[PATCH v2] ARM: OMAP3LOGIC: Adding DSS support

Hi Tomi,


On Tue, 2011-12-13 at 09:52 +0200, Alex wrote:

This patch adds DSS2 support to the LogicPD OMAP 35x Torpedo boardfile. LCD and
TV-out are supported.

Signed-off-by: Alex Gershgorin <redacted>

Overall looks fine. A few questions below about the GPIOs, though.

<snip>

+static void __init omap3logic_display_init(void)
+{
+	int r;
+
+	r = gpio_request_array(omap3logic_dss_gpios,
+			       ARRAY_SIZE(omap3logic_dss_gpios));
+	if (r) {
+		printk(KERN_ERR "failed to get lcd_panel_* gpios\n");
+		return;
+	}
+
+	gpio_export(OMAP3_TORPEDO_LCD_BACKLIGHT_GPIO, 0);
+	gpio_export(OMAP3_TORPEDO_LCD_ENABLE_GPIO, 0);
+	gpio_export(OMAP3_TORPEDO_LCD_PWM_GPIO, 0);

Why do you want to export these GPIOs? They are handled here in the
board file, and I don't think there's any reason the userspace would
need to touch them.

Ok I can remove it from the kernel, if someone wants to use them,
It can be done from userspace.

+	gpio_set_value(OMAP3_TORPEDO_LCD_BACKLIGHT_GPIO, 0);
+	gpio_set_value(OMAP3_TORPEDO_LCD_ENABLE_GPIO, 0);
+	gpio_set_value(OMAP3_TORPEDO_LCD_PWM_GPIO, 0);

These are already set to 0 in gpio_request_array, as you've defined the
flag "GPIOF_OUT_INIT_LOW".

Thanks, I will correct it.

+
+	msleep(50);
+	gpio_set_value(OMAP3_TORPEDO_LCD_PWM_GPIO, 1);

What does this do, and why do you need msleep(50)? I understand
LCD_ENABLE gpio enables the LCD panel, but what exactly do LCD_BACKLIGHT
and LCD_PWM gpios do? Why don't you set/unset LCD_PWM in the panel
enable/disable functions like the other gpios?


LCD_BACKLIGHT supply's power to LED Driver and LCD_PWM used to 
Control the backlight level. 
I'll check your suggestion and if it suits, I'll update the patch accordingly.

 

Thanks,
Alex