137 lines
3.3 KiB
C
137 lines
3.3 KiB
C
/*
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* Copyright (c) 2016 Google, Inc
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* Written by Simon Glass <sjg@chromium.org>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <dm.h>
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#include <backlight.h>
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#include <pwm.h>
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#include <asm/gpio.h>
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#include <power/regulator.h>
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DECLARE_GLOBAL_DATA_PTR;
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struct pwm_backlight_priv {
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struct udevice *reg;
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struct gpio_desc enable;
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struct udevice *pwm;
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uint channel;
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uint period_ns;
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uint default_level;
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uint min_level;
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uint max_level;
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};
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static int pwm_backlight_enable(struct udevice *dev)
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{
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struct pwm_backlight_priv *priv = dev_get_priv(dev);
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struct dm_regulator_uclass_platdata *plat;
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uint duty_cycle;
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int ret;
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plat = dev_get_uclass_platdata(priv->reg);
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debug("%s: Enable '%s', regulator '%s'/'%s'\n", __func__, dev->name,
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priv->reg->name, plat->name);
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ret = regulator_set_enable(priv->reg, true);
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if (ret) {
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debug("%s: Cannot enable regulator for PWM '%s'\n", __func__,
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dev->name);
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return ret;
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}
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mdelay(120);
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duty_cycle = priv->period_ns * (priv->default_level - priv->min_level) /
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(priv->max_level - priv->min_level + 1);
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ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns,
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duty_cycle);
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if (ret)
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return ret;
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ret = pwm_set_enable(priv->pwm, priv->channel, true);
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if (ret)
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return ret;
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mdelay(10);
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dm_gpio_set_value(&priv->enable, 1);
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return 0;
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}
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static int pwm_backlight_ofdata_to_platdata(struct udevice *dev)
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{
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struct pwm_backlight_priv *priv = dev_get_priv(dev);
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struct ofnode_phandle_args args;
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int index, ret, count, len;
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const u32 *cell;
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debug("%s: start\n", __func__);
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ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev,
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"power-supply", &priv->reg);
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if (ret) {
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debug("%s: Cannot get power supply: ret=%d\n", __func__, ret);
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return ret;
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}
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ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable,
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GPIOD_IS_OUT);
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if (ret) {
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debug("%s: Warning: cannot get enable GPIO: ret=%d\n",
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__func__, ret);
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if (ret != -ENOENT)
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return ret;
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}
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ret = dev_read_phandle_with_args(dev, "pwms", "#pwm-cells", 0, 0,
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&args);
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if (ret) {
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debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret);
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return ret;
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}
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ret = uclass_get_device_by_ofnode(UCLASS_PWM, args.node, &priv->pwm);
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if (ret) {
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debug("%s: Cannot get PWM: ret=%d\n", __func__, ret);
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return ret;
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}
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priv->channel = args.args[0];
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priv->period_ns = args.args[1];
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index = dev_read_u32_default(dev, "default-brightness-level", 255);
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cell = dev_read_prop(dev, "brightness-levels", &len);
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count = len / sizeof(u32);
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if (cell && count > index) {
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priv->default_level = fdt32_to_cpu(cell[index]);
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priv->max_level = fdt32_to_cpu(cell[count - 1]);
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} else {
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priv->default_level = index;
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priv->max_level = 255;
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}
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debug("%s: done\n", __func__);
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return 0;
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}
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static int pwm_backlight_probe(struct udevice *dev)
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{
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return 0;
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}
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static const struct backlight_ops pwm_backlight_ops = {
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.enable = pwm_backlight_enable,
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};
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static const struct udevice_id pwm_backlight_ids[] = {
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{ .compatible = "pwm-backlight" },
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{ }
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};
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U_BOOT_DRIVER(pwm_backlight) = {
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.name = "pwm_backlight",
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.id = UCLASS_PANEL_BACKLIGHT,
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.of_match = pwm_backlight_ids,
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.ops = &pwm_backlight_ops,
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.ofdata_to_platdata = pwm_backlight_ofdata_to_platdata,
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.probe = pwm_backlight_probe,
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.priv_auto_alloc_size = sizeof(struct pwm_backlight_priv),
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};
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