Merge tag 'backlight-next-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight

Pull backlight updates from Lee Jones:
 "New Functionality:
   - Prepare and add support for ACPI enumeration; lp855x_bl

  Fix-ups:
   - Use Regmap API to conduct endianess conversions; qcom-wled
   - Remove superfluous code; qcom-wled
   - Fix formatting issues; qcom-wled

  Bug Fixes:
   - Provide error checking/validation of DT supplied strings; qcom-wled
   - Request dynamic amount of values when reading from DT; qcom-wled
   - Fix off-by-one issue when reading from DT; qcom-wled"

* tag 'backlight-next-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: qcom-wled: Respect enabled-strings in set_brightness
  backlight: qcom-wled: Remove unnecessary double whitespace
  backlight: qcom-wled: Provide enabled_strings default for WLED 4 and 5
  backlight: qcom-wled: Remove unnecessary 4th default string in WLED3
  backlight: qcom-wled: Override default length with qcom,enabled-strings
  backlight: qcom-wled: Fix off-by-one maximum with default num_strings
  backlight: qcom-wled: Use cpu_to_le16 macro to perform conversion
  backlight: qcom-wled: Pass number of elements to read to read_u32_array
  backlight: qcom-wled: Validate enabled string indices in DT
  backlight: lp855x: Add support ACPI enumeration
  backlight: lp855x: Add dev helper variable to lp855x_probe()
  backlight: lp855x: Move device_config setting out of lp855x_configure()

2 files changed, 162 insertions, 102 deletions

diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
index e94932c69f54..2b9e2bbbb03e 100644
--- a/drivers/video/backlight/lp855x_bl.c
+++ b/drivers/video/backlight/lp855x_bl.c
@@ -5,6 +5,7 @@
  *			Copyright (C) 2011 Texas Instruments
  */
 
+#include <linux/acpi.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
@@ -170,22 +171,6 @@ static int lp855x_configure(struct lp855x *lp)
 	int i, ret;
 	struct lp855x_platform_data *pd = lp->pdata;
 
-	switch (lp->chip_id) {
-	case LP8550:
-	case LP8551:
-	case LP8552:
-	case LP8553:
-	case LP8556:
-		lp->cfg = &lp855x_dev_cfg;
-		break;
-	case LP8555:
-	case LP8557:
-		lp->cfg = &lp8557_dev_cfg;
-		break;
-	default:
-		return -EINVAL;
-	}
-
 	if (lp->cfg->pre_init_device) {
 		ret = lp->cfg->pre_init_device(lp);
 		if (ret) {
@@ -346,7 +331,7 @@ static int lp855x_parse_dt(struct lp855x *lp)
 {
 	struct device *dev = lp->dev;
 	struct device_node *node = dev->of_node;
-	struct lp855x_platform_data *pdata;
+	struct lp855x_platform_data *pdata = lp->pdata;
 	int rom_length;
 
 	if (!node) {
@@ -354,10 +339,6 @@ static int lp855x_parse_dt(struct lp855x *lp)
 		return -EINVAL;
 	}
 
-	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
-	if (!pdata)
-		return -ENOMEM;
-
 	of_property_read_string(node, "bl-name", &pdata->name);
 	of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
 	of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
@@ -384,8 +365,6 @@ static int lp855x_parse_dt(struct lp855x *lp)
 		pdata->rom_data = &rom[0];
 	}
 
-	lp->pdata = pdata;
-
 	return 0;
 }
 #else
@@ -395,28 +374,89 @@ static int lp855x_parse_dt(struct lp855x *lp)
 }
 #endif
 
+static int lp855x_parse_acpi(struct lp855x *lp)
+{
+	int ret;
+
+	/*
+	 * On ACPI the device has already been initialized by the firmware
+	 * and is in register mode, so we can read back the settings from
+	 * the registers.
+	 */
+	ret = i2c_smbus_read_byte_data(lp->client, lp->cfg->reg_brightness);
+	if (ret < 0)
+		return ret;
+
+	lp->pdata->initial_brightness = ret;
+
+	ret = i2c_smbus_read_byte_data(lp->client, lp->cfg->reg_devicectrl);
+	if (ret < 0)
+		return ret;
+
+	lp->pdata->device_control = ret;
+	return 0;
+}
+
 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 {
+	const struct acpi_device_id *acpi_id = NULL;
+	struct device *dev = &cl->dev;
 	struct lp855x *lp;
 	int ret;
 
 	if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 		return -EIO;
 
-	lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
+	lp = devm_kzalloc(dev, sizeof(struct lp855x), GFP_KERNEL);
 	if (!lp)
 		return -ENOMEM;
 
 	lp->client = cl;
-	lp->dev = &cl->dev;
-	lp->chipname = id->name;
-	lp->chip_id = id->driver_data;
-	lp->pdata = dev_get_platdata(&cl->dev);
+	lp->dev = dev;
+	lp->pdata = dev_get_platdata(dev);
+
+	if (id) {
+		lp->chipname = id->name;
+		lp->chip_id = id->driver_data;
+	} else {
+		acpi_id = acpi_match_device(dev->driver->acpi_match_table, dev);
+		if (!acpi_id)
+			return -ENODEV;
+
+		lp->chipname = acpi_id->id;
+		lp->chip_id = acpi_id->driver_data;
+	}
+
+	switch (lp->chip_id) {
+	case LP8550:
+	case LP8551:
+	case LP8552:
+	case LP8553:
+	case LP8556:
+		lp->cfg = &lp855x_dev_cfg;
+		break;
+	case LP8555:
+	case LP8557:
+		lp->cfg = &lp8557_dev_cfg;
+		break;
+	default:
+		return -EINVAL;
+	}
 
 	if (!lp->pdata) {
-		ret = lp855x_parse_dt(lp);
-		if (ret < 0)
-			return ret;
+		lp->pdata = devm_kzalloc(dev, sizeof(*lp->pdata), GFP_KERNEL);
+		if (!lp->pdata)
+			return -ENOMEM;
+
+		if (id) {
+			ret = lp855x_parse_dt(lp);
+			if (ret < 0)
+				return ret;
+		} else {
+			ret = lp855x_parse_acpi(lp);
+			if (ret < 0)
+				return ret;
+		}
 	}
 
 	if (lp->pdata->period_ns > 0)
@@ -424,30 +464,27 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 	else
 		lp->mode = REGISTER_BASED;
 
-	lp->supply = devm_regulator_get(lp->dev, "power");
+	lp->supply = devm_regulator_get(dev, "power");
 	if (IS_ERR(lp->supply)) {
 		if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
 			return -EPROBE_DEFER;
 		lp->supply = NULL;
 	}
 
-	lp->enable = devm_regulator_get_optional(lp->dev, "enable");
+	lp->enable = devm_regulator_get_optional(dev, "enable");
 	if (IS_ERR(lp->enable)) {
 		ret = PTR_ERR(lp->enable);
 		if (ret == -ENODEV) {
 			lp->enable = NULL;
 		} else {
-			if (ret != -EPROBE_DEFER)
-				dev_err(lp->dev, "error getting enable regulator: %d\n",
-					ret);
-			return ret;
+			return dev_err_probe(dev, ret, "getting enable regulator\n");
 		}
 	}
 
 	if (lp->supply) {
 		ret = regulator_enable(lp->supply);
 		if (ret < 0) {
-			dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
+			dev_err(dev, "failed to enable supply: %d\n", ret);
 			return ret;
 		}
 	}
@@ -455,7 +492,7 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 	if (lp->enable) {
 		ret = regulator_enable(lp->enable);
 		if (ret < 0) {
-			dev_err(lp->dev, "failed to enable vddio: %d\n", ret);
+			dev_err(dev, "failed to enable vddio: %d\n", ret);
 			goto disable_supply;
 		}
 
@@ -470,20 +507,19 @@ static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 
 	ret = lp855x_configure(lp);
 	if (ret) {
-		dev_err(lp->dev, "device config err: %d", ret);
+		dev_err(dev, "device config err: %d", ret);
 		goto disable_vddio;
 	}
 
 	ret = lp855x_backlight_register(lp);
 	if (ret) {
-		dev_err(lp->dev,
-			"failed to register backlight. err: %d\n", ret);
+		dev_err(dev, "failed to register backlight. err: %d\n", ret);
 		goto disable_vddio;
 	}
 
-	ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
+	ret = sysfs_create_group(&dev->kobj, &lp855x_attr_group);
 	if (ret) {
-		dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
+		dev_err(dev, "failed to register sysfs. err: %d\n", ret);
 		goto disable_vddio;
 	}
 
@@ -540,10 +576,20 @@ static const struct i2c_device_id lp855x_ids[] = {
 };
 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
 
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id lp855x_acpi_match[] = {
+	/* Xiaomi specific HID used for the LP8556 on the Mi Pad 2 */
+	{ "XMCC0001", LP8556 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, lp855x_acpi_match);
+#endif
+
 static struct i2c_driver lp855x_driver = {
 	.driver = {
 		   .name = "lp855x",
 		   .of_match_table = of_match_ptr(lp855x_dt_ids),
+		   .acpi_match_table = ACPI_PTR(lp855x_acpi_match),
 		   },
 	.probe = lp855x_probe,
 	.remove = lp855x_remove,
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
index d094299c2a48..306bcc6ccb92 100644
--- a/drivers/video/backlight/qcom-wled.c
+++ b/drivers/video/backlight/qcom-wled.c
@@ -231,14 +231,14 @@ struct wled {
 static int wled3_set_brightness(struct wled *wled, u16 brightness)
 {
 	int rc, i;
-	u8 v[2];
+	__le16 v;
 
-	v[0] = brightness & 0xff;
-	v[1] = (brightness >> 8) & 0xf;
+	v = cpu_to_le16(brightness & WLED3_SINK_REG_BRIGHT_MAX);
 
-	for (i = 0;  i < wled->cfg.num_strings; ++i) {
+	for (i = 0; i < wled->cfg.num_strings; ++i) {
 		rc = regmap_bulk_write(wled->regmap, wled->ctrl_addr +
-				       WLED3_SINK_REG_BRIGHT(i), v, 2);
+				       WLED3_SINK_REG_BRIGHT(wled->cfg.enabled_strings[i]),
+				       &v, sizeof(v));
 		if (rc < 0)
 			return rc;
 	}
@@ -250,18 +250,18 @@ static int wled4_set_brightness(struct wled *wled, u16 brightness)
 {
 	int rc, i;
 	u16 low_limit = wled->max_brightness * 4 / 1000;
-	u8 v[2];
+	__le16 v;
 
 	/* WLED4's lower limit of operation is 0.4% */
 	if (brightness > 0 && brightness < low_limit)
 		brightness = low_limit;
 
-	v[0] = brightness & 0xff;
-	v[1] = (brightness >> 8) & 0xf;
+	v = cpu_to_le16(brightness & WLED3_SINK_REG_BRIGHT_MAX);
 
-	for (i = 0;  i < wled->cfg.num_strings; ++i) {
+	for (i = 0; i < wled->cfg.num_strings; ++i) {
 		rc = regmap_bulk_write(wled->regmap, wled->sink_addr +
-				       WLED4_SINK_REG_BRIGHT(i), v, 2);
+				       WLED4_SINK_REG_BRIGHT(wled->cfg.enabled_strings[i]),
+				       &v, sizeof(v));
 		if (rc < 0)
 			return rc;
 	}
@@ -273,21 +273,20 @@ static int wled5_set_brightness(struct wled *wled, u16 brightness)
 {
 	int rc, offset;
 	u16 low_limit = wled->max_brightness * 1 / 1000;
-	u8 v[2];
+	__le16 v;
 
 	/* WLED5's lower limit is 0.1% */
 	if (brightness < low_limit)
 		brightness = low_limit;
 
-	v[0] = brightness & 0xff;
-	v[1] = (brightness >> 8) & 0x7f;
+	v = cpu_to_le16(brightness & WLED5_SINK_REG_BRIGHT_MAX_15B);
 
 	offset = (wled->cfg.mod_sel == MOD_A) ?
 		  WLED5_SINK_REG_MOD_A_BRIGHTNESS_LSB :
 		  WLED5_SINK_REG_MOD_B_BRIGHTNESS_LSB;
 
 	rc = regmap_bulk_write(wled->regmap, wled->sink_addr + offset,
-			       v, 2);
+			       &v, sizeof(v));
 	return rc;
 }
 
@@ -572,7 +571,7 @@ unlock_mutex:
 
 static void wled_auto_string_detection(struct wled *wled)
 {
-	int rc = 0, i, delay_time_us;
+	int rc = 0, i, j, delay_time_us;
 	u32 sink_config = 0;
 	u8 sink_test = 0, sink_valid = 0, val;
 	bool fault_set;
@@ -619,14 +618,15 @@ static void wled_auto_string_detection(struct wled *wled)
 
 	/* Iterate through the strings one by one */
 	for (i = 0; i < wled->cfg.num_strings; i++) {
-		sink_test = BIT((WLED4_SINK_REG_CURR_SINK_SHFT + i));
+		j = wled->cfg.enabled_strings[i];
+		sink_test = BIT((WLED4_SINK_REG_CURR_SINK_SHFT + j));
 
 		/* Enable feedback control */
 		rc = regmap_write(wled->regmap, wled->ctrl_addr +
-				  WLED3_CTRL_REG_FEEDBACK_CONTROL, i + 1);
+				  WLED3_CTRL_REG_FEEDBACK_CONTROL, j + 1);
 		if (rc < 0) {
 			dev_err(wled->dev, "Failed to enable feedback for SINK %d rc = %d\n",
-				i + 1, rc);
+				j + 1, rc);
 			goto failed_detect;
 		}
 
@@ -635,7 +635,7 @@ static void wled_auto_string_detection(struct wled *wled)
 				  WLED4_SINK_REG_CURR_SINK, sink_test);
 		if (rc < 0) {
 			dev_err(wled->dev, "Failed to configure SINK %d rc=%d\n",
-				i + 1, rc);
+				j + 1, rc);
 			goto failed_detect;
 		}
 
@@ -662,7 +662,7 @@ static void wled_auto_string_detection(struct wled *wled)
 
 		if (fault_set)
 			dev_dbg(wled->dev, "WLED OVP fault detected with SINK %d\n",
-				i + 1);
+				j + 1);
 		else
 			sink_valid |= sink_test;
 
@@ -702,15 +702,16 @@ static void wled_auto_string_detection(struct wled *wled)
 	/* Enable valid sinks */
 	if (wled->version == 4) {
 		for (i = 0; i < wled->cfg.num_strings; i++) {
+			j = wled->cfg.enabled_strings[i];
 			if (sink_config &
-			    BIT(WLED4_SINK_REG_CURR_SINK_SHFT + i))
+			    BIT(WLED4_SINK_REG_CURR_SINK_SHFT + j))
 				val = WLED4_SINK_REG_STR_MOD_MASK;
 			else
 				/* Disable modulator_en for unused sink */
 				val = 0;
 
 			rc = regmap_write(wled->regmap, wled->sink_addr +
-					  WLED4_SINK_REG_STR_MOD_EN(i), val);
+					  WLED4_SINK_REG_STR_MOD_EN(j), val);
 			if (rc < 0) {
 				dev_err(wled->dev, "Failed to configure MODULATOR_EN rc=%d\n",
 					rc);
@@ -949,7 +950,7 @@ static const struct wled_config wled3_config_defaults = {
 	.cs_out_en = false,
 	.ext_gen = false,
 	.cabc = false,
-	.enabled_strings = {0, 1, 2, 3},
+	.enabled_strings = {0, 1, 2},
 };
 
 static int wled4_setup(struct wled *wled)
@@ -1080,6 +1081,7 @@ static const struct wled_config wled4_config_defaults = {
 	.cabc = false,
 	.external_pfet = false,
 	.auto_detection_enabled = false,
+	.enabled_strings = {0, 1, 2, 3},
 };
 
 static int wled5_setup(struct wled *wled)
@@ -1193,6 +1195,7 @@ static const struct wled_config wled5_config_defaults = {
 	.cabc = false,
 	.external_pfet = false,
 	.auto_detection_enabled = false,
+	.enabled_strings = {0, 1, 2, 3},
 };
 
 static const u32 wled3_boost_i_limit_values[] = {
@@ -1256,21 +1259,6 @@ static const struct wled_var_cfg wled5_ovp_cfg = {
 	.size = 16,
 };
 
-static u32 wled3_num_strings_values_fn(u32 idx)
-{
-	return idx + 1;
-}
-
-static const struct wled_var_cfg wled3_num_strings_cfg = {
-	.fn = wled3_num_strings_values_fn,
-	.size = 3,
-};
-
-static const struct wled_var_cfg wled4_num_strings_cfg = {
-	.fn = wled3_num_strings_values_fn,
-	.size = 4,
-};
-
 static u32 wled3_switch_freq_values_fn(u32 idx)
 {
 	return 19200 / (2 * (1 + idx));
@@ -1344,11 +1332,6 @@ static int wled_configure(struct wled *wled)
 			.val_ptr = &cfg->switch_freq,
 			.cfg = &wled3_switch_freq_cfg,
 		},
-		{
-			.name = "qcom,num-strings",
-			.val_ptr = &cfg->num_strings,
-			.cfg = &wled3_num_strings_cfg,
-		},
 	};
 
 	const struct wled_u32_opts wled4_opts[] = {
@@ -1372,11 +1355,6 @@ static int wled_configure(struct wled *wled)
 			.val_ptr = &cfg->switch_freq,
 			.cfg = &wled3_switch_freq_cfg,
 		},
-		{
-			.name = "qcom,num-strings",
-			.val_ptr = &cfg->num_strings,
-			.cfg = &wled4_num_strings_cfg,
-		},
 	};
 
 	const struct wled_u32_opts wled5_opts[] = {
@@ -1401,11 +1379,6 @@ static int wled_configure(struct wled *wled)
 			.cfg = &wled3_switch_freq_cfg,
 		},
 		{
-			.name = "qcom,num-strings",
-			.val_ptr = &cfg->num_strings,
-			.cfg = &wled4_num_strings_cfg,
-		},
-		{
 			.name = "qcom,modulator-sel",
 			.val_ptr = &cfg->mod_sel,
 			.cfg = &wled5_mod_sel_cfg,
@@ -1523,16 +1496,57 @@ static int wled_configure(struct wled *wled)
 			*bool_opts[i].val_ptr = true;
 	}
 
-	cfg->num_strings = cfg->num_strings + 1;
-
 	string_len = of_property_count_elems_of_size(dev->of_node,
 						     "qcom,enabled-strings",
 						     sizeof(u32));
-	if (string_len > 0)
-		of_property_read_u32_array(dev->of_node,
+	if (string_len > 0) {
+		if (string_len > wled->max_string_count) {
+			dev_err(dev, "Cannot have more than %d strings\n",
+				wled->max_string_count);
+			return -EINVAL;
+		}
+
+		rc = of_property_read_u32_array(dev->of_node,
 						"qcom,enabled-strings",
 						wled->cfg.enabled_strings,
-						sizeof(u32));
+						string_len);
+		if (rc) {
+			dev_err(dev, "Failed to read %d elements from qcom,enabled-strings: %d\n",
+				string_len, rc);
+			return rc;
+		}
+
+		for (i = 0; i < string_len; ++i) {
+			if (wled->cfg.enabled_strings[i] >= wled->max_string_count) {
+				dev_err(dev,
+					"qcom,enabled-strings index %d at %d is out of bounds\n",
+					wled->cfg.enabled_strings[i], i);
+				return -EINVAL;
+			}
+		}
+
+		cfg->num_strings = string_len;
+	}
+
+	rc = of_property_read_u32(dev->of_node, "qcom,num-strings", &val);
+	if (!rc) {
+		if (val < 1 || val > wled->max_string_count) {
+			dev_err(dev, "qcom,num-strings must be between 1 and %d\n",
+				wled->max_string_count);
+			return -EINVAL;
+		}
+
+		if (string_len > 0) {
+			dev_warn(dev, "Only one of qcom,num-strings or qcom,enabled-strings"
+				      " should be set\n");
+			if (val > string_len) {
+				dev_err(dev, "qcom,num-strings exceeds qcom,enabled-strings\n");
+				return -EINVAL;
+			}
+		}
+
+		cfg->num_strings = val;
+	}
 
 	return 0;
 }