leds: leds-menf21bmc: Introduce MEN 14F021P00 BMC LED driver

Added driver to support the 14F021P00 BMC LEDs.
The BMC is a Board Management Controller including four LEDs which
can be switched on and off.
Signed-off-by: Andreas Werner <andreas.werner@men.de>
Acked-by: Bryan Wu <cooloney@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/leds/Kconfig

@@ -468,6 +468,15 @@ config LEDS_OT200
 	  This option enables support for the LEDs on the Bachmann OT200.
 	  Say Y to enable LEDs on the Bachmann OT200.
 
+config LEDS_MENF21BMC
+	tristate "LED support for the MEN 14F021P00 BMC"
+	depends on LEDS_CLASS && MFD_MENF21BMC
+	help
+	  Say Y here to include support for the MEN 14F021P00 BMC LEDs.
+
+	  This driver can also be built as a module. If so the module
+	  will be called leds-menf21bmc.
+
 comment "LED driver for blink(1) USB RGB LED is under Special HID drivers (HID_THINGM)"
 
 config LEDS_BLINKM

drivers/leds/Makefile

@@ -54,6 +54,7 @@ obj-$(CONFIG_LEDS_MAX8997)		+= leds-max8997.o
 obj-$(CONFIG_LEDS_LM355x)		+= leds-lm355x.o
 obj-$(CONFIG_LEDS_BLINKM)		+= leds-blinkm.o
 obj-$(CONFIG_LEDS_VERSATILE)		+= leds-versatile.o
+obj-$(CONFIG_LEDS_MENF21BMC)		+= leds-menf21bmc.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o

drivers/leds/leds-menf21bmc.c

+/*
+ *  MEN 14F021P00 Board Management Controller (BMC) LEDs Driver.
+ *
+ *  This is the core LED driver of the MEN 14F021P00 BMC.
+ *  There are four LEDs available which can be switched on and off.
+ *  STATUS LED, HOT SWAP LED, USER LED 1, USER LED 2
+ *
+ *  Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH
+ *
+ *  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.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/leds.h>
+#include <linux/i2c.h>
+
+#define BMC_CMD_LED_GET_SET	0xA0
+#define BMC_BIT_LED_STATUS	BIT(0)
+#define BMC_BIT_LED_HOTSWAP	BIT(1)
+#define BMC_BIT_LED_USER1	BIT(2)
+#define BMC_BIT_LED_USER2	BIT(3)
+
+struct menf21bmc_led {
+	struct led_classdev cdev;
+	u8 led_bit;
+	const char *name;
+	struct i2c_client *i2c_client;
+};
+
+static struct menf21bmc_led leds[] = {
+	{
+		.name = "menf21bmc:led_status",
+		.led_bit = BMC_BIT_LED_STATUS,
+	},
+	{
+		.name = "menf21bmc:led_hotswap",
+		.led_bit = BMC_BIT_LED_HOTSWAP,
+	},
+	{
+		.name = "menf21bmc:led_user1",
+		.led_bit = BMC_BIT_LED_USER1,
+	},
+	{
+		.name = "menf21bmc:led_user2",
+		.led_bit = BMC_BIT_LED_USER2,
+	}
+};
+
+static DEFINE_MUTEX(led_lock);
+
+static void
+menf21bmc_led_set(struct led_classdev *led_cdev, enum led_brightness value)
+{
+	int led_val;
+	struct menf21bmc_led *led = container_of(led_cdev,
+					struct menf21bmc_led, cdev);
+
+	mutex_lock(&led_lock);
+	led_val = i2c_smbus_read_byte_data(led->i2c_client,
+					   BMC_CMD_LED_GET_SET);
+	if (led_val < 0)
+		goto err_out;
+
+	if (value == LED_OFF)
+		led_val &= ~led->led_bit;
+	else
+		led_val |= led->led_bit;
+
+	i2c_smbus_write_byte_data(led->i2c_client,
+				  BMC_CMD_LED_GET_SET, led_val);
+err_out:
+	mutex_unlock(&led_lock);
+}
+
+static int menf21bmc_led_probe(struct platform_device *pdev)
+{
+	int i;
+	int ret;
+	struct i2c_client *i2c_client = to_i2c_client(pdev->dev.parent);
+
+	for (i = 0; i < ARRAY_SIZE(leds); i++) {
+		leds[i].cdev.name = leds[i].name;
+		leds[i].cdev.brightness_set = menf21bmc_led_set;
+		leds[i].i2c_client = i2c_client;
+		ret = led_classdev_register(&pdev->dev, &leds[i].cdev);
+		if (ret < 0)
+			goto err_free_leds;
+	}
+	dev_info(&pdev->dev, "MEN 140F21P00 BMC LED device enabled\n");
+
+	return 0;
+
+err_free_leds:
+	dev_err(&pdev->dev, "failed to register LED device\n");
+
+	for (i = i - 1; i >= 0; i--)
+		led_classdev_unregister(&leds[i].cdev);
+
+	return ret;
+}
+
+static int menf21bmc_led_remove(struct platform_device *pdev)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(leds); i++)
+		led_classdev_unregister(&leds[i].cdev);
+
+	return 0;
+}
+
+static struct platform_driver menf21bmc_led = {
+	.probe		= menf21bmc_led_probe,
+	.remove		= menf21bmc_led_remove,
+	.driver		= {
+		.name		= "menf21bmc_led",
+		.owner		= THIS_MODULE,
+	},
+};
+
+module_platform_driver(menf21bmc_led);
+
+MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
+MODULE_DESCRIPTION("MEN 14F021P00 BMC led driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:menf21bmc_led");