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Subject[PATCH v2] i2c: i2c-stm32f7: add PM Runtime support
Date
Use PM Runtime API to enable/disable clock

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
Version history:
v2:
* missing define
v1:
* Initial
---
---
drivers/i2c/busses/i2c-stm32f7.c | 144 +++++++++++++++++++++++++++------------
1 file changed, 101 insertions(+), 43 deletions(-)

diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 62d023e..3b98b68 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -27,6 +27,8 @@
#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/reset.h>
#include <linux/slab.h>

@@ -163,6 +165,8 @@
#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)
@@ -1545,15 +1549,13 @@ 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);

@@ -1569,8 +1571,9 @@ 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;
}
@@ -1592,39 +1595,37 @@ 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) {
@@ -1649,8 +1650,9 @@ 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;
}

@@ -1676,13 +1678,9 @@ 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 */
@@ -1703,7 +1701,7 @@ 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);
@@ -1712,7 +1710,7 @@ 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 */
@@ -1723,11 +1721,10 @@ 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;
}
@@ -1745,6 +1742,10 @@ 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);
@@ -1755,10 +1756,11 @@ 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;
}
@@ -1819,6 +1821,7 @@ 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");
@@ -1888,8 +1891,6 @@ 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)",
@@ -1908,18 +1909,35 @@ 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);

@@ -1936,12 +1954,51 @@ 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);

- clk_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;
+
+ 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},
{},
@@ -1952,6 +2009,7 @@ 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,
--
2.7.4
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