forked from Minki/linux
i2c: imx: add runtime pm support to improve the performance
In our former i2c driver, i2c clk is enabled and disabled in xfer function, which contributes to power saving. However, the clk enable process brings a busy wait delay until the core is stable. As a result, the performance is sacrificed. To weigh the power consumption and i2c bus performance, runtime pm is the good solution for it. The clk is enabled when a i2c transfer starts, and disabled after a specifically defined delay. If CONFIG_PM is disabled the net result of this patch is that the clock is never disabled. Without the patch the test case (many eeprom reads) executes with approx: real 1m7.735s user 0m0.488s sys 0m20.040s With the patch the same test case (many eeprom reads) executes with approx: real 0m54.241s user 0m0.440s sys 0m5.920s Signed-off-by: Fugang Duan <B38611@freescale.com> Signed-off-by: Gao Pan <b54642@freescale.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> [wsa: sorted includes] Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Gao Pan
Wolfram Sang
parent
a5f650182b
commit
588eb93ea4
@ -53,6 +53,7 @@
|
||||
#include <linux/pinctrl/consumer.h>
|
||||
#include <linux/platform_data/i2c-imx.h>
|
||||
#include <linux/platform_device.h>
|
||||
#include <linux/pm_runtime.h>
|
||||
#include <linux/sched.h>
|
||||
#include <linux/slab.h>
|
||||
|
||||
@ -120,6 +121,8 @@
|
||||
#define I2CR_IEN_OPCODE_0 0x0
|
||||
#define I2CR_IEN_OPCODE_1 I2CR_IEN
|
||||
|
||||
#define I2C_PM_TIMEOUT 10 /* ms */
|
||||
|
||||
/** Variables ******************************************************************
|
||||
*******************************************************************************/
|
||||
|
||||
@ -527,9 +530,6 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
|
||||
|
||||
i2c_imx_set_clk(i2c_imx);
|
||||
|
||||
result = clk_prepare_enable(i2c_imx->clk);
|
||||
if (result)
|
||||
return result;
|
||||
imx_i2c_write_reg(i2c_imx->ifdr, i2c_imx, IMX_I2C_IFDR);
|
||||
/* Enable I2C controller */
|
||||
imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
|
||||
@ -582,7 +582,6 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
|
||||
/* Disable I2C controller */
|
||||
temp = i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
|
||||
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
|
||||
clk_disable_unprepare(i2c_imx->clk);
|
||||
}
|
||||
|
||||
static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
|
||||
@ -901,6 +900,10 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
|
||||
|
||||
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
|
||||
|
||||
result = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
|
||||
if (result < 0)
|
||||
goto out;
|
||||
|
||||
/* Start I2C transfer */
|
||||
result = i2c_imx_start(i2c_imx);
|
||||
if (result) {
|
||||
@ -964,6 +967,10 @@ fail0:
|
||||
/* Stop I2C transfer */
|
||||
i2c_imx_stop(i2c_imx);
|
||||
|
||||
pm_runtime_mark_last_busy(i2c_imx->adapter.dev.parent);
|
||||
pm_runtime_put_autosuspend(i2c_imx->adapter.dev.parent);
|
||||
|
||||
out:
|
||||
dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
|
||||
(result < 0) ? "error" : "success msg",
|
||||
(result < 0) ? result : num);
|
||||
@ -1083,7 +1090,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
|
||||
|
||||
ret = clk_prepare_enable(i2c_imx->clk);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "can't enable I2C clock\n");
|
||||
dev_err(&pdev->dev, "can't enable I2C clock, ret=%d\n", ret);
|
||||
return ret;
|
||||
}
|
||||
|
||||
@ -1107,6 +1114,18 @@ static int i2c_imx_probe(struct platform_device *pdev)
|
||||
/* Set up adapter data */
|
||||
i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
|
||||
|
||||
/* Set up platform driver data */
|
||||
platform_set_drvdata(pdev, i2c_imx);
|
||||
|
||||
pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT);
|
||||
pm_runtime_use_autosuspend(&pdev->dev);
|
||||
pm_runtime_set_active(&pdev->dev);
|
||||
pm_runtime_enable(&pdev->dev);
|
||||
|
||||
ret = pm_runtime_get_sync(&pdev->dev);
|
||||
if (ret < 0)
|
||||
goto rpm_disable;
|
||||
|
||||
/* Set up clock divider */
|
||||
i2c_imx->bitrate = IMX_I2C_BIT_RATE;
|
||||
ret = of_property_read_u32(pdev->dev.of_node,
|
||||
@ -1125,12 +1144,11 @@ static int i2c_imx_probe(struct platform_device *pdev)
|
||||
ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
|
||||
if (ret < 0) {
|
||||
dev_err(&pdev->dev, "registration failed\n");
|
||||
goto clk_disable;
|
||||
goto rpm_disable;
|
||||
}
|
||||
|
||||
/* Set up platform driver data */
|
||||
platform_set_drvdata(pdev, i2c_imx);
|
||||
clk_disable_unprepare(i2c_imx->clk);
|
||||
pm_runtime_mark_last_busy(&pdev->dev);
|
||||
pm_runtime_put_autosuspend(&pdev->dev);
|
||||
|
||||
dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", irq);
|
||||
dev_dbg(&i2c_imx->adapter.dev, "device resources: %pR\n", res);
|
||||
@ -1143,6 +1161,12 @@ static int i2c_imx_probe(struct platform_device *pdev)
|
||||
|
||||
return 0; /* Return OK */
|
||||
|
||||
rpm_disable:
|
||||
pm_runtime_put_noidle(&pdev->dev);
|
||||
pm_runtime_disable(&pdev->dev);
|
||||
pm_runtime_set_suspended(&pdev->dev);
|
||||
pm_runtime_dont_use_autosuspend(&pdev->dev);
|
||||
|
||||
clk_disable:
|
||||
clk_disable_unprepare(i2c_imx->clk);
|
||||
return ret;
|
||||
@ -1151,6 +1175,11 @@ clk_disable:
|
||||
static int i2c_imx_remove(struct platform_device *pdev)
|
||||
{
|
||||
struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
|
||||
int ret;
|
||||
|
||||
ret = pm_runtime_get_sync(&pdev->dev);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
|
||||
/* remove adapter */
|
||||
dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
|
||||
@ -1165,17 +1194,54 @@ static int i2c_imx_remove(struct platform_device *pdev)
|
||||
imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2CR);
|
||||
imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR);
|
||||
|
||||
clk_disable_unprepare(i2c_imx->clk);
|
||||
|
||||
pm_runtime_put_noidle(&pdev->dev);
|
||||
pm_runtime_disable(&pdev->dev);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
#ifdef CONFIG_PM
|
||||
static int i2c_imx_runtime_suspend(struct device *dev)
|
||||
{
|
||||
struct imx_i2c_struct *i2c_imx = dev_get_drvdata(dev);
|
||||
|
||||
clk_disable_unprepare(i2c_imx->clk);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int i2c_imx_runtime_resume(struct device *dev)
|
||||
{
|
||||
struct imx_i2c_struct *i2c_imx = dev_get_drvdata(dev);
|
||||
int ret;
|
||||
|
||||
ret = clk_prepare_enable(i2c_imx->clk);
|
||||
if (ret)
|
||||
dev_err(dev, "can't enable I2C clock, ret=%d\n", ret);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static const struct dev_pm_ops i2c_imx_pm_ops = {
|
||||
SET_RUNTIME_PM_OPS(i2c_imx_runtime_suspend,
|
||||
i2c_imx_runtime_resume, NULL)
|
||||
};
|
||||
#define I2C_IMX_PM_OPS (&i2c_imx_pm_ops)
|
||||
#else
|
||||
#define I2C_IMX_PM_OPS NULL
|
||||
#endif /* CONFIG_PM */
|
||||
|
||||
static struct platform_driver i2c_imx_driver = {
|
||||
.probe = i2c_imx_probe,
|
||||
.remove = i2c_imx_remove,
|
||||
.driver = {
|
||||
.name = DRIVER_NAME,
|
||||
.driver = {
|
||||
.name = DRIVER_NAME,
|
||||
.pm = I2C_IMX_PM_OPS,
|
||||
.of_match_table = i2c_imx_dt_ids,
|
||||
},
|
||||
.id_table = imx_i2c_devtype,
|
||||
.id_table = imx_i2c_devtype,
|
||||
};
|
||||
|
||||
static int __init i2c_adap_imx_init(void)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user