1 files changed, 479 insertions, 0 deletions

diff --git a/drivers/video/backlight/as3711_bl.c b/drivers/video/backlight/as3711_bl.c
new file mode 100644
index 000000000..734a91589
--- /dev/null
+++ b/drivers/video/backlight/as3711_bl.c
@@ -0,0 +1,479 @@
+/*
+ * AS3711 PMIC backlight driver, using DCDC Step Up Converters
+ *
+ * Copyright (C) 2012 Renesas Electronics Corporation
+ * Author: Guennadi Liakhovetski, <g.liakhovetski@gmx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the version 2 of the GNU General Public License as
+ * published by the Free Software Foundation
+ */
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <linux/kernel.h>
+#include <linux/mfd/as3711.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+enum as3711_bl_type {
+	AS3711_BL_SU1,
+	AS3711_BL_SU2,
+};
+
+struct as3711_bl_data {
+	bool powered;
+	const char *fb_name;
+	struct device *fb_dev;
+	enum as3711_bl_type type;
+	int brightness;
+	struct backlight_device *bl;
+};
+
+struct as3711_bl_supply {
+	struct as3711_bl_data su1;
+	struct as3711_bl_data su2;
+	const struct as3711_bl_pdata *pdata;
+	struct as3711 *as3711;
+};
+
+static struct as3711_bl_supply *to_supply(struct as3711_bl_data *su)
+{
+	switch (su->type) {
+	case AS3711_BL_SU1:
+		return container_of(su, struct as3711_bl_supply, su1);
+	case AS3711_BL_SU2:
+		return container_of(su, struct as3711_bl_supply, su2);
+	}
+	return NULL;
+}
+
+static int as3711_set_brightness_auto_i(struct as3711_bl_data *data,
+					unsigned int brightness)
+{
+	struct as3711_bl_supply *supply = to_supply(data);
+	struct as3711 *as3711 = supply->as3711;
+	const struct as3711_bl_pdata *pdata = supply->pdata;
+	int ret = 0;
+
+	/* Only all equal current values are supported */
+	if (pdata->su2_auto_curr1)
+		ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
+				   brightness);
+	if (!ret && pdata->su2_auto_curr2)
+		ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
+				   brightness);
+	if (!ret && pdata->su2_auto_curr3)
+		ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
+				   brightness);
+
+	return ret;
+}
+
+static int as3711_set_brightness_v(struct as3711 *as3711,
+				   unsigned int brightness,
+				   unsigned int reg)
+{
+	if (brightness > 31)
+		return -EINVAL;
+
+	return regmap_update_bits(as3711->regmap, reg, 0xf0,
+				  brightness << 4);
+}
+
+static int as3711_bl_su2_reset(struct as3711_bl_supply *supply)
+{
+	struct as3711 *as3711 = supply->as3711;
+	int ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_5,
+				     3, supply->pdata->su2_fbprot);
+	if (!ret)
+		ret = regmap_update_bits(as3711->regmap,
+					 AS3711_STEPUP_CONTROL_2, 1, 0);
+	if (!ret)
+		ret = regmap_update_bits(as3711->regmap,
+					 AS3711_STEPUP_CONTROL_2, 1, 1);
+	return ret;
+}
+
+/*
+ * Someone with less fragile or less expensive hardware could try to simplify
+ * the brightness adjustment procedure.
+ */
+static int as3711_bl_update_status(struct backlight_device *bl)
+{
+	struct as3711_bl_data *data = bl_get_data(bl);
+	struct as3711_bl_supply *supply = to_supply(data);
+	struct as3711 *as3711 = supply->as3711;
+	int brightness = bl->props.brightness;
+	int ret = 0;
+
+	dev_dbg(&bl->dev, "%s(): brightness %u, pwr %x, blank %x, state %x\n",
+		__func__, bl->props.brightness, bl->props.power,
+		bl->props.fb_blank, bl->props.state);
+
+	if (bl->props.power != FB_BLANK_UNBLANK ||
+	    bl->props.fb_blank != FB_BLANK_UNBLANK ||
+	    bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
+		brightness = 0;
+
+	if (data->type == AS3711_BL_SU1) {
+		ret = as3711_set_brightness_v(as3711, brightness,
+					      AS3711_STEPUP_CONTROL_1);
+	} else {
+		const struct as3711_bl_pdata *pdata = supply->pdata;
+
+		switch (pdata->su2_feedback) {
+		case AS3711_SU2_VOLTAGE:
+			ret = as3711_set_brightness_v(as3711, brightness,
+						      AS3711_STEPUP_CONTROL_2);
+			break;
+		case AS3711_SU2_CURR_AUTO:
+			ret = as3711_set_brightness_auto_i(data, brightness / 4);
+			if (ret < 0)
+				return ret;
+			if (brightness) {
+				ret = as3711_bl_su2_reset(supply);
+				if (ret < 0)
+					return ret;
+				udelay(500);
+				ret = as3711_set_brightness_auto_i(data, brightness);
+			} else {
+				ret = regmap_update_bits(as3711->regmap,
+						AS3711_STEPUP_CONTROL_2, 1, 0);
+			}
+			break;
+		/* Manual one current feedback pin below */
+		case AS3711_SU2_CURR1:
+			ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
+					   brightness);
+			break;
+		case AS3711_SU2_CURR2:
+			ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
+					   brightness);
+			break;
+		case AS3711_SU2_CURR3:
+			ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
+					   brightness);
+			break;
+		default:
+			ret = -EINVAL;
+		}
+	}
+	if (!ret)
+		data->brightness = brightness;
+
+	return ret;
+}
+
+static int as3711_bl_get_brightness(struct backlight_device *bl)
+{
+	struct as3711_bl_data *data = bl_get_data(bl);
+
+	return data->brightness;
+}
+
+static const struct backlight_ops as3711_bl_ops = {
+	.update_status	= as3711_bl_update_status,
+	.get_brightness	= as3711_bl_get_brightness,
+};
+
+static int as3711_bl_init_su2(struct as3711_bl_supply *supply)
+{
+	struct as3711 *as3711 = supply->as3711;
+	const struct as3711_bl_pdata *pdata = supply->pdata;
+	u8 ctl = 0;
+	int ret;
+
+	dev_dbg(as3711->dev, "%s(): use %u\n", __func__, pdata->su2_feedback);
+
+	/* Turn SU2 off */
+	ret = regmap_write(as3711->regmap, AS3711_STEPUP_CONTROL_2, 0);
+	if (ret < 0)
+		return ret;
+
+	switch (pdata->su2_feedback) {
+	case AS3711_SU2_VOLTAGE:
+		ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 0);
+		break;
+	case AS3711_SU2_CURR1:
+		ctl = 1;
+		ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 1);
+		break;
+	case AS3711_SU2_CURR2:
+		ctl = 4;
+		ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 2);
+		break;
+	case AS3711_SU2_CURR3:
+		ctl = 0x10;
+		ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 3);
+		break;
+	case AS3711_SU2_CURR_AUTO:
+		if (pdata->su2_auto_curr1)
+			ctl = 2;
+		if (pdata->su2_auto_curr2)
+			ctl |= 8;
+		if (pdata->su2_auto_curr3)
+			ctl |= 0x20;
+		ret = 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (!ret)
+		ret = regmap_write(as3711->regmap, AS3711_CURR_CONTROL, ctl);
+
+	return ret;
+}
+
+static int as3711_bl_register(struct platform_device *pdev,
+			      unsigned int max_brightness, struct as3711_bl_data *su)
+{
+	struct backlight_properties props = {.type = BACKLIGHT_RAW,};
+	struct backlight_device *bl;
+
+	/* max tuning I = 31uA for voltage- and 38250uA for current-feedback */
+	props.max_brightness = max_brightness;
+
+	bl = devm_backlight_device_register(&pdev->dev,
+				       su->type == AS3711_BL_SU1 ?
+				       "as3711-su1" : "as3711-su2",
+				       &pdev->dev, su,
+				       &as3711_bl_ops, &props);
+	if (IS_ERR(bl)) {
+		dev_err(&pdev->dev, "failed to register backlight\n");
+		return PTR_ERR(bl);
+	}
+
+	bl->props.brightness = props.max_brightness;
+
+	backlight_update_status(bl);
+
+	su->bl = bl;
+
+	return 0;
+}
+
+static int as3711_backlight_parse_dt(struct device *dev)
+{
+	struct as3711_bl_pdata *pdata = dev_get_platdata(dev);
+	struct device_node *bl =
+		of_find_node_by_name(dev->parent->of_node, "backlight"), *fb;
+	int ret;
+
+	if (!bl) {
+		dev_dbg(dev, "backlight node not found\n");
+		return -ENODEV;
+	}
+
+	fb = of_parse_phandle(bl, "su1-dev", 0);
+	if (fb) {
+		pdata->su1_fb = fb->full_name;
+
+		ret = of_property_read_u32(bl, "su1-max-uA", &pdata->su1_max_uA);
+		if (pdata->su1_max_uA <= 0)
+			ret = -EINVAL;
+		if (ret < 0)
+			return ret;
+	}
+
+	fb = of_parse_phandle(bl, "su2-dev", 0);
+	if (fb) {
+		int count = 0;
+
+		pdata->su2_fb = fb->full_name;
+
+		ret = of_property_read_u32(bl, "su2-max-uA", &pdata->su2_max_uA);
+		if (pdata->su2_max_uA <= 0)
+			ret = -EINVAL;
+		if (ret < 0)
+			return ret;
+
+		if (of_find_property(bl, "su2-feedback-voltage", NULL)) {
+			pdata->su2_feedback = AS3711_SU2_VOLTAGE;
+			count++;
+		}
+		if (of_find_property(bl, "su2-feedback-curr1", NULL)) {
+			pdata->su2_feedback = AS3711_SU2_CURR1;
+			count++;
+		}
+		if (of_find_property(bl, "su2-feedback-curr2", NULL)) {
+			pdata->su2_feedback = AS3711_SU2_CURR2;
+			count++;
+		}
+		if (of_find_property(bl, "su2-feedback-curr3", NULL)) {
+			pdata->su2_feedback = AS3711_SU2_CURR3;
+			count++;
+		}
+		if (of_find_property(bl, "su2-feedback-curr-auto", NULL)) {
+			pdata->su2_feedback = AS3711_SU2_CURR_AUTO;
+			count++;
+		}
+		if (count != 1)
+			return -EINVAL;
+
+		count = 0;
+		if (of_find_property(bl, "su2-fbprot-lx-sd4", NULL)) {
+			pdata->su2_fbprot = AS3711_SU2_LX_SD4;
+			count++;
+		}
+		if (of_find_property(bl, "su2-fbprot-gpio2", NULL)) {
+			pdata->su2_fbprot = AS3711_SU2_GPIO2;
+			count++;
+		}
+		if (of_find_property(bl, "su2-fbprot-gpio3", NULL)) {
+			pdata->su2_fbprot = AS3711_SU2_GPIO3;
+			count++;
+		}
+		if (of_find_property(bl, "su2-fbprot-gpio4", NULL)) {
+			pdata->su2_fbprot = AS3711_SU2_GPIO4;
+			count++;
+		}
+		if (count != 1)
+			return -EINVAL;
+
+		count = 0;
+		if (of_find_property(bl, "su2-auto-curr1", NULL)) {
+			pdata->su2_auto_curr1 = true;
+			count++;
+		}
+		if (of_find_property(bl, "su2-auto-curr2", NULL)) {
+			pdata->su2_auto_curr2 = true;
+			count++;
+		}
+		if (of_find_property(bl, "su2-auto-curr3", NULL)) {
+			pdata->su2_auto_curr3 = true;
+			count++;
+		}
+
+		/*
+		 * At least one su2-auto-curr* must be specified iff
+		 * AS3711_SU2_CURR_AUTO is used
+		 */
+		if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO))
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int as3711_backlight_probe(struct platform_device *pdev)
+{
+	struct as3711_bl_pdata *pdata = dev_get_platdata(&pdev->dev);
+	struct as3711 *as3711 = dev_get_drvdata(pdev->dev.parent);
+	struct as3711_bl_supply *supply;
+	struct as3711_bl_data *su;
+	unsigned int max_brightness;
+	int ret;
+
+	if (!pdata) {
+		dev_err(&pdev->dev, "No platform data, exiting...\n");
+		return -ENODEV;
+	}
+
+	if (pdev->dev.parent->of_node) {
+		ret = as3711_backlight_parse_dt(&pdev->dev);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "DT parsing failed: %d\n", ret);
+			return ret;
+		}
+	}
+
+	if (!pdata->su1_fb && !pdata->su2_fb) {
+		dev_err(&pdev->dev, "No framebuffer specified\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Due to possible hardware damage I chose to block all modes,
+	 * unsupported on my hardware. Anyone, wishing to use any of those modes
+	 * will have to first review the code, then activate and test it.
+	 */
+	if (pdata->su1_fb ||
+	    pdata->su2_fbprot != AS3711_SU2_GPIO4 ||
+	    pdata->su2_feedback != AS3711_SU2_CURR_AUTO) {
+		dev_warn(&pdev->dev,
+			 "Attention! An untested mode has been chosen!\n"
+			 "Please, review the code, enable, test, and report success:-)\n");
+		return -EINVAL;
+	}
+
+	supply = devm_kzalloc(&pdev->dev, sizeof(*supply), GFP_KERNEL);
+	if (!supply)
+		return -ENOMEM;
+
+	supply->as3711 = as3711;
+	supply->pdata = pdata;
+
+	if (pdata->su1_fb) {
+		su = &supply->su1;
+		su->fb_name = pdata->su1_fb;
+		su->type = AS3711_BL_SU1;
+
+		max_brightness = min(pdata->su1_max_uA, 31);
+		ret = as3711_bl_register(pdev, max_brightness, su);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (pdata->su2_fb) {
+		su = &supply->su2;
+		su->fb_name = pdata->su2_fb;
+		su->type = AS3711_BL_SU2;
+
+		switch (pdata->su2_fbprot) {
+		case AS3711_SU2_GPIO2:
+		case AS3711_SU2_GPIO3:
+		case AS3711_SU2_GPIO4:
+		case AS3711_SU2_LX_SD4:
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		switch (pdata->su2_feedback) {
+		case AS3711_SU2_VOLTAGE:
+			max_brightness = min(pdata->su2_max_uA, 31);
+			break;
+		case AS3711_SU2_CURR1:
+		case AS3711_SU2_CURR2:
+		case AS3711_SU2_CURR3:
+		case AS3711_SU2_CURR_AUTO:
+			max_brightness = min(pdata->su2_max_uA / 150, 255);
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		ret = as3711_bl_init_su2(supply);
+		if (ret < 0)
+			return ret;
+
+		ret = as3711_bl_register(pdev, max_brightness, su);
+		if (ret < 0)
+			return ret;
+	}
+
+	platform_set_drvdata(pdev, supply);
+
+	return 0;
+}
+
+static struct platform_driver as3711_backlight_driver = {
+	.driver		= {
+		.name	= "as3711-backlight",
+	},
+	.probe		= as3711_backlight_probe,
+};
+
+module_platform_driver(as3711_backlight_driver);
+
+MODULE_DESCRIPTION("Backlight Driver for AS3711 PMICs");
+MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:as3711-backlight");