Initial import

1 files changed, 165 insertions, 0 deletions

diff --git a/drivers/video/backlight/ot200_bl.c b/drivers/video/backlight/ot200_bl.c
new file mode 100644
index 000000000..3acdb9f64
--- /dev/null
+++ b/drivers/video/backlight/ot200_bl.c
@@ -0,0 +1,165 @@
+/*
+ * Copyright (C) 2012 Bachmann electronic GmbH
+ *	Christian Gmeiner <christian.gmeiner@gmail.com>
+ *
+ * Backlight driver for ot200 visualisation device from
+ * Bachmann electronic GmbH.
+ *
+ * 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/module.h>
+#include <linux/fb.h>
+#include <linux/backlight.h>
+#include <linux/gpio.h>
+#include <linux/platform_device.h>
+#include <linux/cs5535.h>
+
+static struct cs5535_mfgpt_timer *pwm_timer;
+
+/* this array defines the mapping of brightness in % to pwm frequency */
+static const u8 dim_table[101] = {0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2,
+				  2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4,
+				  4, 5, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 9, 9,
+				  10, 10, 11, 11, 12, 12, 13, 14, 15, 15, 16,
+				  17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28,
+				  30, 31, 33, 35, 37, 39, 41, 43, 45, 47, 50,
+				  53, 55, 58, 61, 65, 68, 72, 75, 79, 84, 88,
+				  93, 97, 103, 108, 114, 120, 126, 133, 140,
+				  147, 155, 163};
+
+struct ot200_backlight_data {
+	int current_brightness;
+};
+
+#define GPIO_DIMM	27
+#define SCALE		1
+#define CMP1MODE	0x2	/* compare on GE; output high on compare
+				 * greater than or equal */
+#define PWM_SETUP	(SCALE | CMP1MODE << 6 | MFGPT_SETUP_CNTEN)
+#define MAX_COMP2	163
+
+static int ot200_backlight_update_status(struct backlight_device *bl)
+{
+	struct ot200_backlight_data *data = bl_get_data(bl);
+	int brightness = bl->props.brightness;
+
+	if (bl->props.state & BL_CORE_FBBLANK)
+		brightness = 0;
+
+	/* enable or disable PWM timer */
+	if (brightness == 0)
+		cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, 0);
+	else if (data->current_brightness == 0) {
+		cs5535_mfgpt_write(pwm_timer, MFGPT_REG_COUNTER, 0);
+		cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP,
+			MFGPT_SETUP_CNTEN);
+	}
+
+	/* apply new brightness value */
+	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1,
+		MAX_COMP2 - dim_table[brightness]);
+	data->current_brightness = brightness;
+
+	return 0;
+}
+
+static int ot200_backlight_get_brightness(struct backlight_device *bl)
+{
+	struct ot200_backlight_data *data = bl_get_data(bl);
+	return data->current_brightness;
+}
+
+static const struct backlight_ops ot200_backlight_ops = {
+	.update_status	= ot200_backlight_update_status,
+	.get_brightness	= ot200_backlight_get_brightness,
+};
+
+static int ot200_backlight_probe(struct platform_device *pdev)
+{
+	struct backlight_device *bl;
+	struct ot200_backlight_data *data;
+	struct backlight_properties props;
+	int retval = 0;
+
+	/* request gpio */
+	if (devm_gpio_request(&pdev->dev, GPIO_DIMM,
+				"ot200 backlight dimmer") < 0) {
+		dev_err(&pdev->dev, "failed to request GPIO %d\n", GPIO_DIMM);
+		return -ENODEV;
+	}
+
+	/* request timer */
+	pwm_timer = cs5535_mfgpt_alloc_timer(7, MFGPT_DOMAIN_ANY);
+	if (!pwm_timer) {
+		dev_err(&pdev->dev, "MFGPT 7 not available\n");
+		return -ENODEV;
+	}
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data) {
+		retval = -ENOMEM;
+		goto error_devm_kzalloc;
+	}
+
+	/* setup gpio */
+	cs5535_gpio_set(GPIO_DIMM, GPIO_OUTPUT_ENABLE);
+	cs5535_gpio_set(GPIO_DIMM, GPIO_OUTPUT_AUX1);
+
+	/* setup timer */
+	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1, 0);
+	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP2, MAX_COMP2);
+	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, PWM_SETUP);
+
+	data->current_brightness = 100;
+	props.max_brightness = 100;
+	props.brightness = 100;
+	props.type = BACKLIGHT_RAW;
+
+	bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
+					&pdev->dev, data, &ot200_backlight_ops,
+					&props);
+	if (IS_ERR(bl)) {
+		dev_err(&pdev->dev, "failed to register backlight\n");
+		retval = PTR_ERR(bl);
+		goto error_devm_kzalloc;
+	}
+
+	platform_set_drvdata(pdev, bl);
+
+	return 0;
+
+error_devm_kzalloc:
+	cs5535_mfgpt_free_timer(pwm_timer);
+	return retval;
+}
+
+static int ot200_backlight_remove(struct platform_device *pdev)
+{
+	/* on module unload set brightness to 100% */
+	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_COUNTER, 0);
+	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
+	cs5535_mfgpt_write(pwm_timer, MFGPT_REG_CMP1,
+		MAX_COMP2 - dim_table[100]);
+
+	cs5535_mfgpt_free_timer(pwm_timer);
+
+	return 0;
+}
+
+static struct platform_driver ot200_backlight_driver = {
+	.driver		= {
+		.name	= "ot200-backlight",
+	},
+	.probe		= ot200_backlight_probe,
+	.remove		= ot200_backlight_remove,
+};
+
+module_platform_driver(ot200_backlight_driver);
+
+MODULE_DESCRIPTION("backlight driver for ot200 visualisation device");
+MODULE_AUTHOR("Christian Gmeiner <christian.gmeiner@gmail.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ot200-backlight");