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path: root/drivers/video/backlight/as3711_bl.c
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Diffstat (limited to 'drivers/video/backlight/as3711_bl.c')
-rw-r--r--drivers/video/backlight/as3711_bl.c482
1 files changed, 482 insertions, 0 deletions
diff --git a/drivers/video/backlight/as3711_bl.c b/drivers/video/backlight/as3711_bl.c
new file mode 100644
index 0000000000..28437c2da0
--- /dev/null
+++ b/drivers/video/backlight/as3711_bl.c
@@ -0,0 +1,482 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AS3711 PMIC backlight driver, using DCDC Step Up Converters
+ *
+ * Copyright (C) 2012 Renesas Electronics Corporation
+ * Author: Guennadi Liakhovetski, <g.liakhovetski@gmx.de>
+ */
+
+#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;
+ 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;
+ int ret = 0;
+
+ brightness = backlight_get_brightness(bl);
+
+ 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, *fb;
+ int ret;
+
+ bl = of_get_child_by_name(dev->parent->of_node, "backlight");
+ if (!bl) {
+ dev_dbg(dev, "backlight node not found\n");
+ return -ENODEV;
+ }
+
+ fb = of_parse_phandle(bl, "su1-dev", 0);
+ if (fb) {
+ of_node_put(fb);
+
+ pdata->su1_fb = true;
+
+ ret = of_property_read_u32(bl, "su1-max-uA", &pdata->su1_max_uA);
+ if (pdata->su1_max_uA <= 0)
+ ret = -EINVAL;
+ if (ret < 0)
+ goto err_put_bl;
+ }
+
+ fb = of_parse_phandle(bl, "su2-dev", 0);
+ if (fb) {
+ int count = 0;
+
+ of_node_put(fb);
+
+ pdata->su2_fb = true;
+
+ ret = of_property_read_u32(bl, "su2-max-uA", &pdata->su2_max_uA);
+ if (pdata->su2_max_uA <= 0)
+ ret = -EINVAL;
+ if (ret < 0)
+ goto err_put_bl;
+
+ if (of_property_read_bool(bl, "su2-feedback-voltage")) {
+ pdata->su2_feedback = AS3711_SU2_VOLTAGE;
+ count++;
+ }
+ if (of_property_read_bool(bl, "su2-feedback-curr1")) {
+ pdata->su2_feedback = AS3711_SU2_CURR1;
+ count++;
+ }
+ if (of_property_read_bool(bl, "su2-feedback-curr2")) {
+ pdata->su2_feedback = AS3711_SU2_CURR2;
+ count++;
+ }
+ if (of_property_read_bool(bl, "su2-feedback-curr3")) {
+ pdata->su2_feedback = AS3711_SU2_CURR3;
+ count++;
+ }
+ if (of_property_read_bool(bl, "su2-feedback-curr-auto")) {
+ pdata->su2_feedback = AS3711_SU2_CURR_AUTO;
+ count++;
+ }
+ if (count != 1) {
+ ret = -EINVAL;
+ goto err_put_bl;
+ }
+
+ count = 0;
+ if (of_property_read_bool(bl, "su2-fbprot-lx-sd4")) {
+ pdata->su2_fbprot = AS3711_SU2_LX_SD4;
+ count++;
+ }
+ if (of_property_read_bool(bl, "su2-fbprot-gpio2")) {
+ pdata->su2_fbprot = AS3711_SU2_GPIO2;
+ count++;
+ }
+ if (of_property_read_bool(bl, "su2-fbprot-gpio3")) {
+ pdata->su2_fbprot = AS3711_SU2_GPIO3;
+ count++;
+ }
+ if (of_property_read_bool(bl, "su2-fbprot-gpio4")) {
+ pdata->su2_fbprot = AS3711_SU2_GPIO4;
+ count++;
+ }
+ if (count != 1) {
+ ret = -EINVAL;
+ goto err_put_bl;
+ }
+
+ count = 0;
+ if (of_property_read_bool(bl, "su2-auto-curr1")) {
+ pdata->su2_auto_curr1 = true;
+ count++;
+ }
+ if (of_property_read_bool(bl, "su2-auto-curr2")) {
+ pdata->su2_auto_curr2 = true;
+ count++;
+ }
+ if (of_property_read_bool(bl, "su2-auto-curr3")) {
+ 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)) {
+ ret = -EINVAL;
+ goto err_put_bl;
+ }
+ }
+
+ of_node_put(bl);
+
+ return 0;
+
+err_put_bl:
+ of_node_put(bl);
+
+ return ret;
+}
+
+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->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->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 v2");
+MODULE_ALIAS("platform:as3711-backlight");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 15:45:42 +0000