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Commit 90ad2cbe authored by Lucas Stach's avatar Lucas Stach Committed by Wolfram Sang
Browse files

i2c: imx: use clk notifier for rate changes 



Instead of repeatedly calling clk_get_rate for each transfer, register
a clock notifier to update the cached divider value each time the clock
rate actually changes.

Signed-off-by: default avatarLucas Stach <l.stach@pengutronix.de>
Reviewed-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 398432ed

drivers/i2c/busses/i2c-imx.c

+25 −7
Original line number Diff line number Diff line
@@ -194,6 +194,7 @@ struct imx_i2c_dma { 
struct imx_i2c_struct {

	struct i2c_adapter	adapter;

	struct clk		*clk;

	struct notifier_block	clk_change_nb;

	void __iomem		*base;

	wait_queue_head_t	queue;

	unsigned long		i2csr;
@@ -467,15 +468,14 @@ static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx) 
	return 0;

}



static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx)

static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,

			    unsigned int i2c_clk_rate)

{

	struct imx_i2c_clk_pair *i2c_clk_div = i2c_imx->hwdata->clk_div;

	unsigned int i2c_clk_rate;

	unsigned int div;

	int i;



	/* Divider value calculation */

	i2c_clk_rate = clk_get_rate(i2c_imx->clk);

	if (i2c_imx->cur_clk == i2c_clk_rate)

		return;
@@ -510,6 +510,20 @@ static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx) 
#endif

}



static int i2c_imx_clk_notifier_call(struct notifier_block *nb,

				     unsigned long action, void *data)

{

	struct clk_notifier_data *ndata = data;

	struct imx_i2c_struct *i2c_imx = container_of(&ndata->clk,

						      struct imx_i2c_struct,

						      clk);



	if (action & POST_RATE_CHANGE)

		i2c_imx_set_clk(i2c_imx, ndata->new_rate);



	return NOTIFY_OK;

}



static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)

{

	unsigned int temp = 0;
@@ -517,8 +531,6 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) 


	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);



	i2c_imx_set_clk(i2c_imx);



	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);
@@ -1131,6 +1143,9 @@ static int i2c_imx_probe(struct platform_device *pdev) 
				   "clock-frequency", &i2c_imx->bitrate);

	if (ret < 0 && pdata && pdata->bitrate)

		i2c_imx->bitrate = pdata->bitrate;

	i2c_imx->clk_change_nb.notifier_call = i2c_imx_clk_notifier_call;

	clk_notifier_register(i2c_imx->clk, &i2c_imx->clk_change_nb);

	i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));



	/* Set up chip registers to defaults */

	imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
@@ -1141,12 +1156,12 @@ static int i2c_imx_probe(struct platform_device *pdev) 
	ret = i2c_imx_init_recovery_info(i2c_imx, pdev);

	/* Give it another chance if pinctrl used is not ready yet */

	if (ret == -EPROBE_DEFER)

		goto rpm_disable;

		goto clk_notifier_unregister;



	/* Add I2C adapter */

	ret = i2c_add_numbered_adapter(&i2c_imx->adapter);

	if (ret < 0)

		goto rpm_disable;

		goto clk_notifier_unregister;



	pm_runtime_mark_last_busy(&pdev->dev);

	pm_runtime_put_autosuspend(&pdev->dev);
@@ -1162,6 +1177,8 @@ static int i2c_imx_probe(struct platform_device *pdev) 


	return 0;   /* Return OK */



clk_notifier_unregister:

	clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);

rpm_disable:

	pm_runtime_put_noidle(&pdev->dev);

	pm_runtime_disable(&pdev->dev);
@@ -1195,6 +1212,7 @@ 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_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);

	clk_disable_unprepare(i2c_imx->clk);



	pm_runtime_put_noidle(&pdev->dev);