leds: Add user LED driver for NIC78bx device

Add the driver to support User LEDs on PXI Embedded Controller.

Signed-off-by: Hui Chun Ong <[e-mail]>
Signed-off-by: Brad Mouring <[e-mail]>
Acked-by: Mika Westerberg <[e-mail]>
Signed-off-by: Jacek Anaszewski <[e-mail]>

drivers/leds/Kconfig

···
 	  support in kernel. To compile this driver as a module, choose 'm' here:
 	  the module will be called uleds.
 
+config LEDS_NIC78BX
+	tristate "LED support for NI PXI NIC78bx devices"
+	depends on LEDS_CLASS
+	depends on X86 && ACPI
+	help
+	  This option enables support for the User1 and User2 LEDs on NI
+	  PXI NIC78bx devices.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called leds-nic78bx.
+
 comment "LED Triggers"
 source "drivers/leds/trigger/Kconfig"
 

drivers/leds/Makefile

···
 obj-$(CONFIG_LEDS_IS31FL32XX)		+= leds-is31fl32xx.o
 obj-$(CONFIG_LEDS_PM8058)		+= leds-pm8058.o
 obj-$(CONFIG_LEDS_MLXCPLD)		+= leds-mlxcpld.o
+obj-$(CONFIG_LEDS_NIC78BX)		+= leds-nic78bx.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o

drivers/leds/leds-nic78bx.c

···
+/*
+ * Copyright (C) 2016 National Instruments Corp.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/acpi.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#define NIC78BX_USER1_LED_MASK		0x3
+#define NIC78BX_USER1_GREEN_LED		BIT(0)
+#define NIC78BX_USER1_YELLOW_LED	BIT(1)
+
+#define NIC78BX_USER2_LED_MASK		0xC
+#define NIC78BX_USER2_GREEN_LED		BIT(2)
+#define NIC78BX_USER2_YELLOW_LED	BIT(3)
+
+#define NIC78BX_LOCK_REG_OFFSET		1
+#define NIC78BX_LOCK_VALUE		0xA5
+#define NIC78BX_UNLOCK_VALUE		0x5A
+
+#define NIC78BX_USER_LED_IO_SIZE	2
+
+struct nic78bx_led_data {
+	u16 io_base;
+	spinlock_t lock;
+	struct platform_device *pdev;
+};
+
+struct nic78bx_led {
+	u8 bit;
+	u8 mask;
+	struct nic78bx_led_data *data;
+	struct led_classdev cdev;
+};
+
+static inline struct nic78bx_led *to_nic78bx_led(struct led_classdev *cdev)
+{
+	return container_of(cdev, struct nic78bx_led, cdev);
+}
+
+static void nic78bx_brightness_set(struct led_classdev *cdev,
+				  enum led_brightness brightness)
+{
+	struct nic78bx_led *nled = to_nic78bx_led(cdev);
+	unsigned long flags;
+	u8 value;
+
+	spin_lock_irqsave(&nled->data->lock, flags);
+	value = inb(nled->data->io_base);
+
+	if (brightness) {
+		value &= ~nled->mask;
+		value |= nled->bit;
+	} else {
+		value &= ~nled->bit;
+	}
+
+	outb(value, nled->data->io_base);
+	spin_unlock_irqrestore(&nled->data->lock, flags);
+}
+
+static enum led_brightness nic78bx_brightness_get(struct led_classdev *cdev)
+{
+	struct nic78bx_led *nled = to_nic78bx_led(cdev);
+	unsigned long flags;
+	u8 value;
+
+	spin_lock_irqsave(&nled->data->lock, flags);
+	value = inb(nled->data->io_base);
+	spin_unlock_irqrestore(&nled->data->lock, flags);
+
+	return (value & nled->bit) ? 1 : LED_OFF;
+}
+
+static struct nic78bx_led nic78bx_leds[] = {
+	{
+		.bit = NIC78BX_USER1_GREEN_LED,
+		.mask = NIC78BX_USER1_LED_MASK,
+		.cdev = {
+			.name = "nilrt:green:user1",
+			.max_brightness = 1,
+			.brightness_set = nic78bx_brightness_set,
+			.brightness_get = nic78bx_brightness_get,
+		}
+	},
+	{
+		.bit = NIC78BX_USER1_YELLOW_LED,
+		.mask = NIC78BX_USER1_LED_MASK,
+		.cdev = {
+			.name = "nilrt:yellow:user1",
+			.max_brightness = 1,
+			.brightness_set = nic78bx_brightness_set,
+			.brightness_get = nic78bx_brightness_get,
+		}
+	},
+	{
+		.bit = NIC78BX_USER2_GREEN_LED,
+		.mask = NIC78BX_USER2_LED_MASK,
+		.cdev = {
+			.name = "nilrt:green:user2",
+			.max_brightness = 1,
+			.brightness_set = nic78bx_brightness_set,
+			.brightness_get = nic78bx_brightness_get,
+		}
+	},
+	{
+		.bit = NIC78BX_USER2_YELLOW_LED,
+		.mask = NIC78BX_USER2_LED_MASK,
+		.cdev = {
+			.name = "nilrt:yellow:user2",
+			.max_brightness = 1,
+			.brightness_set = nic78bx_brightness_set,
+			.brightness_get = nic78bx_brightness_get,
+		}
+	}
+};
+
+static int nic78bx_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct nic78bx_led_data *led_data;
+	struct resource *io_rc;
+	int ret, i;
+
+	led_data = devm_kzalloc(dev, sizeof(*led_data), GFP_KERNEL);
+	if (!led_data)
+		return -ENOMEM;
+
+	led_data->pdev = pdev;
+	platform_set_drvdata(pdev, led_data);
+
+	io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
+	if (!io_rc) {
+		dev_err(dev, "missing IO resources\n");
+		return -EINVAL;
+	}
+
+	if (resource_size(io_rc) < NIC78BX_USER_LED_IO_SIZE) {
+		dev_err(dev, "IO region too small\n");
+		return -EINVAL;
+	}
+
+	if (!devm_request_region(dev, io_rc->start, resource_size(io_rc),
+				 KBUILD_MODNAME)) {
+		dev_err(dev, "failed to get IO region\n");
+		return -EBUSY;
+	}
+
+	led_data->io_base = io_rc->start;
+	spin_lock_init(&led_data->lock);
+
+	for (i = 0; i < ARRAY_SIZE(nic78bx_leds); i++) {
+		nic78bx_leds[i].data = led_data;
+
+		ret = devm_led_classdev_register(dev, &nic78bx_leds[i].cdev);
+		if (ret)
+			return ret;
+	}
+
+	/* Unlock LED register */
+	outb(NIC78BX_UNLOCK_VALUE,
+	     led_data->io_base + NIC78BX_LOCK_REG_OFFSET);
+
+	return ret;
+}
+
+static int nic78bx_remove(struct platform_device *pdev)
+{
+	struct nic78bx_led_data *led_data = platform_get_drvdata(pdev);
+
+	/* Lock LED register */
+	outb(NIC78BX_LOCK_VALUE,
+	     led_data->io_base + NIC78BX_LOCK_REG_OFFSET);
+
+	return 0;
+}
+
+static const struct acpi_device_id led_device_ids[] = {
+	{"NIC78B3", 0},
+	{"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, led_device_ids);
+
+static struct platform_driver led_driver = {
+	.probe = nic78bx_probe,
+	.remove = nic78bx_remove,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.acpi_match_table = ACPI_PTR(led_device_ids),
+	},
+};
+
+module_platform_driver(led_driver);
+
+MODULE_DESCRIPTION("National Instruments PXI User LEDs driver");
+MODULE_AUTHOR("Hui Chun Ong <[e-mail]>");
+MODULE_LICENSE("GPL");