summaryrefslogtreecommitdiffstats
path: root/drivers/video/backlight/rt4831-backlight.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/video/backlight/rt4831-backlight.c')
-rw-r--r--drivers/video/backlight/rt4831-backlight.c232
1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/video/backlight/rt4831-backlight.c b/drivers/video/backlight/rt4831-backlight.c
new file mode 100644
index 0000000000..7d1af4c2ca
--- /dev/null
+++ b/drivers/video/backlight/rt4831-backlight.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <dt-bindings/leds/rt4831-backlight.h>
+#include <linux/backlight.h>
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define RT4831_REG_BLCFG 0x02
+#define RT4831_REG_BLDIML 0x04
+#define RT4831_REG_ENABLE 0x08
+#define RT4831_REG_BLOPT2 0x11
+
+#define RT4831_BLMAX_BRIGHTNESS 2048
+
+#define RT4831_BLOVP_MASK GENMASK(7, 5)
+#define RT4831_BLOVP_SHIFT 5
+#define RT4831_BLPWMEN_MASK BIT(0)
+#define RT4831_BLEN_MASK BIT(4)
+#define RT4831_BLCH_MASK GENMASK(3, 0)
+#define RT4831_BLDIML_MASK GENMASK(2, 0)
+#define RT4831_BLDIMH_MASK GENMASK(10, 3)
+#define RT4831_BLDIMH_SHIFT 3
+#define RT4831_BLOCP_MASK GENMASK(1, 0)
+
+#define RT4831_BLOCP_MINUA 900000
+#define RT4831_BLOCP_MAXUA 1800000
+#define RT4831_BLOCP_STEPUA 300000
+
+struct rt4831_priv {
+ struct device *dev;
+ struct regmap *regmap;
+ struct backlight_device *bl;
+};
+
+static int rt4831_bl_update_status(struct backlight_device *bl_dev)
+{
+ struct rt4831_priv *priv = bl_get_data(bl_dev);
+ int brightness = backlight_get_brightness(bl_dev);
+ unsigned int enable = brightness ? RT4831_BLEN_MASK : 0;
+ u8 v[2];
+ int ret;
+
+ if (brightness) {
+ v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
+ v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;
+
+ ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
+ if (ret)
+ return ret;
+ }
+
+ return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);
+
+}
+
+static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
+{
+ struct rt4831_priv *priv = bl_get_data(bl_dev);
+ unsigned int val;
+ u8 v[2];
+ int ret;
+
+ ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
+ if (ret)
+ return ret;
+
+ if (!(val & RT4831_BLEN_MASK))
+ return 0;
+
+ ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
+ if (ret)
+ return ret;
+
+ ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;
+
+ return ret;
+}
+
+static const struct backlight_ops rt4831_bl_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .update_status = rt4831_bl_update_status,
+ .get_brightness = rt4831_bl_get_brightness,
+};
+
+static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
+ struct backlight_properties *bl_props)
+{
+ struct device *dev = priv->dev;
+ u8 propval;
+ u32 brightness, ocp_uA;
+ unsigned int val = 0;
+ int ret;
+
+ /* common properties */
+ ret = device_property_read_u32(dev, "max-brightness", &brightness);
+ if (ret)
+ brightness = RT4831_BLMAX_BRIGHTNESS;
+
+ bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);
+
+ ret = device_property_read_u32(dev, "default-brightness", &brightness);
+ if (ret)
+ brightness = bl_props->max_brightness;
+
+ bl_props->brightness = min_t(u32, brightness, bl_props->max_brightness);
+
+ /* vendor properties */
+ if (device_property_read_bool(dev, "richtek,pwm-enable"))
+ val = RT4831_BLPWMEN_MASK;
+
+ ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
+ if (ret)
+ return ret;
+
+ ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
+ if (ret)
+ propval = RT4831_BLOVPLVL_21V;
+
+ propval = min_t(u8, propval, RT4831_BLOVPLVL_29V);
+ ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLOVP_MASK,
+ propval << RT4831_BLOVP_SHIFT);
+ if (ret)
+ return ret;
+
+ /*
+ * This OCP level is used to protect and limit the inductor current.
+ * If inductor peak current reach the level, low-side MOSFET will be
+ * turned off. Meanwhile, the output channel current may be limited.
+ * To match the configured channel current, the inductor chosen must
+ * be higher than the OCP level.
+ *
+ * Not like the OVP level, the default 21V can be used in the most
+ * application. But if the chosen OCP level is smaller than needed,
+ * it will also affect the backlight channel output current to be
+ * smaller than the register setting.
+ */
+ ret = device_property_read_u32(dev, "richtek,bled-ocp-microamp",
+ &ocp_uA);
+ if (!ret) {
+ ocp_uA = clamp_val(ocp_uA, RT4831_BLOCP_MINUA,
+ RT4831_BLOCP_MAXUA);
+ val = DIV_ROUND_UP(ocp_uA - RT4831_BLOCP_MINUA,
+ RT4831_BLOCP_STEPUA);
+ ret = regmap_update_bits(priv->regmap, RT4831_REG_BLOPT2,
+ RT4831_BLOCP_MASK, val);
+ if (ret)
+ return ret;
+ }
+
+ ret = device_property_read_u8(dev, "richtek,channel-use", &propval);
+ if (ret) {
+ dev_err(dev, "richtek,channel-use DT property missing\n");
+ return ret;
+ }
+
+ if (!(propval & RT4831_BLCH_MASK)) {
+ dev_err(dev, "No channel specified\n");
+ return -EINVAL;
+ }
+
+ return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
+}
+
+static int rt4831_bl_probe(struct platform_device *pdev)
+{
+ struct rt4831_priv *priv;
+ struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
+ .scale = BACKLIGHT_SCALE_LINEAR };
+ int ret;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = &pdev->dev;
+
+ priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+ if (!priv->regmap) {
+ dev_err(&pdev->dev, "Failed to init regmap\n");
+ return -ENODEV;
+ }
+
+ ret = rt4831_parse_backlight_properties(priv, &bl_props);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to parse backlight properties\n");
+ return ret;
+ }
+
+ priv->bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, priv,
+ &rt4831_bl_ops, &bl_props);
+ if (IS_ERR(priv->bl)) {
+ dev_err(&pdev->dev, "Failed to register backlight\n");
+ return PTR_ERR(priv->bl);
+ }
+
+ backlight_update_status(priv->bl);
+ platform_set_drvdata(pdev, priv);
+
+ return 0;
+}
+
+static void rt4831_bl_remove(struct platform_device *pdev)
+{
+ struct rt4831_priv *priv = platform_get_drvdata(pdev);
+ struct backlight_device *bl_dev = priv->bl;
+
+ bl_dev->props.brightness = 0;
+ backlight_update_status(priv->bl);
+}
+
+static const struct of_device_id __maybe_unused rt4831_bl_of_match[] = {
+ { .compatible = "richtek,rt4831-backlight", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);
+
+static struct platform_driver rt4831_bl_driver = {
+ .driver = {
+ .name = "rt4831-backlight",
+ .of_match_table = rt4831_bl_of_match,
+ },
+ .probe = rt4831_bl_probe,
+ .remove_new = rt4831_bl_remove,
+};
+module_platform_driver(rt4831_bl_driver);
+
+MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
+MODULE_LICENSE("GPL v2");