[PATCH] leds: Add user LED driver for NIC78bx device

[Hui Chun Ong <hui.chun.ong@ni.com>]

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

Signed-off-by: Hui Chun Ong <hui.chun.ong@ni.com>
Signed-off-by: Brad Mouring <brad.mouring@ni.com>
---
 drivers/leds/Kconfig       |  11 +++
 drivers/leds/Makefile      |   1 +
 drivers/leds/leds-ni78bx.c | 210 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 222 insertions(+)
 create mode 100644 drivers/leds/leds-ni78bx.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 7a628c6..5540795 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -659,6 +659,17 @@ config LEDS_MLXCPLD
 	  This option enabled support for the LEDs on the Mellanox
 	  boards. Say Y to enabled these.
 
+config LEDS_NI78BX
+	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-ni78bx.
+
 comment "LED Triggers"
 source "drivers/leds/trigger/Kconfig"
 
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 3965070..9758d1e 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -71,6 +71,7 @@ obj-$(CONFIG_LEDS_IS31FL319X)		+= leds-is31fl319x.o
 obj-$(CONFIG_LEDS_IS31FL32XX)		+= leds-is31fl32xx.o
 obj-$(CONFIG_LEDS_PM8058)		+= leds-pm8058.o
 obj-$(CONFIG_LEDS_MLXCPLD)		+= leds-mlxcpld.o
+obj-$(CONFIG_LEDS_NI78BX)		+= leds-ni78bx.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o
diff --git a/drivers/leds/leds-ni78bx.c b/drivers/leds/leds-ni78bx.c
new file mode 100644
index 0000000..3da4675
--- /dev/null
+++ b/drivers/leds/leds-ni78bx.c
@@ -0,0 +1,210 @@
+/*
+ * 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/mutex.h>
+
+#define USER1_LED_MASK		0x3
+#define USER1_GREEN_LED		BIT(0)
+#define USER1_YELLOW_LED	BIT(1)
+
+#define USER2_LED_MASK		0xC
+#define USER2_GREEN_LED		BIT(2)
+#define USER2_YELLOW_LED	BIT(3)
+
+#define LOCK_REG_OFFSET		1
+#define LOCK_VALUE		0xA5
+#define UNLOCK_VALUE		0x5A
+
+#define USER_LED_IO_SIZE	2
+
+static u16 io_base;
+static DEFINE_MUTEX(led_lock);
+
+struct ni78bx_led {
+	u8 bit;
+	u8 mask;
+	struct led_classdev cdev;
+};
+
+static inline struct ni78bx_led *to_ni78bx_led(struct led_classdev *cdev)
+{
+	return container_of(cdev, struct ni78bx_led, cdev);
+}
+
+static void ni78bx_brightness_set(struct led_classdev *cdev,
+				  enum led_brightness brightness)
+{
+	struct ni78bx_led *nled = to_ni78bx_led(cdev);
+	u8 value;
+
+	mutex_lock(&led_lock);
+
+	value = inb(io_base);
+
+	if (brightness) {
+		value &= ~nled->mask;
+		value |= nled->bit;
+	} else {
+		value &= ~nled->bit;
+	}
+
+	outb(value, io_base);
+	mutex_unlock(&led_lock);
+}
+
+static enum led_brightness ni78bx_brightness_get(struct led_classdev *cdev)
+{
+	struct ni78bx_led *nled = to_ni78bx_led(cdev);
+	u8 value;
+
+	mutex_lock(&led_lock);
+	value = inb(io_base);
+	mutex_unlock(&led_lock);
+
+	return (value & nled->bit) ? 1 : LED_OFF;
+}
+
+static struct ni78bx_led ni78bx_leds[] = {
+	{
+		.bit = USER1_GREEN_LED,
+		.mask = USER1_LED_MASK,
+		.cdev = {
+			.name = "nilrt:green:user1",
+			.max_brightness = 1,
+			.brightness_set = ni78bx_brightness_set,
+			.brightness_get = ni78bx_brightness_get,
+		}
+	},
+	{
+		.bit = USER1_YELLOW_LED,
+		.mask = USER1_LED_MASK,
+		.cdev = {
+			.name = "nilrt:yellow:user1",
+			.max_brightness = 1,
+			.brightness_set = ni78bx_brightness_set,
+			.brightness_get = ni78bx_brightness_get,
+		}
+	},
+	{
+		.bit = USER2_GREEN_LED,
+		.mask = USER2_LED_MASK,
+		.cdev = {
+			.name = "nilrt:green:user2",
+			.max_brightness = 1,
+			.brightness_set = ni78bx_brightness_set,
+			.brightness_get = ni78bx_brightness_get,
+		}
+	},
+	{
+		.bit = USER2_YELLOW_LED,
+		.mask = USER2_LED_MASK,
+		.cdev = {
+			.name = "nilrt:yellow:user2",
+			.max_brightness = 1,
+			.brightness_set = ni78bx_brightness_set,
+			.brightness_get = ni78bx_brightness_get,
+		}
+	}
+};
+
+static acpi_status
+ni78bx_resources(struct acpi_resource *res, void *data)
+{
+	struct acpi_device *led = data;
+	u16 io_size;
+
+	switch (res->type) {
+	case ACPI_RESOURCE_TYPE_IO:
+		if (io_base != 0) {
+			dev_err(&led->dev, "too many IO resources\n");
+			return AE_ERROR;
+		}
+
+		io_base = res->data.io.minimum;
+		io_size = res->data.io.address_length;
+
+		if (io_size < USER_LED_IO_SIZE) {
+			dev_err(&led->dev, "memory region too small\n");
+			return AE_ERROR;
+		}
+
+		if (!devm_request_region(&led->dev, io_base, io_size,
+					 KBUILD_MODNAME)) {
+			dev_err(&led->dev, "failed to get memory region\n");
+			return AE_ERROR;
+		}
+
+		return AE_OK;
+
+	default:
+		/* Ignore unsupported resources */
+		return AE_OK;
+	}
+}
+
+static int ni78bx_remove(struct acpi_device *pdev)
+{
+	/* Lock LED register */
+	outb(LOCK_VALUE, io_base + LOCK_REG_OFFSET);
+
+	return 0;
+}
+
+static int ni78bx_add(struct acpi_device *pdev)
+{
+	int ret, i;
+	acpi_status status;
+
+	status = acpi_walk_resources(pdev->handle, METHOD_NAME__CRS,
+				     ni78bx_resources, pdev);
+
+	if (ACPI_FAILURE(status) || io_base == 0)
+		return -ENODEV;
+
+	/* Unlock LED register */
+	outb(UNLOCK_VALUE, io_base + LOCK_REG_OFFSET);
+
+	for (i = 0; i < ARRAY_SIZE(ni78bx_leds); i++) {
+		ret = devm_led_classdev_register(&pdev->dev,
+						 &ni78bx_leds[i].cdev);
+		if (ret)
+			return ret;
+	}
+
+	return ret;
+}
+
+static const struct acpi_device_id led_device_ids[] = {
+	{"NIC78B3", 0},
+	{"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, led_device_ids);
+
+static struct acpi_driver led_acpi_driver = {
+	.name = KBUILD_MODNAME,
+	.ids = led_device_ids,
+	.ops = {
+		.add = ni78bx_add,
+		.remove = ni78bx_remove,
+	},
+};
+
+module_acpi_driver(led_acpi_driver);
+
+MODULE_DESCRIPTION("National Instruments PXI User LEDs driver");
+MODULE_AUTHOR("Hui Chun Ong <hui.chun.ong@ni.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4