfer
* @regmap: holds SYSCFG phandle for Fast Mode Plus bits
+ * @wakeup_src: boolean to know if the device is a wakeup source
*/
struct stm32f7_i2c_dev {
struct i2c_adapter adap;
@@ -323,6 +326,7 @@ struct stm32f7_i2c_dev {
struct stm32_i2c_dma *dma;
bool use_dma;
struct regmap *regmap;
+ bool wakeup_src;
};

/*
@@ -1691,6 +1695,9 @@ static int stm32f7_i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
return ret;
}

+static void stm32f7_i2c_enable_wakeup(struct stm32f7_i2c_dev *i2c_dev,
+ bool enable);
+
static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
{
struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(slave->adapter);
@@ -1717,6 +1724,9 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
if (ret < 0)
return ret;

+ if (!stm32f7_i2c_is_slave_registered(i2c_dev))
+ stm32f7_i2c_enable_wakeup(i2c_dev, true);
+
if (id == 0) {
/* Configure Own Address 1 */
oar1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_OAR1);
@@ -1758,6 +1768,9 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)

ret = 0;
pm_free:
+ if (!stm32f7_i2c_is_slave_registered(i2c_dev))
+ stm32f7_i2c_enable_wakeup(i2c_dev, false);
+
pm_runtime_mark_last_busy(dev);
pm_runtime_put_autosuspend(dev);

@@ -1791,8 +1804,10 @@ static int stm32f7_i2c_unreg_slave(struct i2c_client *slave)

i2c_dev->slave[id] = NULL;

- if (!(stm32f7_i2c_is_slave_registered(i2c_dev)))
+ if (!stm32f7_i2c_is_slave_registered(i2c_dev)) {
stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK);
+ stm32f7_i2c_enable_wakeup(i2c_dev, false);
+ }

pm_runtime_mark_last_busy(i2c_dev->dev);
pm_runtime_put_autosuspend(i2c_dev->dev);
@@ -1879,6 +1894,9 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
return irq_error ? : -ENOENT;
}

+ i2c_dev->wakeup_src = of_property_read_bool(pdev->dev.of_node,
+ "wakeup-source");
+
i2c_dev->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(i2c_dev->clk)) {
dev_err(&pdev->dev, "Error: Missing controller clock\n");
@@ -1985,6 +2003,16 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
goto clk_free;
}

+ if (i2c_dev->wakeup_src) {
+ device_set_wakeup_capable(i2c_dev->dev, true);
+
+ ret = dev_pm_set_wake_irq(i2c_dev->dev, irq_event);
+ if (ret) {
+ dev_err(i2c_dev->dev, "Failed to set wake up irq\n");
+ goto clr_wakeup_capable;
+ }
+ }
+
platform_set_drvdata(pdev, i2c_dev);

pm_runtime_set_autosuspend_delay(i2c_dev->dev,
@@ -2014,6 +2042,13 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
pm_runtime_set_suspended(i2c_dev->dev);
pm_runtime_dont_use_autosuspend(i2c_dev->dev);

+ if (i2c_dev->wakeup_src)
+ dev_pm_clear_wake_irq(i2c_dev->dev);
+
+clr_wakeup_capable:
+ if (i2c_dev->wakeup_src)
+ device_set_wakeup_capable(i2c_dev->dev, false);
+
if (i2c_dev->dma) {
stm32_i2c_dma_free(i2c_dev->dma);
i2c_dev->dma = NULL;
@@ -2032,6 +2067,15 @@ static int stm32f7_i2c_remove(struct platform_device *pdev)
i2c_del_adapter(&i2c_dev->adap);
pm_runtime_get_sync(i2c_dev->dev);

+ if (i2c_dev->wakeup_src) {
+ dev_pm_clear_wake_irq(i2c_dev->dev);
+ /*
+ * enforce that wakeup is disabled and that the device
+ * is marked as non wakeup capable
+ */
+ device_init_wakeup(i2c_dev->dev, false);
+ }
+
pm_runtime_put_noidle(i2c_dev->dev);
pm_runtime_disable(i2c_dev->dev);
pm_runtime_set_suspended(i2c_dev->dev);
@@ -2127,20 +2171,41 @@ stm32f7_i2c_regs_restore(struct stm32f7_i2c_dev *i2c_dev)
return ret;
}

+static void stm32f7_i2c_enable_wakeup(struct stm32f7_i2c_dev *i2c_dev,
+ bool enable)
+{
+ void __iomem *base = i2c_dev->base;
+ u32 mask = STM32F7_I2C_CR1_WUPEN;
+
+ if (!i2c_dev->wakeup_src)
+ return;
+
+ if (enable) {
+ device_set_wakeup_enable(i2c_dev->dev, true);
+ stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, mask);
+ } else {
+ device_set_wakeup_enable(i2c_dev->dev, false);
+ stm32f7_i2c_clr_bits(base + STM32F7_I2C_CR1, mask);
+ }
+}
+
static int __maybe_unused stm32f7_i2c_suspend(struct device *dev)
{
struct stm32f7_i2c_dev *i2c_dev = dev_get_drvdata(dev);
int ret;

i2c_mark_adapter_suspended(&i2c_dev->adap);
- ret = stm32f7_i2c_regs_backup(i2c_dev);
- if (ret < 0) {
- i2c_mark_adapter_resumed(&i2c_dev->adap);
- return ret;
- }

- pinctrl_pm_select_sleep_state(dev);
- pm_runtime_force_suspend(dev);
+ if (!device_may_wakeup(dev) && !dev->power.wakeup_path) {
+ ret = stm32f7_i2c_regs_backup(i2c_dev);
+ if (ret < 0) {
+ i2c_mark_adapter_resumed(&i2c_dev->adap);
+ return ret;
+ }
+
+ pinctrl_pm_select_sleep_state(dev);
+ pm_runtime_force_suspend(dev);
+ }

return 0;
}
@@ -2150,14 +2215,17 @@ static int __maybe_unused stm32f7_i2c_resume(struct device *dev)
struct stm32f7_i2c_dev *i2c_dev = dev_get_drvdata(dev);
int ret;

- ret = pm_runtime_force_resume(dev);
- if (ret < 0)
- return ret;
- pinctrl_pm_select_default_state(dev);
+ if (!device_may_wakeup(dev) && !dev->power.wakeup_path) {
+ ret = pm_runtime_force_resume(dev);
+ if (ret < 0)
+ return ret;
+ pinctrl_pm_select_default_state(dev);
+
+ ret = stm32f7_i2c_regs_restore(i2c_dev);
+ if (ret < 0)
+ return ret;
+ }

- ret = stm32f7_i2c_regs_restore(i2c_dev);
- if (ret < 0)
- return ret;
i2c_mark_adapter_resumed(&i2c_dev->adap);

return 0;
--
2.7.4
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