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![Johan Hovold](/assets/img/avatar_default.png)
Fix child-node lookup during probe, which ended up searching the whole
device tree depth-first starting at the parent rather than just matching
on its children.
To make things worse, the parent mfd node was also prematurely freed,
while the child backlight node was leaked.
Cc: stable <stable@vger.kernel.org> # 3.9
Fixes: 47ec340cb8
("mfd: max8925: Support dt for backlight")
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
211 lines
5.3 KiB
C
211 lines
5.3 KiB
C
/*
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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 <haojian.zhuang@marvell.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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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int brightness = bl->props.brightness;
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if (bl->props.power != FB_BLANK_UNBLANK)
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brightness = 0;
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if (bl->props.fb_blank != FB_BLANK_UNBLANK)
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brightness = 0;
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if (bl->props.state & BL_CORE_SUSPENDED)
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brightness = 0;
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return max8925_backlight_set(bl, brightness);
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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 <haojian.zhuang@marvell.com>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:max8925-backlight");
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