leds: Add driver for PC Engines APU/APU2 LEDs

This patch implements the driver to support the front panel LEDs
for PC Engines APU and APU2 boards.

Signed-off-by: Alan Mizrahi <alan@mizrahi.com.ve>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

drivers/leds/Kconfig

@@ -57,6 +57,16 @@ config LEDS_AAT1290
 	depends on PINCTRL
 	help
 	 This option enables support for the LEDs on the AAT1290.
+config LEDS_APU
+	tristate "Front panel LED support for PC Engines APU/APU2 boards"
+	depends on LEDS_CLASS
+	depends on X86 && DMI
+	help
+	  This driver makes the PC Engines APU/APU2 front panel LEDs
+	  accessible from userspace programs through the LED subsystem.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called leds-apu.
 
 config LEDS_AS3645A
 	tristate "AS3645A LED flash controller support"

drivers/leds/Makefile

@@ -8,6 +8,7 @@ obj-$(CONFIG_LEDS_TRIGGERS)		+= led-triggers.o
 # LED Platform Drivers
 obj-$(CONFIG_LEDS_88PM860X)		+= leds-88pm860x.o
 obj-$(CONFIG_LEDS_AAT1290)		+= leds-aat1290.o
+obj-$(CONFIG_LEDS_APU)			+= leds-apu.o
 obj-$(CONFIG_LEDS_AS3645A)		+= leds-as3645a.o
 obj-$(CONFIG_LEDS_BCM6328)		+= leds-bcm6328.o
 obj-$(CONFIG_LEDS_BCM6358)		+= leds-bcm6358.o

drivers/leds/leds-apu.c

@@ -0,0 +1,278 @@
+/*
+ * drivers/leds/leds-apu.c
+ * Copyright (C) 2017 Alan Mizrahi, alan at mizrahi dot com dot ve
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/dmi.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define APU1_FCH_ACPI_MMIO_BASE 0xFED80000
+#define APU1_FCH_GPIO_BASE      (APU1_FCH_ACPI_MMIO_BASE + 0x01BD)
+#define APU1_LEDON              0x08
+#define APU1_LEDOFF             0xC8
+#define APU1_NUM_GPIO           3
+#define APU1_IOSIZE             sizeof(u8)
+
+#define APU2_FCH_ACPI_MMIO_BASE 0xFED80000
+#define APU2_FCH_GPIO_BASE      (APU2_FCH_ACPI_MMIO_BASE + 0x1500)
+#define APU2_GPIO_BIT_WRITE     22
+#define APU2_APU2_NUM_GPIO      4
+#define APU2_IOSIZE             sizeof(u32)
+
+/* LED access parameters */
+struct apu_param {
+	void __iomem *addr; /* for ioread/iowrite */
+};
+
+/* LED private data */
+struct apu_led_priv {
+	struct led_classdev cdev;
+	struct apu_param param;
+};
+#define cdev_to_priv(c) container_of(c, struct apu_led_priv, cdev)
+
+/* LED profile */
+struct apu_led_profile {
+	const char *name;
+	enum led_brightness brightness;
+	unsigned long offset; /* for devm_ioremap */
+};
+
+/* Supported platform types */
+enum apu_led_platform_types {
+	APU1_LED_PLATFORM,
+	APU2_LED_PLATFORM,
+};
+
+struct apu_led_pdata {
+	struct platform_device *pdev;
+	struct apu_led_priv *pled;
+	const struct apu_led_profile *profile;
+	enum apu_led_platform_types platform;
+	int num_led_instances;
+	int iosize; /* for devm_ioremap() */
+	spinlock_t lock;
+};
+
+static struct apu_led_pdata *apu_led;
+
+static const struct apu_led_profile apu1_led_profile[] = {
+	{ "apu:green:1", LED_ON,  APU1_FCH_GPIO_BASE + 0 * APU1_IOSIZE },
+	{ "apu:green:2", LED_OFF, APU1_FCH_GPIO_BASE + 1 * APU1_IOSIZE },
+	{ "apu:green:3", LED_OFF, APU1_FCH_GPIO_BASE + 2 * APU1_IOSIZE },
+};
+
+static const struct apu_led_profile apu2_led_profile[] = {
+	{ "apu2:green:1", LED_ON,  APU2_FCH_GPIO_BASE + 68 * APU2_IOSIZE },
+	{ "apu2:green:2", LED_OFF, APU2_FCH_GPIO_BASE + 69 * APU2_IOSIZE },
+	{ "apu2:green:3", LED_OFF, APU2_FCH_GPIO_BASE + 70 * APU2_IOSIZE },
+};
+
+static const struct dmi_system_id apu_led_dmi_table[] __initconst = {
+	{
+		.ident = "apu",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "APU")
+		}
+	},
+	{
+		.ident = "apu2",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "PC Engines"),
+			DMI_MATCH(DMI_BOARD_NAME, "APU2")
+		}
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(dmi, apu_led_dmi_table);
+
+static void apu1_led_brightness_set(struct led_classdev *led, enum led_brightness value)
+{
+	struct apu_led_priv *pled = cdev_to_priv(led);
+
+	spin_lock(&apu_led->lock);
+	iowrite8(value ? APU1_LEDON : APU1_LEDOFF, pled->param.addr);
+	spin_unlock(&apu_led->lock);
+}
+
+static void apu2_led_brightness_set(struct led_classdev *led, enum led_brightness value)
+{
+	struct apu_led_priv *pled = cdev_to_priv(led);
+	u32 value_new;
+
+	spin_lock(&apu_led->lock);
+
+	value_new = ioread32(pled->param.addr);
+
+	if (value)
+		value_new &= ~BIT(APU2_GPIO_BIT_WRITE);
+	else
+		value_new |= BIT(APU2_GPIO_BIT_WRITE);
+
+	iowrite32(value_new, pled->param.addr);
+
+	spin_unlock(&apu_led->lock);
+}
+
+static int apu_led_config(struct device *dev, struct apu_led_pdata *apuld)
+{
+	int i;
+	int err;
+
+	apu_led->pled = devm_kzalloc(dev,
+		sizeof(struct apu_led_priv) * apu_led->num_led_instances,
+		GFP_KERNEL);
+
+	if (!apu_led->pled)
+		return -ENOMEM;
+
+	for (i = 0; i < apu_led->num_led_instances; i++) {
+		struct apu_led_priv *pled = &apu_led->pled[i];
+		struct led_classdev *led_cdev = &pled->cdev;
+
+		led_cdev->name = apu_led->profile[i].name;
+		led_cdev->brightness = apu_led->profile[i].brightness;
+		led_cdev->max_brightness = 1;
+		led_cdev->flags = LED_CORE_SUSPENDRESUME;
+		if (apu_led->platform == APU1_LED_PLATFORM)
+			led_cdev->brightness_set = apu1_led_brightness_set;
+		else if (apu_led->platform == APU2_LED_PLATFORM)
+			led_cdev->brightness_set = apu2_led_brightness_set;
+
+		pled->param.addr = devm_ioremap(dev,
+				apu_led->profile[i].offset, apu_led->iosize);
+		if (!pled->param.addr) {
+			err = -ENOMEM;
+			goto error;
+		}
+
+		err = led_classdev_register(dev, led_cdev);
+		if (err)
+			goto error;
+
+		led_cdev->brightness_set(led_cdev, apu_led->profile[i].brightness);
+	}
+
+	return 0;
+
+error:
+	while (i-- > 0)
+		led_classdev_unregister(&apu_led->pled[i].cdev);
+
+	return err;
+}
+
+static int __init apu_led_probe(struct platform_device *pdev)
+{
+	apu_led = devm_kzalloc(&pdev->dev, sizeof(*apu_led), GFP_KERNEL);
+
+	if (!apu_led)
+		return -ENOMEM;
+
+	apu_led->pdev = pdev;
+
+	if (dmi_match(DMI_BOARD_NAME, "APU")) {
+		apu_led->profile = apu1_led_profile;
+		apu_led->platform = APU1_LED_PLATFORM;
+		apu_led->num_led_instances = ARRAY_SIZE(apu1_led_profile);
+		apu_led->iosize = APU1_IOSIZE;
+	} else if (dmi_match(DMI_BOARD_NAME, "APU2")) {
+		apu_led->profile = apu2_led_profile;
+		apu_led->platform = APU2_LED_PLATFORM;
+		apu_led->num_led_instances = ARRAY_SIZE(apu2_led_profile);
+		apu_led->iosize = APU2_IOSIZE;
+	}
+
+	spin_lock_init(&apu_led->lock);
+	return apu_led_config(&pdev->dev, apu_led);
+}
+
+static struct platform_driver apu_led_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+	},
+};
+
+static int __init apu_led_init(void)
+{
+	struct platform_device *pdev;
+	int err;
+
+	if (!dmi_match(DMI_SYS_VENDOR, "PC Engines")) {
+		pr_err("No PC Engines board detected\n");
+		return -ENODEV;
+	}
+	if (!(dmi_match(DMI_PRODUCT_NAME, "APU") || dmi_match(DMI_PRODUCT_NAME, "APU2"))) {
+		pr_err("Unknown PC Engines board: %s\n",
+				dmi_get_system_info(DMI_PRODUCT_NAME));
+		return -ENODEV;
+	}
+
+	pdev = platform_device_register_simple(KBUILD_MODNAME, -1, NULL, 0);
+	if (IS_ERR(pdev)) {
+		pr_err("Device allocation failed\n");
+		return PTR_ERR(pdev);
+	}
+
+	err = platform_driver_probe(&apu_led_driver, apu_led_probe);
+	if (err) {
+		pr_err("Probe platform driver failed\n");
+		platform_device_unregister(pdev);
+	}
+
+	return err;
+}
+
+static void __exit apu_led_exit(void)
+{
+	int i;
+
+	for (i = 0; i < apu_led->num_led_instances; i++)
+		led_classdev_unregister(&apu_led->pled[i].cdev);
+
+	platform_device_unregister(apu_led->pdev);
+	platform_driver_unregister(&apu_led_driver);
+}
+
+module_init(apu_led_init);
+module_exit(apu_led_exit);
+
+MODULE_AUTHOR("Alan Mizrahi");
+MODULE_DESCRIPTION("PC Engines APU family LED driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:leds_apu");