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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: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Lucas Stach 2018-03-08 14:25:17 +01:00 committed by Wolfram Sang
parent 398432edde
commit 90ad2cbe88
1 changed files with 25 additions and 7 deletions
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32
drivers/i2c/busses/i2c-imx.c
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@ -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);