git.openwrt.org Git - openwrt/staging/ldir.git/blob

   1 From 28644cb31e076ccc6645c692a7ff43414230f361 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Fri, 6 Feb 2015 13:50:57 +0000
   4 Subject: [PATCH 058/703] BCM270x_DT: Add pwr_led, and the required "input"
   5  trigger
   6
   7 The "input" trigger makes the associated GPIO an input.  This is to support
   8 the Raspberry Pi PWR LED, which is driven by external hardware in normal use.
   9
  10 N.B. pwr_led is not available on Model A or B boards.
  11
  12 leds-gpio: Implement the brightness_get method
  13
  14 The power LED uses some clever logic that means it is driven
  15 by a voltage measuring circuit when configured as input, otherwise
  16 it is driven by the GPIO output value. This patch wires up the
  17 brightness_get method for leds-gpio so that user-space can monitor
  18 the LED value via /sys/class/gpio/led1/brightness. Using the input
  19 trigger this returns an indication of the system power health,
  20 otherwise it is just whatever value the trigger has written most
  21 recently.
  22
  23 See: https://github.com/raspberrypi/linux/issues/1064
  24 ---
  25  drivers/leds/leds-gpio.c             | 17 ++++++++-
  26  drivers/leds/trigger/Kconfig         |  7 ++++
  27  drivers/leds/trigger/Makefile        |  1 +
  28  drivers/leds/trigger/ledtrig-input.c | 55 ++++++++++++++++++++++++++++
  29  include/linux/leds.h                 |  3 ++
  30  5 files changed, 82 insertions(+), 1 deletion(-)
  31  create mode 100644 drivers/leds/trigger/ledtrig-input.c
  32
  33 --- a/drivers/leds/leds-gpio.c
  34 +++ b/drivers/leds/leds-gpio.c
  35 @@ -50,8 +50,15 @@ static void gpio_led_set(struct led_clas
  36                 led_dat->platform_gpio_blink_set(led_dat->gpiod, level,
  37                                                  NULL, NULL);
  38                 led_dat->blinking = 0;
  39 +       } else if (led_dat->cdev.flags & SET_GPIO_INPUT) {
  40 +               gpiod_direction_input(led_dat->gpiod);
  41 +               led_dat->cdev.flags &= ~SET_GPIO_INPUT;
  42 +       } else if (led_dat->cdev.flags & SET_GPIO_OUTPUT) {
  43 +               gpiod_direction_output(led_dat->gpiod, level);
  44 +               led_dat->cdev.flags &= ~SET_GPIO_OUTPUT;
  45         } else {
  46 -               if (led_dat->can_sleep)
  47 +               if (led_dat->can_sleep ||
  48 +                       (led_dat->cdev.flags & (SET_GPIO_INPUT | SET_GPIO_OUTPUT) ))
  49                         gpiod_set_value_cansleep(led_dat->gpiod, level);
  50                 else
  51                         gpiod_set_value(led_dat->gpiod, level);
  52 @@ -65,6 +72,13 @@ static int gpio_led_set_blocking(struct
  53         return 0;
  54  }
  55
  56 +static enum led_brightness gpio_led_get(struct led_classdev *led_cdev)
  57 +{
  58 +       struct gpio_led_data *led_dat =
  59 +               container_of(led_cdev, struct gpio_led_data, cdev);
  60 +       return gpiod_get_value_cansleep(led_dat->gpiod) ? LED_FULL : LED_OFF;
  61 +}
  62 +
  63  static int gpio_blink_set(struct led_classdev *led_cdev,
  64         unsigned long *delay_on, unsigned long *delay_off)
  65  {
  66 @@ -122,6 +136,7 @@ static int create_gpio_led(const struct
  67                 led_dat->platform_gpio_blink_set = blink_set;
  68                 led_dat->cdev.blink_set = gpio_blink_set;
  69         }
  70 +       led_dat->cdev.brightness_get = gpio_led_get;
  71         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) {
  72                 state = gpiod_get_value_cansleep(led_dat->gpiod);
  73                 if (state < 0)
  74 --- a/drivers/leds/trigger/Kconfig
  75 +++ b/drivers/leds/trigger/Kconfig
  76 @@ -113,6 +113,13 @@ config LEDS_TRIGGER_CAMERA
  77           This enables direct flash/torch on/off by the driver, kernel space.
  78           If unsure, say Y.
  79
  80 +config LEDS_TRIGGER_INPUT
  81 +       tristate "LED Input Trigger"
  82 +       depends on LEDS_TRIGGERS
  83 +       help
  84 +         This allows the GPIOs assigned to be LEDs to be initialised to inputs.
  85 +         If unsure, say Y.
  86 +
  87  config LEDS_TRIGGER_PANIC
  88         bool "LED Panic Trigger"
  89         help
  90 --- a/drivers/leds/trigger/Makefile
  91 +++ b/drivers/leds/trigger/Makefile
  92 @@ -11,5 +11,6 @@ obj-$(CONFIG_LEDS_TRIGGER_ACTIVITY)   += l
  93  obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON)  += ledtrig-default-on.o
  94  obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT)   += ledtrig-transient.o
  95  obj-$(CONFIG_LEDS_TRIGGER_CAMERA)      += ledtrig-camera.o
  96 +obj-$(CONFIG_LEDS_TRIGGER_INPUT)       += ledtrig-input.o
  97  obj-$(CONFIG_LEDS_TRIGGER_PANIC)       += ledtrig-panic.o
  98  obj-$(CONFIG_LEDS_TRIGGER_NETDEV)      += ledtrig-netdev.o
  99 --- /dev/null
 100 +++ b/drivers/leds/trigger/ledtrig-input.c
 101 @@ -0,0 +1,55 @@
 102 +/*
 103 + * Set LED GPIO to Input "Trigger"
 104 + *
 105 + * Copyright 2015 Phil Elwell <phil@raspberrypi.org>
 106 + *
 107 + * Based on Nick Forbes's ledtrig-default-on.c.
 108 + *
 109 + * This program is free software; you can redistribute it and/or modify
 110 + * it under the terms of the GNU General Public License version 2 as
 111 + * published by the Free Software Foundation.
 112 + *
 113 + */
 114 +
 115 +#include <linux/module.h>
 116 +#include <linux/kernel.h>
 117 +#include <linux/init.h>
 118 +#include <linux/leds.h>
 119 +#include <linux/gpio.h>
 120 +#include "../leds.h"
 121 +
 122 +static int input_trig_activate(struct led_classdev *led_cdev)
 123 +{
 124 +       led_cdev->flags |= SET_GPIO_INPUT;
 125 +       led_set_brightness(led_cdev, 0);
 126 +       return 0;
 127 +}
 128 +
 129 +static void input_trig_deactivate(struct led_classdev *led_cdev)
 130 +{
 131 +       led_cdev->flags |= SET_GPIO_OUTPUT;
 132 +       led_set_brightness(led_cdev, 0);
 133 +}
 134 +
 135 +static struct led_trigger input_led_trigger = {
 136 +       .name     = "input",
 137 +       .activate = input_trig_activate,
 138 +       .deactivate = input_trig_deactivate,
 139 +};
 140 +
 141 +static int __init input_trig_init(void)
 142 +{
 143 +       return led_trigger_register(&input_led_trigger);
 144 +}
 145 +
 146 +static void __exit input_trig_exit(void)
 147 +{
 148 +       led_trigger_unregister(&input_led_trigger);
 149 +}
 150 +
 151 +module_init(input_trig_init);
 152 +module_exit(input_trig_exit);
 153 +
 154 +MODULE_AUTHOR("Phil Elwell <phil@raspberrypi.org>");
 155 +MODULE_DESCRIPTION("Set LED GPIO to Input \"trigger\"");
 156 +MODULE_LICENSE("GPL");
 157 --- a/include/linux/leds.h
 158 +++ b/include/linux/leds.h
 159 @@ -50,6 +50,9 @@ struct led_classdev {
 160  #define LED_PANIC_INDICATOR    BIT(20)
 161  #define LED_BRIGHT_HW_CHANGED  BIT(21)
 162  #define LED_RETAIN_AT_SHUTDOWN BIT(22)
 163 +       /* Additions for Raspberry Pi PWR LED */
 164 +#define SET_GPIO_INPUT         BIT(30)
 165 +#define SET_GPIO_OUTPUT                BIT(31)
 166
 167         /* set_brightness_work / blink_timer flags, atomic, private. */
 168         unsigned long           work_flags;