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![Boris Brezillon](/assets/img/avatar_default.png)
Call pwm_apply_args() just after requesting the PWM device so that the polarity and period are initialized according to the information provided in pwm_args. This is an intermediate state, and pwm_apply_args() should be dropped as soon as the atomic PWM infrastructure is in place and the driver makes use of it. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
330 lines
7.7 KiB
C
330 lines
7.7 KiB
C
/*
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* TI LP8788 MFD - backlight driver
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*
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* Copyright 2012 Texas Instruments
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*
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* Author: Milo(Woogyom) Kim <milo.kim@ti.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/backlight.h>
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#include <linux/err.h>
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#include <linux/mfd/lp8788.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/pwm.h>
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#include <linux/slab.h>
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/* Register address */
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#define LP8788_BL_CONFIG 0x96
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#define LP8788_BL_EN BIT(0)
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#define LP8788_BL_PWM_INPUT_EN BIT(5)
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#define LP8788_BL_FULLSCALE_SHIFT 2
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#define LP8788_BL_DIM_MODE_SHIFT 1
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#define LP8788_BL_PWM_POLARITY_SHIFT 6
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#define LP8788_BL_BRIGHTNESS 0x97
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#define LP8788_BL_RAMP 0x98
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#define LP8788_BL_RAMP_RISE_SHIFT 4
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#define MAX_BRIGHTNESS 127
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#define DEFAULT_BL_NAME "lcd-backlight"
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struct lp8788_bl_config {
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enum lp8788_bl_ctrl_mode bl_mode;
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enum lp8788_bl_dim_mode dim_mode;
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enum lp8788_bl_full_scale_current full_scale;
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enum lp8788_bl_ramp_step rise_time;
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enum lp8788_bl_ramp_step fall_time;
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enum pwm_polarity pwm_pol;
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};
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struct lp8788_bl {
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struct lp8788 *lp;
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struct backlight_device *bl_dev;
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struct lp8788_backlight_platform_data *pdata;
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enum lp8788_bl_ctrl_mode mode;
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struct pwm_device *pwm;
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};
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static struct lp8788_bl_config default_bl_config = {
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.bl_mode = LP8788_BL_REGISTER_ONLY,
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.dim_mode = LP8788_DIM_EXPONENTIAL,
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.full_scale = LP8788_FULLSCALE_1900uA,
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.rise_time = LP8788_RAMP_8192us,
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.fall_time = LP8788_RAMP_8192us,
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.pwm_pol = PWM_POLARITY_NORMAL,
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};
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static inline bool is_brightness_ctrl_by_pwm(enum lp8788_bl_ctrl_mode mode)
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{
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return mode == LP8788_BL_COMB_PWM_BASED;
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}
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static inline bool is_brightness_ctrl_by_register(enum lp8788_bl_ctrl_mode mode)
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{
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return mode == LP8788_BL_REGISTER_ONLY ||
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mode == LP8788_BL_COMB_REGISTER_BASED;
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}
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static int lp8788_backlight_configure(struct lp8788_bl *bl)
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{
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struct lp8788_backlight_platform_data *pdata = bl->pdata;
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struct lp8788_bl_config *cfg = &default_bl_config;
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int ret;
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u8 val;
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/*
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* Update chip configuration if platform data exists,
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* otherwise use the default settings.
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*/
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if (pdata) {
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cfg->bl_mode = pdata->bl_mode;
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cfg->dim_mode = pdata->dim_mode;
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cfg->full_scale = pdata->full_scale;
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cfg->rise_time = pdata->rise_time;
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cfg->fall_time = pdata->fall_time;
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cfg->pwm_pol = pdata->pwm_pol;
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}
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/* Brightness ramp up/down */
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val = (cfg->rise_time << LP8788_BL_RAMP_RISE_SHIFT) | cfg->fall_time;
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ret = lp8788_write_byte(bl->lp, LP8788_BL_RAMP, val);
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if (ret)
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return ret;
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/* Fullscale current setting */
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val = (cfg->full_scale << LP8788_BL_FULLSCALE_SHIFT) |
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(cfg->dim_mode << LP8788_BL_DIM_MODE_SHIFT);
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/* Brightness control mode */
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switch (cfg->bl_mode) {
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case LP8788_BL_REGISTER_ONLY:
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val |= LP8788_BL_EN;
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break;
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case LP8788_BL_COMB_PWM_BASED:
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case LP8788_BL_COMB_REGISTER_BASED:
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val |= LP8788_BL_EN | LP8788_BL_PWM_INPUT_EN |
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(cfg->pwm_pol << LP8788_BL_PWM_POLARITY_SHIFT);
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break;
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default:
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dev_err(bl->lp->dev, "invalid mode: %d\n", cfg->bl_mode);
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return -EINVAL;
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}
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bl->mode = cfg->bl_mode;
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return lp8788_write_byte(bl->lp, LP8788_BL_CONFIG, val);
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}
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static void lp8788_pwm_ctrl(struct lp8788_bl *bl, int br, int max_br)
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{
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unsigned int period;
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unsigned int duty;
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struct device *dev;
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struct pwm_device *pwm;
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if (!bl->pdata)
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return;
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period = bl->pdata->period_ns;
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duty = br * period / max_br;
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dev = bl->lp->dev;
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/* request PWM device with the consumer name */
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if (!bl->pwm) {
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pwm = devm_pwm_get(dev, LP8788_DEV_BACKLIGHT);
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if (IS_ERR(pwm)) {
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dev_err(dev, "can not get PWM device\n");
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return;
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}
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bl->pwm = pwm;
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/*
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* FIXME: pwm_apply_args() should be removed when switching to
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* the atomic PWM API.
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*/
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pwm_apply_args(pwm);
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}
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pwm_config(bl->pwm, duty, period);
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if (duty)
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pwm_enable(bl->pwm);
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else
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pwm_disable(bl->pwm);
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}
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static int lp8788_bl_update_status(struct backlight_device *bl_dev)
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{
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struct lp8788_bl *bl = bl_get_data(bl_dev);
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enum lp8788_bl_ctrl_mode mode = bl->mode;
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if (bl_dev->props.state & BL_CORE_SUSPENDED)
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bl_dev->props.brightness = 0;
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if (is_brightness_ctrl_by_pwm(mode)) {
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int brt = bl_dev->props.brightness;
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int max = bl_dev->props.max_brightness;
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lp8788_pwm_ctrl(bl, brt, max);
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} else if (is_brightness_ctrl_by_register(mode)) {
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u8 brt = bl_dev->props.brightness;
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lp8788_write_byte(bl->lp, LP8788_BL_BRIGHTNESS, brt);
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}
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return 0;
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}
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static const struct backlight_ops lp8788_bl_ops = {
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.options = BL_CORE_SUSPENDRESUME,
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.update_status = lp8788_bl_update_status,
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};
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static int lp8788_backlight_register(struct lp8788_bl *bl)
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{
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struct backlight_device *bl_dev;
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struct backlight_properties props;
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struct lp8788_backlight_platform_data *pdata = bl->pdata;
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int init_brt;
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char *name;
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props.type = BACKLIGHT_PLATFORM;
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props.max_brightness = MAX_BRIGHTNESS;
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/* Initial brightness */
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if (pdata)
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init_brt = min_t(int, pdata->initial_brightness,
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props.max_brightness);
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else
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init_brt = 0;
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props.brightness = init_brt;
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/* Backlight device name */
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if (!pdata || !pdata->name)
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name = DEFAULT_BL_NAME;
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else
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name = pdata->name;
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bl_dev = backlight_device_register(name, bl->lp->dev, bl,
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&lp8788_bl_ops, &props);
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if (IS_ERR(bl_dev))
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return PTR_ERR(bl_dev);
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bl->bl_dev = bl_dev;
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return 0;
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}
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static void lp8788_backlight_unregister(struct lp8788_bl *bl)
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{
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struct backlight_device *bl_dev = bl->bl_dev;
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backlight_device_unregister(bl_dev);
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}
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static ssize_t lp8788_get_bl_ctl_mode(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct lp8788_bl *bl = dev_get_drvdata(dev);
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enum lp8788_bl_ctrl_mode mode = bl->mode;
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char *strmode;
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if (is_brightness_ctrl_by_pwm(mode))
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strmode = "PWM based";
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else if (is_brightness_ctrl_by_register(mode))
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strmode = "Register based";
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else
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strmode = "Invalid mode";
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return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
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}
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static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp8788_get_bl_ctl_mode, NULL);
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static struct attribute *lp8788_attributes[] = {
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&dev_attr_bl_ctl_mode.attr,
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NULL,
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};
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static const struct attribute_group lp8788_attr_group = {
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.attrs = lp8788_attributes,
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};
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static int lp8788_backlight_probe(struct platform_device *pdev)
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{
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struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
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struct lp8788_bl *bl;
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int ret;
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bl = devm_kzalloc(lp->dev, sizeof(struct lp8788_bl), GFP_KERNEL);
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if (!bl)
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return -ENOMEM;
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bl->lp = lp;
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if (lp->pdata)
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bl->pdata = lp->pdata->bl_pdata;
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platform_set_drvdata(pdev, bl);
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ret = lp8788_backlight_configure(bl);
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if (ret) {
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dev_err(lp->dev, "backlight config err: %d\n", ret);
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goto err_dev;
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}
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ret = lp8788_backlight_register(bl);
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if (ret) {
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dev_err(lp->dev, "register backlight err: %d\n", ret);
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goto err_dev;
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}
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ret = sysfs_create_group(&pdev->dev.kobj, &lp8788_attr_group);
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if (ret) {
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dev_err(lp->dev, "register sysfs err: %d\n", ret);
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goto err_sysfs;
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}
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backlight_update_status(bl->bl_dev);
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return 0;
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err_sysfs:
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lp8788_backlight_unregister(bl);
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err_dev:
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return ret;
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}
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static int lp8788_backlight_remove(struct platform_device *pdev)
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{
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struct lp8788_bl *bl = platform_get_drvdata(pdev);
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struct backlight_device *bl_dev = bl->bl_dev;
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bl_dev->props.brightness = 0;
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backlight_update_status(bl_dev);
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sysfs_remove_group(&pdev->dev.kobj, &lp8788_attr_group);
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lp8788_backlight_unregister(bl);
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return 0;
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}
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static struct platform_driver lp8788_bl_driver = {
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.probe = lp8788_backlight_probe,
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.remove = lp8788_backlight_remove,
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.driver = {
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.name = LP8788_DEV_BACKLIGHT,
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},
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};
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module_platform_driver(lp8788_bl_driver);
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MODULE_DESCRIPTION("Texas Instruments LP8788 Backlight Driver");
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MODULE_AUTHOR("Milo Kim");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:lp8788-backlight");
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