diff options
Diffstat (limited to 'drivers/video/pwm_backlight.c')
| -rw-r--r-- | drivers/video/pwm_backlight.c | 187 |
1 files changed, 153 insertions, 34 deletions
diff --git a/drivers/video/pwm_backlight.c b/drivers/video/pwm_backlight.c index 5395317..c13a907 100644 --- a/drivers/video/pwm_backlight.c +++ b/drivers/video/pwm_backlight.c @@ -4,6 +4,8 @@ * Written by Simon Glass <sjg@chromium.org> */ +#define LOG_CATEGORY UCLASS_PANEL_BACKLIGHT + #include <common.h> #include <dm.h> #include <backlight.h> @@ -11,48 +13,156 @@ #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; + u32 *levels; + int num_levels; uint default_level; + int cur_level; uint min_level; uint max_level; + bool enabled; }; -static int pwm_backlight_enable(struct udevice *dev) +static int set_pwm(struct pwm_backlight_priv *priv) { - struct pwm_backlight_priv *priv = dev_get_priv(dev); - struct dm_regulator_uclass_platdata *plat; uint duty_cycle; int ret; - if (priv->reg) { - plat = dev_get_uclass_platdata(priv->reg); - debug("%s: Enable '%s', regulator '%s'/'%s'\n", __func__, - dev->name, priv->reg->name, plat->name); - ret = regulator_set_enable(priv->reg, true); - if (ret) { - debug("%s: Cannot enable regulator for PWM '%s'\n", - __func__, dev->name); - return ret; - } - mdelay(120); - } - - duty_cycle = priv->period_ns * (priv->default_level - priv->min_level) / + 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); + + 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", + __func__, 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 ret; + return log_ret(ret); ret = pwm_set_enable(priv->pwm, priv->channel, true); if (ret) - return ret; - mdelay(10); - dm_gpio_set_value(&priv->enable, 1); + 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; } @@ -64,31 +174,32 @@ static int pwm_backlight_ofdata_to_platdata(struct udevice *dev) int index, ret, count, len; const u32 *cell; - debug("%s: start\n", __func__); + log_debug("start\n"); ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev, "power-supply", &priv->reg); if (ret) - debug("%s: Cannot get power supply: ret=%d\n", __func__, 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) { - debug("%s: Warning: cannot get enable GPIO: ret=%d\n", - __func__, ret); + log_debug("Warning: cannot get enable GPIO: ret=%d\n", ret); if (ret != -ENOENT) - return ret; + return log_ret(ret); } ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0, &args); if (ret) { - debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret); - return 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) { - debug("%s: Cannot get PWM: ret=%d\n", __func__, ret); - return 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]; @@ -96,13 +207,20 @@ static int pwm_backlight_ofdata_to_platdata(struct udevice *dev) cell = dev_read_prop(dev, "brightness-levels", &len); count = len / sizeof(u32); if (cell && count > index) { - priv->default_level = fdt32_to_cpu(cell[index]); - priv->max_level = fdt32_to_cpu(cell[count - 1]); + 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; } - debug("%s: done\n", __func__); + priv->cur_level = priv->default_level; + log_debug("done\n"); return 0; @@ -114,7 +232,8 @@ static int pwm_backlight_probe(struct udevice *dev) } static const struct backlight_ops pwm_backlight_ops = { - .enable = pwm_backlight_enable, + .enable = pwm_backlight_enable, + .set_brightness = pwm_backlight_set_brightness, }; static const struct udevice_id pwm_backlight_ids[] = { |