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197 lines
4.9 KiB
197 lines
4.9 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Backlight driver for Maxim MAX8925 |
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* |
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* Copyright (C) 2009 Marvell International Ltd. |
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* Haojian Zhuang <[email protected]> |
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*/ |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/platform_device.h> |
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#include <linux/fb.h> |
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#include <linux/i2c.h> |
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#include <linux/backlight.h> |
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#include <linux/mfd/max8925.h> |
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#include <linux/slab.h> |
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#include <linux/module.h> |
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#define MAX_BRIGHTNESS (0xff) |
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#define MIN_BRIGHTNESS (0) |
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#define LWX_FREQ(x) (((x - 601) / 100) & 0x7) |
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struct max8925_backlight_data { |
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struct max8925_chip *chip; |
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int current_brightness; |
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int reg_mode_cntl; |
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int reg_cntl; |
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}; |
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static int max8925_backlight_set(struct backlight_device *bl, int brightness) |
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{ |
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struct max8925_backlight_data *data = bl_get_data(bl); |
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struct max8925_chip *chip = data->chip; |
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unsigned char value; |
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int ret; |
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if (brightness > MAX_BRIGHTNESS) |
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value = MAX_BRIGHTNESS; |
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else |
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value = brightness; |
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ret = max8925_reg_write(chip->i2c, data->reg_cntl, value); |
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if (ret < 0) |
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goto out; |
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if (!data->current_brightness && brightness) |
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/* enable WLED output */ |
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ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 1); |
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else if (!brightness) |
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/* disable WLED output */ |
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ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 0); |
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if (ret < 0) |
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goto out; |
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dev_dbg(chip->dev, "set brightness %d\n", value); |
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data->current_brightness = value; |
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return 0; |
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out: |
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dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n", |
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value, ret); |
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return ret; |
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} |
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static int max8925_backlight_update_status(struct backlight_device *bl) |
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{ |
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return max8925_backlight_set(bl, backlight_get_brightness(bl)); |
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} |
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static int max8925_backlight_get_brightness(struct backlight_device *bl) |
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{ |
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struct max8925_backlight_data *data = bl_get_data(bl); |
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struct max8925_chip *chip = data->chip; |
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int ret; |
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ret = max8925_reg_read(chip->i2c, data->reg_cntl); |
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if (ret < 0) |
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return -EINVAL; |
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data->current_brightness = ret; |
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dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness); |
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return ret; |
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} |
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static const struct backlight_ops max8925_backlight_ops = { |
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.options = BL_CORE_SUSPENDRESUME, |
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.update_status = max8925_backlight_update_status, |
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.get_brightness = max8925_backlight_get_brightness, |
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}; |
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static void max8925_backlight_dt_init(struct platform_device *pdev) |
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{ |
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struct device_node *nproot = pdev->dev.parent->of_node, *np; |
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struct max8925_backlight_pdata *pdata; |
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u32 val; |
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if (!nproot || !IS_ENABLED(CONFIG_OF)) |
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return; |
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pdata = devm_kzalloc(&pdev->dev, |
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sizeof(struct max8925_backlight_pdata), |
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GFP_KERNEL); |
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if (!pdata) |
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return; |
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np = of_get_child_by_name(nproot, "backlight"); |
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if (!np) { |
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dev_err(&pdev->dev, "failed to find backlight node\n"); |
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return; |
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} |
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if (!of_property_read_u32(np, "maxim,max8925-dual-string", &val)) |
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pdata->dual_string = val; |
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of_node_put(np); |
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pdev->dev.platform_data = pdata; |
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} |
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static int max8925_backlight_probe(struct platform_device *pdev) |
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{ |
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struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent); |
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struct max8925_backlight_pdata *pdata; |
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struct max8925_backlight_data *data; |
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struct backlight_device *bl; |
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struct backlight_properties props; |
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struct resource *res; |
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unsigned char value; |
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int ret = 0; |
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data = devm_kzalloc(&pdev->dev, sizeof(struct max8925_backlight_data), |
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GFP_KERNEL); |
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if (data == NULL) |
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return -ENOMEM; |
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res = platform_get_resource(pdev, IORESOURCE_REG, 0); |
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if (!res) { |
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dev_err(&pdev->dev, "No REG resource for mode control!\n"); |
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return -ENXIO; |
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} |
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data->reg_mode_cntl = res->start; |
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res = platform_get_resource(pdev, IORESOURCE_REG, 1); |
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if (!res) { |
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dev_err(&pdev->dev, "No REG resource for control!\n"); |
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return -ENXIO; |
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} |
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data->reg_cntl = res->start; |
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data->chip = chip; |
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data->current_brightness = 0; |
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memset(&props, 0, sizeof(struct backlight_properties)); |
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props.type = BACKLIGHT_RAW; |
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props.max_brightness = MAX_BRIGHTNESS; |
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bl = devm_backlight_device_register(&pdev->dev, "max8925-backlight", |
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&pdev->dev, data, |
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&max8925_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_BRIGHTNESS; |
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platform_set_drvdata(pdev, bl); |
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value = 0; |
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if (!pdev->dev.platform_data) |
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max8925_backlight_dt_init(pdev); |
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pdata = pdev->dev.platform_data; |
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if (pdata) { |
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if (pdata->lxw_scl) |
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value |= (1 << 7); |
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if (pdata->lxw_freq) |
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value |= (LWX_FREQ(pdata->lxw_freq) << 4); |
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if (pdata->dual_string) |
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value |= (1 << 1); |
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} |
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ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value); |
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if (ret < 0) |
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return ret; |
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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 max8925_backlight_driver = { |
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.driver = { |
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.name = "max8925-backlight", |
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}, |
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.probe = max8925_backlight_probe, |
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}; |
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module_platform_driver(max8925_backlight_driver); |
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MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925"); |
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MODULE_AUTHOR("Haojian Zhuang <[email protected]>"); |
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MODULE_LICENSE("GPL"); |
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MODULE_ALIAS("platform:max8925-backlight");
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