| /* |
| * Backlight driver for Wolfson Microelectronics WM831x PMICs |
| * |
| * Copyright 2009 Wolfson Microelectonics plc |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #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) |
| { |
| int brightness = bl->props.brightness; |
| |
| if (bl->props.power != FB_BLANK_UNBLANK) |
| brightness = 0; |
| |
| if (bl->props.fb_blank != FB_BLANK_UNBLANK) |
| brightness = 0; |
| |
| if (bl->props.state & BL_CORE_SUSPENDED) |
| brightness = 0; |
| |
| return wm831x_backlight_set(bl, brightness); |
| } |
| |
| 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; |
| 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 (pdev->dev.parent->platform_data) { |
| wm831x_pdata = pdev->dev.parent->platform_data; |
| 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; |
| |
| props.type = BACKLIGHT_RAW; |
| props.max_brightness = max_isel; |
| bl = backlight_device_register("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 int wm831x_backlight_remove(struct platform_device *pdev) |
| { |
| struct backlight_device *bl = platform_get_drvdata(pdev); |
| |
| backlight_device_unregister(bl); |
| return 0; |
| } |
| |
| static struct platform_driver wm831x_backlight_driver = { |
| .driver = { |
| .name = "wm831x-backlight", |
| .owner = THIS_MODULE, |
| }, |
| .probe = wm831x_backlight_probe, |
| .remove = wm831x_backlight_remove, |
| }; |
| |
| 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"); |