| Message ID | 20191106064005.8016-1-jitao.shi@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/panel: seperate panel power control from panel prepare/unprepare | expand |
Hi Jitao. On Wed, Nov 06, 2019 at 02:40:05PM +0800, Jitao Shi wrote: > Some dsi panels require the dsi lanes keeping low before panel power > on. So seperate the panel power control and the communication with panel. > > And put the power control in drm_panel_prepare_power and > drm_panel_unprepare_power. Put the communication with panel in > drm_panel_prepare and drm_panel_unprepare. > > Signed-off-by: Jitao Shi <jitao.shi@mediatek.com> Panels that requires power before communicating often/always have some timing constraints. Power need to be applied in XYZ micro seconds before it is safe to communicate with the panel. To support this a typical pattern is: panel_xxx_prepare() { // power on the panel using one or a few regulators // wait until panel is known to be ready // Communicate with the panel } first driver I looked at (panel-feiyang-fy07024di26a30d.c) follows this pattern. So we have the timing spelled out in the enable() function and the sequence is obvious. What will the benefit be from a separate drm_panel_prepare_power() function pointer? Sam > --- > drivers/gpu/drm/drm_panel.c | 38 +++++++++++++++++++++++++++++++++++++ > include/drm/drm_panel.h | 17 +++++++++++++++++ > 2 files changed, 55 insertions(+) > > diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c > index 6b0bf42039cf..e57f6385d2cc 100644 > --- a/drivers/gpu/drm/drm_panel.c > +++ b/drivers/gpu/drm/drm_panel.c > @@ -131,6 +131,24 @@ void drm_panel_detach(struct drm_panel *panel) > } > EXPORT_SYMBOL(drm_panel_detach); > > +/** > + * drm_panel_prepare_power - power on a panel's power > + * @panel: DRM panel > + * > + * Calling this function will enable power and deassert any reset signals to > + * the panel. > + * > + * Return: 0 on success or a negative error code on failure. > + */ > +int drm_panel_prepare_power(struct drm_panel *panel) > +{ > + if (panel && panel->funcs && panel->funcs->prepare_power) > + return panel->funcs->prepare_power(panel); > + > + return panel ? -ENOSYS : -EINVAL; > +} > +EXPORT_SYMBOL(drm_panel_prepare_power); > + > /** > * drm_panel_prepare - power on a panel > * @panel: DRM panel > @@ -170,6 +188,26 @@ int drm_panel_unprepare(struct drm_panel *panel) > } > EXPORT_SYMBOL(drm_panel_unprepare); > > +/** > + * drm_panel_unprepare_power - power off a panel > + * @panel: DRM panel > + * > + * Calling this function will completely power off a panel (assert the panel's > + * reset, turn off power supplies, ...). After this function has completed, it > + * is usually no longer possible to communicate with the panel until another > + * call to drm_panel_prepare_power and drm_panel_prepare(). > + * > + * Return: 0 on success or a negative error code on failure. > + */ > +int drm_panel_unprepare_power(struct drm_panel *panel) > +{ > + if (panel && panel->funcs && panel->funcs->unprepare_power) > + return panel->funcs->unprepare_power(panel); > + > + return panel ? -ENOSYS : -EINVAL; > +} > +EXPORT_SYMBOL(drm_panel_unprepare_power); > + > /** > * drm_panel_enable - enable a panel > * @panel: DRM panel > diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h > index 624bd15ecfab..0d8c4855405c 100644 > --- a/include/drm/drm_panel.h > +++ b/include/drm/drm_panel.h > @@ -61,6 +61,13 @@ struct display_timing; > * the panel. This is the job of the .unprepare() function. > */ > struct drm_panel_funcs { > + /** > + * @prepare_power: > + * > + * Turn on panel power. > + */ > + int (*prepare_power)(struct drm_panel *panel); > + > /** > * @prepare: > * > @@ -89,6 +96,13 @@ struct drm_panel_funcs { > */ > int (*unprepare)(struct drm_panel *panel); > > + /** > + * @unprepare_power: > + * > + * Turn off panel_power. > + */ > + int (*unprepare_power)(struct drm_panel *panel); > + > /** > * @get_modes: > * > @@ -155,6 +169,9 @@ void drm_panel_remove(struct drm_panel *panel); > int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector); > void drm_panel_detach(struct drm_panel *panel); > > +int drm_panel_prepare_power(struct drm_panel *panel); > +int drm_panel_unprepare_power(struct drm_panel *panel); > + > int drm_panel_prepare(struct drm_panel *panel); > int drm_panel_unprepare(struct drm_panel *panel); > > -- > 2.21.0
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c index 6b0bf42039cf..e57f6385d2cc 100644 --- a/drivers/gpu/drm/drm_panel.c +++ b/drivers/gpu/drm/drm_panel.c @@ -131,6 +131,24 @@ void drm_panel_detach(struct drm_panel *panel) } EXPORT_SYMBOL(drm_panel_detach); +/** + * drm_panel_prepare_power - power on a panel's power + * @panel: DRM panel + * + * Calling this function will enable power and deassert any reset signals to + * the panel. + * + * Return: 0 on success or a negative error code on failure. + */ +int drm_panel_prepare_power(struct drm_panel *panel) +{ + if (panel && panel->funcs && panel->funcs->prepare_power) + return panel->funcs->prepare_power(panel); + + return panel ? -ENOSYS : -EINVAL; +} +EXPORT_SYMBOL(drm_panel_prepare_power); + /** * drm_panel_prepare - power on a panel * @panel: DRM panel @@ -170,6 +188,26 @@ int drm_panel_unprepare(struct drm_panel *panel) } EXPORT_SYMBOL(drm_panel_unprepare); +/** + * drm_panel_unprepare_power - power off a panel + * @panel: DRM panel + * + * Calling this function will completely power off a panel (assert the panel's + * reset, turn off power supplies, ...). After this function has completed, it + * is usually no longer possible to communicate with the panel until another + * call to drm_panel_prepare_power and drm_panel_prepare(). + * + * Return: 0 on success or a negative error code on failure. + */ +int drm_panel_unprepare_power(struct drm_panel *panel) +{ + if (panel && panel->funcs && panel->funcs->unprepare_power) + return panel->funcs->unprepare_power(panel); + + return panel ? -ENOSYS : -EINVAL; +} +EXPORT_SYMBOL(drm_panel_unprepare_power); + /** * drm_panel_enable - enable a panel * @panel: DRM panel diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h index 624bd15ecfab..0d8c4855405c 100644 --- a/include/drm/drm_panel.h +++ b/include/drm/drm_panel.h @@ -61,6 +61,13 @@ struct display_timing; * the panel. This is the job of the .unprepare() function. */ struct drm_panel_funcs { + /** + * @prepare_power: + * + * Turn on panel power. + */ + int (*prepare_power)(struct drm_panel *panel); + /** * @prepare: * @@ -89,6 +96,13 @@ struct drm_panel_funcs { */ int (*unprepare)(struct drm_panel *panel); + /** + * @unprepare_power: + * + * Turn off panel_power. + */ + int (*unprepare_power)(struct drm_panel *panel); + /** * @get_modes: * @@ -155,6 +169,9 @@ void drm_panel_remove(struct drm_panel *panel); int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector); void drm_panel_detach(struct drm_panel *panel); +int drm_panel_prepare_power(struct drm_panel *panel); +int drm_panel_unprepare_power(struct drm_panel *panel); + int drm_panel_prepare(struct drm_panel *panel); int drm_panel_unprepare(struct drm_panel *panel);
Some dsi panels require the dsi lanes keeping low before panel power on. So seperate the panel power control and the communication with panel. And put the power control in drm_panel_prepare_power and drm_panel_unprepare_power. Put the communication with panel in drm_panel_prepare and drm_panel_unprepare. Signed-off-by: Jitao Shi <jitao.shi@mediatek.com> --- drivers/gpu/drm/drm_panel.c | 38 +++++++++++++++++++++++++++++++++++++ include/drm/drm_panel.h | 17 +++++++++++++++++ 2 files changed, 55 insertions(+)