[PATCH 3/4] cpufreq: imx6q: Fix regulator/clock error handling

[l.stach@pengutronix.de (Lucas Stach)]

Am Donnerstag, den 22.10.2015, 10:47 +0200 schrieb Sascha Hauer:
> When one of the regulator_get/clk_get calls fails the driver just
> returns -ENOENT. To properly handle the -EPROBE_DEFER case we have
> to forward the actual error value instead. This patch fixes that.
> 
> Since all clocks/regulators are global static variables the IS_ERR()
> check in the error path in probe() may erroneously work on the values
> assigned in the previous probe run. This means we have to reinitialize
> the variables between two probe runs().
> 
> The probe function already is quite overloaded, so this patch moves
> the regulator and clock allocation into a separate function and the
> dropping of these resourced into a corresponding cleanup function.
> This is easier to review for correctness than the current mix of
> reverse-cleanup and !IS_ERR checks at the end of probe().
> 
> While at it leave a comment that these resource allocations can't use
> devm_* to prevent people from trying to convert it.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Nice cleanup overall, one nit below.

> ---
>  drivers/cpufreq/imx6q-cpufreq.c | 166 ++++++++++++++++++++++++----------------
>  1 file changed, 102 insertions(+), 64 deletions(-)
> 
> diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
> index 7557d1e..ce0c6bd 100644
> --- a/drivers/cpufreq/imx6q-cpufreq.c
> +++ b/drivers/cpufreq/imx6q-cpufreq.c
> @@ -176,6 +176,99 @@ static struct cpufreq_driver imx6q_cpufreq_driver = {
>  	.attr = cpufreq_generic_attr,
>  };
>  
> +static int imx6q_cpufreq_get_resources(struct platform_device *pdev)

Given that all the resources are attached to the cpu_dev anyway, do you
really see a use for this parameter?

> +{
> +	/*
> +	 * Do not use devm_* here. The resources are bound to the
> +	 * cpu_dev and not to this drivers platform_device.
> +	 */
> +	arm_clk = clk_get(cpu_dev, "arm");
> +	if (IS_ERR(arm_clk))
> +		return PTR_ERR(arm_clk);
> +
> +	pll1_sys_clk = clk_get(cpu_dev, "pll1_sys");
> +	if (IS_ERR(pll1_sys_clk))
> +		return PTR_ERR(pll1_sys_clk);
> +
> +	pll1_sw_clk = clk_get(cpu_dev, "pll1_sw");
> +	if (IS_ERR(pll1_sw_clk))
> +		return PTR_ERR(pll1_sw_clk);
> +
> +	step_clk = clk_get(cpu_dev, "step");
> +	if (IS_ERR(step_clk))
> +		return PTR_ERR(step_clk);
> +
> +	pll2_pfd2_396m_clk = clk_get(cpu_dev, "pll2_pfd2_396m");
> +	if (IS_ERR(pll2_pfd2_396m_clk))
> +		return PTR_ERR(pll2_pfd2_396m_clk);
> +
> +	if (of_machine_is_compatible("fsl,imx6ul")) {
> +		pll2_bus_clk = clk_get(cpu_dev, "pll2_bus");
> +		if (IS_ERR(pll2_bus_clk))
> +			return PTR_ERR(pll2_bus_clk);
> +
> +		secondary_sel_clk = clk_get(cpu_dev, "secondary_sel");
> +		if (IS_ERR(secondary_sel_clk))
> +			return PTR_ERR(secondary_sel_clk);
> +	}
> +
> +	arm_reg = regulator_get(cpu_dev, "arm");
> +	if (IS_ERR(arm_reg))
> +		return PTR_ERR(arm_reg);
> +
> +	pu_reg = regulator_get_optional(cpu_dev, "pu");
> +
> +	soc_reg = regulator_get(cpu_dev, "soc");
> +	if (IS_ERR(soc_reg))
> +		return PTR_ERR(soc_reg);
> +
> +	return 0;
> +}
> +
[...]

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