* Tomi Valkeinen <[email protected]> [140515 22:51]: > On 15/05/14 21:25, Tony Lindgren wrote: > > * Tomi Valkeinen <[email protected]> [140515 01:42]: > >> On 14/05/14 00:26, Tony Lindgren wrote: > >> > >>> + /* lcd MO */ > >>> + ddata->mo_gpio = sharp_ls_get_gpio_of(&pdev->dev, 0, 1, "mode"); > >>> + if (PTR_ERR(ddata->mo_gpio) == -EPROBE_DEFER) > >>> + return -EPROBE_DEFER; > >>> + > >>> + if (!IS_ERR(ddata->mo_gpio)) > >>> + if (gpiod_get_raw_value_cansleep(ddata->mo_gpio)) > >>> + ddata->flags |= SHARP_LS_QVGA; > >> > >> Shouldn't there be an explicit flag in the DT data for this? If the > >> panel's MO pin is hardwired to, say, pull up, then the mode-gpios won't > >> have MO gpio, right? So something like: > >> > >> > >> mode-gpios = <0 /* high, lcd MO */ > >> &gpio1 2 GPIO_ACTIVE_HIGH /* gpio2, lcd LR */ > >> &gpio1 3 GPIO_ACTIVE_HIGH>; /* gpio3, lcd UD */ > >> > >> vga-mode; /* MO hardwired high */ > > > > Yeah holes there are just fine. I figured let's keep the custom > > vga-mode property out of the way until we actually run into a panel > > that's not using a GPIO for mode. > > Ok, I'm fine with that, but in that case I think we have to use all the > panels in the same mode, i.e. the driver either sets the MO gpio always > low and uses VGA mode, or sets the MO always high and uses QVGA mode.
OK let's default to VGA mode for now. > In your omap3-evm.dts patch, you set the MO gpio ACTIVE_LOW in order to > change the mode, even if it really should be ACTIVE_HIGH. But if you do > that, and we later add the support to the panel driver to manage the MO > gpio dynamically (i.e. the user can select VGA/QVGA at runtime), then > the panel won't work as the driver uses wrong polarity for the pin. Getting the configured value seemed to work just fine with gpiod_get_raw_value_cansleep(ddata->mo_gpio). But yeah I agree the lack and confusion between polarity and desired default value for a GPIO is is sucky. The ACTIVE_HIGH probably should mean polarity. I don't know if there's an easy solution to that short of adding a new GPIO binding that contains both the polarity and the desired default value. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
