linux-kernel - Re: [PATCH] pinctrl: gpio: vt8500: Add pin control driver for Wondermedia SoCs

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Date:	Wed, 27 Feb 2013 15:21:40 -0700
From:	Stephen Warren <swarren@...dotorg.org>
To:	Tony Prisk <linux@...sktech.co.nz>
CC:	linux-arm-kernel@...ts.infradead.org, grant.likely@...retlab.ca,
	linus.walleij@...aro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] pinctrl: gpio: vt8500: Add pin control driver for Wondermedia
 SoCs

On 02/14/2013 07:48 PM, Tony Prisk wrote:

Sorry for the slow review.

No patch description?

>  arch/arm/Kconfig                   |    4 +-
>  arch/arm/boot/dts/wm8850-w70v2.dts |   15 +
>  arch/arm/boot/dts/wm8850.dtsi      |    7 +-
>  arch/arm/mach-vt8500/Kconfig       |    1 +
>  drivers/pinctrl/Kconfig            |   10 +
>  drivers/pinctrl/Makefile           |    2 +
>  drivers/pinctrl/pinctrl-wm8850.c   |  166 +++++++++++
>  drivers/pinctrl/pinctrl-wmt.c      |  565 ++++++++++++++++++++++++++++++++++++
>  drivers/pinctrl/pinctrl-wmt.h      |   73 +++++

No DT binding documentation?

It doesnt' seem a good idea to add the pinctrl driver and touch the
various DT files in a single patch.


> diff --git a/arch/arm/boot/dts/wm8850.dtsi b/arch/arm/boot/dts/wm8850.dtsi

> +/*
>  		gpio: gpio-controller@...10000 {
>  			compatible = "wm,wm8650-gpio";
>  			gpio-controller;
>  			reg = <0xd8110000 0x10000>;
>  			#gpio-cells = <3>;
>  		};
> +*/
> +		pinmux: pinmux@...10000 {
> +			compatible = "wm,wm8850-gpio";
> +			reg = <0xd8110000 0x10000>;
> +		};

If the old code is wrong, why not delete it? but the main change is just
removing the GPIO-related properties - is the new driver no longer a
GPIO provider, why?

> diff --git a/arch/arm/mach-vt8500/Kconfig b/arch/arm/mach-vt8500/Kconfig

> @@ -29,5 +29,6 @@ config ARCH_WM8850
>  	depends on ARCH_MULTI_V7
>  	select ARCH_VT8500
>  	select CPU_V7
> +	select PINCTRL

Don't you want to select the specific pinctrl driver here too; is it
actually useful for it to be optional?

> diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig

> +config PINCTRL_WM8850
> +	bool "Wondermedia WM8850 pin controller driver"
> +	depends on ARCH_VT8500
> +	select PINCTRL_WMT

If this is user-visible, there should be a description.

> diff --git a/drivers/pinctrl/pinctrl-wm8850.c b/drivers/pinctrl/pinctrl-wm8850.c

> +/* Please keep sorted by bank/bit */
> +#define WMT_PIN_EXTGPIO0	WMT_PIN(0, 0)
> +#define WMT_PIN_EXTGPIO1	WMT_PIN(0, 1)
...
> +#define WMT_PIN_I2C2_SCL	WMT_PIN(5, 12)
> +#define WMT_PIN_I2C2_SDA	WMT_PIN(5, 13)

There are a lot of gaps in that list. Does the HW really not support pin
muxing on the rest of the bits in the registers?

> diff --git a/drivers/pinctrl/pinctrl-wmt.c b/drivers/pinctrl/pinctrl-wmt.c

> +static int wmt_pmx_gpio_set_direction(struct pinctrl_dev *pctldev,
> +				      struct pinctrl_gpio_range *range,
> +				      unsigned offset,
> +				      bool input)
> +{
> +	struct wmt_pinctrl_data *data = pinctrl_dev_get_drvdata(pctldev);
> +#include <linux/pinctrl/consumer.h>

That should be at the top of the file.

> +	wmt_set_pinmux(data, (input ? WMT_FSEL_GPIO_IN : WMT_FSEL_GPIO_OUT),
> +		       offset);

Nit: The inner brackets are redundant.

> +static int wmt_get_groups_count(struct pinctrl_dev *pctldev)
> +{
> +	struct wmt_pinctrl_data *data = pinctrl_dev_get_drvdata(pctldev);
> +
> +	return data->ngroups;
> +}
> +
> +static const char *wmt_get_group_name(struct pinctrl_dev *pctldev,
> +					 unsigned selector)
> +{
> +	struct wmt_pinctrl_data *data = pinctrl_dev_get_drvdata(pctldev);
> +
> +	return data->groups[selector];
> +}

Hmmm. Given there's a 1:1 mapping between pin names and group names, I
wonder if this core driver shouldn't synthesize the array of group names
from the array of pins instead of requiring the per-SoC driver to
duplicate all the pin names in a group array.

Of course, we should probably fix the pinctrl core to allow pin muxing
on pins in addition to groups too. I keep feeling guilty about not
having done that before.

> +static int wmt_pctl_dt_node_to_map_pull(struct wmt_pinctrl_data *data,
...
> +	struct pinctrl_map *map = *maps;
> +
> +
> +	if (pull > 2) {

Nit: redundant blank line there.

> +	configs[0] = 0;

= pull;?

> +static struct gpio_chip wmt_gpio_chip = {
...
> +	.can_sleep = 0,

Nit: No need to set that; 0 is the default for any
not-explicitly-initialized fields.

> +int wmt_pinctrl_probe(struct platform_device *pdev,
...
> +	dev_info(&pdev->dev, "Pin controller initialized\n");

Nit: I'm never really sure that's useful.
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