diff options
Diffstat (limited to 'drivers/video/backlight/as3711_bl.c')
| -rw-r--r-- | drivers/video/backlight/as3711_bl.c | 492 |
1 files changed, 492 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..ca544aa76 --- /dev/null +++ b/drivers/video/backlight/as3711_bl.c @@ -0,0 +1,492 @@ +/* + * 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; + 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, *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_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) { + ret = -EINVAL; + goto err_put_bl; + } + + 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) { + ret = -EINVAL; + goto err_put_bl; + } + + 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)) { + 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"); +MODULE_ALIAS("platform:as3711-backlight"); |