i2c: i2c-stm32f7: add PM Runtime support

Use PM Runtime API to enable/disable clock

Signed-off-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 e9f0c0b..13e1213 100644 (file)
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -28,6 +28,8 @@
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
 #include <linux/slab.h>
@@ -165,6 +167,8 @@
 #define STM32F7_SCLH_MAX                       BIT(8)
 #define STM32F7_SCLL_MAX                       BIT(8)
 
+#define STM32F7_AUTOSUSPEND_DELAY              (HZ / 100)
+
 /**
  * struct stm32f7_i2c_spec - private i2c specification timing
  * @rate: I2C bus speed (Hz)
@@ -1549,15 +1553,13 @@ static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
        i2c_dev->msg_id = 0;
        f7_msg->smbus = false;
 
-       ret = clk_enable(i2c_dev->clk);
-       if (ret) {
-               dev_err(i2c_dev->dev, "Failed to enable clock\n");
+       ret = pm_runtime_get_sync(i2c_dev->dev);
+       if (ret < 0)
                return ret;
-       }
 
        ret = stm32f7_i2c_wait_free_bus(i2c_dev);
        if (ret)
-               goto clk_free;
+               goto pm_free;
 
        stm32f7_i2c_xfer_msg(i2c_dev, msgs);
 
@@ -1573,8 +1575,9 @@ static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
                ret = -ETIMEDOUT;
        }
 
-clk_free:
-       clk_disable(i2c_dev->clk);
+pm_free:
+       pm_runtime_mark_last_busy(i2c_dev->dev);
+       pm_runtime_put_autosuspend(i2c_dev->dev);
 
        return (ret < 0) ? ret : num;
 }
@@ -1596,39 +1599,37 @@ static int stm32f7_i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
        f7_msg->read_write = read_write;
        f7_msg->smbus = true;
 
-       ret = clk_enable(i2c_dev->clk);
-       if (ret) {
-               dev_err(i2c_dev->dev, "Failed to enable clock\n");
+       ret = pm_runtime_get_sync(dev);
+       if (ret < 0)
                return ret;
-       }
 
        ret = stm32f7_i2c_wait_free_bus(i2c_dev);
        if (ret)
-               goto clk_free;
+               goto pm_free;
 
        ret = stm32f7_i2c_smbus_xfer_msg(i2c_dev, flags, command, data);
        if (ret)
-               goto clk_free;
+               goto pm_free;
 
        timeout = wait_for_completion_timeout(&i2c_dev->complete,
                                              i2c_dev->adap.timeout);
        ret = f7_msg->result;
        if (ret)
-               goto clk_free;
+               goto pm_free;
 
        if (!timeout) {
                dev_dbg(dev, "Access to slave 0x%x timed out\n", f7_msg->addr);
                if (i2c_dev->use_dma)
                        dmaengine_terminate_all(dma->chan_using);
                ret = -ETIMEDOUT;
-               goto clk_free;
+               goto pm_free;
        }
 
        /* Check PEC */
        if ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK && read_write) {
                ret = stm32f7_i2c_smbus_check_pec(i2c_dev);
                if (ret)
-                       goto clk_free;
+                       goto pm_free;
        }
 
        if (read_write && size != I2C_SMBUS_QUICK) {
@@ -1653,8 +1654,9 @@ static int stm32f7_i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
                }
        }
 
-clk_free:
-       clk_disable(i2c_dev->clk);
+pm_free:
+       pm_runtime_mark_last_busy(dev);
+       pm_runtime_put_autosuspend(dev);
        return ret;
 }
 
@@ -1680,13 +1682,9 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
        if (ret)
                return ret;
 
-       if (!(stm32f7_i2c_is_slave_registered(i2c_dev))) {
-               ret = clk_enable(i2c_dev->clk);
-               if (ret) {
-                       dev_err(dev, "Failed to enable clock\n");
-                       return ret;
-               }
-       }
+       ret = pm_runtime_get_sync(dev);
+       if (ret < 0)
+               return ret;
 
        if (id == 0) {
                /* Configure Own Address 1 */
@@ -1707,7 +1705,7 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
                oar2 &= ~STM32F7_I2C_OAR2_MASK;
                if (slave->flags & I2C_CLIENT_TEN) {
                        ret = -EOPNOTSUPP;
-                       goto exit;
+                       goto pm_free;
                }
 
                oar2 |= STM32F7_I2C_OAR2_OA2_7(slave->addr);
@@ -1716,7 +1714,7 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
                writel_relaxed(oar2, i2c_dev->base + STM32F7_I2C_OAR2);
        } else {
                ret = -ENODEV;
-               goto exit;
+               goto pm_free;
        }
 
        /* Enable ACK */
@@ -1727,11 +1725,10 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
                STM32F7_I2C_CR1_PE;
        stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, mask);
 
-       return 0;
-
-exit:
-       if (!(stm32f7_i2c_is_slave_registered(i2c_dev)))
-               clk_disable(i2c_dev->clk);
+       ret = 0;
+pm_free:
+       pm_runtime_mark_last_busy(dev);
+       pm_runtime_put_autosuspend(dev);
 
        return ret;
 }
@@ -1749,6 +1746,10 @@ static int stm32f7_i2c_unreg_slave(struct i2c_client *slave)
 
        WARN_ON(!i2c_dev->slave[id]);
 
+       ret = pm_runtime_get_sync(i2c_dev->dev);
+       if (ret < 0)
+               return ret;
+
        if (id == 0) {
                mask = STM32F7_I2C_OAR1_OA1EN;
                stm32f7_i2c_clr_bits(base + STM32F7_I2C_OAR1, mask);
@@ -1759,10 +1760,11 @@ 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);
-               clk_disable(i2c_dev->clk);
-       }
+
+       pm_runtime_mark_last_busy(i2c_dev->dev);
+       pm_runtime_put_autosuspend(i2c_dev->dev);
 
        return 0;
 }
@@ -1847,6 +1849,7 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
                dev_err(&pdev->dev, "Error: Missing controller clock\n");
                return PTR_ERR(i2c_dev->clk);
        }
+
        ret = clk_prepare_enable(i2c_dev->clk);
        if (ret) {
                dev_err(&pdev->dev, "Failed to prepare_enable clock\n");
@@ -1920,8 +1923,6 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
        if (ret)
                goto clk_free;
 
-       stm32f7_i2c_hw_config(i2c_dev);
-
        adap = &i2c_dev->adap;
        i2c_set_adapdata(adap, i2c_dev);
        snprintf(adap->name, sizeof(adap->name), "STM32F7 I2C(%pa)",
@@ -1940,18 +1941,35 @@ static int stm32f7_i2c_probe(struct platform_device *pdev)
                                             STM32F7_I2C_TXDR,
                                             STM32F7_I2C_RXDR);
 
-       ret = i2c_add_adapter(adap);
-       if (ret)
-               goto clk_free;
-
        platform_set_drvdata(pdev, i2c_dev);
 
-       clk_disable(i2c_dev->clk);
+       pm_runtime_set_autosuspend_delay(i2c_dev->dev,
+                                        STM32F7_AUTOSUSPEND_DELAY);
+       pm_runtime_use_autosuspend(i2c_dev->dev);
+       pm_runtime_set_active(i2c_dev->dev);
+       pm_runtime_enable(i2c_dev->dev);
+
+       pm_runtime_get_noresume(&pdev->dev);
+
+       stm32f7_i2c_hw_config(i2c_dev);
+
+       ret = i2c_add_adapter(adap);
+       if (ret)
+               goto pm_disable;
 
        dev_info(i2c_dev->dev, "STM32F7 I2C-%d bus adapter\n", adap->nr);
 
+       pm_runtime_mark_last_busy(i2c_dev->dev);
+       pm_runtime_put_autosuspend(i2c_dev->dev);
+
        return 0;
 
+pm_disable:
+       pm_runtime_put_noidle(i2c_dev->dev);
+       pm_runtime_disable(i2c_dev->dev);
+       pm_runtime_set_suspended(i2c_dev->dev);
+       pm_runtime_dont_use_autosuspend(i2c_dev->dev);
+
 clk_free:
        clk_disable_unprepare(i2c_dev->clk);
 
@@ -1968,11 +1986,50 @@ static int stm32f7_i2c_remove(struct platform_device *pdev)
        }
 
        i2c_del_adapter(&i2c_dev->adap);
+       pm_runtime_get_sync(i2c_dev->dev);
+
+       clk_disable_unprepare(i2c_dev->clk);
+
+       pm_runtime_put_noidle(i2c_dev->dev);
+       pm_runtime_disable(i2c_dev->dev);
+       pm_runtime_set_suspended(i2c_dev->dev);
+       pm_runtime_dont_use_autosuspend(i2c_dev->dev);
+
+       return 0;
+}
+
+#ifdef CONFIG_PM
+static int stm32f7_i2c_runtime_suspend(struct device *dev)
+{
+       struct stm32f7_i2c_dev *i2c_dev = dev_get_drvdata(dev);
+
+       if (!stm32f7_i2c_is_slave_registered(i2c_dev))
+               clk_disable_unprepare(i2c_dev->clk);
+
+       return 0;
+}
+
+static int stm32f7_i2c_runtime_resume(struct device *dev)
+{
+       struct stm32f7_i2c_dev *i2c_dev = dev_get_drvdata(dev);
+       int ret;
 
-       clk_unprepare(i2c_dev->clk);
+       if (!stm32f7_i2c_is_slave_registered(i2c_dev)) {
+               ret = clk_prepare_enable(i2c_dev->clk);
+               if (ret) {
+                       dev_err(dev, "failed to prepare_enable clock\n");
+                       return ret;
+               }
+       }
 
        return 0;
 }
+#endif
+
+static const struct dev_pm_ops stm32f7_i2c_pm_ops = {
+       SET_RUNTIME_PM_OPS(stm32f7_i2c_runtime_suspend,
+                          stm32f7_i2c_runtime_resume, NULL)
+};
 
 static const struct of_device_id stm32f7_i2c_match[] = {
        { .compatible = "st,stm32f7-i2c", .data = &stm32f7_setup},
@@ -1984,6 +2041,7 @@ static struct platform_driver stm32f7_i2c_driver = {
        .driver = {
                .name = "stm32f7-i2c",
                .of_match_table = stm32f7_i2c_match,
+               .pm = &stm32f7_i2c_pm_ops,
        },
        .probe = stm32f7_i2c_probe,
        .remove = stm32f7_i2c_remove,