443 строки
10 KiB
C
443 строки
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* leds-lp3944.c - driver for National Semiconductor LP3944 Funlight Chip
|
|
*
|
|
* Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it>
|
|
*/
|
|
|
|
/*
|
|
* I2C driver for National Semiconductor LP3944 Funlight Chip
|
|
* http://www.national.com/pf/LP/LP3944.html
|
|
*
|
|
* This helper chip can drive up to 8 leds, with two programmable DIM modes;
|
|
* it could even be used as a gpio expander but this driver assumes it is used
|
|
* as a led controller.
|
|
*
|
|
* The DIM modes are used to set _blink_ patterns for leds, the pattern is
|
|
* specified supplying two parameters:
|
|
* - period: from 0s to 1.6s
|
|
* - duty cycle: percentage of the period the led is on, from 0 to 100
|
|
*
|
|
* LP3944 can be found on Motorola A910 smartphone, where it drives the rgb
|
|
* leds, the camera flash light and the displays backlights.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/leds.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/leds-lp3944.h>
|
|
|
|
/* Read Only Registers */
|
|
#define LP3944_REG_INPUT1 0x00 /* LEDs 0-7 InputRegister (Read Only) */
|
|
#define LP3944_REG_REGISTER1 0x01 /* None (Read Only) */
|
|
|
|
#define LP3944_REG_PSC0 0x02 /* Frequency Prescaler 0 (R/W) */
|
|
#define LP3944_REG_PWM0 0x03 /* PWM Register 0 (R/W) */
|
|
#define LP3944_REG_PSC1 0x04 /* Frequency Prescaler 1 (R/W) */
|
|
#define LP3944_REG_PWM1 0x05 /* PWM Register 1 (R/W) */
|
|
#define LP3944_REG_LS0 0x06 /* LEDs 0-3 Selector (R/W) */
|
|
#define LP3944_REG_LS1 0x07 /* LEDs 4-7 Selector (R/W) */
|
|
|
|
/* These registers are not used to control leds in LP3944, they can store
|
|
* arbitrary values which the chip will ignore.
|
|
*/
|
|
#define LP3944_REG_REGISTER8 0x08
|
|
#define LP3944_REG_REGISTER9 0x09
|
|
|
|
#define LP3944_DIM0 0
|
|
#define LP3944_DIM1 1
|
|
|
|
/* period in ms */
|
|
#define LP3944_PERIOD_MIN 0
|
|
#define LP3944_PERIOD_MAX 1600
|
|
|
|
/* duty cycle is a percentage */
|
|
#define LP3944_DUTY_CYCLE_MIN 0
|
|
#define LP3944_DUTY_CYCLE_MAX 100
|
|
|
|
#define ldev_to_led(c) container_of(c, struct lp3944_led_data, ldev)
|
|
|
|
/* Saved data */
|
|
struct lp3944_led_data {
|
|
u8 id;
|
|
enum lp3944_type type;
|
|
struct led_classdev ldev;
|
|
struct i2c_client *client;
|
|
};
|
|
|
|
struct lp3944_data {
|
|
struct mutex lock;
|
|
struct i2c_client *client;
|
|
struct lp3944_led_data leds[LP3944_LEDS_MAX];
|
|
};
|
|
|
|
static int lp3944_reg_read(struct i2c_client *client, u8 reg, u8 *value)
|
|
{
|
|
int tmp;
|
|
|
|
tmp = i2c_smbus_read_byte_data(client, reg);
|
|
if (tmp < 0)
|
|
return tmp;
|
|
|
|
*value = tmp;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int lp3944_reg_write(struct i2c_client *client, u8 reg, u8 value)
|
|
{
|
|
return i2c_smbus_write_byte_data(client, reg, value);
|
|
}
|
|
|
|
/**
|
|
* lp3944_dim_set_period() - Set the period for DIM status
|
|
*
|
|
* @client: the i2c client
|
|
* @dim: either LP3944_DIM0 or LP3944_DIM1
|
|
* @period: period of a blink, that is a on/off cycle, expressed in ms.
|
|
*/
|
|
static int lp3944_dim_set_period(struct i2c_client *client, u8 dim, u16 period)
|
|
{
|
|
u8 psc_reg;
|
|
u8 psc_value;
|
|
int err;
|
|
|
|
if (dim == LP3944_DIM0)
|
|
psc_reg = LP3944_REG_PSC0;
|
|
else if (dim == LP3944_DIM1)
|
|
psc_reg = LP3944_REG_PSC1;
|
|
else
|
|
return -EINVAL;
|
|
|
|
/* Convert period to Prescaler value */
|
|
if (period > LP3944_PERIOD_MAX)
|
|
return -EINVAL;
|
|
|
|
psc_value = (period * 255) / LP3944_PERIOD_MAX;
|
|
|
|
err = lp3944_reg_write(client, psc_reg, psc_value);
|
|
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* lp3944_dim_set_dutycycle - Set the duty cycle for DIM status
|
|
*
|
|
* @client: the i2c client
|
|
* @dim: either LP3944_DIM0 or LP3944_DIM1
|
|
* @duty_cycle: percentage of a period during which a led is ON
|
|
*/
|
|
static int lp3944_dim_set_dutycycle(struct i2c_client *client, u8 dim,
|
|
u8 duty_cycle)
|
|
{
|
|
u8 pwm_reg;
|
|
u8 pwm_value;
|
|
int err;
|
|
|
|
if (dim == LP3944_DIM0)
|
|
pwm_reg = LP3944_REG_PWM0;
|
|
else if (dim == LP3944_DIM1)
|
|
pwm_reg = LP3944_REG_PWM1;
|
|
else
|
|
return -EINVAL;
|
|
|
|
/* Convert duty cycle to PWM value */
|
|
if (duty_cycle > LP3944_DUTY_CYCLE_MAX)
|
|
return -EINVAL;
|
|
|
|
pwm_value = (duty_cycle * 255) / LP3944_DUTY_CYCLE_MAX;
|
|
|
|
err = lp3944_reg_write(client, pwm_reg, pwm_value);
|
|
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* lp3944_led_set() - Set the led status
|
|
*
|
|
* @led: a lp3944_led_data structure
|
|
* @status: one of LP3944_LED_STATUS_OFF
|
|
* LP3944_LED_STATUS_ON
|
|
* LP3944_LED_STATUS_DIM0
|
|
* LP3944_LED_STATUS_DIM1
|
|
*/
|
|
static int lp3944_led_set(struct lp3944_led_data *led, u8 status)
|
|
{
|
|
struct lp3944_data *data = i2c_get_clientdata(led->client);
|
|
u8 id = led->id;
|
|
u8 reg;
|
|
u8 val = 0;
|
|
int err;
|
|
|
|
dev_dbg(&led->client->dev, "%s: %s, status before normalization:%d\n",
|
|
__func__, led->ldev.name, status);
|
|
|
|
switch (id) {
|
|
case LP3944_LED0:
|
|
case LP3944_LED1:
|
|
case LP3944_LED2:
|
|
case LP3944_LED3:
|
|
reg = LP3944_REG_LS0;
|
|
break;
|
|
case LP3944_LED4:
|
|
case LP3944_LED5:
|
|
case LP3944_LED6:
|
|
case LP3944_LED7:
|
|
id -= LP3944_LED4;
|
|
reg = LP3944_REG_LS1;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (status > LP3944_LED_STATUS_DIM1)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Invert status only when it's < 2 (i.e. 0 or 1) which means it's
|
|
* controlling the on/off state directly.
|
|
* When, instead, status is >= 2 don't invert it because it would mean
|
|
* to mess with the hardware blinking mode.
|
|
*/
|
|
if (led->type == LP3944_LED_TYPE_LED_INVERTED && status < 2)
|
|
status = 1 - status;
|
|
|
|
mutex_lock(&data->lock);
|
|
lp3944_reg_read(led->client, reg, &val);
|
|
|
|
val &= ~(LP3944_LED_STATUS_MASK << (id << 1));
|
|
val |= (status << (id << 1));
|
|
|
|
dev_dbg(&led->client->dev, "%s: %s, reg:%d id:%d status:%d val:%#x\n",
|
|
__func__, led->ldev.name, reg, id, status, val);
|
|
|
|
/* set led status */
|
|
err = lp3944_reg_write(led->client, reg, val);
|
|
mutex_unlock(&data->lock);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int lp3944_led_set_blink(struct led_classdev *led_cdev,
|
|
unsigned long *delay_on,
|
|
unsigned long *delay_off)
|
|
{
|
|
struct lp3944_led_data *led = ldev_to_led(led_cdev);
|
|
u16 period;
|
|
u8 duty_cycle;
|
|
int err;
|
|
|
|
/* units are in ms */
|
|
if (*delay_on + *delay_off > LP3944_PERIOD_MAX)
|
|
return -EINVAL;
|
|
|
|
if (*delay_on == 0 && *delay_off == 0) {
|
|
/* Special case: the leds subsystem requires a default user
|
|
* friendly blink pattern for the LED. Let's blink the led
|
|
* slowly (1Hz).
|
|
*/
|
|
*delay_on = 500;
|
|
*delay_off = 500;
|
|
}
|
|
|
|
period = (*delay_on) + (*delay_off);
|
|
|
|
/* duty_cycle is the percentage of period during which the led is ON */
|
|
duty_cycle = 100 * (*delay_on) / period;
|
|
|
|
/* invert duty cycle for inverted leds, this has the same effect of
|
|
* swapping delay_on and delay_off
|
|
*/
|
|
if (led->type == LP3944_LED_TYPE_LED_INVERTED)
|
|
duty_cycle = 100 - duty_cycle;
|
|
|
|
/* NOTE: using always the first DIM mode, this means that all leds
|
|
* will have the same blinking pattern.
|
|
*
|
|
* We could find a way later to have two leds blinking in hardware
|
|
* with different patterns at the same time, falling back to software
|
|
* control for the other ones.
|
|
*/
|
|
err = lp3944_dim_set_period(led->client, LP3944_DIM0, period);
|
|
if (err)
|
|
return err;
|
|
|
|
err = lp3944_dim_set_dutycycle(led->client, LP3944_DIM0, duty_cycle);
|
|
if (err)
|
|
return err;
|
|
|
|
dev_dbg(&led->client->dev, "%s: OK hardware accelerated blink!\n",
|
|
__func__);
|
|
|
|
lp3944_led_set(led, LP3944_LED_STATUS_DIM0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int lp3944_led_set_brightness(struct led_classdev *led_cdev,
|
|
enum led_brightness brightness)
|
|
{
|
|
struct lp3944_led_data *led = ldev_to_led(led_cdev);
|
|
|
|
dev_dbg(&led->client->dev, "%s: %s, %d\n",
|
|
__func__, led_cdev->name, brightness);
|
|
|
|
return lp3944_led_set(led, !!brightness);
|
|
}
|
|
|
|
static int lp3944_configure(struct i2c_client *client,
|
|
struct lp3944_data *data,
|
|
struct lp3944_platform_data *pdata)
|
|
{
|
|
int i, err = 0;
|
|
|
|
for (i = 0; i < pdata->leds_size; i++) {
|
|
struct lp3944_led *pled = &pdata->leds[i];
|
|
struct lp3944_led_data *led = &data->leds[i];
|
|
led->client = client;
|
|
led->id = i;
|
|
|
|
switch (pled->type) {
|
|
|
|
case LP3944_LED_TYPE_LED:
|
|
case LP3944_LED_TYPE_LED_INVERTED:
|
|
led->type = pled->type;
|
|
led->ldev.name = pled->name;
|
|
led->ldev.max_brightness = 1;
|
|
led->ldev.brightness_set_blocking =
|
|
lp3944_led_set_brightness;
|
|
led->ldev.blink_set = lp3944_led_set_blink;
|
|
led->ldev.flags = LED_CORE_SUSPENDRESUME;
|
|
|
|
err = led_classdev_register(&client->dev, &led->ldev);
|
|
if (err < 0) {
|
|
dev_err(&client->dev,
|
|
"couldn't register LED %s\n",
|
|
led->ldev.name);
|
|
goto exit;
|
|
}
|
|
|
|
/* to expose the default value to userspace */
|
|
led->ldev.brightness =
|
|
(enum led_brightness) pled->status;
|
|
|
|
/* Set the default led status */
|
|
err = lp3944_led_set(led, pled->status);
|
|
if (err < 0) {
|
|
dev_err(&client->dev,
|
|
"%s couldn't set STATUS %d\n",
|
|
led->ldev.name, pled->status);
|
|
goto exit;
|
|
}
|
|
break;
|
|
|
|
case LP3944_LED_TYPE_NONE:
|
|
default:
|
|
break;
|
|
|
|
}
|
|
}
|
|
return 0;
|
|
|
|
exit:
|
|
if (i > 0)
|
|
for (i = i - 1; i >= 0; i--)
|
|
switch (pdata->leds[i].type) {
|
|
|
|
case LP3944_LED_TYPE_LED:
|
|
case LP3944_LED_TYPE_LED_INVERTED:
|
|
led_classdev_unregister(&data->leds[i].ldev);
|
|
break;
|
|
|
|
case LP3944_LED_TYPE_NONE:
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static int lp3944_probe(struct i2c_client *client,
|
|
const struct i2c_device_id *id)
|
|
{
|
|
struct lp3944_platform_data *lp3944_pdata =
|
|
dev_get_platdata(&client->dev);
|
|
struct lp3944_data *data;
|
|
int err;
|
|
|
|
if (lp3944_pdata == NULL) {
|
|
dev_err(&client->dev, "no platform data\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Let's see whether this adapter can support what we need. */
|
|
if (!i2c_check_functionality(client->adapter,
|
|
I2C_FUNC_SMBUS_BYTE_DATA)) {
|
|
dev_err(&client->dev, "insufficient functionality!\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
data = devm_kzalloc(&client->dev, sizeof(struct lp3944_data),
|
|
GFP_KERNEL);
|
|
if (!data)
|
|
return -ENOMEM;
|
|
|
|
data->client = client;
|
|
i2c_set_clientdata(client, data);
|
|
|
|
mutex_init(&data->lock);
|
|
|
|
err = lp3944_configure(client, data, lp3944_pdata);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
dev_info(&client->dev, "lp3944 enabled\n");
|
|
return 0;
|
|
}
|
|
|
|
static int lp3944_remove(struct i2c_client *client)
|
|
{
|
|
struct lp3944_platform_data *pdata = dev_get_platdata(&client->dev);
|
|
struct lp3944_data *data = i2c_get_clientdata(client);
|
|
int i;
|
|
|
|
for (i = 0; i < pdata->leds_size; i++)
|
|
switch (data->leds[i].type) {
|
|
case LP3944_LED_TYPE_LED:
|
|
case LP3944_LED_TYPE_LED_INVERTED:
|
|
led_classdev_unregister(&data->leds[i].ldev);
|
|
break;
|
|
|
|
case LP3944_LED_TYPE_NONE:
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* lp3944 i2c driver struct */
|
|
static const struct i2c_device_id lp3944_id[] = {
|
|
{"lp3944", 0},
|
|
{}
|
|
};
|
|
|
|
MODULE_DEVICE_TABLE(i2c, lp3944_id);
|
|
|
|
static struct i2c_driver lp3944_driver = {
|
|
.driver = {
|
|
.name = "lp3944",
|
|
},
|
|
.probe = lp3944_probe,
|
|
.remove = lp3944_remove,
|
|
.id_table = lp3944_id,
|
|
};
|
|
|
|
module_i2c_driver(lp3944_driver);
|
|
|
|
MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");
|
|
MODULE_DESCRIPTION("LP3944 Fun Light Chip");
|
|
MODULE_LICENSE("GPL");
|