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Date:   Thu, 14 Jul 2022 14:06:03 +0200
From:   Henning Schild <henning.schild@siemens.com>
To:     <linux-kernel@vger.kernel.org>, <linux-gpio@vger.kernel.org>,
        "Bartosz Golaszewski" <brgl@bgdev.pl>,
        Linus Walleij <linus.walleij@linaro.org>,
        Tasanakorn Phaipool <tasanakorn@gmail.com>,
        Pavel Machek <pavel@ucw.cz>
Cc:     Sheng-Yuan Huang <syhuang3@nuvoton.com>,
        Kuan-Wei Ho <cwho@nuvoton.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>
Subject: Re: [PATCH v3 2/3] leds: simatic-ipc-leds-gpio: add new model 227G
Message-ID: <20220714140603.3a38ff50@md1za8fc.ad001.siemens.net>
In-Reply-To: <20220712143237.13992-3-henning.schild@siemens.com>
References: <20220712143237.13992-1-henning.schild@siemens.com>
        <20220712143237.13992-3-henning.schild@siemens.com>
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Am Tue, 12 Jul 2022 16:32:36 +0200
schrieb Henning Schild <henning.schild@siemens.com>:

> This adds support of the Siemens Simatic IPC227G. Its LEDs are
> connected to GPIO pins provided by the gpio_nct6116d module. We make
> sure that gets loaded, if not enabled in the kernel config no LED
> support will be available.
> 
> Signed-off-by: Henning Schild <henning.schild@siemens.com>
> ---
>  drivers/leds/simple/simatic-ipc-leds-gpio.c   | 42
> ++++++++++++++++--- drivers/platform/x86/simatic-ipc.c            |
> 4 +- .../platform_data/x86/simatic-ipc-base.h      |  1 +
>  include/linux/platform_data/x86/simatic-ipc.h |  1 +
>  4 files changed, 42 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/leds/simple/simatic-ipc-leds-gpio.c
> b/drivers/leds/simple/simatic-ipc-leds-gpio.c index
> 4c9e663a90ba..2931e2e2dcd4 100644 ---
> a/drivers/leds/simple/simatic-ipc-leds-gpio.c +++
> b/drivers/leds/simple/simatic-ipc-leds-gpio.c @@ -13,28 +13,45 @@
>  #include <linux/leds.h>
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
> +#include <linux/platform_data/x86/simatic-ipc-base.h>
>  
> -static struct gpiod_lookup_table simatic_ipc_led_gpio_table = {
> +struct gpiod_lookup_table *simatic_ipc_led_gpio_table;
> +
> +static struct gpiod_lookup_table simatic_ipc_led_gpio_table_127e = {
>  	.dev_id = "leds-gpio",
>  	.table = {
> -		GPIO_LOOKUP_IDX("apollolake-pinctrl.0", 51, NULL, 0,
> GPIO_ACTIVE_LOW), GPIO_LOOKUP_IDX("apollolake-pinctrl.0", 52, NULL,
> 1, GPIO_ACTIVE_LOW), GPIO_LOOKUP_IDX("apollolake-pinctrl.0", 53,
> NULL, 2, GPIO_ACTIVE_LOW), GPIO_LOOKUP_IDX("apollolake-pinctrl.0",
> 57, NULL, 3, GPIO_ACTIVE_LOW),
> GPIO_LOOKUP_IDX("apollolake-pinctrl.0", 58, NULL, 4,
> GPIO_ACTIVE_LOW), GPIO_LOOKUP_IDX("apollolake-pinctrl.0", 60, NULL,
> 5, GPIO_ACTIVE_LOW),
> +		GPIO_LOOKUP_IDX("apollolake-pinctrl.0", 51, NULL, 0,
> GPIO_ACTIVE_LOW), GPIO_LOOKUP_IDX("apollolake-pinctrl.0", 56, NULL,
> 6, GPIO_ACTIVE_LOW), GPIO_LOOKUP_IDX("apollolake-pinctrl.0", 59,
> NULL, 7, GPIO_ACTIVE_HIGH), },
>  };
>  
> +static struct gpiod_lookup_table simatic_ipc_led_gpio_table_227g = {
> +	.dev_id = "leds-gpio",
> +	.table = {
> +		GPIO_LOOKUP_IDX("gpio_nct6116d-2", 0, NULL, 0,
> GPIO_ACTIVE_LOW),
> +		GPIO_LOOKUP_IDX("gpio_nct6116d-2", 1, NULL, 1,
> GPIO_ACTIVE_LOW),
> +		GPIO_LOOKUP_IDX("gpio_nct6116d-2", 2, NULL, 2,
> GPIO_ACTIVE_LOW),
> +		GPIO_LOOKUP_IDX("gpio_nct6116d-2", 3, NULL, 3,
> GPIO_ACTIVE_LOW),
> +		GPIO_LOOKUP_IDX("gpio_nct6116d-2", 4, NULL, 4,
> GPIO_ACTIVE_LOW),
> +		GPIO_LOOKUP_IDX("gpio_nct6116d-2", 5, NULL, 5,
> GPIO_ACTIVE_LOW),
> +		GPIO_LOOKUP_IDX("gpio_nct6116d-2", 6, NULL, 6,
> GPIO_ACTIVE_LOW),
> +		GPIO_LOOKUP_IDX("gpio_nct6116d-3", 6, NULL, 7,
> GPIO_ACTIVE_HIGH),
> +	}
> +};
> +
>  static const struct gpio_led simatic_ipc_gpio_leds[] = {
> -	{ .name = "green:" LED_FUNCTION_STATUS "-3" },
>  	{ .name = "red:" LED_FUNCTION_STATUS "-1" },
>  	{ .name = "green:" LED_FUNCTION_STATUS "-1" },
>  	{ .name = "red:" LED_FUNCTION_STATUS "-2" },
>  	{ .name = "green:" LED_FUNCTION_STATUS "-2" },
>  	{ .name = "red:" LED_FUNCTION_STATUS "-3" },
> +	{ .name = "green:" LED_FUNCTION_STATUS "-3" },
>  };
>  
>  static const struct gpio_led_platform_data
> simatic_ipc_gpio_leds_pdata = { @@ -46,7 +63,7 @@ static struct
> platform_device *simatic_leds_pdev; 
>  static int simatic_ipc_leds_gpio_remove(struct platform_device *pdev)
>  {
> -	gpiod_remove_lookup_table(&simatic_ipc_led_gpio_table);
> +	gpiod_remove_lookup_table(simatic_ipc_led_gpio_table);
>  	platform_device_unregister(simatic_leds_pdev);
>  
>  	return 0;
> @@ -54,10 +71,25 @@ static int simatic_ipc_leds_gpio_remove(struct
> platform_device *pdev) 
>  static int simatic_ipc_leds_gpio_probe(struct platform_device *pdev)
>  {
> +	const struct simatic_ipc_platform *plat =
> pdev->dev.platform_data; struct gpio_desc *gpiod;
>  	int err;
>  
> -	gpiod_add_lookup_table(&simatic_ipc_led_gpio_table);
> +	switch (plat->devmode) {
> +	case SIMATIC_IPC_DEVICE_127E:
> +		simatic_ipc_led_gpio_table =
> &simatic_ipc_led_gpio_table_127e;
> +		break;
> +	case SIMATIC_IPC_DEVICE_227G:
> +		if (!IS_ENABLED(CONFIG_GPIO_NCT6116D))
> +			return -ENOTSUPP;
> +		request_module("gpio_nct6116d");

When i did send v3 i wanted to point attention mainly to this here and
get an opinion on that.

Here i am in a context where i already know exactly which board i am
on. Now i need to bring up my gpio before putting those LEDs on top.

I meanwhile managed to add the chip nct6116d into gpio/gpio-f7188x.c,
which i think looks better and is significantly less code. Easier to
maintain hopefully, but less strict separation of concerns. With a
Fintec driver driving a Nuvoton chip ... no matter how very similar
they are, some people might have objections. I will send the code in a
few days so we can discuss.

But be it in that existing gpio driver or in a new one, the need to init
that one from here or the simatic-platform will remain. And for hwmon
and watchdog i plan to use the same "request_module" trick.

Only here it is guarded by an IS_ENABLED because the feature is not
optional, it is needed for LEDs. And for watchdog i just request the
module ... so it comes up should it be configured into the kernel.

checkpatch did not like ENOTSUPP, happy to take suggestions on a better
error code to say "LEDs can only work when GPIO is enabled ... and
probed"

regards,
Henning

> +		simatic_ipc_led_gpio_table =
> &simatic_ipc_led_gpio_table_227g;
> +		break;
> +	default:
> +		return -ENODEV;
> +	}
> +
> +	gpiod_add_lookup_table(simatic_ipc_led_gpio_table);
>  	simatic_leds_pdev = platform_device_register_resndata(NULL,
>  		"leds-gpio", PLATFORM_DEVID_NONE, NULL, 0,
>  		&simatic_ipc_gpio_leds_pdata,
> diff --git a/drivers/platform/x86/simatic-ipc.c
> b/drivers/platform/x86/simatic-ipc.c index ca3647b751d5..1825ef21a86d
> 100644 --- a/drivers/platform/x86/simatic-ipc.c
> +++ b/drivers/platform/x86/simatic-ipc.c
> @@ -41,6 +41,7 @@ static struct {
>  	{SIMATIC_IPC_IPC127E, SIMATIC_IPC_DEVICE_127E,
> SIMATIC_IPC_DEVICE_NONE}, {SIMATIC_IPC_IPC227D,
> SIMATIC_IPC_DEVICE_227D, SIMATIC_IPC_DEVICE_NONE},
> {SIMATIC_IPC_IPC227E, SIMATIC_IPC_DEVICE_427E,
> SIMATIC_IPC_DEVICE_227E},
> +	{SIMATIC_IPC_IPC227G, SIMATIC_IPC_DEVICE_227G,
> SIMATIC_IPC_DEVICE_NONE}, {SIMATIC_IPC_IPC277E,
> SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_227E},
> {SIMATIC_IPC_IPC427D, SIMATIC_IPC_DEVICE_427E,
> SIMATIC_IPC_DEVICE_NONE}, {SIMATIC_IPC_IPC427E,
> SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_427E}, @@ -65,7 +66,8 @@
> static int register_platform_devices(u32 station_id) } 
>  	if (ledmode != SIMATIC_IPC_DEVICE_NONE) {
> -		if (ledmode == SIMATIC_IPC_DEVICE_127E)
> +		if (ledmode == SIMATIC_IPC_DEVICE_127E ||
> +		    ledmode == SIMATIC_IPC_DEVICE_227G)
>  			pdevname = KBUILD_MODNAME "_leds_gpio";
>  		platform_data.devmode = ledmode;
>  		ipc_led_platform_device =
> diff --git a/include/linux/platform_data/x86/simatic-ipc-base.h
> b/include/linux/platform_data/x86/simatic-ipc-base.h index
> 39fefd48cf4d..57d6a10dfc9e 100644 ---
> a/include/linux/platform_data/x86/simatic-ipc-base.h +++
> b/include/linux/platform_data/x86/simatic-ipc-base.h @@ -19,6 +19,7 @@
>  #define SIMATIC_IPC_DEVICE_427E 2
>  #define SIMATIC_IPC_DEVICE_127E 3
>  #define SIMATIC_IPC_DEVICE_227E 4
> +#define SIMATIC_IPC_DEVICE_227G 5
>  
>  struct simatic_ipc_platform {
>  	u8	devmode;
> diff --git a/include/linux/platform_data/x86/simatic-ipc.h
> b/include/linux/platform_data/x86/simatic-ipc.h index
> f3b76b39776b..7a2e79f3be0b 100644 ---
> a/include/linux/platform_data/x86/simatic-ipc.h +++
> b/include/linux/platform_data/x86/simatic-ipc.h @@ -31,6 +31,7 @@
> enum simatic_ipc_station_ids { SIMATIC_IPC_IPC427E = 0x00000A01,
>  	SIMATIC_IPC_IPC477E = 0x00000A02,
>  	SIMATIC_IPC_IPC127E = 0x00000D01,
> +	SIMATIC_IPC_IPC227G = 0x00000F01,
>  };
>  
>  static inline u32 simatic_ipc_get_station_id(u8 *data, int max_len)