233 lines
6.2 KiB
C
233 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <dt-bindings/leds/rt4831-backlight.h>
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#include <linux/backlight.h>
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#include <linux/bitops.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/property.h>
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#include <linux/regmap.h>
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#define RT4831_REG_BLCFG 0x02
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#define RT4831_REG_BLDIML 0x04
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#define RT4831_REG_ENABLE 0x08
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#define RT4831_REG_BLOPT2 0x11
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#define RT4831_BLMAX_BRIGHTNESS 2048
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#define RT4831_BLOVP_MASK GENMASK(7, 5)
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#define RT4831_BLOVP_SHIFT 5
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#define RT4831_BLPWMEN_MASK BIT(0)
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#define RT4831_BLEN_MASK BIT(4)
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#define RT4831_BLCH_MASK GENMASK(3, 0)
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#define RT4831_BLDIML_MASK GENMASK(2, 0)
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#define RT4831_BLDIMH_MASK GENMASK(10, 3)
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#define RT4831_BLDIMH_SHIFT 3
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#define RT4831_BLOCP_MASK GENMASK(1, 0)
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#define RT4831_BLOCP_MINUA 900000
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#define RT4831_BLOCP_MAXUA 1800000
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#define RT4831_BLOCP_STEPUA 300000
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struct rt4831_priv {
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struct device *dev;
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struct regmap *regmap;
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struct backlight_device *bl;
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};
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static int rt4831_bl_update_status(struct backlight_device *bl_dev)
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{
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struct rt4831_priv *priv = bl_get_data(bl_dev);
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int brightness = backlight_get_brightness(bl_dev);
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unsigned int enable = brightness ? RT4831_BLEN_MASK : 0;
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u8 v[2];
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int ret;
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if (brightness) {
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v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
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v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;
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ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
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if (ret)
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return ret;
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}
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return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);
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}
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static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
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{
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struct rt4831_priv *priv = bl_get_data(bl_dev);
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unsigned int val;
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u8 v[2];
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int ret;
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ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
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if (ret)
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return ret;
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if (!(val & RT4831_BLEN_MASK))
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return 0;
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ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
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if (ret)
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return ret;
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ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;
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return ret;
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}
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static const struct backlight_ops rt4831_bl_ops = {
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.options = BL_CORE_SUSPENDRESUME,
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.update_status = rt4831_bl_update_status,
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.get_brightness = rt4831_bl_get_brightness,
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};
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static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
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struct backlight_properties *bl_props)
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{
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struct device *dev = priv->dev;
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u8 propval;
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u32 brightness, ocp_uA;
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unsigned int val = 0;
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int ret;
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/* common properties */
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ret = device_property_read_u32(dev, "max-brightness", &brightness);
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if (ret)
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brightness = RT4831_BLMAX_BRIGHTNESS;
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bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);
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ret = device_property_read_u32(dev, "default-brightness", &brightness);
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if (ret)
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brightness = bl_props->max_brightness;
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bl_props->brightness = min_t(u32, brightness, bl_props->max_brightness);
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/* vendor properties */
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if (device_property_read_bool(dev, "richtek,pwm-enable"))
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val = RT4831_BLPWMEN_MASK;
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ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
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if (ret)
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return ret;
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ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
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if (ret)
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propval = RT4831_BLOVPLVL_21V;
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propval = min_t(u8, propval, RT4831_BLOVPLVL_29V);
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ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLOVP_MASK,
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propval << RT4831_BLOVP_SHIFT);
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if (ret)
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return ret;
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/*
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* This OCP level is used to protect and limit the inductor current.
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* If inductor peak current reach the level, low-side MOSFET will be
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* turned off. Meanwhile, the output channel current may be limited.
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* To match the configured channel current, the inductor chosen must
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* be higher than the OCP level.
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*
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* Not like the OVP level, the default 21V can be used in the most
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* application. But if the chosen OCP level is smaller than needed,
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* it will also affect the backlight channel output current to be
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* smaller than the register setting.
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*/
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ret = device_property_read_u32(dev, "richtek,bled-ocp-microamp",
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&ocp_uA);
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if (!ret) {
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ocp_uA = clamp_val(ocp_uA, RT4831_BLOCP_MINUA,
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RT4831_BLOCP_MAXUA);
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val = DIV_ROUND_UP(ocp_uA - RT4831_BLOCP_MINUA,
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RT4831_BLOCP_STEPUA);
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ret = regmap_update_bits(priv->regmap, RT4831_REG_BLOPT2,
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RT4831_BLOCP_MASK, val);
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if (ret)
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return ret;
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}
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ret = device_property_read_u8(dev, "richtek,channel-use", &propval);
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if (ret) {
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dev_err(dev, "richtek,channel-use DT property missing\n");
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return ret;
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}
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if (!(propval & RT4831_BLCH_MASK)) {
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dev_err(dev, "No channel specified\n");
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return -EINVAL;
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}
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return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
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}
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static int rt4831_bl_probe(struct platform_device *pdev)
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{
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struct rt4831_priv *priv;
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struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
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.scale = BACKLIGHT_SCALE_LINEAR };
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int ret;
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->dev = &pdev->dev;
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priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
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if (!priv->regmap) {
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dev_err(&pdev->dev, "Failed to init regmap\n");
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return -ENODEV;
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}
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ret = rt4831_parse_backlight_properties(priv, &bl_props);
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if (ret) {
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dev_err(&pdev->dev, "Failed to parse backlight properties\n");
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return ret;
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}
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priv->bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, priv,
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&rt4831_bl_ops, &bl_props);
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if (IS_ERR(priv->bl)) {
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dev_err(&pdev->dev, "Failed to register backlight\n");
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return PTR_ERR(priv->bl);
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}
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backlight_update_status(priv->bl);
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platform_set_drvdata(pdev, priv);
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return 0;
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}
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static void rt4831_bl_remove(struct platform_device *pdev)
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{
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struct rt4831_priv *priv = platform_get_drvdata(pdev);
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struct backlight_device *bl_dev = priv->bl;
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bl_dev->props.brightness = 0;
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backlight_update_status(priv->bl);
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}
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static const struct of_device_id __maybe_unused rt4831_bl_of_match[] = {
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{ .compatible = "richtek,rt4831-backlight", },
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{}
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};
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MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);
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static struct platform_driver rt4831_bl_driver = {
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.driver = {
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.name = "rt4831-backlight",
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.of_match_table = rt4831_bl_of_match,
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},
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.probe = rt4831_bl_probe,
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.remove_new = rt4831_bl_remove,
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};
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module_platform_driver(rt4831_bl_driver);
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MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
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MODULE_LICENSE("GPL v2");
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