target/linux/brcm2708/patches-4.4/0074-BCM270x_DT-Add-pwr_led-and-the-required-input-trigge.patch

   1 From a2b52a3af1314e2b691d9518afb3051193758671 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 074/170] 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             | 18 +++++++++++-
  26  drivers/leds/trigger/Kconfig         |  7 +++++
  27  drivers/leds/trigger/Makefile        |  1 +
  28  drivers/leds/trigger/ledtrig-input.c | 54 ++++++++++++++++++++++++++++++++++++
  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 @@ -42,6 +42,13 @@ static void gpio_led_work(struct work_st
  36                 led_dat->platform_gpio_blink_set(led_dat->gpiod,
  37                                         led_dat->new_level, 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 +       }
  43 +       else if (led_dat->cdev.flags & SET_GPIO_OUTPUT) {
  44 +               gpiod_direction_output(led_dat->gpiod, led_dat->new_level);
  45 +               led_dat->cdev.flags &= ~SET_GPIO_OUTPUT;
  46         } else
  47                 gpiod_set_value_cansleep(led_dat->gpiod, led_dat->new_level);
  48  }
  49 @@ -62,7 +69,8 @@ static void gpio_led_set(struct led_clas
  50          * seem to have a reliable way to know if we're already in one; so
  51          * let's just assume the worst.
  52          */
  53 -       if (led_dat->can_sleep) {
  54 +       if (led_dat->can_sleep ||
  55 +           (led_dat->cdev.flags & (SET_GPIO_INPUT | SET_GPIO_OUTPUT) )) {
  56                 led_dat->new_level = level;
  57                 schedule_work(&led_dat->work);
  58         } else {
  59 @@ -75,6 +83,13 @@ static void gpio_led_set(struct led_clas
  60         }
  61  }
  62
  63 +static enum led_brightness gpio_led_get(struct led_classdev *led_cdev)
  64 +{
  65 +       struct gpio_led_data *led_dat =
  66 +               container_of(led_cdev, struct gpio_led_data, cdev);
  67 +       return gpiod_get_value_cansleep(led_dat->gpiod) ? LED_FULL : LED_OFF;
  68 +}
  69 +
  70  static int gpio_blink_set(struct led_classdev *led_cdev,
  71         unsigned long *delay_on, unsigned long *delay_off)
  72  {
  73 @@ -131,6 +146,7 @@ static int create_gpio_led(const struct
  74                 led_dat->cdev.blink_set = gpio_blink_set;
  75         }
  76         led_dat->cdev.brightness_set = gpio_led_set;
  77 +       led_dat->cdev.brightness_get = gpio_led_get;
  78         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
  79                 state = !!gpiod_get_value_cansleep(led_dat->gpiod);
  80         else
  81 --- a/drivers/leds/trigger/Kconfig
  82 +++ b/drivers/leds/trigger/Kconfig
  83 @@ -126,4 +126,11 @@ config LEDS_TRIGGER_USBDEV
  84           This allows LEDs to be controlled by the presence/activity of
  85           an USB device. If unsure, say N.
  86
  87 +config LEDS_TRIGGER_INPUT
  88 +       tristate "LED Input Trigger"
  89 +       depends on LEDS_TRIGGERS
  90 +       help
  91 +         This allows the GPIOs assigned to be LEDs to be initialised to inputs.
  92 +         If unsure, say Y.
  93 +
  94  endif # LEDS_TRIGGERS
  95 --- a/drivers/leds/trigger/Makefile
  96 +++ b/drivers/leds/trigger/Makefile
  97 @@ -8,3 +8,4 @@ obj-$(CONFIG_LEDS_TRIGGER_CPU)          += ledtr
  98  obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON)  += ledtrig-default-on.o
  99  obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT)   += ledtrig-transient.o
 100  obj-$(CONFIG_LEDS_TRIGGER_CAMERA)      += ledtrig-camera.o
 101 +obj-$(CONFIG_LEDS_TRIGGER_INPUT)       += ledtrig-input.o
 102 --- /dev/null
 103 +++ b/drivers/leds/trigger/ledtrig-input.c
 104 @@ -0,0 +1,54 @@
 105 +/*
 106 + * Set LED GPIO to Input "Trigger"
 107 + *
 108 + * Copyright 2015 Phil Elwell <phil@raspberrypi.org>
 109 + *
 110 + * Based on Nick Forbes's ledtrig-default-on.c.
 111 + *
 112 + * This program is free software; you can redistribute it and/or modify
 113 + * it under the terms of the GNU General Public License version 2 as
 114 + * published by the Free Software Foundation.
 115 + *
 116 + */
 117 +
 118 +#include <linux/module.h>
 119 +#include <linux/kernel.h>
 120 +#include <linux/init.h>
 121 +#include <linux/leds.h>
 122 +#include <linux/gpio.h>
 123 +#include "../leds.h"
 124 +
 125 +static void input_trig_activate(struct led_classdev *led_cdev)
 126 +{
 127 +       led_cdev->flags |= SET_GPIO_INPUT;
 128 +       led_set_brightness_async(led_cdev, 0);
 129 +}
 130 +
 131 +static void input_trig_deactivate(struct led_classdev *led_cdev)
 132 +{
 133 +       led_cdev->flags |= SET_GPIO_OUTPUT;
 134 +       led_set_brightness_async(led_cdev, 0);
 135 +}
 136 +
 137 +static struct led_trigger input_led_trigger = {
 138 +       .name     = "input",
 139 +       .activate = input_trig_activate,
 140 +       .deactivate = input_trig_deactivate,
 141 +};
 142 +
 143 +static int __init input_trig_init(void)
 144 +{
 145 +       return led_trigger_register(&input_led_trigger);
 146 +}
 147 +
 148 +static void __exit input_trig_exit(void)
 149 +{
 150 +       led_trigger_unregister(&input_led_trigger);
 151 +}
 152 +
 153 +module_init(input_trig_init);
 154 +module_exit(input_trig_exit);
 155 +
 156 +MODULE_AUTHOR("Phil Elwell <phil@raspberrypi.org>");
 157 +MODULE_DESCRIPTION("Set LED GPIO to Input \"trigger\"");
 158 +MODULE_LICENSE("GPL");
 159 --- a/include/linux/leds.h
 160 +++ b/include/linux/leds.h
 161 @@ -48,6 +48,9 @@ struct led_classdev {
 162  #define SET_BRIGHTNESS_ASYNC   (1 << 21)
 163  #define SET_BRIGHTNESS_SYNC    (1 << 22)
 164  #define LED_DEV_CAP_FLASH      (1 << 23)
 165 +       /* Additions for Raspberry Pi PWR LED */
 166 +#define SET_GPIO_INPUT         (1 << 30)
 167 +#define SET_GPIO_OUTPUT                (1 << 31)
 168
 169         /* Set LED brightness level */
 170         /* Must not sleep, use a workqueue if needed */