[PATCH v4 3/5] backlight: lm3533: Support initialization from Device Tree

[Bjorn Andersson <bjorn.andersson@linaro.org>]

From: Bjorn Andersson <bjorn.andersson@sonymobile.com>

Implement support for initialization of the lm3533 backlight from Device
Tree.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---

This patch only depends on the acceptance of the DT binding (doesn't have to be
merged together with the mfd patch).

Changes since v3:
- Moved backlight DT parsing from mfd driver
- Gave driver its own compatible

 drivers/video/backlight/lm3533_bl.c | 98 +++++++++++++++++++++++++++++++++++--
 1 file changed, 95 insertions(+), 3 deletions(-)

diff --git a/drivers/video/backlight/lm3533_bl.c b/drivers/video/backlight/lm3533_bl.c
index 0e2337f367b6..2f132199e604 100644
--- a/drivers/video/backlight/lm3533_bl.c
+++ b/drivers/video/backlight/lm3533_bl.c
@@ -22,6 +22,7 @@
 
 
 #define LM3533_HVCTRLBANK_COUNT		2
+#define LM3533_BL_DEFAULT_BRIGHTNESS	200
 #define LM3533_BL_MAX_BRIGHTNESS	255
 
 #define LM3533_REG_CTRLBANK_AB_BCONF	0x1a
@@ -269,6 +270,86 @@ static int lm3533_bl_setup(struct lm3533_bl *bl,
 	return lm3533_ctrlbank_set_pwm(&bl->cb, pdata->pwm);
 }
 
+static int lm3533_of_parse_pwm_zones(struct device_node *node)
+{
+	const char *propname = "ti,pwm-zones";
+	u32 zones[5];
+	int count;
+	int ret;
+	int i;
+
+	count = of_property_count_u32_elems(node, propname);
+	if (count == -EINVAL)
+		return 0;
+	if (count <= 0)
+		return count;
+	if (count >= ARRAY_SIZE(zones))
+		return -EINVAL;
+
+	ret = of_property_read_u32_array(node, propname, zones, count);
+	if (ret < 0)
+		return ret;
+
+	/* Enable pwm input, and enable the selected zones */
+	ret = BIT(0);
+	for (i = 0; i < count; i++)
+		ret |= BIT(zones[i] + 1);
+
+	return ret;
+}
+
+static struct lm3533_bl_platform_data *lm3533_bl_of_parse(struct device *dev,
+							  int *id)
+{
+	struct lm3533_bl_platform_data *bl_pdata;
+	struct device_node *node = dev->of_node;
+	int ret;
+	u32 reg;
+	u32 val;
+
+	bl_pdata = devm_kzalloc(dev, sizeof(*bl_pdata), GFP_KERNEL);
+	if (!bl_pdata)
+		return NULL;
+
+	ret = of_property_read_u32(node, "reg", &reg);
+	if (ret < 0) {
+		dev_err(dev, "invalid reg property\n");
+		return NULL;
+	}
+	*id = reg;
+
+	ret = of_property_read_string(node, "label",
+				      (const char **)&bl_pdata->name);
+	if (ret < 0) {
+		dev_err(dev, "unable to parse label\n");
+		return NULL;
+	}
+
+	ret = of_property_read_u32(node, "led-max-microamp", &val);
+	if (ret < 0) {
+		dev_err(dev, "unable to parse led-max-microamp\n");
+		return NULL;
+	}
+	bl_pdata->max_current = val;
+
+	val = LM3533_BL_DEFAULT_BRIGHTNESS;
+	ret = of_property_read_u32(node, "default-brightness", &val);
+	if (ret < 0 && ret != -EINVAL) {
+		dev_err(dev, "unable to parse default-brightness\n");
+		return NULL;
+	}
+	bl_pdata->default_brightness = val;
+
+	ret = lm3533_of_parse_pwm_zones(node);
+	if (ret < 0) {
+		dev_err(dev, "failed to parse ti,pwm-zones\n");
+		return NULL;
+	}
+	bl_pdata->pwm = ret;
+
+	return bl_pdata;
+}
+
 static int lm3533_bl_probe(struct platform_device *pdev)
 {
 	struct lm3533 *lm3533;
@@ -277,6 +358,7 @@ static int lm3533_bl_probe(struct platform_device *pdev)
 	struct backlight_device *bd;
 	struct backlight_properties props;
 	int ret;
+	int id;
 
 	dev_dbg(&pdev->dev, "%s\n", __func__);
 
@@ -284,14 +366,17 @@ static int lm3533_bl_probe(struct platform_device *pdev)
 	if (!lm3533)
 		return -EINVAL;
 
+	id = pdev->id;
 	pdata = dev_get_platdata(&pdev->dev);
+	if (!pdata)
+		pdata = lm3533_bl_of_parse(&pdev->dev, &id);
 	if (!pdata) {
 		dev_err(&pdev->dev, "no platform data\n");
 		return -EINVAL;
 	}
 
-	if (pdev->id < 0 || pdev->id >= LM3533_HVCTRLBANK_COUNT) {
-		dev_err(&pdev->dev, "illegal backlight id %d\n", pdev->id);
+	if (id < 0 || id >= LM3533_HVCTRLBANK_COUNT) {
+		dev_err(&pdev->dev, "illegal backlight id %d\n", id);
 		return -EINVAL;
 	}
 
@@ -300,7 +385,7 @@ static int lm3533_bl_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	bl->lm3533 = lm3533;
-	bl->id = pdev->id;
+	bl->id = id;
 
 	bl->cb.lm3533 = lm3533;
 	bl->cb.id = lm3533_bl_get_ctrlbank_id(bl);
@@ -394,10 +479,17 @@ static void lm3533_bl_shutdown(struct platform_device *pdev)
 	lm3533_ctrlbank_disable(&bl->cb);
 }
 
+static const struct of_device_id lm3533_bl_of_match[] = {
+	{ .compatible = "ti,lm3533-backlight", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, lm3533_bl_of_match);
+
 static struct platform_driver lm3533_bl_driver = {
 	.driver = {
 		.name	= "lm3533-backlight",
 		.pm	= &lm3533_bl_pm_ops,
+		.of_match_table = lm3533_bl_of_match,
 	},
 	.probe		= lm3533_bl_probe,
 	.remove		= lm3533_bl_remove,
-- 
2.11.0