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Subject[PATCH v3 1/2] i2c: davinci: Add PM Runtime Support
Date
66AK2G has I2C instances that are not apart of the ALWAYS_ON power domain
like other Keystone 2 SoCs and OMAPL138. Therefore, pm_runtime
is required to insure the power domain used by the specific I2C instance is
properly turned on along with its functional clock.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
---
Version 3 changes:
Remove several statements that set clk to NULL
Fix error path

drivers/i2c/busses/i2c-davinci.c | 64 +++++++++++++++++++++++++++++++++-------
1 file changed, 53 insertions(+), 11 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index b8c4353..57612cb 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -36,6 +36,7 @@
#include <linux/gpio.h>
#include <linux/of_device.h>
#include <linux/platform_data/i2c-davinci.h>
+#include <linux/pm_runtime.h>

/* ----- global defines ----------------------------------------------- */

@@ -122,6 +123,9 @@
/* set the SDA GPIO low */
#define DAVINCI_I2C_DCLR_PDCLR1 BIT(1)

+/* timeout for pm runtime autosuspend */
+#define DAVINCI_I2C_PM_TIMEOUT 1000 /* ms */
+
struct davinci_i2c_dev {
struct device *dev;
void __iomem *base;
@@ -541,10 +545,17 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)

dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);

+ ret = pm_runtime_get_sync(dev->dev);
+ if (ret < 0) {
+ dev_err(dev->dev, "Failed to runtime_get device: %d\n", ret);
+ pm_runtime_put_noidle(dev->dev);
+ return ret;
+ }
+
ret = i2c_davinci_wait_bus_not_busy(dev);
if (ret < 0) {
dev_warn(dev->dev, "timeout waiting for bus ready\n");
- return ret;
+ goto out;
}

for (i = 0; i < num; i++) {
@@ -552,14 +563,19 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
ret);
if (ret < 0)
- return ret;
+ goto out;
}

+ ret = num;
#ifdef CONFIG_CPU_FREQ
complete(&dev->xfr_complete);
#endif

- return num;
+out:
+ pm_runtime_mark_last_busy(dev->dev);
+ pm_runtime_put_autosuspend(dev->dev);
+
+ return ret;
}

static u32 i2c_davinci_func(struct i2c_adapter *adap)
@@ -599,6 +615,9 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
int count = 0;
u16 w;

+ if (pm_runtime_suspended(dev->dev))
+ return IRQ_NONE;
+
while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
if (count++ == 100) {
@@ -802,12 +821,22 @@ static int davinci_i2c_probe(struct platform_device *pdev)
dev->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(dev->clk))
return PTR_ERR(dev->clk);
- clk_prepare_enable(dev->clk);

mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
dev->base = devm_ioremap_resource(&pdev->dev, mem);
if (IS_ERR(dev->base)) {
- r = PTR_ERR(dev->base);
+ return PTR_ERR(dev->base);
+ }
+
+ pm_runtime_set_autosuspend_delay(dev->dev,
+ DAVINCI_I2C_PM_TIMEOUT);
+ pm_runtime_use_autosuspend(dev->dev);
+
+ pm_runtime_enable(dev->dev);
+
+ r = pm_runtime_get_sync(dev->dev);
+ if (r < 0) {
+ dev_err(dev->dev, "failed to runtime_get device: %d\n", r);
goto err_unuse_clocks;
}

@@ -849,27 +878,40 @@ static int davinci_i2c_probe(struct platform_device *pdev)
if (r)
goto err_unuse_clocks;

+ pm_runtime_mark_last_busy(dev->dev);
+ pm_runtime_put_autosuspend(dev->dev);
+
return 0;

err_unuse_clocks:
- clk_disable_unprepare(dev->clk);
- dev->clk = NULL;
+ pm_runtime_dont_use_autosuspend(dev->dev);
+ pm_runtime_put_sync(dev->dev);
+ pm_runtime_disable(dev->dev);
+
return r;
}

static int davinci_i2c_remove(struct platform_device *pdev)
{
struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
+ int ret;

i2c_davinci_cpufreq_deregister(dev);

i2c_del_adapter(&dev->adapter);

- clk_disable_unprepare(dev->clk);
- dev->clk = NULL;
+ ret = pm_runtime_get_sync(&pdev->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(&pdev->dev);
+ return ret;
+ }

davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);

+ pm_runtime_dont_use_autosuspend(dev->dev);
+ pm_runtime_put_sync(dev->dev);
+ pm_runtime_disable(dev->dev);
+
return 0;
}

@@ -880,7 +922,6 @@ static int davinci_i2c_suspend(struct device *dev)

/* put I2C into reset */
davinci_i2c_reset_ctrl(i2c_dev, 0);
- clk_disable_unprepare(i2c_dev->clk);

return 0;
}
@@ -889,7 +930,6 @@ static int davinci_i2c_resume(struct device *dev)
{
struct davinci_i2c_dev *i2c_dev = dev_get_drvdata(dev);

- clk_prepare_enable(i2c_dev->clk);
/* take I2C out of reset */
davinci_i2c_reset_ctrl(i2c_dev, 1);

@@ -899,6 +939,8 @@ static int davinci_i2c_resume(struct device *dev)
static const struct dev_pm_ops davinci_i2c_pm = {
.suspend = davinci_i2c_suspend,
.resume = davinci_i2c_resume,
+ SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+ pm_runtime_force_resume)
};

#define davinci_i2c_pm_ops (&davinci_i2c_pm)
--
2.9.4.dirty
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