From: Lucas Stach l.stach@pengutronix.de
commit 90ad2cbe88c22d0215225ab9594eeead0eb24fde upstream
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 Signed-off-by: Sudip Mukherjee sudipm.mukherjee@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/i2c/busses/i2c-imx.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-)
--- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -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; @@ -468,15 +469,14 @@ static int i2c_imx_acked(struct imx_i2c_ 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;
@@ -511,6 +511,20 @@ static void i2c_imx_set_clk(struct imx_i #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; @@ -518,8 +532,6 @@ static int i2c_imx_start(struct imx_i2c_
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 "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 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
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 platfor 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);