linux-kernel - Re: [PATCH 1/2] cpufreq: mediatek: Add MT8173 cpufreq driver

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Date:	Thu, 30 Apr 2015 09:42:18 +0200
From:	Sascha Hauer <s.hauer@...gutronix.de>
To:	"pi-cheng.chen" <pi-cheng.chen@...aro.org>
Cc:	Viresh Kumar <viresh.kumar@...aro.org>,
	Mike Turquette <mturquette@...aro.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	"Joe.C" <yingjoe.chen@...iatek.com>,
	Eddie Huang <eddie.huang@...iatek.com>,
	Howard Chen <ibanezchen@...il.com>, fan.chen@...iatek.com,
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	linaro-kernel@...ts.linaro.org, linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH 1/2] cpufreq: mediatek: Add MT8173 cpufreq driver

On Mon, Apr 20, 2015 at 05:27:26PM +0800, pi-cheng.chen wrote:
> This patch implements MT8173 specific cpufreq driver with OPP table defined
> in the driver code.
> 
> Signed-off-by: pi-cheng.chen <pi-cheng.chen@...aro.org>
> ---
>  drivers/cpufreq/Kconfig.arm      |   6 +
>  drivers/cpufreq/Makefile         |   1 +
>  drivers/cpufreq/mt8173-cpufreq.c | 509 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 516 insertions(+)
>  create mode 100644 drivers/cpufreq/mt8173-cpufreq.c
> 
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index 1b06fc4..25643c7 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> +
> +static int mt8173_cpufreq_dvfs_init(struct cpu_dvfs_info *info)
> +{
> +	struct device *cpu_dev;
> +	struct regulator *proc_reg, *sram_reg;
> +	struct clk *cpu_clk, *inter_pll;
> +	unsigned long rate;
> +	int cpu, ret;
> +
> +	cpu = cpumask_first(&info->cpus);
> +
> +try_next_cpu:
> +	cpu_dev = get_cpu_device(cpu);
> +	proc_reg = regulator_get_exclusive(cpu_dev, "proc");
> +	sram_reg = regulator_get_exclusive(cpu_dev, "sram");
> +	cpu_clk = clk_get(cpu_dev, "cpu");
> +	inter_pll = clk_get(cpu_dev, "intermediate");
> +
> +	if (IS_ERR_OR_NULL(proc_reg) || IS_ERR_OR_NULL(cpu_clk) ||
> +	    IS_ERR_OR_NULL(inter_pll)) {
> +		cpu = cpumask_next(cpu, &info->cpus);
> +		if (cpu >= nr_cpu_ids)
> +			return -ENODEV;
> +
> +		goto try_next_cpu;
> +	}

Please keep an eye on the error pathes. This one is quite broken. You
get references to resources here which you never release. Also
-EPROBE_DEFER is a valid return value from regulator_get which is not
handled here.

Also IS_ERR_OR_NULL() is most probably wrong here. Should be IS_ERR().

Sascha

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