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linux/drivers/leds/leds-lp3944.c
Wolfram Sang fbae3fb154 i2c: Remove all i2c_set_clientdata(client, NULL) in drivers 
I2C drivers can use the clientdata-pointer to point to private data. As I2C
devices are not really unregistered, but merely detached from their driver, it
used to be the drivers obligation to clear this pointer during remove() or a
failed probe(). As a couple of drivers forgot to do this, it was agreed that it
was cleaner if the i2c-core does this clearance when appropriate, as there is
no guarantee for the lifetime of the clientdata-pointer after remove() anyhow.
This feature was added to the core with commit
e4a7b9b04d to fix the faulty drivers.

As there is no need anymore to clear the clientdata-pointer, remove all current
occurrences in the drivers to simplify the code and prevent confusion.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2010-06-03 11:33:58 +02:00

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/*
* leds-lp3944.c - driver for National Semiconductor LP3944 Funlight Chip
*
* Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it>
*
* 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.
*
*/
/*
* 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/workqueue.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;
enum lp3944_status status;
struct led_classdev ldev;
struct i2c_client *client;
struct work_struct work;
};
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 -EINVAL;
*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);
}
/**
* 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;
}
/**
* 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;
}
/**
* 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 only 0 and 1, leave unchanged the other values,
* remember we are abusing status to set blink patterns
*/
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__);
led->status = LP3944_LED_STATUS_DIM0;
schedule_work(&led->work);
return 0;
}
static void 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);
led->status = brightness;
schedule_work(&led->work);
}
static void lp3944_led_work(struct work_struct *work)
{
struct lp3944_led_data *led;
led = container_of(work, struct lp3944_led_data, work);
lp3944_led_set(led, led->status);
}
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->status = pled->status;
led->ldev.name = pled->name;
led->ldev.max_brightness = 1;
led->ldev.brightness_set = lp3944_led_set_brightness;
led->ldev.blink_set = lp3944_led_set_blink;
led->ldev.flags = LED_CORE_SUSPENDRESUME;
INIT_WORK(&led->work, lp3944_led_work);
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 = led->status;
/* Set the default led status */
err = lp3944_led_set(led, led->status);
if (err < 0) {
dev_err(&client->dev,
"%s couldn't set STATUS %d\n",
led->ldev.name, led->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);
cancel_work_sync(&data->leds[i].work);
break;
case LP3944_LED_TYPE_NONE:
default:
break;
}
return err;
}
static int __devinit lp3944_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct lp3944_platform_data *lp3944_pdata = client->dev.platform_data;
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 = kzalloc(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) {
kfree(data);
return err;
}
dev_info(&client->dev, "lp3944 enabled\n");
return 0;
}
static int __devexit lp3944_remove(struct i2c_client *client)
{
struct lp3944_platform_data *pdata = client->dev.platform_data;
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);
cancel_work_sync(&data->leds[i].work);
break;
case LP3944_LED_TYPE_NONE:
default:
break;
}
kfree(data);
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 = __devexit_p(lp3944_remove),
.id_table = lp3944_id,
};
static int __init lp3944_module_init(void)
{
return i2c_add_driver(&lp3944_driver);
}
static void __exit lp3944_module_exit(void)
{
i2c_del_driver(&lp3944_driver);
}
module_init(lp3944_module_init);
module_exit(lp3944_module_exit);
MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");
MODULE_DESCRIPTION("LP3944 Fun Light Chip");
MODULE_LICENSE("GPL");
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