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1 From 766357a4f8476461035dcfe2c6b43f532366f533 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] BCM270x_DT: Add pwr_led, and the required "input" trigger
5
6 The "input" trigger makes the associated GPIO an input. This is to support
7 the Raspberry Pi PWR LED, which is driven by external hardware in normal use.
8
9 N.B. pwr_led is not available on Model A or B boards.
10
11 leds-gpio: Implement the brightness_get method
12
13 The power LED uses some clever logic that means it is driven
14 by a voltage measuring circuit when configured as input, otherwise
15 it is driven by the GPIO output value. This patch wires up the
16 brightness_get method for leds-gpio so that user-space can monitor
17 the LED value via /sys/class/gpio/led1/brightness. Using the input
18 trigger this returns an indication of the system power health,
19 otherwise it is just whatever value the trigger has written most
20 recently.
21
22 See: https://github.com/raspberrypi/linux/issues/1064
23 ---
24 drivers/leds/leds-gpio.c | 18 +++++++++++-
25 drivers/leds/trigger/Kconfig | 7 +++++
26 drivers/leds/trigger/Makefile | 1 +
27 drivers/leds/trigger/ledtrig-input.c | 54 ++++++++++++++++++++++++++++++++++++
28 include/linux/leds.h | 3 ++
29 5 files changed, 82 insertions(+), 1 deletion(-)
30 create mode 100644 drivers/leds/trigger/ledtrig-input.c
31
32 --- a/drivers/leds/leds-gpio.c
33 +++ b/drivers/leds/leds-gpio.c
34 @@ -50,8 +50,15 @@ static void gpio_led_set(struct led_clas
35 led_dat->platform_gpio_blink_set(led_dat->gpiod, level,
36 NULL, NULL);
37 led_dat->blinking = 0;
38 + } else if (led_dat->cdev.flags & SET_GPIO_INPUT) {
39 + gpiod_direction_input(led_dat->gpiod);
40 + led_dat->cdev.flags &= ~SET_GPIO_INPUT;
41 + } else if (led_dat->cdev.flags & SET_GPIO_OUTPUT) {
42 + gpiod_direction_output(led_dat->gpiod, level);
43 + led_dat->cdev.flags &= ~SET_GPIO_OUTPUT;
44 } else {
45 - if (led_dat->can_sleep)
46 + if (led_dat->can_sleep ||
47 + (led_dat->cdev.flags & (SET_GPIO_INPUT | SET_GPIO_OUTPUT) ))
48 gpiod_set_value_cansleep(led_dat->gpiod, level);
49 else
50 gpiod_set_value(led_dat->gpiod, level);
51 @@ -65,6 +72,13 @@ static int gpio_led_set_blocking(struct
52 return 0;
53 }
54
55 +static enum led_brightness gpio_led_get(struct led_classdev *led_cdev)
56 +{
57 + struct gpio_led_data *led_dat =
58 + container_of(led_cdev, struct gpio_led_data, cdev);
59 + return gpiod_get_value_cansleep(led_dat->gpiod) ? LED_FULL : LED_OFF;
60 +}
61 +
62 static int gpio_blink_set(struct led_classdev *led_cdev,
63 unsigned long *delay_on, unsigned long *delay_off)
64 {
65 @@ -122,6 +136,8 @@ static int create_gpio_led(const struct
66 led_dat->platform_gpio_blink_set = blink_set;
67 led_dat->cdev.blink_set = gpio_blink_set;
68 }
69 + led_dat->cdev.brightness_set = gpio_led_set;
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 @@ -116,6 +116,13 @@ 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 depends on LEDS_TRIGGERS
90 --- a/drivers/leds/trigger/Makefile
91 +++ b/drivers/leds/trigger/Makefile
92 @@ -9,5 +9,6 @@ obj-$(CONFIG_LEDS_TRIGGER_CPU) += ledtr
93 obj-$(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 +1,54 @@
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 void input_trig_activate(struct led_classdev *led_cdev)
123 +{
124 + led_cdev->flags |= SET_GPIO_INPUT;
125 + led_set_brightness(led_cdev, 0);
126 +}
127 +
128 +static void input_trig_deactivate(struct led_classdev *led_cdev)
129 +{
130 + led_cdev->flags |= SET_GPIO_OUTPUT;
131 + led_set_brightness(led_cdev, 0);
132 +}
133 +
134 +static struct led_trigger input_led_trigger = {
135 + .name = "input",
136 + .activate = input_trig_activate,
137 + .deactivate = input_trig_deactivate,
138 +};
139 +
140 +static int __init input_trig_init(void)
141 +{
142 + return led_trigger_register(&input_led_trigger);
143 +}
144 +
145 +static void __exit input_trig_exit(void)
146 +{
147 + led_trigger_unregister(&input_led_trigger);
148 +}
149 +
150 +module_init(input_trig_init);
151 +module_exit(input_trig_exit);
152 +
153 +MODULE_AUTHOR("Phil Elwell <phil@raspberrypi.org>");
154 +MODULE_DESCRIPTION("Set LED GPIO to Input \"trigger\"");
155 +MODULE_LICENSE("GPL");
156 --- a/include/linux/leds.h
157 +++ b/include/linux/leds.h
158 @@ -52,6 +52,9 @@ struct led_classdev {
159 #define LED_DEV_CAP_FLASH (1 << 24)
160 #define LED_HW_PLUGGABLE (1 << 25)
161 #define LED_PANIC_INDICATOR (1 << 26)
162 + /* Additions for Raspberry Pi PWR LED */
163 +#define SET_GPIO_INPUT (1 << 30)
164 +#define SET_GPIO_OUTPUT (1 << 31)
165
166 /* Set LED brightness level
167 * Must not sleep. Use brightness_set_blocking for drivers
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