leds: simatic-ipc-leds: add new driver for Siemens Industial PCs

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>
Acked-by: Pavel Machek <pavel@ucw.cz>
Link: https://lore.kernel.org/r/20211213120502.20661-3-henning.schild@siemens.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

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

drivers/leds/Makefile

@@ -105,3 +105,6 @@ obj-$(CONFIG_LEDS_TRIGGERS)		+= trigger/
 
 # LED Blink
 obj-y					+= blink/
+
+# Simple LED drivers
+obj-y					+= simple/

drivers/leds/simple/Kconfig

+# 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
+	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.

drivers/leds/simple/Makefile

+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_LEDS_SIEMENS_SIMATIC_IPC)	+= simatic-ipc-leds.o

drivers/leds/simple/simatic-ipc-leds.c

+// 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>");