| Message ID | 1377704922-2824-4-git-send-email-mperttunen@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 08/28/2013 09:48 AM, Mikko Perttunen wrote: > The Vdd regulator used to be enabled only at tegra_output_hdmi_enable, > which is called after a sink is detected. However, the HDMI hotplug pin > works by returning the voltage supplied by the Vdd pin, so this meant > that the hotplug pin was never asserted and the sink was not detected > unless the Vdd regulator was set to be always on. > > This patch moves the enable to the tegra_hdmi_drm_init function to make > sure the regulator will get enabled. The DT binding document isn't very clear on this topic (and should be fixed): What is this regulator intended to control? If this regulator solely controls the supply to the hotplug detection circuit, this change makes sense. If the regulator mainly supplies something else (e.g. part of the HDMI core on the Tegra chip), then perhaps this change isn't correct. The correct approach might be to introduce another (optional) regulator specifically for the hotplug circuit. Presumably both DT properties vdd-supply and hotplug-supply could point at the same regulator if that's the way the HW was wired up.
On 09/04/2013 09:44 PM, Stephen Warren wrote: > On 08/28/2013 09:48 AM, Mikko Perttunen wrote: >> The Vdd regulator used to be enabled only at tegra_output_hdmi_enable, >> which is called after a sink is detected. However, the HDMI hotplug pin >> works by returning the voltage supplied by the Vdd pin, so this meant >> that the hotplug pin was never asserted and the sink was not detected >> unless the Vdd regulator was set to be always on. >> >> This patch moves the enable to the tegra_hdmi_drm_init function to make >> sure the regulator will get enabled. > > The DT binding document isn't very clear on this topic (and should be > fixed): What is this regulator intended to control? If this regulator > solely controls the supply to the hotplug detection circuit, this change > makes sense. If the regulator mainly supplies something else (e.g. part > of the HDMI core on the Tegra chip), then perhaps this change isn't > correct. The correct approach might be to introduce another (optional) > regulator specifically for the hotplug circuit. Presumably both DT > properties vdd-supply and hotplug-supply could point at the same > regulator if that's the way the HW was wired up. > -- > To unsubscribe from this list: send the line "unsubscribe linux-tegra" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > AFAICT, it controls the Vdd pin on the HDMI port, so it just affects the hotplug pin and the DDC I2C bus power.
On 09/04/2013 04:03 PM, Mikko Perttunen wrote: > On 09/04/2013 09:44 PM, Stephen Warren wrote: >> On 08/28/2013 09:48 AM, Mikko Perttunen wrote: >>> The Vdd regulator used to be enabled only at tegra_output_hdmi_enable, >>> which is called after a sink is detected. However, the HDMI hotplug pin >>> works by returning the voltage supplied by the Vdd pin, so this meant >>> that the hotplug pin was never asserted and the sink was not detected >>> unless the Vdd regulator was set to be always on. >>> >>> This patch moves the enable to the tegra_hdmi_drm_init function to make >>> sure the regulator will get enabled. >> >> The DT binding document isn't very clear on this topic (and should be >> fixed): What is this regulator intended to control? If this regulator >> solely controls the supply to the hotplug detection circuit, this change >> makes sense. If the regulator mainly supplies something else (e.g. part >> of the HDMI core on the Tegra chip), then perhaps this change isn't >> correct. The correct approach might be to introduce another (optional) >> regulator specifically for the hotplug circuit. Presumably both DT >> properties vdd-supply and hotplug-supply could point at the same >> regulator if that's the way the HW was wired up. >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-tegra" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > AFAICT, it controls the Vdd pin on the HDMI port, so it just affects the > hotplug pin and the DDC I2C bus power. Ah OK, then this code change makes sense. It'd be useful to put what you just wrote into the binding doc.
diff --git a/drivers/gpu/host1x/drm/hdmi.c b/drivers/gpu/host1x/drm/hdmi.c index 140339b..96a6ae1 100644 --- a/drivers/gpu/host1x/drm/hdmi.c +++ b/drivers/gpu/host1x/drm/hdmi.c @@ -716,12 +716,6 @@ static int tegra_output_hdmi_enable(struct tegra_output *output) h_back_porch = mode->htotal - mode->hsync_end; h_front_porch = mode->hsync_start - mode->hdisplay; - err = regulator_enable(hdmi->vdd); - if (err < 0) { - dev_err(hdmi->dev, "failed to enable VDD regulator: %d\n", err); - return err; - } - err = regulator_enable(hdmi->pll); if (err < 0) { dev_err(hdmi->dev, "failed to enable PLL regulator: %d\n", err); @@ -943,7 +937,6 @@ static int tegra_output_hdmi_disable(struct tegra_output *output) tegra_periph_reset_assert(hdmi->clk); clk_disable(hdmi->clk); regulator_disable(hdmi->pll); - regulator_disable(hdmi->vdd); return 0; } @@ -1240,6 +1233,12 @@ static int tegra_hdmi_drm_init(struct host1x_client *client, struct tegra_hdmi *hdmi = host1x_client_to_hdmi(client); int err; + err = regulator_enable(hdmi->vdd); + if (err < 0) { + dev_err(client->dev, "vdd regulator enable failed: %d\n", err); + return err; + } + hdmi->output.type = TEGRA_OUTPUT_HDMI; hdmi->output.dev = client->dev; hdmi->output.ops = &hdmi_ops; @@ -1283,6 +1282,8 @@ static int tegra_hdmi_drm_exit(struct host1x_client *client) return err; } + regulator_disable(hdmi->vdd); + return 0; }
The Vdd regulator used to be enabled only at tegra_output_hdmi_enable, which is called after a sink is detected. However, the HDMI hotplug pin works by returning the voltage supplied by the Vdd pin, so this meant that the hotplug pin was never asserted and the sink was not detected unless the Vdd regulator was set to be always on. This patch moves the enable to the tegra_hdmi_drm_init function to make sure the regulator will get enabled. Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com> --- drivers/gpu/host1x/drm/hdmi.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-)