drivers/leds/leds-menf21bmc.c

   1 /*
   2  *  MEN 14F021P00 Board Management Controller (BMC) LEDs Driver.
   3  *
   4  *  This is the core LED driver of the MEN 14F021P00 BMC.
   5  *  There are four LEDs available which can be switched on and off.
   6  *  STATUS LED, HOT SWAP LED, USER LED 1, USER LED 2
   7  *
   8  *  Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH
   9  *
  10  *  This program is free software; you can redistribute  it and/or modify it
  11  *  under  the terms of  the GNU General  Public License as published by the
  12  *  Free Software Foundation;  either version 2 of the  License, or (at your
  13  *  option) any later version.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/leds.h>
  20 #include <linux/i2c.h>
  21
  22 #define BMC_CMD_LED_GET_SET     0xA0
  23 #define BMC_BIT_LED_STATUS      BIT(0)
  24 #define BMC_BIT_LED_HOTSWAP     BIT(1)
  25 #define BMC_BIT_LED_USER1       BIT(2)
  26 #define BMC_BIT_LED_USER2       BIT(3)
  27
  28 struct menf21bmc_led {
  29         struct led_classdev cdev;
  30         u8 led_bit;
  31         const char *name;
  32         struct i2c_client *i2c_client;
  33 };
  34
  35 static struct menf21bmc_led leds[] = {
  36         {
  37                 .name = "menf21bmc:led_status",
  38                 .led_bit = BMC_BIT_LED_STATUS,
  39         },
  40         {
  41                 .name = "menf21bmc:led_hotswap",
  42                 .led_bit = BMC_BIT_LED_HOTSWAP,
  43         },
  44         {
  45                 .name = "menf21bmc:led_user1",
  46                 .led_bit = BMC_BIT_LED_USER1,
  47         },
  48         {
  49                 .name = "menf21bmc:led_user2",
  50                 .led_bit = BMC_BIT_LED_USER2,
  51         }
  52 };
  53
  54 static DEFINE_MUTEX(led_lock);
  55
  56 static void
  57 menf21bmc_led_set(struct led_classdev *led_cdev, enum led_brightness value)
  58 {
  59         int led_val;
  60         struct menf21bmc_led *led = container_of(led_cdev,
  61                                         struct menf21bmc_led, cdev);
  62
  63         mutex_lock(&led_lock);
  64         led_val = i2c_smbus_read_byte_data(led->i2c_client,
  65                                            BMC_CMD_LED_GET_SET);
  66         if (led_val < 0)
  67                 goto err_out;
  68
  69         if (value == LED_OFF)
  70                 led_val &= ~led->led_bit;
  71         else
  72                 led_val |= led->led_bit;
  73
  74         i2c_smbus_write_byte_data(led->i2c_client,
  75                                   BMC_CMD_LED_GET_SET, led_val);
  76 err_out:
  77         mutex_unlock(&led_lock);
  78 }
  79
  80 static int menf21bmc_led_probe(struct platform_device *pdev)
  81 {
  82         int i;
  83         int ret;
  84         struct i2c_client *i2c_client = to_i2c_client(pdev->dev.parent);
  85
  86         for (i = 0; i < ARRAY_SIZE(leds); i++) {
  87                 leds[i].cdev.name = leds[i].name;
  88                 leds[i].cdev.brightness_set = menf21bmc_led_set;
  89                 leds[i].i2c_client = i2c_client;
  90                 ret = led_classdev_register(&pdev->dev, &leds[i].cdev);
  91                 if (ret < 0)
  92                         goto err_free_leds;
  93         }
  94         dev_info(&pdev->dev, "MEN 140F21P00 BMC LED device enabled\n");
  95
  96         return 0;
  97
  98 err_free_leds:
  99         dev_err(&pdev->dev, "failed to register LED device\n");
 100
 101         for (i = i - 1; i >= 0; i--)
 102                 led_classdev_unregister(&leds[i].cdev);
 103
 104         return ret;
 105 }
 106
 107 static int menf21bmc_led_remove(struct platform_device *pdev)
 108 {
 109         int i;
 110
 111         for (i = 0; i < ARRAY_SIZE(leds); i++)
 112                 led_classdev_unregister(&leds[i].cdev);
 113
 114         return 0;
 115 }
 116
 117 static struct platform_driver menf21bmc_led = {
 118         .probe          = menf21bmc_led_probe,
 119         .remove         = menf21bmc_led_remove,
 120         .driver         = {
 121                 .name           = "menf21bmc_led",
 122         },
 123 };
 124
 125 module_platform_driver(menf21bmc_led);
 126
 127 MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
 128 MODULE_DESCRIPTION("MEN 14F021P00 BMC led driver");
 129 MODULE_LICENSE("GPL v2");
 130 MODULE_ALIAS("platform:menf21bmc_led");