diff options
Diffstat (limited to 'drivers/leds/leds-lp3944.c')
-rw-r--r-- | drivers/leds/leds-lp3944.c | 439 |
1 files changed, 439 insertions, 0 deletions
diff --git a/drivers/leds/leds-lp3944.c b/drivers/leds/leds-lp3944.c new file mode 100644 index 0000000000..8ea746c499 --- /dev/null +++ b/drivers/leds/leds-lp3944.c @@ -0,0 +1,439 @@ +// 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) +{ + 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 void 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; + } +} + +/* 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"); |