backlight: add backlight driver for pandora

This is fine-tuned driver for pandora's backlight connected to
TWL4030 PWM0 and LED driver chip.

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index e54a337..8dd3c6f 100644 (file)
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -222,6 +222,12 @@ config BACKLIGHT_PWM
          If you have a LCD backlight adjustable by PWM, say Y to enable
          this driver.
 
+config BACKLIGHT_PANDORA
+       tristate "Backlight Driver for Pandora"
+       depends on BACKLIGHT_CLASS_DEVICE && TWL4030_CORE
+       help
+         If you have a Pandora, say Y to enable it's backlight driver.
+
 config BACKLIGHT_DA903X
        tristate "Backlight Driver for DA9030/DA9034 using WLED"
        depends on PMIC_DA903X

diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 44c0f81..555b8a6 100644 (file)
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_BACKLIGHT_OMAP1) += omap1_bl.o
 obj-$(CONFIG_BACKLIGHT_PROGEAR) += progear_bl.o
 obj-$(CONFIG_BACKLIGHT_CARILLO_RANCH) += cr_bllcd.o
 obj-$(CONFIG_BACKLIGHT_PWM)    += pwm_bl.o
+obj-$(CONFIG_BACKLIGHT_PANDORA)        += pandora_bl.o
 obj-$(CONFIG_BACKLIGHT_DA903X) += da903x_bl.o
 obj-$(CONFIG_BACKLIGHT_MAX8925)        += max8925_bl.o
 obj-$(CONFIG_BACKLIGHT_MBP_NVIDIA) += mbp_nvidia_bl.o

diff --git a/drivers/video/backlight/pandora_bl.c b/drivers/video/backlight/pandora_bl.c
new file mode 100644 (file)
index 0000000..89b8c59
--- /dev/null
+++ b/drivers/video/backlight/pandora_bl.c
@@ -0,0 +1,194 @@
+/*
+ * Backlight driver for TWL4030 PWM0 -> TPS61161 combo.
+ * Based on pwm_bl.c
+ *
+ * Author: Gražvydas Ignotas <notasas@gmail.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/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/fb.h>
+#include <linux/backlight.h>
+#include <linux/i2c/twl.h>
+#include <linux/err.h>
+
+#define TWL_PWM0_ON    0x00
+#define TWL_PWM0_OFF   0x01
+
+#define TWL_INTBR_GPBR1        0x0c
+#define TWL_INTBR_PMBR1        0x0d
+
+#define PWM0_CLK_ENABLE        1
+#define PWM0_ENABLE    4
+
+/* range accepted by hardware */
+#define MIN_VALUE 9
+#define MAX_VALUE 63
+#define MAX_USER_VALUE (MAX_VALUE - MIN_VALUE)
+
+static int old_brightness;
+
+static void pwm0_disable(void)
+{
+       u8 r;
+
+       /* first disable PWM0 output, then clock */
+       twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_GPBR1);
+       r &= ~PWM0_ENABLE;
+       twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
+       r &= ~PWM0_CLK_ENABLE;
+       twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
+}
+
+static int pwm0_backlight_update_status(struct backlight_device *bl)
+{
+       int brightness = bl->props.brightness;
+       u8 r;
+
+       if (bl->props.power != FB_BLANK_UNBLANK)
+               brightness = 0;
+
+       /* ignore fb blank for now
+       if (bl->props.fb_blank != FB_BLANK_UNBLANK)
+               brightness = 0;
+       */
+
+       if ((unsigned int)brightness > MAX_USER_VALUE)
+               brightness = MAX_USER_VALUE;
+
+       if (brightness == 0) {
+               if (old_brightness != 0)
+                       pwm0_disable();
+
+               goto done;
+       }
+
+       if (old_brightness == 0) {
+               /* set PWM duty cycle to max. TPS61161 seems to use this
+                * to calibrate it's PWM sensitivity when it starts. */
+               twl_i2c_write_u8(TWL4030_MODULE_PWM0, MAX_VALUE,
+                                       TWL_PWM0_OFF);
+
+               /* first enable clock, then PWM0 out */
+               twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_GPBR1);
+               r &= ~PWM0_ENABLE;
+               r |= PWM0_CLK_ENABLE;
+               twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
+               r |= PWM0_ENABLE;
+               twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_GPBR1);
+
+               /* TI made it very easy to enable digital control, so easy that
+                * it often triggers unintentionally and disabes PWM control,
+                * so wait until 1 wire mode detection window ends. */
+               udelay(2000);
+       }
+
+       twl_i2c_write_u8(TWL4030_MODULE_PWM0, MIN_VALUE + brightness,
+                               TWL_PWM0_OFF);
+
+done:
+       old_brightness = brightness;
+       return 0;
+}
+
+static int pwm0_backlight_get_brightness(struct backlight_device *bl)
+{
+       return bl->props.brightness;
+}
+
+static const struct backlight_ops pwm0_backlight_ops = {
+       .update_status  = pwm0_backlight_update_status,
+       .get_brightness = pwm0_backlight_get_brightness,
+};
+
+static int pwm0_backlight_probe(struct platform_device *pdev)
+{
+       struct backlight_properties props;
+       struct backlight_device *bl;
+       u8 r;
+
+       memset(&props, 0, sizeof(props));
+       props.max_brightness = MAX_USER_VALUE;
+       bl = backlight_device_register(pdev->name, &pdev->dev,
+                       NULL, &pwm0_backlight_ops, &props);
+       if (IS_ERR(bl)) {
+               dev_err(&pdev->dev, "failed to register backlight\n");
+               return PTR_ERR(bl);
+       }
+
+       /* 64 cycle period, ON position 0 */
+       twl_i2c_write_u8(TWL4030_MODULE_PWM0, 0x80, TWL_PWM0_ON);
+
+       bl->props.brightness = MAX_USER_VALUE;
+       backlight_update_status(bl);
+
+       /* enable PWM function in pin mux (i2c addr 0x49 0x92) */
+       twl_i2c_read_u8(TWL4030_MODULE_INTBR, &r, TWL_INTBR_PMBR1);
+       r &= ~0x0c;
+       r |= 0x04;
+       twl_i2c_write_u8(TWL4030_MODULE_INTBR, r, TWL_INTBR_PMBR1);
+
+       return 0;
+}
+
+static int pwm0_backlight_remove(struct platform_device *pdev)
+{
+       struct backlight_device *bl = platform_get_drvdata(pdev);
+       backlight_device_unregister(bl);
+       return 0;
+}
+
+#ifdef CONFIG_PM
+static int pwm0_backlight_suspend(struct platform_device *pdev,
+                                pm_message_t state)
+{
+       pwm0_disable();
+       old_brightness = 0;
+
+       return 0;
+}
+
+static int pwm0_backlight_resume(struct platform_device *pdev)
+{
+       struct backlight_device *bl = platform_get_drvdata(pdev);
+
+       backlight_update_status(bl);
+       return 0;
+}
+#else
+#define pwm0_backlight_suspend NULL
+#define pwm0_backlight_resume  NULL
+#endif
+
+static struct platform_driver pwm0_backlight_driver = {
+       .driver         = {
+               .name   = "twl4030-pwm0-bl",
+               .owner  = THIS_MODULE,
+       },
+       .probe          = pwm0_backlight_probe,
+       .remove         = pwm0_backlight_remove,
+       .suspend        = pwm0_backlight_suspend,
+       .resume         = pwm0_backlight_resume,
+};
+
+static int __init pwm0_backlight_init(void)
+{
+       return platform_driver_register(&pwm0_backlight_driver);
+}
+module_init(pwm0_backlight_init);
+
+static void __exit pwm0_backlight_exit(void)
+{
+       platform_driver_unregister(&pwm0_backlight_driver);
+}
+module_exit(pwm0_backlight_exit);
+
+MODULE_DESCRIPTION("TWL4030 PWM0 Backlight Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:twl4030-pwm0-bl");