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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * Copyright (c) 2016 Google, Inc
- * Written by Simon Glass <sjg@chromium.org>
- */
- #define LOG_CATEGORY UCLASS_PANEL_BACKLIGHT
- #include <common.h>
- #include <dm.h>
- #include <backlight.h>
- #include <malloc.h>
- #include <pwm.h>
- #include <asm/gpio.h>
- #include <power/regulator.h>
- /**
- * Private information for the PWM backlight
- *
- * If @num_levels is 0 then the levels are simple values with the backlight
- * value going between the minimum (default 0) and the maximum (default 255).
- * Otherwise the levels are an index into @levels (0..n-1).
- *
- * @reg: Regulator to enable to turn the backlight on (NULL if none)
- * @enable, GPIO to set to enable the backlight (can be missing)
- * @pwm: PWM to use to change the backlight brightness
- * @channel: PWM channel to use
- * @period_ns: Period of the backlight in nanoseconds
- * @levels: Levels for the backlight, or NULL if not using indexed levels
- * @num_levels: Number of levels
- * @cur_level: Current level for the backlight (index or value)
- * @default_level: Default level for the backlight (index or value)
- * @min_level: Minimum level of the backlight (full off)
- * @min_level: Maximum level of the backlight (full on)
- * @enabled: true if backlight is enabled
- */
- struct pwm_backlight_priv {
- struct udevice *reg;
- struct gpio_desc enable;
- struct udevice *pwm;
- uint channel;
- uint period_ns;
- /*
- * the polarity of one PWM
- * 0: normal polarity
- * 1: inverted polarity
- */
- bool polarity;
- u32 *levels;
- int num_levels;
- uint default_level;
- int cur_level;
- uint min_level;
- uint max_level;
- bool enabled;
- };
- static int set_pwm(struct pwm_backlight_priv *priv)
- {
- uint duty_cycle;
- int ret;
- duty_cycle = priv->period_ns * (priv->cur_level - priv->min_level) /
- (priv->max_level - priv->min_level + 1);
- ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns,
- duty_cycle);
- if (ret)
- return log_ret(ret);
- ret = pwm_set_invert(priv->pwm, priv->channel, priv->polarity);
- if (ret == -ENOSYS && !priv->polarity)
- ret = 0;
- return log_ret(ret);
- }
- static int enable_sequence(struct udevice *dev, int seq)
- {
- struct pwm_backlight_priv *priv = dev_get_priv(dev);
- int ret;
- switch (seq) {
- case 0:
- if (priv->reg) {
- __maybe_unused struct dm_regulator_uclass_platdata
- *plat;
- plat = dev_get_uclass_platdata(priv->reg);
- log_debug("Enable '%s', regulator '%s'/'%s'\n",
- dev->name, priv->reg->name, plat->name);
- ret = regulator_set_enable(priv->reg, true);
- if (ret) {
- log_debug("Cannot enable regulator for PWM '%s'\n",
- dev->name);
- return log_ret(ret);
- }
- mdelay(120);
- }
- break;
- case 1:
- mdelay(10);
- dm_gpio_set_value(&priv->enable, 1);
- break;
- }
- return 0;
- }
- static int pwm_backlight_enable(struct udevice *dev)
- {
- struct pwm_backlight_priv *priv = dev_get_priv(dev);
- int ret;
- ret = enable_sequence(dev, 0);
- if (ret)
- return log_ret(ret);
- ret = set_pwm(priv);
- if (ret)
- return log_ret(ret);
- ret = pwm_set_enable(priv->pwm, priv->channel, true);
- if (ret)
- return log_ret(ret);
- ret = enable_sequence(dev, 1);
- if (ret)
- return log_ret(ret);
- priv->enabled = true;
- return 0;
- }
- static int pwm_backlight_set_brightness(struct udevice *dev, int percent)
- {
- struct pwm_backlight_priv *priv = dev_get_priv(dev);
- bool disable = false;
- int level;
- int ret;
- if (!priv->enabled) {
- ret = enable_sequence(dev, 0);
- if (ret)
- return log_ret(ret);
- }
- if (percent == BACKLIGHT_OFF) {
- disable = true;
- percent = 0;
- }
- if (percent == BACKLIGHT_DEFAULT) {
- level = priv->default_level;
- } else {
- if (priv->levels) {
- level = priv->levels[percent * (priv->num_levels - 1)
- / 100];
- } else {
- level = priv->min_level +
- (priv->max_level - priv->min_level) *
- percent / 100;
- }
- }
- priv->cur_level = level;
- ret = set_pwm(priv);
- if (ret)
- return log_ret(ret);
- if (!priv->enabled) {
- ret = enable_sequence(dev, 1);
- if (ret)
- return log_ret(ret);
- priv->enabled = true;
- }
- if (disable) {
- dm_gpio_set_value(&priv->enable, 0);
- if (priv->reg) {
- ret = regulator_set_enable(priv->reg, false);
- if (ret)
- return log_ret(ret);
- }
- priv->enabled = false;
- }
- return 0;
- }
- static int pwm_backlight_ofdata_to_platdata(struct udevice *dev)
- {
- struct pwm_backlight_priv *priv = dev_get_priv(dev);
- struct ofnode_phandle_args args;
- int index, ret, count, len;
- const u32 *cell;
- log_debug("start\n");
- ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev,
- "power-supply", &priv->reg);
- if (ret)
- log_debug("Cannot get power supply: ret=%d\n", ret);
- ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable,
- GPIOD_IS_OUT);
- if (ret) {
- log_debug("Warning: cannot get enable GPIO: ret=%d\n", ret);
- if (ret != -ENOENT)
- return log_ret(ret);
- }
- ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0,
- &args);
- if (ret) {
- log_debug("Cannot get PWM phandle: ret=%d\n", ret);
- return log_ret(ret);
- }
- ret = uclass_get_device_by_ofnode(UCLASS_PWM, args.node, &priv->pwm);
- if (ret) {
- log_debug("Cannot get PWM: ret=%d\n", ret);
- return log_ret(ret);
- }
- if (args.args_count < 2)
- return log_msg_ret("Not enough arguments to pwm\n", -EINVAL);
- priv->channel = args.args[0];
- priv->period_ns = args.args[1];
- if (args.args_count > 2)
- priv->polarity = args.args[2];
- index = dev_read_u32_default(dev, "default-brightness-level", 255);
- cell = dev_read_prop(dev, "brightness-levels", &len);
- count = len / sizeof(u32);
- if (cell && count > index) {
- priv->levels = malloc(len);
- if (!priv->levels)
- return log_ret(-ENOMEM);
- dev_read_u32_array(dev, "brightness-levels", priv->levels,
- count);
- priv->num_levels = count;
- priv->default_level = priv->levels[index];
- priv->max_level = priv->levels[count - 1];
- } else {
- priv->default_level = index;
- priv->max_level = 255;
- }
- priv->cur_level = priv->default_level;
- log_debug("done\n");
- return 0;
- }
- static int pwm_backlight_probe(struct udevice *dev)
- {
- return 0;
- }
- static const struct backlight_ops pwm_backlight_ops = {
- .enable = pwm_backlight_enable,
- .set_brightness = pwm_backlight_set_brightness,
- };
- static const struct udevice_id pwm_backlight_ids[] = {
- { .compatible = "pwm-backlight" },
- { }
- };
- U_BOOT_DRIVER(pwm_backlight) = {
- .name = "pwm_backlight",
- .id = UCLASS_PANEL_BACKLIGHT,
- .of_match = pwm_backlight_ids,
- .ops = &pwm_backlight_ops,
- .ofdata_to_platdata = pwm_backlight_ofdata_to_platdata,
- .probe = pwm_backlight_probe,
- .priv_auto_alloc_size = sizeof(struct pwm_backlight_priv),
- };
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