--- /dev/null
+/*
+ * 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 = dev_get_platdata(pdev->dev.parent);
+ 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 (wm831x_pdata)
+ 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;
+
+ memset(&props, 0, sizeof(props));
+ props.type = BACKLIGHT_RAW;
+ props.max_brightness = max_isel;
+ bl = devm_backlight_device_register(&pdev->dev, "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 struct platform_driver wm831x_backlight_driver = {
+ .driver = {
+ .name = "wm831x-backlight",
+ },
+ .probe = wm831x_backlight_probe,
+};
+
+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");
Code Review / kvmfornfv.git / blobdiff