On Tuesday, October 28, 2014 9:02 AM, Dmitry Eremin-Solenikov wrote:

Please, re-order these headers alphabetically.
It enhances the readability.

+
+struct locomo_bl {
+	void __iomem *regs;
+	int current_intensity;
+	int gpio_fl_vr;
+};
+
+static const struct {
+	u16 duty, bpwf;
+	bool vr;
+} locomo_bl_pwm[] = {
+	{ 0, 161, false },
+	{ 117, 161, false },
+	{ 163, 148, false },
+	{ 194, 161, false },
+	{ 194, 161, true },
+};
+
+static int locomo_bl_set_intensity(struct backlight_device *bd)
+{
+	int intensity = bd->props.brightness;
+	struct locomo_bl *bl = dev_get_drvdata(&bd->dev);
+
+	if (bd->props.power != FB_BLANK_UNBLANK)
+		intensity = 0;
+	if (bd->props.fb_blank != FB_BLANK_UNBLANK)
+		intensity = 0;
+	if (bd->props.state & BL_CORE_SUSPENDED)
+		intensity = 0;
+
+	gpio_set_value(bl->gpio_fl_vr, locomo_bl_pwm[intensity].vr);
+
+	writew(locomo_bl_pwm[intensity].bpwf, bl->regs + LOCOMO_ALS);
+	udelay(100);
+	writew(locomo_bl_pwm[intensity].duty, bl->regs + LOCOMO_ALD);
+	udelay(100);

How about changing udelay() to usleep_range()?

+	writew(locomo_bl_pwm[intensity].bpwf | LOCOMO_ALC_EN,
+			bl->regs + LOCOMO_ALS);

+
+	bl->current_intensity = intensity;
+	if (bd->props.state & BL_CORE_SUSPENDED)
+		writew(0x00, bl->regs + LOCOMO_ALS);
+
+	return 0;
+}
+
+static int locomo_bl_get_intensity(struct backlight_device *bd)
+{
+	struct locomo_bl *bl = dev_get_drvdata(&bd->dev);
+
+	return bl->current_intensity;
+}
+
+static const struct backlight_ops locomo_bl_ops = {
+	.options	= BL_CORE_SUSPENDRESUME,
+	.get_brightness = locomo_bl_get_intensity,
+	.update_status  = locomo_bl_set_intensity,
+};
+
+static int locomo_bl_probe(struct platform_device *dev)
+{
+	struct backlight_properties props;
+	struct resource *res;
+	struct locomo_bl_platform_data *pdata;
+	struct locomo_bl *bl;
+	struct backlight_device *locomo_bl_device;
+	int rc;
+
+	bl = devm_kmalloc(&dev->dev, sizeof(struct locomo_bl), GFP_KERNEL);
+	if (!bl)
+		return -ENOMEM;
+
+	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;

There is no need to check this, because devm_ioremap_resource()
will check this.

+	bl->regs = devm_ioremap_resource(&dev->dev, res);
+	if (!bl->regs)
+		return -EINVAL;

The correct usage is as follows.

	if (IS_ERR(base))
		return PTR_ERR(base);

Please change it as below.

	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
	bl->regs = devm_ioremap_resource(&dev->dev, res);
	if (IS_ERR(bl->regs))
		 return PTR_ERR(bl->regs);

+
+	pdata = dev_get_platdata(&dev->dev);
+	if (!pdata)
+		return -EINVAL;
+
+	bl->gpio_fl_vr = pdata->gpio_fl_vr;
+	rc = devm_gpio_request_one(&dev->dev, bl->gpio_fl_vr,
+			GPIOF_OUT_INIT_LOW, "FL VR");
+	if (rc)
+		return rc;
+
+	writew(0, bl->regs + LOCOMO_ALS);
+	writew(0, bl->regs + LOCOMO_ALD);
+
+	memset(&props, 0, sizeof(struct backlight_properties));
+	props.type = BACKLIGHT_RAW;
+	props.max_brightness = ARRAY_SIZE(locomo_bl_pwm) - 1;
+	props.brightness = props.max_brightness / 2;
+	locomo_bl_device = backlight_device_register("locomo-bl",

Please use devm_backlight_device_register().

+						&dev->dev, bl,
+						&locomo_bl_ops, &props);

+
+	if (IS_ERR(locomo_bl_device))
+		return PTR_ERR(locomo_bl_device);
+
+	platform_set_drvdata(dev, locomo_bl_device);
+
+	/* Set up frontlight so that screen is readable */
+	backlight_update_status(locomo_bl_device);
+
+	return 0;
+}
+
+static int locomo_bl_remove(struct platform_device *dev)
+{
+	struct backlight_device *locomo_bl_device = platform_get_drvdata(dev);
+
+	locomo_bl_device->props.brightness = 0;
+	locomo_bl_device->props.power = 0;
+	locomo_bl_set_intensity(locomo_bl_device);
+
+	backlight_device_unregister(locomo_bl_device);

If devm_backlight_device_register() is used in probe(),
there is no need to call backlight_device_unregister() in remove().

+
+	return 0;
+}
+
+static void locomo_bl_shutdown(struct platform_device *dev)
+{
+	struct backlight_device *locomo_bl_device = platform_get_drvdata(dev);
+
+	locomo_bl_device->props.brightness = 0;
+	locomo_bl_device->props.power = 0;
+	locomo_bl_set_intensity(locomo_bl_device);
+}
+
+static struct platform_driver locomo_bl_driver = {
+	.driver = {
+		.name	= "locomo-backlight",
+		.owner	= THIS_MODULE,
+	},
+	.probe	= locomo_bl_probe,
+	.remove	= locomo_bl_remove,
+	/* Turn off bl on power off/reboot */
+	.shutdown = locomo_bl_shutdown,
+};
+
+module_platform_driver(locomo_bl_driver);
+
+MODULE_AUTHOR("John Lenz [off-list ref], Pavel Machek [off-list ref]");

This might make checkpatch warning.
Please split these authors to lines as below.

MODULE_AUTHOR("John Lenz [off-list ref]");
MODULE_AUTHOR("Pavel Machek [off-list ref]");

+MODULE_DESCRIPTION("Collie Backlight driver");

What does mean 'Collie'? 'Locomo' looks better.

+MODULE_LICENSE("GPL");

How about using "GPL v2"?

Thank you.

Best regards,
Jingoo Han

+MODULE_ALIAS("platform:locomo-backlight");
--
2.1.1