backlight: pm8941-wled: Move PM8941 WLED driver to backlight

The Qualcomm PM8941 WLED block is used for backlight and should therefor
be in the backlight framework and not in the LED framework. This moves
the driver and adapts to the backlight api instead.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Tested-by: Rob Clark <robdclark@gmail.com>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

3 files changed, 435 insertions, 0 deletions

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 0505b796d743..5ffa4b4e26c0 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -299,6 +299,13 @@ config BACKLIGHT_TOSA
 	  If you have an Sharp SL-6000 Zaurus say Y to enable a driver
 	  for its backlight
 
+config BACKLIGHT_PM8941_WLED
+	tristate "Qualcomm PM8941 WLED Driver"
+	select REGMAP
+	help
+	  If you have the Qualcomm PM8941, say Y to enable a driver for the
+	  WLED block.
+
 config BACKLIGHT_SAHARA
 	tristate "Tabletkiosk Sahara Touch-iT Backlight Driver"
 	depends on X86
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index d67073f9d421..16ec534cff30 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_BACKLIGHT_OMAP1)		+= omap1_bl.o
 obj-$(CONFIG_BACKLIGHT_OT200)		+= ot200_bl.o
 obj-$(CONFIG_BACKLIGHT_PANDORA)		+= pandora_bl.o
 obj-$(CONFIG_BACKLIGHT_PCF50633)	+= pcf50633-backlight.o
+obj-$(CONFIG_BACKLIGHT_PM8941_WLED)	+= pm8941-wled.o
 obj-$(CONFIG_BACKLIGHT_PWM)		+= pwm_bl.o
 obj-$(CONFIG_BACKLIGHT_SAHARA)		+= kb3886_bl.o
 obj-$(CONFIG_BACKLIGHT_SKY81452)	+= sky81452-backlight.o
diff --git a/drivers/video/backlight/pm8941-wled.c b/drivers/video/backlight/pm8941-wled.c
new file mode 100644
index 000000000000..c704c3236034
--- /dev/null
+++ b/drivers/video/backlight/pm8941-wled.c
@@ -0,0 +1,427 @@
+/* Copyright (c) 2015, Sony Mobile Communications, AB.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/backlight.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+
+#define PM8941_WLED_REG_VAL_BASE		0x40
+#define  PM8941_WLED_REG_VAL_MAX		0xFFF
+
+#define PM8941_WLED_REG_MOD_EN			0x46
+#define  PM8941_WLED_REG_MOD_EN_BIT		BIT(7)
+#define  PM8941_WLED_REG_MOD_EN_MASK		BIT(7)
+
+#define PM8941_WLED_REG_SYNC			0x47
+#define  PM8941_WLED_REG_SYNC_MASK		0x07
+#define  PM8941_WLED_REG_SYNC_LED1		BIT(0)
+#define  PM8941_WLED_REG_SYNC_LED2		BIT(1)
+#define  PM8941_WLED_REG_SYNC_LED3		BIT(2)
+#define  PM8941_WLED_REG_SYNC_ALL		0x07
+#define  PM8941_WLED_REG_SYNC_CLEAR		0x00
+
+#define PM8941_WLED_REG_FREQ			0x4c
+#define  PM8941_WLED_REG_FREQ_MASK		0x0f
+
+#define PM8941_WLED_REG_OVP			0x4d
+#define  PM8941_WLED_REG_OVP_MASK		0x03
+
+#define PM8941_WLED_REG_BOOST			0x4e
+#define  PM8941_WLED_REG_BOOST_MASK		0x07
+
+#define PM8941_WLED_REG_SINK			0x4f
+#define  PM8941_WLED_REG_SINK_MASK		0xe0
+#define  PM8941_WLED_REG_SINK_SHFT		0x05
+
+/* Per-'string' registers below */
+#define PM8941_WLED_REG_STR_OFFSET		0x10
+
+#define PM8941_WLED_REG_STR_MOD_EN_BASE		0x60
+#define  PM8941_WLED_REG_STR_MOD_MASK		BIT(7)
+#define  PM8941_WLED_REG_STR_MOD_EN		BIT(7)
+
+#define PM8941_WLED_REG_STR_SCALE_BASE		0x62
+#define  PM8941_WLED_REG_STR_SCALE_MASK		0x1f
+
+#define PM8941_WLED_REG_STR_MOD_SRC_BASE	0x63
+#define  PM8941_WLED_REG_STR_MOD_SRC_MASK	0x01
+#define  PM8941_WLED_REG_STR_MOD_SRC_INT	0x00
+#define  PM8941_WLED_REG_STR_MOD_SRC_EXT	0x01
+
+#define PM8941_WLED_REG_STR_CABC_BASE		0x66
+#define  PM8941_WLED_REG_STR_CABC_MASK		BIT(7)
+#define  PM8941_WLED_REG_STR_CABC_EN		BIT(7)
+
+struct pm8941_wled_config {
+	u32 i_boost_limit;
+	u32 ovp;
+	u32 switch_freq;
+	u32 num_strings;
+	u32 i_limit;
+	bool cs_out_en;
+	bool ext_gen;
+	bool cabc_en;
+};
+
+struct pm8941_wled {
+	const char *name;
+	struct regmap *regmap;
+	u16 addr;
+
+	struct pm8941_wled_config cfg;
+};
+
+static int pm8941_wled_update_status(struct backlight_device *bl)
+{
+	struct pm8941_wled *wled = bl_get_data(bl);
+	u16 val = bl->props.brightness;
+	u8 ctrl = 0;
+	int rc;
+	int i;
+
+	if (bl->props.power != FB_BLANK_UNBLANK ||
+	    bl->props.fb_blank != FB_BLANK_UNBLANK ||
+	    bl->props.state & BL_CORE_FBBLANK)
+		val = 0;
+
+	if (val != 0)
+		ctrl = PM8941_WLED_REG_MOD_EN_BIT;
+
+	rc = regmap_update_bits(wled->regmap,
+			wled->addr + PM8941_WLED_REG_MOD_EN,
+			PM8941_WLED_REG_MOD_EN_MASK, ctrl);
+	if (rc)
+		return rc;
+
+	for (i = 0; i < wled->cfg.num_strings; ++i) {
+		u8 v[2] = { val & 0xff, (val >> 8) & 0xf };
+
+		rc = regmap_bulk_write(wled->regmap,
+				wled->addr + PM8941_WLED_REG_VAL_BASE + 2 * i,
+				v, 2);
+		if (rc)
+			return rc;
+	}
+
+	rc = regmap_update_bits(wled->regmap,
+			wled->addr + PM8941_WLED_REG_SYNC,
+			PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_ALL);
+	if (rc)
+		return rc;
+
+	rc = regmap_update_bits(wled->regmap,
+			wled->addr + PM8941_WLED_REG_SYNC,
+			PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_CLEAR);
+	return rc;
+}
+
+static int pm8941_wled_setup(struct pm8941_wled *wled)
+{
+	int rc;
+	int i;
+
+	rc = regmap_update_bits(wled->regmap,
+			wled->addr + PM8941_WLED_REG_OVP,
+			PM8941_WLED_REG_OVP_MASK, wled->cfg.ovp);
+	if (rc)
+		return rc;
+
+	rc = regmap_update_bits(wled->regmap,
+			wled->addr + PM8941_WLED_REG_BOOST,
+			PM8941_WLED_REG_BOOST_MASK, wled->cfg.i_boost_limit);
+	if (rc)
+		return rc;
+
+	rc = regmap_update_bits(wled->regmap,
+			wled->addr + PM8941_WLED_REG_FREQ,
+			PM8941_WLED_REG_FREQ_MASK, wled->cfg.switch_freq);
+	if (rc)
+		return rc;
+
+	if (wled->cfg.cs_out_en) {
+		u8 all = (BIT(wled->cfg.num_strings) - 1)
+				<< PM8941_WLED_REG_SINK_SHFT;
+
+		rc = regmap_update_bits(wled->regmap,
+				wled->addr + PM8941_WLED_REG_SINK,
+				PM8941_WLED_REG_SINK_MASK, all);
+		if (rc)
+			return rc;
+	}
+
+	for (i = 0; i < wled->cfg.num_strings; ++i) {
+		u16 addr = wled->addr + PM8941_WLED_REG_STR_OFFSET * i;
+
+		rc = regmap_update_bits(wled->regmap,
+				addr + PM8941_WLED_REG_STR_MOD_EN_BASE,
+				PM8941_WLED_REG_STR_MOD_MASK,
+				PM8941_WLED_REG_STR_MOD_EN);
+		if (rc)
+			return rc;
+
+		if (wled->cfg.ext_gen) {
+			rc = regmap_update_bits(wled->regmap,
+					addr + PM8941_WLED_REG_STR_MOD_SRC_BASE,
+					PM8941_WLED_REG_STR_MOD_SRC_MASK,
+					PM8941_WLED_REG_STR_MOD_SRC_EXT);
+			if (rc)
+				return rc;
+		}
+
+		rc = regmap_update_bits(wled->regmap,
+				addr + PM8941_WLED_REG_STR_SCALE_BASE,
+				PM8941_WLED_REG_STR_SCALE_MASK,
+				wled->cfg.i_limit);
+		if (rc)
+			return rc;
+
+		rc = regmap_update_bits(wled->regmap,
+				addr + PM8941_WLED_REG_STR_CABC_BASE,
+				PM8941_WLED_REG_STR_CABC_MASK,
+				wled->cfg.cabc_en ?
+					PM8941_WLED_REG_STR_CABC_EN : 0);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+static const struct pm8941_wled_config pm8941_wled_config_defaults = {
+	.i_boost_limit = 3,
+	.i_limit = 20,
+	.ovp = 2,
+	.switch_freq = 5,
+	.num_strings = 0,
+	.cs_out_en = false,
+	.ext_gen = false,
+	.cabc_en = false,
+};
+
+struct pm8941_wled_var_cfg {
+	const u32 *values;
+	u32 (*fn)(u32);
+	int size;
+};
+
+static const u32 pm8941_wled_i_boost_limit_values[] = {
+	105, 385, 525, 805, 980, 1260, 1400, 1680,
+};
+
+static const struct pm8941_wled_var_cfg pm8941_wled_i_boost_limit_cfg = {
+	.values = pm8941_wled_i_boost_limit_values,
+	.size = ARRAY_SIZE(pm8941_wled_i_boost_limit_values),
+};
+
+static const u32 pm8941_wled_ovp_values[] = {
+	35, 32, 29, 27,
+};
+
+static const struct pm8941_wled_var_cfg pm8941_wled_ovp_cfg = {
+	.values = pm8941_wled_ovp_values,
+	.size = ARRAY_SIZE(pm8941_wled_ovp_values),
+};
+
+static u32 pm8941_wled_num_strings_values_fn(u32 idx)
+{
+	return idx + 1;
+}
+
+static const struct pm8941_wled_var_cfg pm8941_wled_num_strings_cfg = {
+	.fn = pm8941_wled_num_strings_values_fn,
+	.size = 3,
+};
+
+static u32 pm8941_wled_switch_freq_values_fn(u32 idx)
+{
+	return 19200 / (2 * (1 + idx));
+}
+
+static const struct pm8941_wled_var_cfg pm8941_wled_switch_freq_cfg = {
+	.fn = pm8941_wled_switch_freq_values_fn,
+	.size = 16,
+};
+
+static const struct pm8941_wled_var_cfg pm8941_wled_i_limit_cfg = {
+	.size = 26,
+};
+
+static u32 pm8941_wled_values(const struct pm8941_wled_var_cfg *cfg, u32 idx)
+{
+	if (idx >= cfg->size)
+		return UINT_MAX;
+	if (cfg->fn)
+		return cfg->fn(idx);
+	if (cfg->values)
+		return cfg->values[idx];
+	return idx;
+}
+
+static int pm8941_wled_configure(struct pm8941_wled *wled, struct device *dev)
+{
+	struct pm8941_wled_config *cfg = &wled->cfg;
+	u32 val;
+	int rc;
+	u32 c;
+	int i;
+	int j;
+
+	const struct {
+		const char *name;
+		u32 *val_ptr;
+		const struct pm8941_wled_var_cfg *cfg;
+	} u32_opts[] = {
+		{
+			"qcom,current-boost-limit",
+			&cfg->i_boost_limit,
+			.cfg = &pm8941_wled_i_boost_limit_cfg,
+		},
+		{
+			"qcom,current-limit",
+			&cfg->i_limit,
+			.cfg = &pm8941_wled_i_limit_cfg,
+		},
+		{
+			"qcom,ovp",
+			&cfg->ovp,
+			.cfg = &pm8941_wled_ovp_cfg,
+		},
+		{
+			"qcom,switching-freq",
+			&cfg->switch_freq,
+			.cfg = &pm8941_wled_switch_freq_cfg,
+		},
+		{
+			"qcom,num-strings",
+			&cfg->num_strings,
+			.cfg = &pm8941_wled_num_strings_cfg,
+		},
+	};
+	const struct {
+		const char *name;
+		bool *val_ptr;
+	} bool_opts[] = {
+		{ "qcom,cs-out", &cfg->cs_out_en, },
+		{ "qcom,ext-gen", &cfg->ext_gen, },
+		{ "qcom,cabc", &cfg->cabc_en, },
+	};
+
+	rc = of_property_read_u32(dev->of_node, "reg", &val);
+	if (rc || val > 0xffff) {
+		dev_err(dev, "invalid IO resources\n");
+		return rc ? rc : -EINVAL;
+	}
+	wled->addr = val;
+
+	rc = of_property_read_string(dev->of_node, "label", &wled->name);
+	if (rc)
+		wled->name = dev->of_node->name;
+
+	*cfg = pm8941_wled_config_defaults;
+	for (i = 0; i < ARRAY_SIZE(u32_opts); ++i) {
+		rc = of_property_read_u32(dev->of_node, u32_opts[i].name, &val);
+		if (rc == -EINVAL) {
+			continue;
+		} else if (rc) {
+			dev_err(dev, "error reading '%s'\n", u32_opts[i].name);
+			return rc;
+		}
+
+		c = UINT_MAX;
+		for (j = 0; c != val; j++) {
+			c = pm8941_wled_values(u32_opts[i].cfg, j);
+			if (c == UINT_MAX) {
+				dev_err(dev, "invalid value for '%s'\n",
+					u32_opts[i].name);
+				return -EINVAL;
+			}
+		}
+
+		dev_dbg(dev, "'%s' = %u\n", u32_opts[i].name, c);
+		*u32_opts[i].val_ptr = j;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(bool_opts); ++i) {
+		if (of_property_read_bool(dev->of_node, bool_opts[i].name))
+			*bool_opts[i].val_ptr = true;
+	}
+
+	cfg->num_strings = cfg->num_strings + 1;
+
+	return 0;
+}
+
+static const struct backlight_ops pm8941_wled_ops = {
+	.update_status = pm8941_wled_update_status,
+};
+
+static int pm8941_wled_probe(struct platform_device *pdev)
+{
+	struct backlight_properties props;
+	struct backlight_device *bl;
+	struct pm8941_wled *wled;
+	struct regmap *regmap;
+	int rc;
+
+	regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!regmap) {
+		dev_err(&pdev->dev, "Unable to get regmap\n");
+		return -EINVAL;
+	}
+
+	wled = devm_kzalloc(&pdev->dev, sizeof(*wled), GFP_KERNEL);
+	if (!wled)
+		return -ENOMEM;
+
+	wled->regmap = regmap;
+
+	rc = pm8941_wled_configure(wled, &pdev->dev);
+	if (rc)
+		return rc;
+
+	rc = pm8941_wled_setup(wled);
+	if (rc)
+		return rc;
+
+	memset(&props, 0, sizeof(struct backlight_properties));
+	props.type = BACKLIGHT_RAW;
+	props.max_brightness = PM8941_WLED_REG_VAL_MAX;
+	bl = devm_backlight_device_register(&pdev->dev, wled->name,
+					    &pdev->dev, wled,
+					    &pm8941_wled_ops, &props);
+	if (IS_ERR(bl))
+		return PTR_ERR(bl);
+
+	return 0;
+};
+
+static const struct of_device_id pm8941_wled_match_table[] = {
+	{ .compatible = "qcom,pm8941-wled" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, pm8941_wled_match_table);
+
+static struct platform_driver pm8941_wled_driver = {
+	.probe = pm8941_wled_probe,
+	.driver	= {
+		.name = "pm8941-wled",
+		.of_match_table	= pm8941_wled_match_table,
+	},
+};
+
+module_platform_driver(pm8941_wled_driver);
+
+MODULE_DESCRIPTION("pm8941 wled driver");
+MODULE_LICENSE("GPL v2");