[PATCH v7 1/1] i2c: lpi2c: use clk notifier for rate changes

[Andi Shyti]

Hi Alexander,

is it my mail client not working or is is your patch that has
gone through something terribly bad?

Andi

On Tue, Nov 07, 2023 at 03:12:01PM +0100, Alexander Stein wrote:
> * CLKLO = I2C_CLK_RATIO * CLKHI, SETHOLD = CLKHI, DATAVD = CLKHI/2 */
>  static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
>  {
> @@ -207,7 +224,7 @@ static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
>  
>  	lpi2c_imx_set_mode(lpi2c_imx);
>  
> -	clk_rate = clk_get_rate(lpi2c_imx->clks[0].clk);
> +	clk_rate = atomic_read(&lpi2c_imx->rate_per);
>  	if (!clk_rate)
>  		return -EINVAL;
>  
> @@ -590,6 +607,27 @@ static int lpi2c_imx_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	lpi2c_imx->clk_change_nb.notifier_call = lpi2c_imx_clk_change_cb;
> +	ret = devm_clk_notifier_register(&pdev->dev, lpi2c_imx->clks[0].clk,
> +					 &lpi2c_imx->clk_change_nb);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret,
> +				     "can't register peripheral clock notifier\n");
> +	/*
> +	 * Lock the clock rate to avoid rate change between clk_get_rate() and
> +	 * atomic_set()
> +	 */
> +	ret = clk_rate_exclusive_get(lpi2c_imx->clks[0].clk);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret,
> +				     "can't lock I2C peripheral clock rate\n");
> +
> +	atomic_set(&lpi2c_imx->rate_per, clk_get_rate(lpi2c_imx->clks[0].clk));
> +	clk_rate_exclusive_put(lpi2c_imx->clks[0].clk);
> +	if (!atomic_read(&lpi2c_imx->rate_per))
> +		return dev_err_probe(&pdev->dev, -EINVAL,
> +				     "can't get I2C peripheral clock rate\n");
> +
>  	pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT);
>  	pm_runtime_use_autosuspend(&pdev->dev);
>  	pm_runtime_get_noresume(&pdev->dev);
> -- 
> 2.34.1
>