i2c: stm32f7: allow controller to be wakeup-source

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>
Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 5c3e8ac..378956a 100644 (file)
--- 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 +1695,24 @@ pm_free:
        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 stm32f7_i2c_reg_slave(struct i2c_client *slave)
 {
        struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(slave->adapter);
@@ -1717,6 +1739,9 @@ 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 +1783,9 @@ 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 +1819,10 @@ 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 +1909,9 @@ 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 +2018,16 @@ 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 +2057,13 @@ pm_disable:
        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 +2082,15 @@ 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);
@@ -2073,8 +2132,8 @@ static int __maybe_unused stm32f7_i2c_runtime_resume(struct device *dev)
        return 0;
 }
 
-static int __maybe_unused
-stm32f7_i2c_regs_backup(struct stm32f7_i2c_dev *i2c_dev)
+#ifdef CONFIG_PM_SLEEP
+static int stm32f7_i2c_regs_backup(struct stm32f7_i2c_dev *i2c_dev)
 {
        int ret;
        struct stm32f7_i2c_regs *backup_regs = &i2c_dev->backup_regs;
@@ -2095,8 +2154,7 @@ stm32f7_i2c_regs_backup(struct stm32f7_i2c_dev *i2c_dev)
        return ret;
 }
 
-static int __maybe_unused
-stm32f7_i2c_regs_restore(struct stm32f7_i2c_dev *i2c_dev)
+static int stm32f7_i2c_regs_restore(struct stm32f7_i2c_dev *i2c_dev)
 {
        u32 cr1;
        int ret;
@@ -2127,41 +2185,48 @@ stm32f7_i2c_regs_restore(struct stm32f7_i2c_dev *i2c_dev)
        return ret;
 }
 
-static int __maybe_unused stm32f7_i2c_suspend(struct device *dev)
+static int 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;
 }
 
-static int __maybe_unused stm32f7_i2c_resume(struct device *dev)
+static int 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;
 }
+#endif
 
 static const struct dev_pm_ops stm32f7_i2c_pm_ops = {
        SET_RUNTIME_PM_OPS(stm32f7_i2c_runtime_suspend,