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