Re: [linux-sunxi] [PATCH 2/5] pwm: Add Allwinner A31 SoC support

Re: [linux-sunxi] [PATCH 2/5] pwm: Add Allwinner A31 SoC support

[LABBE Corentin]

Hello

I have a minor comment below

On Tue, Oct 11, 2016 at 02:34:46PM +0800, Icenowy Zheng wrote:
> This adds a generic PWM framework driver for the PWM controller found
> on Allwinner A31 and A31s SoCs.
> 
> The PWM controller is different with other Allwinner SoCs, with a
> control register per channel (in other SoCs the control register is
> shared), and each channel are allocated 16 bytes of address (but only 8
> bytes are used.)
> 
> In order to use the driver for all channels, device nodes should be
> created per channel.
> 
> Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
> ---
>  drivers/pwm/Kconfig     |  10 ++
>  drivers/pwm/Makefile    |   1 +
>  drivers/pwm/pwm-sun6i.c | 323 ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 334 insertions(+)
>  create mode 100644 drivers/pwm/pwm-sun6i.c
> 
> +
> +static int sun6i_pwm_probe(struct platform_device *pdev)
> +{
> +	struct sun6i_pwm_chip *pwm;
> +	struct resource *res;
> +	u32 val;
> +	int ret;
> +	const struct of_device_id *match;
> +
> +	match = of_match_device(sun6i_pwm_dt_ids, &pdev->dev);

match is not used after.

Regards

Corentin Labbe

Re: [PATCH 2/5] pwm: Add Allwinner A31 SoC support

[Maxime Ripard]

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Hi,

On Tue, Oct 11, 2016 at 02:34:46PM +0800, Icenowy Zheng wrote:
> This adds a generic PWM framework driver for the PWM controller found
> on Allwinner A31 and A31s SoCs.
> 
> The PWM controller is different with other Allwinner SoCs, with a
> control register per channel (in other SoCs the control register is
> shared), and each channel are allocated 16 bytes of address (but only 8
> bytes are used.)
> 
> In order to use the driver for all channels, device nodes should be
> created per channel.

I don't think there's any need for a new driver that duplicates most
of the logic. The bitfields look roughly the same, and the only
difference is the split difference.

This is something that can easily be handled without creating a new
driver using regmap's reg_field, or through an intermediate functino
that returns the register offset.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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