On Thu, Jul 17, 2014 at 4:10 AM, divya ojha <odivya77@xxxxxxxxx> wrote: > Hi Rob, > > On Tue, Jul 8, 2014 at 9:30 PM, Rob Clark <robdclark@xxxxxxxxx> wrote: >> Now that we (almost) have enough dependencies in place (MMCC, RPM, etc), >> add necessary DT support so that we can use drm/msm on upstream kernel. >> >> Signed-off-by: Rob Clark <robdclark@xxxxxxxxx> >> --- >> I thought I sent this already, but looks like I've forgot. > .. >> diff --git a/drivers/gpu/drm/msm/hdmi/hdmi.c b/drivers/gpu/drm/msm/hdmi/hdmi.c >> index 7f7aade..041c2fc 100644 >> --- a/drivers/gpu/drm/msm/hdmi/hdmi.c >> +++ b/drivers/gpu/drm/msm/hdmi/hdmi.c >> @@ -123,7 +123,8 @@ struct hdmi *hdmi_init(struct drm_device *dev, struct drm_encoder *encoder) >> for (i = 0; i < config->hpd_reg_cnt; i++) { >> struct regulator *reg; >> >> - reg = devm_regulator_get(&pdev->dev, config->hpd_reg_names[i]); >> + reg = devm_regulator_get_exclusive(&pdev->dev, >> + config->hpd_reg_names[i]); >> if (IS_ERR(reg)) { >> ret = PTR_ERR(reg); >> dev_err(dev->dev, "failed to get hpd regulator: %s (%d)\n", >> @@ -138,7 +139,8 @@ struct hdmi *hdmi_init(struct drm_device *dev, struct drm_encoder *encoder) >> for (i = 0; i < config->pwr_reg_cnt; i++) { >> struct regulator *reg; >> >> - reg = devm_regulator_get(&pdev->dev, config->pwr_reg_names[i]); >> + reg = devm_regulator_get_exclusive(&pdev->dev, >> + config->pwr_reg_names[i]); >> if (IS_ERR(reg)) { >> ret = PTR_ERR(reg); >> dev_err(dev->dev, "failed to get pwr regulator: %s (%d)\n", > > Don't we need to have a if(regulator_enabled) check after > devm_regulator_get function ? > I see a similar test after camera regulator_get function call. tbh, I'm not 100% sure. Normally I would say that any driver using some resource (regulator, etc) should take it's own reference irrespective of whether some other driver already has the regulator/etc, enabled. Otherwise the reference counting doesn't work out. The thing I'm not 100% sure about is interaction w/ bootloader, in cases where bootloader does initial modeset. I've had some problems in this area in the past when I was trying to get DSI working on my nexus4. I doubt the correct solution is for the driver to check if regulator is already enabled by bootloader before enabling it, but I'm not sure if something else somewhere needs to drop references to resources enabled by bootloader. BR, -R > -Regards > Divya -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html