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