backlight: Support VGA/QVGA mode switching in tosa_lcd

LCD driver on tosa requires reprogramming TG after mode
switching. Add support for switching to QVGA mode.
Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

drivers/video/backlight/tosa_lcd.c

@@ -39,6 +39,7 @@ struct tosa_lcd_data {
 	struct i2c_client *i2c;
 
 	int lcd_power;
+	bool is_vga;
 };
 
 static int tosa_tg_send(struct spi_device *spi, int adrs, uint8_t data)
@@ -81,8 +82,12 @@ static void tosa_lcd_tg_init(struct tosa_lcd_data *data)
 static void tosa_lcd_tg_on(struct tosa_lcd_data *data)
 {
 	struct spi_device *spi = data->spi;
-	const int value = TG_REG0_COLOR | TG_REG0_UD | TG_REG0_LR;
-	tosa_tg_send(spi, TG_PNLCTL, value | TG_REG0_VQV); /* this depends on mode */
+	int value = TG_REG0_COLOR | TG_REG0_UD | TG_REG0_LR;
+
+	if (data->is_vga)
+		value |= TG_REG0_VQV;
+
+	tosa_tg_send(spi, TG_PNLCTL, value);
 
 	/* TG LCD pannel power up */
 	tosa_tg_send(spi, TG_PINICTL,0x4);
@@ -142,9 +147,25 @@ static int tosa_lcd_get_power(struct lcd_device *lcd)
 	return data->lcd_power;
 }
 
+static int tosa_lcd_set_mode(struct lcd_device *lcd, struct fb_videomode *mode)
+{
+	struct tosa_lcd_data *data = lcd_get_data(lcd);
+
+	if (mode->xres == 320 || mode->yres == 320)
+		data->is_vga = false;
+	else
+		data->is_vga = true;
+
+	if (POWER_IS_ON(data->lcd_power))
+		tosa_lcd_tg_on(data);
+
+	return 0;
+}
+
 static struct lcd_ops tosa_lcd_ops = {
 	.set_power = tosa_lcd_set_power,
 	.get_power = tosa_lcd_get_power,
+	.set_mode = tosa_lcd_set_mode,
 };
 
 static int __devinit tosa_lcd_probe(struct spi_device *spi)
@@ -156,6 +177,8 @@ static int __devinit tosa_lcd_probe(struct spi_device *spi)
 	if (!data)
 		return -ENOMEM;
 
+	data->is_vga = true; /* defaut to VGA mode */
+
 	/*
 	 * bits_per_word cannot be configured in platform data
 	 */