Re: [PATCH v6 12/12] leds: simatic-ipc-leds-gpio: add GPIO version of Siemens driver

[Henning Schild <henning.schild@siemens.com>]

Am Mon,  6 Jun 2022 19:41:38 +0300
schrieb Andy Shevchenko <andriy.shevchenko@linux.intel.com>:

> From: Henning Schild <henning.schild@siemens.com>
> 
> On Apollo Lake the pinctrl drivers will now come up without ACPI. Use
> that instead of open coding it.
> Create a new driver for that which can later be filled with more GPIO
> based models, and which has different dependencies.
> 
> Signed-off-by: Henning Schild <henning.schild@siemens.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/leds/simple/Kconfig                 |   7 +-
>  drivers/leds/simple/Makefile                |   1 +
>  drivers/leds/simple/simatic-ipc-leds-gpio.c | 105
> ++++++++++++++++++++ drivers/leds/simple/simatic-ipc-leds.c      |
> 80 +-------------- drivers/platform/x86/simatic-ipc.c          |   5
> +- 5 files changed, 117 insertions(+), 81 deletions(-)
>  create mode 100644 drivers/leds/simple/simatic-ipc-leds-gpio.c
> 
> diff --git a/drivers/leds/simple/Kconfig b/drivers/leds/simple/Kconfig
> index bbf8cff3c3f6..fd2b8225d926 100644
> --- a/drivers/leds/simple/Kconfig
> +++ b/drivers/leds/simple/Kconfig
> @@ -1,12 +1,11 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  config LEDS_SIEMENS_SIMATIC_IPC
>  	tristate "LED driver for Siemens Simatic IPCs"
> -	depends on LEDS_CLASS
> +	depends on LEDS_GPIO
>  	depends on SIEMENS_SIMATIC_IPC
> -	select P2SB
>  	help
>  	  This option enables support for the LEDs of several
> Industrial PCs from Siemens.
>  
> -	  To compile this driver as a module, choose M here: the
> module
> -	  will be called simatic-ipc-leds.
> +	  To compile this driver as a module, choose M here: the
> modules
> +	  will be called simatic-ipc-leds and simatic-ipc-leds-gpio.
> diff --git a/drivers/leds/simple/Makefile
> b/drivers/leds/simple/Makefile index 8481f1e9e360..1c7ef5e1324b 100644
> --- a/drivers/leds/simple/Makefile
> +++ b/drivers/leds/simple/Makefile
> @@ -1,2 +1,3 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_LEDS_SIEMENS_SIMATIC_IPC)	+= simatic-ipc-leds.o
> +obj-$(CONFIG_LEDS_SIEMENS_SIMATIC_IPC)	+=
> simatic-ipc-leds-gpio.o diff --git
> a/drivers/leds/simple/simatic-ipc-leds-gpio.c
> b/drivers/leds/simple/simatic-ipc-leds-gpio.c new file mode 100644
> index 000000000000..4c9e663a90ba --- /dev/null
> +++ b/drivers/leds/simple/simatic-ipc-leds-gpio.c
> @@ -0,0 +1,105 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Siemens SIMATIC IPC driver for GPIO based LEDs
> + *
> + * Copyright (c) Siemens AG, 2022
> + *
> + * Authors:
> + *  Henning Schild <henning.schild@siemens.com>
> + */
> +
> +#include <linux/gpio/machine.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +static struct gpiod_lookup_table simatic_ipc_led_gpio_table = {
> +	.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", 56, NULL, 6,
> GPIO_ACTIVE_LOW),
> +		GPIO_LOOKUP_IDX("apollolake-pinctrl.0", 59, 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" },
> +};
> +
> +static const struct gpio_led_platform_data
> simatic_ipc_gpio_leds_pdata = {
> +	.num_leds	= ARRAY_SIZE(simatic_ipc_gpio_leds),
> +	.leds		= simatic_ipc_gpio_leds,
> +};
> +
> +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);
> +	platform_device_unregister(simatic_leds_pdev);
> +
> +	return 0;
> +}
> +
> +static int simatic_ipc_leds_gpio_probe(struct platform_device *pdev)
> +{
> +	struct gpio_desc *gpiod;
> +	int err;
> +
> +	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,
> +		sizeof(simatic_ipc_gpio_leds_pdata));

If those GPIOs can not be found that leads to a pretty severe
logging/polling endless loop.

...
[   34.017017] leds-gpio leds-gpio: Skipping unavailable LED gpio 0 (red:status-2)
[   34.017038] leds-gpio leds-gpio: cannot find GPIO chip apollolake-pinctrl.0, deferring
[   34.017158] leds-gpio leds-gpio: Skipping unavailable LED gpio 0 (red:status-2)
[   34.017161] leds-gpio leds-gpio: cannot find GPIO chip apollolake-pinctrl.0, deferring
[   34.017163] leds-gpio leds-gpio: Skipping unavailable LED gpio 0 (green:status-2)
[   34.017166] leds-gpio leds-gpio: cannot find GPIO chip apollolake-pinctrl.0, deferring
[   34.017168] leds-gpio leds-gpio: Skipping unavailable LED gpio 0 (red:status-3)
[   34.017179] leds-gpio leds-gpio: cannot find GPIO chip apollolake-pinctrl.0, deferring
[   34.017275] leds-gpio leds-gpio: cannot find GPIO chip apollolake-pinctrl.0, deferring
[   34.017279] leds-gpio leds-gpio: Skipping unavailable LED gpio 0 (green:status-3)
... 

This can be seen when the kernel is build without
CONFIG_PINCTRL_BROXTON. Can anyone please give advise on how to proceed
here.

I could do something like i proposed in "[PATCH 3/4] leds:
simatic-ipc-leds-gpio: add new model 227G".

if (!IS_ENABLED(CONFIG_PINCTRL_BROXTON)) return -ENO...

before registering the platform device.

An alternative could be to try and handle that -EPROBE_DEFER but that
might be hard because it might well fail a couple of times before
eventually that gpio driver is up, so i think i will send an update
implementing that !IS_ENABLED.

Ideally the gpio subsystem or leds-gpio would break that
polling/printing loop for me, or make sure it would not happen in the
first place.

regards,
Henning

> +	if (IS_ERR(simatic_leds_pdev)) {
> +		err = PTR_ERR(simatic_leds_pdev);
> +		goto out;
> +	}
> +
> +	/* PM_BIOS_BOOT_N */
> +	gpiod = gpiod_get_index(&simatic_leds_pdev->dev, NULL, 6,
> GPIOD_OUT_LOW);
> +	if (IS_ERR(gpiod)) {
> +		err = PTR_ERR(gpiod);
> +		goto out;
> +	}
> +	gpiod_put(gpiod);
> +
> +	/* PM_WDT_OUT */
> +	gpiod = gpiod_get_index(&simatic_leds_pdev->dev, NULL, 7,
> GPIOD_OUT_LOW);
> +	if (IS_ERR(gpiod)) {
> +		err = PTR_ERR(gpiod);
> +		goto out;
> +	}
> +	gpiod_put(gpiod);
> +
> +	return 0;
> +out:
> +	simatic_ipc_leds_gpio_remove(pdev);
> +
> +	return err;
> +}
> +
> +static struct platform_driver simatic_ipc_led_gpio_driver = {
> +	.probe = simatic_ipc_leds_gpio_probe,
> +	.remove = simatic_ipc_leds_gpio_remove,
> +	.driver = {
> +		.name = KBUILD_MODNAME,
> +	}
> +};
> +module_platform_driver(simatic_ipc_led_gpio_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" KBUILD_MODNAME);
> +MODULE_SOFTDEP("pre: platform:leds-gpio");
> +MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>");
> diff --git a/drivers/leds/simple/simatic-ipc-leds.c
> b/drivers/leds/simple/simatic-ipc-leds.c index
> 2e7597c143d8..4894c228c165 100644 ---
> a/drivers/leds/simple/simatic-ipc-leds.c +++
> b/drivers/leds/simple/simatic-ipc-leds.c @@ -15,7 +15,6 @@
>  #include <linux/leds.h>
>  #include <linux/module.h>
>  #include <linux/pci.h>
> -#include <linux/platform_data/x86/p2sb.h>
>  #include <linux/platform_data/x86/simatic-ipc-base.h>
>  #include <linux/platform_device.h>
>  #include <linux/sizes.h>
> @@ -24,7 +23,7 @@
>  #define SIMATIC_IPC_LED_PORT_BASE	0x404E
>  
>  struct simatic_ipc_led {
> -	unsigned int value; /* mask for io and offset for mem */
> +	unsigned int value; /* mask for io */
>  	char *name;
>  	struct led_classdev cdev;
>  };
> @@ -39,21 +38,6 @@ static struct simatic_ipc_led
> simatic_ipc_leds_io[] = { { }
>  };
>  
> -/* the actual start will be discovered with p2sb, 0 is a placeholder
> */ -static struct resource simatic_ipc_led_mem_res =
> DEFINE_RES_MEM_NAMED(0, 0, KBUILD_MODNAME); -
> -static void __iomem *simatic_ipc_led_memory;
> -
> -static struct simatic_ipc_led simatic_ipc_leds_mem[] = {
> -	{0x500 + 0x1A0, "red:" LED_FUNCTION_STATUS "-1"},
> -	{0x500 + 0x1A8, "green:" LED_FUNCTION_STATUS "-1"},
> -	{0x500 + 0x1C8, "red:" LED_FUNCTION_STATUS "-2"},
> -	{0x500 + 0x1D0, "green:" LED_FUNCTION_STATUS "-2"},
> -	{0x500 + 0x1E0, "red:" LED_FUNCTION_STATUS "-3"},
> -	{0x500 + 0x198, "green:" LED_FUNCTION_STATUS "-3"},
> -	{ }
> -};
> -
>  static struct resource simatic_ipc_led_io_res =
>  	DEFINE_RES_IO_NAMED(SIMATIC_IPC_LED_PORT_BASE, SZ_2,
> KBUILD_MODNAME); 
> @@ -89,28 +73,6 @@ static enum led_brightness
> simatic_ipc_led_get_io(struct led_classdev *led_cd) return
> inw(SIMATIC_IPC_LED_PORT_BASE) & led->value ? LED_OFF :
> led_cd->max_brightness; } 
> -static void simatic_ipc_led_set_mem(struct led_classdev *led_cd,
> -				    enum led_brightness brightness)
> -{
> -	struct simatic_ipc_led *led = cdev_to_led(led_cd);
> -	void __iomem *reg = simatic_ipc_led_memory + led->value;
> -	u32 val;
> -
> -	val = readl(reg);
> -	val = (val & ~1) | (brightness == LED_OFF);
> -	writel(val, reg);
> -}
> -
> -static enum led_brightness simatic_ipc_led_get_mem(struct
> led_classdev *led_cd) -{
> -	struct simatic_ipc_led *led = cdev_to_led(led_cd);
> -	void __iomem *reg = simatic_ipc_led_memory + led->value;
> -	u32 val;
> -
> -	val = readl(reg);
> -	return (val & 1) ? LED_OFF : led_cd->max_brightness;
> -}
> -
>  static int simatic_ipc_leds_probe(struct platform_device *pdev)
>  {
>  	const struct simatic_ipc_platform *plat =
> pdev->dev.platform_data; @@ -118,9 +80,7 @@ static int
> simatic_ipc_leds_probe(struct platform_device *pdev) struct
> simatic_ipc_led *ipcled; struct led_classdev *cdev;
>  	struct resource *res;
> -	void __iomem *reg;
> -	int err, type;
> -	u32 val;
> +	int err;
>  
>  	switch (plat->devmode) {
>  	case SIMATIC_IPC_DEVICE_227D:
> @@ -135,51 +95,19 @@ static int simatic_ipc_leds_probe(struct
> platform_device *pdev) }
>  			ipcled = simatic_ipc_leds_io;
>  		}
> -		type = IORESOURCE_IO;
>  		if (!devm_request_region(dev, res->start,
> resource_size(res), KBUILD_MODNAME)) { dev_err(dev, "Unable to
> register IO resource at %pR\n", res); return -EBUSY;
>  		}
>  		break;
> -	case SIMATIC_IPC_DEVICE_127E:
> -		res = &simatic_ipc_led_mem_res;
> -		ipcled = simatic_ipc_leds_mem;
> -		type = IORESOURCE_MEM;
> -
> -		err = p2sb_bar(NULL, 0, res);
> -		if (err)
> -			return err;
> -
> -		/* do the final address calculation */
> -		res->start = res->start + (0xC5 << 16);
> -		res->end = res->start + SZ_4K - 1;
> -
> -		simatic_ipc_led_memory = devm_ioremap_resource(dev,
> res);
> -		if (IS_ERR(simatic_ipc_led_memory))
> -			return PTR_ERR(simatic_ipc_led_memory);
> -
> -		/* initialize power/watchdog LED */
> -		reg = simatic_ipc_led_memory + 0x500 + 0x1D8; /*
> PM_WDT_OUT */
> -		val = readl(reg);
> -		writel(val & ~1, reg);
> -
> -		reg = simatic_ipc_led_memory + 0x500 + 0x1C0; /*
> PM_BIOS_BOOT_N */
> -		val = readl(reg);
> -		writel(val | 1, reg);
> -		break;
>  	default:
>  		return -ENODEV;
>  	}
>  
>  	while (ipcled->value) {
>  		cdev = &ipcled->cdev;
> -		if (type == IORESOURCE_MEM) {
> -			cdev->brightness_set =
> simatic_ipc_led_set_mem;
> -			cdev->brightness_get =
> simatic_ipc_led_get_mem;
> -		} else {
> -			cdev->brightness_set =
> simatic_ipc_led_set_io;
> -			cdev->brightness_get =
> simatic_ipc_led_get_io;
> -		}
> +		cdev->brightness_set = simatic_ipc_led_set_io;
> +		cdev->brightness_get = simatic_ipc_led_get_io;
>  		cdev->max_brightness = LED_ON;
>  		cdev->name = ipcled->name;
>  
> diff --git a/drivers/platform/x86/simatic-ipc.c
> b/drivers/platform/x86/simatic-ipc.c index 26c35e1660cb..ca3647b751d5
> 100644 --- a/drivers/platform/x86/simatic-ipc.c
> +++ b/drivers/platform/x86/simatic-ipc.c
> @@ -51,6 +51,7 @@ static int register_platform_devices(u32 station_id)
>  {
>  	u8 ledmode = SIMATIC_IPC_DEVICE_NONE;
>  	u8 wdtmode = SIMATIC_IPC_DEVICE_NONE;
> +	char *pdevname = KBUILD_MODNAME "_leds";
>  	int i;
>  
>  	platform_data.devmode = SIMATIC_IPC_DEVICE_NONE;
> @@ -64,10 +65,12 @@ static int register_platform_devices(u32
> station_id) }
>  
>  	if (ledmode != SIMATIC_IPC_DEVICE_NONE) {
> +		if (ledmode == SIMATIC_IPC_DEVICE_127E)
> +			pdevname = KBUILD_MODNAME "_leds_gpio";
>  		platform_data.devmode = ledmode;
>  		ipc_led_platform_device =
>  			platform_device_register_data(NULL,
> -				KBUILD_MODNAME "_leds",
> PLATFORM_DEVID_NONE,
> +				pdevname, PLATFORM_DEVID_NONE,
>  				&platform_data,
>  				sizeof(struct simatic_ipc_platform));
>  		if (IS_ERR(ipc_led_platform_device))