kernel/drivers/leds/leds-versatile.c

   1 /*
   2  * Driver for the 8 user LEDs found on the RealViews and Versatiles
   3  * Based on DaVinci's DM365 board code
   4  *
   5  * License terms: GNU General Public License (GPL) version 2
   6  * Author: Linus Walleij <triad@df.lth.se>
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/io.h>
  12 #include <linux/slab.h>
  13 #include <linux/leds.h>
  14 #include <linux/platform_device.h>
  15
  16 struct versatile_led {
  17         void __iomem            *base;
  18         struct led_classdev     cdev;
  19         u8                      mask;
  20 };
  21
  22 /*
  23  * The triggers lines up below will only be used if the
  24  * LED triggers are compiled in.
  25  */
  26 static const struct {
  27         const char *name;
  28         const char *trigger;
  29 } versatile_leds[] = {
  30         { "versatile:0", "heartbeat", },
  31         { "versatile:1", "mmc0", },
  32         { "versatile:2", "cpu0" },
  33         { "versatile:3", "cpu1" },
  34         { "versatile:4", "cpu2" },
  35         { "versatile:5", "cpu3" },
  36         { "versatile:6", },
  37         { "versatile:7", },
  38 };
  39
  40 static void versatile_led_set(struct led_classdev *cdev,
  41                               enum led_brightness b)
  42 {
  43         struct versatile_led *led = container_of(cdev,
  44                                                  struct versatile_led, cdev);
  45         u32 reg = readl(led->base);
  46
  47         if (b != LED_OFF)
  48                 reg |= led->mask;
  49         else
  50                 reg &= ~led->mask;
  51         writel(reg, led->base);
  52 }
  53
  54 static enum led_brightness versatile_led_get(struct led_classdev *cdev)
  55 {
  56         struct versatile_led *led = container_of(cdev,
  57                                                  struct versatile_led, cdev);
  58         u32 reg = readl(led->base);
  59
  60         return (reg & led->mask) ? LED_FULL : LED_OFF;
  61 }
  62
  63 static int versatile_leds_probe(struct platform_device *dev)
  64 {
  65         int i;
  66         struct resource *res;
  67         void __iomem *base;
  68
  69         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
  70         base = devm_ioremap_resource(&dev->dev, res);
  71         if (IS_ERR(base))
  72                 return PTR_ERR(base);
  73
  74         /* All off */
  75         writel(0, base);
  76         for (i = 0; i < ARRAY_SIZE(versatile_leds); i++) {
  77                 struct versatile_led *led;
  78
  79                 led = kzalloc(sizeof(*led), GFP_KERNEL);
  80                 if (!led)
  81                         break;
  82
  83                 led->base = base;
  84                 led->cdev.name = versatile_leds[i].name;
  85                 led->cdev.brightness_set = versatile_led_set;
  86                 led->cdev.brightness_get = versatile_led_get;
  87                 led->cdev.default_trigger = versatile_leds[i].trigger;
  88                 led->mask = BIT(i);
  89
  90                 if (led_classdev_register(NULL, &led->cdev) < 0) {
  91                         kfree(led);
  92                         break;
  93                 }
  94         }
  95
  96         return 0;
  97 }
  98
  99 static struct platform_driver versatile_leds_driver = {
 100         .driver = {
 101                 .name   = "versatile-leds",
 102         },
 103         .probe = versatile_leds_probe,
 104 };
 105
 106 module_platform_driver(versatile_leds_driver);
 107
 108 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
 109 MODULE_DESCRIPTION("ARM Versatile LED driver");
 110 MODULE_LICENSE("GPL v2");