> -----Original Message----- > From: Valkeinen, Tomi > Sent: Tuesday, May 10, 2011 4:44 PM > To: Janorkar, Mayuresh > Cc: linux-omap@xxxxxxxxxxxxxxx > Subject: RE: [PATCH v3 4/4] OMAP: DSS: Add picodlp panel driver > > On Tue, 2011-05-10 at 15:57 +0530, Janorkar, Mayuresh wrote: > > > > It is better to request and initialize the GPIOs in the board file. > The > > > reason for this is that the PicoDLP device should be off if it's not > > > used, or if the driver is not even compiled in. So the board file > should > > > make sure that the GPIOs are in such state that the device is off. > > > > The board file has only init. There is no exit. > > So if I request gpios in init once, I could not find a place to free > them. > > If the GPIOs are not shared, and they go only to picodlp, there's not > really any need to free them. They are not a shared resource, and they > can be kept reserved for picodlp all the time. > > > Is it a good idea to request gpios in platform_enable and free them in > platform_disable? > > No, that wouldn't fix the problem. > > For example, consider a case where the kernel is compiled without > picodlp driver. So platform_enable/disable is never called, and the > GPIOs are never requested or initialized. This means that depending on > the values of the GPIOs, the picodlp could be always on, consuming > power. > > So my suggestion is to request all the GPIOs in the board file, in > display init, and initialize the GPIOs to some sane value so that the > picodlp is off. Then pass the two GPIOs to the picodlp driver, which can > then use the GPIOs, and handle the two other GPIOs in the board file in > platform_enable/disable. Looks fine. I would set: OMAP4_DLP_DISPLAY_SELECT_GPIO to 0, OMAP4_DLP_POWER_ON_GPIO to 0, And pwrgood_gpio to 1, as init values of these gpios. > > Tomi > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
