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