Attempt #3 :
Changes :
---------
* removed JORN.. prefixes except from functions.
* removed file location in head
* fixed (hope) indent issues
* do not exceed 80 chars per line
* added extra checks if driver allocation fails
* return -1 instead of (MAX + 1)
...and probably alot more.

Patch:
* builds
* passes checkpatch.pl (only complaining about signoff-tag)

Oh, and thanks for all the feedback people! (and for doing it nicely)
Only thing not adress so far is richards mdelay question, need to do a quick test before I can answer that.

/Kristoffer

diff --git a/drivers/video/backlight/jornada720_bllcd.c b/drivers/video/backlight/jornada720_bllcd.c
new file mode 100644
index 0000000..0adbc49
--- /dev/null
+++ b/drivers/video/backlight/jornada720_bllcd.c
@@ -0,0 +1,287 @@
+/*
+ *
+ * Backlight and LCD Driver for HP Jornada 720
+ * Copyright (C) 2007 Kristoffer Ericson <Kristoffer.Ericson@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
+ * or any later version as published by the Free Software Foundation.
+ *
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/backlight.h>
+#include <linux/lcd.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/fb.h>
+#include <linux/device.h>
+#include <asm/hardware.h>
+#include <asm/arch/jornada720.h>
+#include <video/s1d13xxxfb.h>
+
+MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson@gmail.com>");
+MODULE_DESCRIPTION("HP Jornada 710/720/728 Backlight/LCD Driver");
+MODULE_LICENSE("GPL");
+
+/* Contrast */
+#define LCD_MAX_CONTR	0xff
+#define LCD_DEF_CONTR	0x80
+/* Brightness */
+#define BL_MAX_BRIGHT	0xff
+#define BL_DEF_BRIGHT	0x19
+
+struct bllcd_device {
+	struct backlight_device *bl_device;
+	struct lcd_device *lcd_device;
+};
+
+/*
+ * BACKLIGHT HANDLING ROUTINES
+ */
+static int jornada_bl_get_brightness(struct backlight_device *dev)
+{
+	int ret;
+
+	/* check if backlight is on */
+	if (!(PPSR & PPC_LDD1))
+		return BL_MAX_BRIGHT;
+
+	jornada_ssp_start();
+	if (jornada_ssp_inout(GETBRIGHTNESS) == -ETIMEDOUT) {
+		printk(KERN_ERR "bl :get brightness timeout\n");
+		ret = -1;
+	} else
+		ret = jornada_ssp_inout(TXDUMMY);
+
+	jornada_ssp_end();
+
+	/* 0 is max brightness */
+	return BL_MAX_BRIGHT - ret;
+}
+
+static int jornada_bl_update_status(struct backlight_device *dev)
+{
+	int ret = 0;
+	int value;
+
+	jornada_ssp_start();
+
+	if (dev->props.power != FB_BLANK_UNBLANK ||
+	dev->props.fb_blank != FB_BLANK_UNBLANK) {
+		ret = jornada_ssp_inout(BRIGHTNESSOFF);
+		if (ret == -ETIMEDOUT) {
+			printk(KERN_ERR "bl : brightness off timeout\n");
+			/* backlight off */
+			PPSR &= ~PPC_LDD1;
+			PPDR |= PPC_LDD1;
+		}
+	} else { /* backlight on */
+		PPSR |= PPC_LDD1;
+		/* send setbrightness cmd */
+		ret = jornada_ssp_inout(SETBRIGHTNESS);
+		if (ret != TXDUMMY) {
+			printk(KERN_ERR "bl :set brightness timeout\n");
+		} else {
+			/* cmd accepted */
+			value = BL_MAX_BRIGHT - dev->props.brightness;
+			if (jornada_ssp_byte(value) == TXDUMMY)
+				ret = value;
+			else
+				printk(KERN_ERR "bl :set brightness failed\n");
+		}
+	}
+
+	jornada_ssp_end();
+
+	return ret;
+}
+
+/*
+ * LCD HANDLING FUNCTIONS
+ */
+static int jornada_lcd_set_contrast(struct lcd_device *pdev, int contrast)
+{
+	int ret = 0;
+
+	jornada_ssp_start();
+
+	ret = jornada_ssp_inout(SETCONTRAST);
+
+	if (ret == -ETIMEDOUT)
+		printk(KERN_ERR "lcd :set contrast timeout\n");
+	else
+		ret = jornada_ssp_byte(contrast);
+
+	jornada_ssp_end();
+
+	return ret;
+}
+
+static int jornada_lcd_set_power(struct lcd_device  *pdev, int power)
+{
+	if (power != FB_BLANK_UNBLANK) {
+		/* turn off LCD */
+		PPSR &= ~PPC_LDD2;
+		PPDR |= PPC_LDD2;
+	} else {
+		/* turn on LCD */
+		PPSR |= PPC_LDD2;
+	}
+
+	return 0;
+}
+
+static int jornada_lcd_get_power(struct lcd_device *pdev)
+{
+	if (PPSR & PPC_LDD2)
+		return FB_BLANK_UNBLANK;
+	else
+		return FB_BLANK_POWERDOWN;
+}
+
+static int jornada_lcd_get_contrast(struct lcd_device *pdev)
+{
+	int ret;
+
+	/* Don't set contrast on off powerd LCD */
+	if (jornada_lcd_get_power(pdev) != FB_BLANK_UNBLANK)
+		return 0;
+
+	jornada_ssp_start();
+
+	ret = jornada_ssp_inout(GETCONTRAST);
+	if (ret != -ETIMEDOUT)
+		ret = jornada_ssp_inout(TXDUMMY);
+	else {
+		printk(KERN_ERR "lcd :get contrast timeout\n");
+		ret = -1;
+	}
+
+	jornada_ssp_end();
+
+	return ret;
+}
+
+static struct backlight_ops jornada_bl_ops = {
+	.get_brightness = jornada_bl_get_brightness,
+	.update_status = jornada_bl_update_status,
+};
+
+static struct lcd_ops jornada_lcd_ops = {
+	.get_contrast = jornada_lcd_get_contrast,
+	.set_contrast = jornada_lcd_set_contrast,
+	.get_power = jornada_lcd_get_power,
+	.set_power = jornada_lcd_set_power,
+};
+
+static int jornada_bl_probe(struct platform_device *pdev)
+{
+	struct bllcd_device *bllcd;
+
+	bllcd = kzalloc(sizeof(*bllcd), GFP_KERNEL);
+	if (bllcd == NULL)
+		return -ENOMEM;
+
+	/* bl driver - name must match fb driver name */
+	bllcd->bl_device = backlight_device_register(S1D_DEVICENAME,
+	&pdev->dev, NULL, &jornada_bl_ops);
+
+	if (IS_ERR(bllcd->bl_device)) {
+		kfree(bllcd);
+		printk(KERN_ERR "bl :failed to register device\n");
+		return -ENODEV;
+	}
+
+	/* lcd driver */
+	bllcd->lcd_device = lcd_device_register(S1D_DEVICENAME,
+				&pdev->dev, NULL, &jornada_lcd_ops);
+	if (IS_ERR(bllcd->lcd_device)) {
+		backlight_device_unregister(bllcd->bl_device);
+		kfree(bllcd);
+		printk(KERN_ERR "lcd :failed to register device\n");
+		return -ENODEV;
+	}
+
+	jornada_lcd_set_contrast(bllcd->lcd_device, LCD_DEF_CONTR);
+	jornada_lcd_set_power(bllcd->lcd_device, FB_BLANK_UNBLANK);
+
+	msleep(100);
+
+	bllcd->bl_device->props.power = FB_BLANK_UNBLANK;
+	bllcd->bl_device->props.brightness = BL_DEF_BRIGHT;
+	jornada_bl_update_status(bllcd->bl_device);
+
+	platform_set_drvdata(pdev, bllcd);
+	printk(KERN_INFO "HP Jornada 7xx Backlight/LCD driver activated\n");
+
+	return 0;
+}
+
+static int jornada_bl_remove(struct platform_device *pdev)
+{
+	struct bllcd_device *bllcd = platform_get_drvdata(pdev);
+
+	bllcd->bl_device->props.power = FB_BLANK_POWERDOWN;
+	bllcd->bl_device->props.brightness = 0;
+	bllcd->bl_device->props.max_brightness = 0;
+
+	backlight_device_unregister(bllcd->bl_device);
+	lcd_device_unregister(bllcd->lcd_device);
+
+	return 0;
+}
+
+static int jornada_bl_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct bllcd_device *bllcd = platform_get_drvdata(pdev);
+
+	bllcd->bl_device->props.power = FB_BLANK_POWERDOWN;
+	bllcd->bl_device->props.brightness = 0;
+	bllcd->bl_device->props.max_brightness = 0;
+	jornada_bl_update_status(bllcd->bl_device);
+
+	jornada_lcd_set_power(bllcd->lcd_device, FB_BLANK_POWERDOWN);
+
+	return 0;
+}
+
+static int jornada_bl_resume(struct platform_device *pdev)
+{
+	struct bllcd_device *bllcd = platform_get_drvdata(pdev);
+
+	bllcd->bl_device->props.power = FB_BLANK_UNBLANK;
+	bllcd->bl_device->props.brightness = BL_DEF_BRIGHT;
+	bllcd->bl_device->props.max_brightness = BL_MAX_BRIGHT;
+	jornada_bl_update_status(bllcd->bl_device);
+
+	jornada_lcd_set_power(bllcd->lcd_device, FB_BLANK_UNBLANK);
+
+	return 0;
+}
+
+static struct platform_driver jornada_bl_driver = {
+	.probe	= jornada_bl_probe,
+	.remove	= jornada_bl_remove,
+#ifdef CONFIG_PM
+	.suspend = jornada_bl_suspend,
+	.resume = jornada_bl_resume,
+#endif
+	.driver = {
+	    .name = "jornada_bllcd",
+	},
+};
+
+static int __init jornada_bl_init(void)
+{
+	return platform_driver_register(&jornada_bl_driver);
+}
+
+static void __exit jornada_bl_exit(void)
+{
+	platform_driver_unregister(&jornada_bl_driver);
+}
+
+module_init(jornada_bl_init);
+module_exit(jornada_bl_exit);





On Wed, 6 Feb 2008 16:44:36 +0000
Russell King - ARM Linux <linux@arm.linux.org.uk> wrote:

> On Wed, Feb 06, 2008 at 05:33:41PM +0100, Kristoffer Ericson wrote:
> > Oki, here is attempt #2 (btw, new mail or just keep thread?)
> 
> Probably better to keep the thread.  More comments 8)
> 
> > +struct jornada_bllcd_device {
> > +	struct backlight_device *jorn_backlight_device;
> > +	struct lcd_device *jorn_lcd_device;
> 
> We're inside a jornada file.  Do these "jorn_" prefixes add anything
> useful that the reader doesn't already know?
> 
> > +static int jornada_bl_update_status(struct backlight_device *dev)
> > +{
> > +	int ret = 0;
> > +
> > +	jornada_ssp_start();
> > +
> > +	if (dev->props.power != FB_BLANK_UNBLANK ||
> > +		dev->props.fb_blank != FB_BLANK_UNBLANK) {
> > +		ret = jornada_ssp_inout(BRIGHTNESSOFF);
> > +		if (ret == -ETIMEDOUT)
> > +			printk(KERN_ERR "jornada720_bl:	\
> > +				BrightnessOff timeout\n");
> > +			/* backlight off */
> > +			PPSR &= ~PPC_LDD1;
> > +			PPDR |= PPC_LDD1;
> 
> Look at the above 5 lines.  What are your expectations if ret != -ETIMEDOUT?
> If C were python you'd have one behaviour due to the indent...
> 
> > +
> > +	} else	{	/* backlight on */
> 
> Too many spaces.
> 
> > +			PPSR |= PPC_LDD1;
> > +			if ((jornada_ssp_inout(SETBRIGHTNESS)) == TXDUMMY) {
> > +			    /* send brightness value (0 is max, 255 lowest) */
> > +				if (jornada_ssp_byte(JORNADA_BL_MAX_BRIGHTNESS -
> > +					 dev->props.brightness) != -ETIMEDOUT)
> > +				ret = (JORNADA_BL_MAX_BRIGHTNESS -
> > +					dev->props.brightness);
> > +			} else
> > +				printk(KERN_ERR "jornada720_bl:	\
> > +					SetBrightness timeout\n");
> > +		}
> 
> If this corresponds with the "} else {" line, it should have one tab.  Plus
> the above indented code section should probably have one less indentation.
> 
> > +	jornada_ssp_end();
> > +
> > +	return ret;
> > +}
> > +
> > +/*
> > + * LCD HANDLING FUNCTIONS
> > + */
> > +static int jornada_lcd_set_contrast(struct lcd_device *pdev, int contrast)
> > +{
> > +	int ret = 0;
> > +
> > +	jornada_ssp_start();
> > +
> > +	ret = jornada_ssp_inout(SETCONTRAST);
> > +
> > +	if (ret == -ETIMEDOUT)
> > +		printk(KERN_ERR "jornada_lcd: failure to set contrast\n");
> > +	 else
> 
> Space before 'else' not required.
> 
> > +		ret = jornada_ssp_byte(contrast);
> > +
> > +	jornada_ssp_end();
> > +
> > +	return ret;
> > +}
> > +
> > +static int jornada_lcd_set_power(struct lcd_device  *pdev, int power)
> > +{
> > +	if (power != FB_BLANK_UNBLANK) {
> > +		/* turn off LCD */
> > +		PPSR &= ~PPC_LDD2;
> > +		PPDR |= PPC_LDD2;
> > +	} else {
> > +		/* turn on LCD */
> > +		PPSR |= PPC_LDD2;
> > +		}
> 
> Wrongly placed }
> 
> > +
> > +	return 0;
> > +}
> > +
> > +static int jornada_lcd_get_power(struct lcd_device *pdev)
> > +{
> > +	if (PPSR & PPC_LDD2)
> > +		return FB_BLANK_UNBLANK;
> > +	else
> > +		return FB_BLANK_POWERDOWN;
> > +}
> > +
> > +static int jornada_lcd_get_contrast(struct lcd_device *pdev)
> > +{
> > +	int ret;
> > +
> > +	/* Don't set contrast on off powerd LCD */
> > +	if (jornada_lcd_get_power(pdev) != FB_BLANK_UNBLANK)
> > +		return 0;
> > +
> > +	jornada_ssp_start();
> > +
> > +	ret = jornada_ssp_inout(GETCONTRAST);
> > +	if (ret != -ETIMEDOUT)
> > +		ret = jornada_ssp_inout(TXDUMMY);
> > +	else {
> > +		printk(KERN_ERR "jornada_lcd: getcontrast failed!\n");
> > +		ret = JORNADA_BL_MAX_BRIGHTNESS + 1;
> > +	}
> > +
> > +	jornada_ssp_end();
> > +
> > +	return ret;
> > +}
> > +
> > +static struct backlight_ops jornada_bl_ops = {
> > +	.get_brightness = jornada_bl_get_brightness,
> > +	.update_status = jornada_bl_update_status,
> > +};
> > +
> > +static struct lcd_ops jornada_lcd_ops = {
> > +	.get_contrast = jornada_lcd_get_contrast,
> > +	.set_contrast = jornada_lcd_set_contrast,
> > +	.get_power = jornada_lcd_get_power,
> > +	.set_power = jornada_lcd_set_power,
> > +};
> > +
> > +static int jornada_bl_probe(struct platform_device *pdev)
> > +{
> > +	struct jornada_bllcd_device *bllcd;
> > +
> > +	bllcd = kzalloc(sizeof(*bllcd), GFP_KERNEL);
> > +	if (bllcd == NULL)
> > +		return -ENOMEM;
> > +
> > +	/* bl driver - name must match fb driver name */
> > +	bllcd->jorn_backlight_device = backlight_device_register(S1D_DEVICENAME,
> > +		&pdev->dev, NULL, &jornada_bl_ops);
> > +
> > +	if (IS_ERR(bllcd->jorn_backlight_device)) {
> > +		kfree(bllcd);
> > +		return PTR_ERR(bllcd->jorn_backlight_device);
> 
> Access after free.  Bad bad bad.
> 
> > +	}
> > +
> > +	/* lcd driver */
> > +	bllcd->jorn_lcd_device = lcd_device_register(S1D_DEVICENAME,
> > +				&pdev->dev, NULL, &jornada_lcd_ops);
> > +	if (IS_ERR(bllcd->jorn_lcd_device)) {
> > +		kfree(bllcd);
> > +		return PTR_ERR(bllcd->jorn_lcd_device);
> 
> Access after free.  Bad bad bad.
> 
> > +	}
> > +
> > +	jornada_lcd_set_contrast(bllcd->jorn_lcd_device,
> > +			JORNADA_LCD_DEFAULT_CONTRAST);
> > +	jornada_lcd_set_power(bllcd->jorn_lcd_device,
> > +			FB_BLANK_UNBLANK);
> > +
> > +	msleep(100);
> > +
> > +	bllcd->jorn_backlight_device->props.power
> > +		= FB_BLANK_UNBLANK;
> > +	bllcd->jorn_backlight_device->props.brightness
> > +		= JORNADA_BL_DEFAULT_BRIGHTNESS;
> 
> If you get rid of the "jorn_" prefix, can these be on one line?
> 
> > +	jornada_bl_update_status(bllcd->jorn_backlight_device);
> > +
> > +	platform_set_drvdata(pdev, bllcd);
> > +	printk(KERN_INFO "HP Jornada 7xx Backlight/LCD driver activated\n");
> > +
> > +	return 0;
> > +}
> > +
> > +static int jornada_bl_remove(struct platform_device *pdev)
> > +{
> > +	struct jornada_bllcd_device *bllcd = platform_get_drvdata(pdev);
> > +
> > +	bllcd->jorn_backlight_device->props.power = FB_BLANK_POWERDOWN;
> > +	bllcd->jorn_backlight_device->props.brightness = 0;
> > +	bllcd->jorn_backlight_device->props.max_brightness = 0;
> > +
> > +	backlight_device_unregister(bllcd->jorn_backlight_device);
> > +	lcd_device_unregister(bllcd->jorn_lcd_device);
> 
> Leaves bllcd allocated - memory leak.
> 
> > +
> > +	return 0;
> > +}
> > +
> > +static int jornada_bl_suspend(struct platform_device *pdev, pm_message_t state)
> > +{
> > +	struct jornada_bllcd_device *bllcd = platform_get_drvdata(pdev);
> > +
> > +	bllcd->jorn_backlight_device->props.power = FB_BLANK_POWERDOWN;
> > +	bllcd->jorn_backlight_device->props.brightness = 0;
> > +	bllcd->jorn_backlight_device->props.max_brightness = 0;
> > +	jornada_bl_update_status(bllcd->jorn_backlight_device);
> > +
> > +	jornada_lcd_set_power(bllcd->jorn_lcd_device, FB_BLANK_POWERDOWN);
> > +
> > +	return 0;
> > +}
> > +
> > +static int jornada_bl_resume(struct platform_device *pdev)
> > +{
> > +	struct jornada_bllcd_device *bllcd = platform_get_drvdata(pdev);
> > +
> > +	bllcd->jorn_backlight_device->props.power
> > +		= FB_BLANK_UNBLANK;
> > +	bllcd->jorn_backlight_device->props.brightness
> > +		= JORNADA_BL_DEFAULT_BRIGHTNESS;
> > +	bllcd->jorn_backlight_device->props.max_brightness
> > +		= JORNADA_BL_MAX_BRIGHTNESS;
> > +	jornada_bl_update_status(bllcd->jorn_backlight_device);
> > +
> > +	jornada_lcd_set_power(bllcd->jorn_lcd_device, FB_BLANK_UNBLANK);
> > +
> > +	return 0;
> > +}
> > +
> > +static struct platform_driver jornada_bl_driver = {
> > +	.probe	= jornada_bl_probe,
> > +	.remove	= jornada_bl_remove,
> > +#ifdef CONFIG_PM
> > +	.suspend = jornada_bl_suspend,
> > +	.resume = jornada_bl_resume,
> > +#endif
> > +	.driver = {
> > +	    .name = "jornada_bllcd",
> 
> a tab, not 4 spaces.
>