树莓派-LED篇

1 leds驱动

新增文件：arch\arm\boot\dts\overlays\example-overlay.dts

/dts-v1/;

/plugin/;

 

/{

compatible = "brcm,bcm2835";

 

fragment@0 {

target = <&gpio>;

__overlay__ {

leds_pins: leds_pins {

brcm,pins = <25>;

brcm,function = <1>; /* out */

};

};

};

 

fragment@1 {

target = <&i2c_arm>;

__overlay__ {

#address-cells = <1>;

#size-cells = <0>;

status = "okay";

 

aw9523b: aw9523b@5b {

compatible = "xxx,aw9523b-leds";

reg = <0x5b>;

pinctrl-names = "default";

pinctrl-0 = <&leds_pins>;

reset-gpios = <&gpio 25 0>;

status = "okay";

};

};

};

 

__overrides__ {

aw9523b = <&aw9523b>,"status";

};

};

 

linux\arch\arm\boot\dts\overlays\Makefile

dtbo-$(RPI_DT_OVERLAYS) += example-leds.dtbo

 

 

linux\drivers\leds\leds-aw9523b.c

/*

 * TI LP8860 4-Channel LED Driver

 *

 * Copyright (C) 2014 Texas Instruments

 *

 * Author: Dan Murphy <dmurphy@ti.com>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * version 2 as published by the Free Software Foundation.

 *

 */

 

#include <linux/i2c.h>

#include <linux/init.h>

#include <linux/leds.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/of.h>

#include <linux/of_gpio.h>

#include <linux/gpio.h>

#include <linux/slab.h>

#include <linux/delay.h>

 

 

#define AW9523B_REG_CHIPID 0x10

#define AW9523B_CHIPID_VALUE 0x23

#define AW9523B_LED_OFFSET 3

#define AW9523B_COLOR_OFFSET 3

 

static struct mutex aw9523b_mutex;

 

enum led_ids {

LED1,

LED2,

LED3,

LED_NUM,

};

 

enum led_colors {

LED1_RED = 0,

LED1_GREEN = 1,

LED1_BLUE = 2,

LED2_RED = 3,

LED2_GREEN = 4,

LED2_BLUE = 5,

LED3_RED = 6,

LED3_GREEN = 7,

LED3_BLUE = 8,

};

 

struct aw9523b_led {

struct aw9523b_led_platform_data *pdata;

struct i2c_client *client;

struct rw_semaphore rwsem;

struct work_struct work;

 

/*

 * Making led_classdev as array is not recommended, because array

 * members prevent using 'container_of' macro. So repetitive works

 * are needed.

 */

struct led_classdev cdev_led1r;

struct led_classdev cdev_led1g;

struct led_classdev cdev_led1b;

 

struct led_classdev cdev_led2r;

struct led_classdev cdev_led2g;

struct led_classdev cdev_led2b;

 

struct led_classdev cdev_led3r;

struct led_classdev cdev_led3g;

struct led_classdev cdev_led3b;

 

 

enum led_ids led_id;

enum led_colors color;

enum led_brightness brightness;

 

int reset_gpio;

};

 

static inline u8 aw9523b_get_base_offset(enum led_ids id, enum led_colors color)

{

return id * AW9523B_LED_OFFSET + color;

}

 

static inline u8 aw9523b_get_reg_addr(enum led_ids id, enum led_colors color,

u8 reg_offset)

{

return reg_offset + aw9523b_get_base_offset(id, color);

}

 

 

/*--------------------------------------------------------------*/

/* AW9523BGU core functions */

/*--------------------------------------------------------------*/

 

static int aw9523b_write_byte(struct i2c_client *client, u8 reg, u8 val)