diff options
Diffstat (limited to 'drivers/video/backlight/wm831x_bl.c')
| -rw-r--r-- | drivers/video/backlight/wm831x_bl.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/drivers/video/backlight/wm831x_bl.c b/drivers/video/backlight/wm831x_bl.c new file mode 100644 index 000000000..c5aaee205 --- /dev/null +++ b/drivers/video/backlight/wm831x_bl.c @@ -0,0 +1,216 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Backlight driver for Wolfson Microelectronics WM831x PMICs + * + * Copyright 2009 Wolfson Microelectonics plc + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/module.h> +#include <linux/fb.h> +#include <linux/backlight.h> +#include <linux/slab.h> + +#include <linux/mfd/wm831x/core.h> +#include <linux/mfd/wm831x/pdata.h> +#include <linux/mfd/wm831x/regulator.h> + +struct wm831x_backlight_data { + struct wm831x *wm831x; + int isink_reg; + int current_brightness; +}; + +static int wm831x_backlight_set(struct backlight_device *bl, int brightness) +{ + struct wm831x_backlight_data *data = bl_get_data(bl); + struct wm831x *wm831x = data->wm831x; + int power_up = !data->current_brightness && brightness; + int power_down = data->current_brightness && !brightness; + int ret; + + if (power_up) { + /* Enable the ISINK */ + ret = wm831x_set_bits(wm831x, data->isink_reg, + WM831X_CS1_ENA, WM831X_CS1_ENA); + if (ret < 0) + goto err; + + /* Enable the DC-DC */ + ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, + WM831X_DC4_ENA, WM831X_DC4_ENA); + if (ret < 0) + goto err; + } + + if (power_down) { + /* DCDC first */ + ret = wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, + WM831X_DC4_ENA, 0); + if (ret < 0) + goto err; + + /* ISINK */ + ret = wm831x_set_bits(wm831x, data->isink_reg, + WM831X_CS1_DRIVE | WM831X_CS1_ENA, 0); + if (ret < 0) + goto err; + } + + /* Set the new brightness */ + ret = wm831x_set_bits(wm831x, data->isink_reg, + WM831X_CS1_ISEL_MASK, brightness); + if (ret < 0) + goto err; + + if (power_up) { + /* Drive current through the ISINK */ + ret = wm831x_set_bits(wm831x, data->isink_reg, + WM831X_CS1_DRIVE, WM831X_CS1_DRIVE); + if (ret < 0) + return ret; + } + + data->current_brightness = brightness; + + return 0; + +err: + /* If we were in the middle of a power transition always shut down + * for safety. + */ + if (power_up || power_down) { + wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); + wm831x_set_bits(wm831x, data->isink_reg, WM831X_CS1_ENA, 0); + } + + return ret; +} + +static int wm831x_backlight_update_status(struct backlight_device *bl) +{ + return wm831x_backlight_set(bl, backlight_get_brightness(bl)); +} + +static int wm831x_backlight_get_brightness(struct backlight_device *bl) +{ + struct wm831x_backlight_data *data = bl_get_data(bl); + + return data->current_brightness; +} + +static const struct backlight_ops wm831x_backlight_ops = { + .options = BL_CORE_SUSPENDRESUME, + .update_status = wm831x_backlight_update_status, + .get_brightness = wm831x_backlight_get_brightness, +}; + +static int wm831x_backlight_probe(struct platform_device *pdev) +{ + struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); + struct wm831x_pdata *wm831x_pdata = dev_get_platdata(pdev->dev.parent); + struct wm831x_backlight_pdata *pdata; + struct wm831x_backlight_data *data; + struct backlight_device *bl; + struct backlight_properties props; + int ret, i, max_isel, isink_reg, dcdc_cfg; + + /* We need platform data */ + if (wm831x_pdata) + pdata = wm831x_pdata->backlight; + else + pdata = NULL; + + if (!pdata) { + dev_err(&pdev->dev, "No platform data supplied\n"); + return -EINVAL; + } + + /* Figure out the maximum current we can use */ + for (i = 0; i < WM831X_ISINK_MAX_ISEL; i++) { + if (wm831x_isinkv_values[i] > pdata->max_uA) + break; + } + + if (i == 0) { + dev_err(&pdev->dev, "Invalid max_uA: %duA\n", pdata->max_uA); + return -EINVAL; + } + max_isel = i - 1; + + if (pdata->max_uA != wm831x_isinkv_values[max_isel]) + dev_warn(&pdev->dev, + "Maximum current is %duA not %duA as requested\n", + wm831x_isinkv_values[max_isel], pdata->max_uA); + + switch (pdata->isink) { + case 1: + isink_reg = WM831X_CURRENT_SINK_1; + dcdc_cfg = 0; + break; + case 2: + isink_reg = WM831X_CURRENT_SINK_2; + dcdc_cfg = WM831X_DC4_FBSRC; + break; + default: + dev_err(&pdev->dev, "Invalid ISINK %d\n", pdata->isink); + return -EINVAL; + } + + /* Configure the ISINK to use for feedback */ + ret = wm831x_reg_unlock(wm831x); + if (ret < 0) + return ret; + + ret = wm831x_set_bits(wm831x, WM831X_DC4_CONTROL, WM831X_DC4_FBSRC, + dcdc_cfg); + + wm831x_reg_lock(wm831x); + if (ret < 0) + return ret; + + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); + if (data == NULL) + return -ENOMEM; + + data->wm831x = wm831x; + data->current_brightness = 0; + data->isink_reg = isink_reg; + + memset(&props, 0, sizeof(props)); + props.type = BACKLIGHT_RAW; + props.max_brightness = max_isel; + bl = devm_backlight_device_register(&pdev->dev, "wm831x", &pdev->dev, + data, &wm831x_backlight_ops, &props); + if (IS_ERR(bl)) { + dev_err(&pdev->dev, "failed to register backlight\n"); + return PTR_ERR(bl); + } + + bl->props.brightness = max_isel; + + platform_set_drvdata(pdev, bl); + + /* Disable the DCDC if it was started so we can bootstrap */ + wm831x_set_bits(wm831x, WM831X_DCDC_ENABLE, WM831X_DC4_ENA, 0); + + backlight_update_status(bl); + + return 0; +} + +static struct platform_driver wm831x_backlight_driver = { + .driver = { + .name = "wm831x-backlight", + }, + .probe = wm831x_backlight_probe, +}; + +module_platform_driver(wm831x_backlight_driver); + +MODULE_DESCRIPTION("Backlight Driver for WM831x PMICs"); +MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:wm831x-backlight"); |