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Date:   Fri, 13 May 2022 21:40:30 +0200
From:   Henning Schild <henning.schild@siemens.com>
To:     <linux-kernel@vger.kernel.org>, <linux-leds@vger.kernel.org>,
        <platform-driver-x86@vger.kernel.org>,
        <linux-watchdog@vger.kernel.org>
Cc:     Srikanth Krishnakar <skrishnakar@gmail.com>,
        Jan Kiszka <jan.kiszka@siemens.com>,
        "Gerd Haeussler" <gerd.haeussler.ext@siemens.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        Mark Gross <mgross@linux.intel.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Pavel Machek <pavel@ucw.cz>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Enrico Weigelt <lkml@metux.net>
Subject: Re: [PATCH v5 2/4] leds: simatic-ipc-leds: add new driver for
 Siemens Industial PCs
Message-ID: <20220513214030.7254b1bf@md1za8fc.ad001.siemens.net>
In-Reply-To: <20211213120502.20661-3-henning.schild@siemens.com>
References: <20211213120502.20661-1-henning.schild@siemens.com>
        <20211213120502.20661-3-henning.schild@siemens.com>
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Am Mon, 13 Dec 2021 13:05:00 +0100
schrieb Henning Schild <henning.schild@siemens.com>:

> This driver adds initial support for several devices from Siemens. It
> is based on a platform driver introduced in an earlier commit.
> 
> One of the supported machines has GPIO connected LEDs, here we poke
> GPIO memory directly because pinctrl does not come up.
> 
> Signed-off-by: Henning Schild <henning.schild@siemens.com>
> ---
>  drivers/leds/Kconfig                   |   3 +
>  drivers/leds/Makefile                  |   3 +
>  drivers/leds/simple/Kconfig            |  11 ++
>  drivers/leds/simple/Makefile           |   2 +
>  drivers/leds/simple/simatic-ipc-leds.c | 202
> +++++++++++++++++++++++++ 5 files changed, 221 insertions(+)
>  create mode 100644 drivers/leds/simple/Kconfig
>  create mode 100644 drivers/leds/simple/Makefile
>  create mode 100644 drivers/leds/simple/simatic-ipc-leds.c
> 
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index ed800f5da7d8..ac6688d7a3f4 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -879,4 +879,7 @@ source "drivers/leds/flash/Kconfig"
>  comment "LED Triggers"
>  source "drivers/leds/trigger/Kconfig"
>  
> +comment "Simple LED drivers"
> +source "drivers/leds/simple/Kconfig"
> +
>  endif # NEW_LEDS
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index c636ec069612..1a719caf14c0 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -105,3 +105,6 @@ obj-$(CONFIG_LEDS_TRIGGERS)		+=
> trigger/ 
>  # LED Blink
>  obj-y					+= blink/
> +
> +# Simple LED drivers
> +obj-y					+= simple/
> diff --git a/drivers/leds/simple/Kconfig b/drivers/leds/simple/Kconfig
> new file mode 100644
> index 000000000000..9f6a68336659
> --- /dev/null
> +++ b/drivers/leds/simple/Kconfig
> @@ -0,0 +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 SIEMENS_SIMATIC_IPC

Trying to bring this into distros i think this one should rather be
"select SIEMENS_SIMATIC_IPC" and the same thought goes for wdt.

Users care about enabling a feature and maybe not too much about having
to enable infra, enabling SIEMENS_SIMATIC_IPC is just infra and useless
without LEDS_SIEMENS_SIMATIC_IPC and/or SIEMENS_SIMATIC_IPC_WDT.

So those two should probably "select" and not "depend".

I will send a patch, feel free to tell me that i am wrong and teach me
about how deps should work.

regards,
Henning

> +	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.
> diff --git a/drivers/leds/simple/Makefile
> b/drivers/leds/simple/Makefile new file mode 100644
> index 000000000000..8481f1e9e360
> --- /dev/null
> +++ b/drivers/leds/simple/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0
> +obj-$(CONFIG_LEDS_SIEMENS_SIMATIC_IPC)	+= simatic-ipc-leds.o
> diff --git a/drivers/leds/simple/simatic-ipc-leds.c
> b/drivers/leds/simple/simatic-ipc-leds.c new file mode 100644
> index 000000000000..ff2c96e73241
> --- /dev/null
> +++ b/drivers/leds/simple/simatic-ipc-leds.c
> @@ -0,0 +1,202 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Siemens SIMATIC IPC driver for LEDs
> + *
> + * Copyright (c) Siemens AG, 2018-2021
> + *
> + * Authors:
> + *  Henning Schild <henning.schild@siemens.com>
> + *  Jan Kiszka <jan.kiszka@siemens.com>
> + *  Gerd Haeussler <gerd.haeussler.ext@siemens.com>
> + */
> +
> +#include <linux/ioport.h>
> +#include <linux/kernel.h>
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/platform_data/x86/simatic-ipc-base.h>
> +#include <linux/platform_device.h>
> +#include <linux/sizes.h>
> +#include <linux/spinlock.h>
> +
> +#define SIMATIC_IPC_LED_PORT_BASE	0x404E
> +
> +struct simatic_ipc_led {
> +	unsigned int value; /* mask for io and offset for mem */
> +	char *name;
> +	struct led_classdev cdev;
> +};
> +
> +static struct simatic_ipc_led simatic_ipc_leds_io[] = {
> +	{1 << 15, "green:" LED_FUNCTION_STATUS "-1" },
> +	{1 << 7,  "yellow:" LED_FUNCTION_STATUS "-1" },
> +	{1 << 14, "red:" LED_FUNCTION_STATUS "-2" },
> +	{1 << 6,  "yellow:" LED_FUNCTION_STATUS "-2" },
> +	{1 << 13, "red:" LED_FUNCTION_STATUS "-3" },
> +	{1 << 5,  "yellow:" LED_FUNCTION_STATUS "-3" },
> +	{ }
> +};
> +
> +/* the actual start will be discovered with PCI, 0 is a placeholder
> */ +struct resource simatic_ipc_led_mem_res = DEFINE_RES_MEM_NAMED(0,
> SZ_4K, KBUILD_MODNAME); +
> +static void *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); +
> +static DEFINE_SPINLOCK(reg_lock);
> +
> +static inline struct simatic_ipc_led *cdev_to_led(struct
> led_classdev *led_cd) +{
> +	return container_of(led_cd, struct simatic_ipc_led, cdev);
> +}
> +
> +static void simatic_ipc_led_set_io(struct led_classdev *led_cd,
> +				   enum led_brightness brightness)
> +{
> +	struct simatic_ipc_led *led = cdev_to_led(led_cd);
> +	unsigned long flags;
> +	unsigned int val;
> +
> +	spin_lock_irqsave(&reg_lock, flags);
> +
> +	val = inw(SIMATIC_IPC_LED_PORT_BASE);
> +	if (brightness == LED_OFF)
> +		outw(val | led->value, SIMATIC_IPC_LED_PORT_BASE);
> +	else
> +		outw(val & ~led->value, SIMATIC_IPC_LED_PORT_BASE);
> +
> +	spin_unlock_irqrestore(&reg_lock, flags);
> +}
> +
> +static enum led_brightness simatic_ipc_led_get_io(struct
> led_classdev *led_cd) +{
> +	struct simatic_ipc_led *led = cdev_to_led(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);
> +
> +	u32 *p;
> +
> +	p = simatic_ipc_led_memory + led->value;
> +	*p = (*p & ~1) | (brightness == LED_OFF);
> +}
> +
> +static enum led_brightness simatic_ipc_led_get_mem(struct
> led_classdev *led_cd) +{
> +	struct simatic_ipc_led *led = cdev_to_led(led_cd);
> +
> +	u32 *p;
> +
> +	p = simatic_ipc_led_memory + led->value;
> +	return (*p & 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;
> +	struct device *dev = &pdev->dev;
> +	struct simatic_ipc_led *ipcled;
> +	struct led_classdev *cdev;
> +	struct resource *res;
> +	int err, type;
> +	u32 *p;
> +
> +	switch (plat->devmode) {
> +	case SIMATIC_IPC_DEVICE_227D:
> +	case SIMATIC_IPC_DEVICE_427E:
> +		res = &simatic_ipc_led_io_res;
> +		ipcled = simatic_ipc_leds_io;
> +		/* on 227D the two bytes work the other way araound
> */
> +		if (plat->devmode == SIMATIC_IPC_DEVICE_227D) {
> +			while (ipcled->value) {
> +				ipcled->value =
> swab16(ipcled->value);
> +				ipcled++;
> +			}
> +			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;
> +
> +		/* get GPIO base from PCI */
> +		res->start = simatic_ipc_get_membase0(PCI_DEVFN(13,
> 0));
> +		if (res->start == 0)
> +			return -ENODEV;
> +
> +		/* do the final address calculation */
> +		res->start = res->start + (0xC5 << 16);
> +		res->end += res->start;
> +
> +		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 */
> +		p = simatic_ipc_led_memory + 0x500 + 0x1D8; /*
> PM_WDT_OUT */
> +		*p = (*p & ~1);
> +		p = simatic_ipc_led_memory + 0x500 + 0x1C0; /*
> PM_BIOS_BOOT_N */
> +		*p = (*p | 1);
> +
> +		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->max_brightness = LED_ON;
> +		cdev->name = ipcled->name;
> +
> +		err = devm_led_classdev_register(dev, cdev);
> +		if (err < 0)
> +			return err;
> +		ipcled++;
> +	}
> +
> +	return 0;
> +}
> +
> +static struct platform_driver simatic_ipc_led_driver = {
> +	.probe = simatic_ipc_leds_probe,
> +	.driver = {
> +		.name = KBUILD_MODNAME,
> +	}
> +};
> +
> +module_platform_driver(simatic_ipc_led_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" KBUILD_MODNAME);
> +MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>");