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linux/drivers/video/backlight/l4f00242t03.c
Alberto Panizzo aff5ce6ca8 drivers/video/backlight/l4f00242t03.c: fix reset sequence 
The reset command is part of the init sequence and it take effect
only if the lcd is powered.

The effect of the bug was that the sequence:
set lcd power_state to FB_BLANK_POWERDOWN
set lcd power_state to FB_BLANK_UNBLANK
Did not produced a complete reboot of the LCD which was showing fuzzy
colours.

This was not experienced before implementing correctly all the LCD power
states with the patch [1].  Since before the patch [1] the regulators were
not touched and the LCD shutdown was reached with a register write.  After
the patch [1] a complete boot sequence with an initial reset is needed for
the display every time the LCD is powered up.

drivers-video-backlight-l4f00242t03c-full-implement-fb-power-states-for-this-lcd.patch

Signed-off-by: Alberto Panizzo <maramaopercheseimorto@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 08:03:06 -08:00

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/*
* l4f00242t03.c -- support for Epson L4F00242T03 LCD
*
* Copyright 2007-2009 Freescale Semiconductor, Inc. All Rights Reserved.
*
* Copyright (c) 2009 Alberto Panizzo <maramaopercheseimorto@gmail.com>
* Inspired by Marek Vasut work in l4f00242t03.c
*
* 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/device.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/lcd.h>
#include <linux/slab.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <linux/spi/l4f00242t03.h>
struct l4f00242t03_priv {
struct spi_device *spi;
struct lcd_device *ld;
int lcd_state;
struct regulator *io_reg;
struct regulator *core_reg;
};
static void l4f00242t03_reset(unsigned int gpio)
{
pr_debug("l4f00242t03_reset.\n");
gpio_set_value(gpio, 1);
mdelay(100);
gpio_set_value(gpio, 0);
mdelay(10); /* tRES >= 100us */
gpio_set_value(gpio, 1);
mdelay(20);
}
#define param(x) ((x) | 0x100)
static void l4f00242t03_lcd_init(struct spi_device *spi)
{
struct l4f00242t03_pdata *pdata = spi->dev.platform_data;
struct l4f00242t03_priv *priv = dev_get_drvdata(&spi->dev);
const u16 cmd[] = { 0x36, param(0), 0x3A, param(0x60) };
dev_dbg(&spi->dev, "initializing LCD\n");
if (priv->io_reg) {
regulator_set_voltage(priv->io_reg, 1800000, 1800000);
regulator_enable(priv->io_reg);
}
if (priv->core_reg) {
regulator_set_voltage(priv->core_reg, 2800000, 2800000);
regulator_enable(priv->core_reg);
}
l4f00242t03_reset(pdata->reset_gpio);
gpio_set_value(pdata->data_enable_gpio, 1);
msleep(60);
spi_write(spi, (const u8 *)cmd, ARRAY_SIZE(cmd) * sizeof(u16));
}
static void l4f00242t03_lcd_powerdown(struct spi_device *spi)
{
struct l4f00242t03_pdata *pdata = spi->dev.platform_data;
struct l4f00242t03_priv *priv = dev_get_drvdata(&spi->dev);
dev_dbg(&spi->dev, "Powering down LCD\n");
gpio_set_value(pdata->data_enable_gpio, 0);
if (priv->io_reg)
regulator_disable(priv->io_reg);
if (priv->core_reg)
regulator_disable(priv->core_reg);
}
static int l4f00242t03_lcd_power_get(struct lcd_device *ld)
{
struct l4f00242t03_priv *priv = lcd_get_data(ld);
return priv->lcd_state;
}
static int l4f00242t03_lcd_power_set(struct lcd_device *ld, int power)
{
struct l4f00242t03_priv *priv = lcd_get_data(ld);
struct spi_device *spi = priv->spi;
const u16 slpout = 0x11;
const u16 dison = 0x29;
const u16 slpin = 0x10;
const u16 disoff = 0x28;
if (power <= FB_BLANK_NORMAL) {
if (priv->lcd_state <= FB_BLANK_NORMAL) {
/* Do nothing, the LCD is running */
} else if (priv->lcd_state < FB_BLANK_POWERDOWN) {
dev_dbg(&spi->dev, "Resuming LCD\n");
spi_write(spi, (const u8 *)&slpout, sizeof(u16));
msleep(60);
spi_write(spi, (const u8 *)&dison, sizeof(u16));
} else {
/* priv->lcd_state == FB_BLANK_POWERDOWN */
l4f00242t03_lcd_init(spi);
priv->lcd_state = FB_BLANK_VSYNC_SUSPEND;
l4f00242t03_lcd_power_set(priv->ld, power);
}
} else if (power < FB_BLANK_POWERDOWN) {
if (priv->lcd_state <= FB_BLANK_NORMAL) {
/* Send the display in standby */
dev_dbg(&spi->dev, "Standby the LCD\n");
spi_write(spi, (const u8 *)&disoff, sizeof(u16));
msleep(60);
spi_write(spi, (const u8 *)&slpin, sizeof(u16));
} else if (priv->lcd_state < FB_BLANK_POWERDOWN) {
/* Do nothing, the LCD is already in standby */
} else {
/* priv->lcd_state == FB_BLANK_POWERDOWN */
l4f00242t03_lcd_init(spi);
priv->lcd_state = FB_BLANK_UNBLANK;
l4f00242t03_lcd_power_set(ld, power);
}
} else {
/* power == FB_BLANK_POWERDOWN */
if (priv->lcd_state != FB_BLANK_POWERDOWN) {
/* Clear the screen before shutting down */
spi_write(spi, (const u8 *)&disoff, sizeof(u16));
msleep(60);
l4f00242t03_lcd_powerdown(spi);
}
}
priv->lcd_state = power;
return 0;
}
static struct lcd_ops l4f_ops = {
.set_power = l4f00242t03_lcd_power_set,
.get_power = l4f00242t03_lcd_power_get,
};
static int __devinit l4f00242t03_probe(struct spi_device *spi)
{
struct l4f00242t03_priv *priv;
struct l4f00242t03_pdata *pdata = spi->dev.platform_data;
int ret;
if (pdata == NULL) {
dev_err(&spi->dev, "Uninitialized platform data.\n");
return -EINVAL;
}
priv = kzalloc(sizeof(struct l4f00242t03_priv), GFP_KERNEL);
if (priv == NULL) {
dev_err(&spi->dev, "No memory for this device.\n");
return -ENOMEM;
}
dev_set_drvdata(&spi->dev, priv);
spi->bits_per_word = 9;
spi_setup(spi);
priv->spi = spi;
ret = gpio_request(pdata->reset_gpio, "lcd l4f00242t03 reset");
if (ret) {
dev_err(&spi->dev,
"Unable to get the lcd l4f00242t03 reset gpio.\n");
goto err;
}
ret = gpio_direction_output(pdata->reset_gpio, 1);
if (ret)
goto err2;
ret = gpio_request(pdata->data_enable_gpio,
"lcd l4f00242t03 data enable");
if (ret) {
dev_err(&spi->dev,
"Unable to get the lcd l4f00242t03 data en gpio.\n");
goto err2;
}
ret = gpio_direction_output(pdata->data_enable_gpio, 0);
if (ret)
goto err3;
if (pdata->io_supply) {
priv->io_reg = regulator_get(NULL, pdata->io_supply);
if (IS_ERR(priv->io_reg)) {
pr_err("%s: Unable to get the IO regulator\n",
__func__);
goto err3;
}
}
if (pdata->core_supply) {
priv->core_reg = regulator_get(NULL, pdata->core_supply);
if (IS_ERR(priv->core_reg)) {
pr_err("%s: Unable to get the core regulator\n",
__func__);
goto err4;
}
}
priv->ld = lcd_device_register("l4f00242t03",
&spi->dev, priv, &l4f_ops);
if (IS_ERR(priv->ld)) {
ret = PTR_ERR(priv->ld);
goto err5;
}
/* Init the LCD */
l4f00242t03_lcd_init(spi);
priv->lcd_state = FB_BLANK_VSYNC_SUSPEND;
l4f00242t03_lcd_power_set(priv->ld, FB_BLANK_UNBLANK);
dev_info(&spi->dev, "Epson l4f00242t03 lcd probed.\n");
return 0;
err5:
if (priv->core_reg)
regulator_put(priv->core_reg);
err4:
if (priv->io_reg)
regulator_put(priv->io_reg);
err3:
gpio_free(pdata->data_enable_gpio);
err2:
gpio_free(pdata->reset_gpio);
err:
kfree(priv);
return ret;
}
static int __devexit l4f00242t03_remove(struct spi_device *spi)
{
struct l4f00242t03_priv *priv = dev_get_drvdata(&spi->dev);
struct l4f00242t03_pdata *pdata = priv->spi->dev.platform_data;
l4f00242t03_lcd_power_set(priv->ld, FB_BLANK_POWERDOWN);
lcd_device_unregister(priv->ld);
dev_set_drvdata(&spi->dev, NULL);
gpio_free(pdata->data_enable_gpio);
gpio_free(pdata->reset_gpio);
if (priv->io_reg)
regulator_put(priv->io_reg);
if (priv->core_reg)
regulator_put(priv->core_reg);
kfree(priv);
return 0;
}
static void l4f00242t03_shutdown(struct spi_device *spi)
{
struct l4f00242t03_priv *priv = dev_get_drvdata(&spi->dev);
if (priv)
l4f00242t03_lcd_power_set(priv->ld, FB_BLANK_POWERDOWN);
}
static struct spi_driver l4f00242t03_driver = {
.driver = {
.name = "l4f00242t03",
.owner = THIS_MODULE,
},
.probe = l4f00242t03_probe,
.remove = __devexit_p(l4f00242t03_remove),
.shutdown = l4f00242t03_shutdown,
};
static __init int l4f00242t03_init(void)
{
return spi_register_driver(&l4f00242t03_driver);
}
static __exit void l4f00242t03_exit(void)
{
spi_unregister_driver(&l4f00242t03_driver);
}
module_init(l4f00242t03_init);
module_exit(l4f00242t03_exit);
MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>");
MODULE_DESCRIPTION("EPSON L4F00242T03 LCD");
MODULE_LICENSE("GPL v2");
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