Re: [PATCH v2 2/2] Add PWM fan controller driver for LGM SoC

From: Tanwar, Rahul
Date: Thu Jun 25 2020 - 00:25:07 EST



Hi Philipp,

On 18/6/2020 8:25 pm, Philipp Zabel wrote:
> Hi Rahul,
>
> On Thu, 2020-06-18 at 20:05 +0800, Rahul Tanwar wrote:
>> Intel Lightning Mountain(LGM) SoC contains a PWM fan controller.
>> This PWM controller does not have any other consumer, it is a
>> dedicated PWM controller for fan attached to the system. Add
>> driver for this PWM fan controller.
>>
>> Signed-off-by: Rahul Tanwar <rahul.tanwar@xxxxxxxxxxxxxxx>
>> ---
>> drivers/pwm/Kconfig | 9 +
>> drivers/pwm/Makefile | 1 +
>> drivers/pwm/pwm-intel-lgm.c | 400 ++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 410 insertions(+)
>> create mode 100644 drivers/pwm/pwm-intel-lgm.c
>>
> [...]
>> diff --git a/drivers/pwm/pwm-intel-lgm.c b/drivers/pwm/pwm-intel-lgm.c
>> new file mode 100644
>> index 000000000000..3c7077acb161
>> --- /dev/null
>> +++ b/drivers/pwm/pwm-intel-lgm.c
>> @@ -0,0 +1,400 @@
> [...]
>> +static int lgm_pwm_probe(struct platform_device *pdev)
>> +{
>> + struct lgm_pwm_chip *pc;
>> + struct device *dev = &pdev->dev;
>> + void __iomem *io_base;
>> + int ret;
>> +
>> + pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
>> + if (!pc)
>> + return -ENOMEM;
>> +
>> + io_base = devm_platform_ioremap_resource(pdev, 0);
>> + if (IS_ERR(io_base))
>> + return PTR_ERR(io_base);
>> +
>> + pc->regmap = devm_regmap_init_mmio(dev, io_base, &pwm_regmap_config);
>> + if (IS_ERR(pc->regmap)) {
>> + ret = PTR_ERR(pc->regmap);
>> + dev_err(dev, "failed to init register map: %pe\n", pc->regmap);
>> + return ret;
>> + }
>> +
>> + pc->clk = devm_clk_get(dev, NULL);
>> + if (IS_ERR(pc->clk)) {
>> + ret = PTR_ERR(pc->clk);
>> + dev_err(dev, "failed to get clock: %pe\n", pc->clk);
>> + return ret;
>> + }
>> +
>> + pc->rst = devm_reset_control_get(dev, NULL);
>> + if (IS_ERR(pc->rst)) {
>> + ret = PTR_ERR(pc->rst);
>> + dev_err(dev, "failed to get reset control: %pe\n", pc->rst);
>> + return ret;
>> + }
> Please use devm_reset_control_get_exclusive() to make it explicit an
> that exclusive reset control is requested. Given how the reset control
> is used, I think this driver could also use
> devm_reset_control_get_shared() to potentially allow sharing a reset
> line with other devices.

devm_reset_control_get() is a wrapper for devm_reset_control_get_exclusive().
Code as below:
static inline struct reset_control *devm_reset_control_get(
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct device *dev, const char *id)
{
ÂÂÂÂÂÂÂ return devm_reset_control_get_exclusive(dev, id);
}
Am i missing something else?

Regards,
Rahul