| Message ID | 20220421041550.643964-1-bjorn.andersson@linaro.org |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | [v4,1/2] dt-bindings: display: msm: Add optional resets | expand |
| Context | Check | Description |
|---|---|---|
| robh/checkpatch | success | |
| robh/patch-applied | success | |
| robh/dt-meta-schema | fail | build log |
On 21/04/2022 07:15, Bjorn Andersson wrote: > It's typical for the bootloader to bring up the display for showing a > boot splash or efi framebuffer. But in some cases the kernel driver ends > up only partially configuring (in particular) the DPU, which might > result in e.g. that two different data paths attempts to push data to > the interface - with resulting graphical artifacts. > > Naturally the end goal would be to inherit the bootloader's > configuration and provide the user with a glitch free handover from the > boot configuration to a running DPU. > > But as implementing seamless transition from the bootloader > configuration to the running OS will be a considerable effort, start by > simply resetting the entire MDSS to its power-on state, to avoid the > partial configuration. > > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > --- > > Changes since v3: > - Rebased upon the mdss dpu/mdp restructuring (https://patchwork.freedesktop.org/series/98525/) > > drivers/gpu/drm/msm/msm_mdss.c | 32 ++++++++++++++++++++++++++++++++ > 1 file changed, 32 insertions(+) > > diff --git a/drivers/gpu/drm/msm/msm_mdss.c b/drivers/gpu/drm/msm/msm_mdss.c > index f6f0d0fa5ab2..20f154dda9cf 100644 > --- a/drivers/gpu/drm/msm/msm_mdss.c > +++ b/drivers/gpu/drm/msm/msm_mdss.c > @@ -4,11 +4,13 @@ > */ > > #include <linux/clk.h> > +#include <linux/delay.h> > #include <linux/irq.h> > #include <linux/irqchip.h> > #include <linux/irqdesc.h> > #include <linux/irqchip/chained_irq.h> > #include <linux/pm_runtime.h> > +#include <linux/reset.h> > > #include "msm_drv.h" > #include "msm_kms.h" > @@ -193,6 +195,32 @@ static void msm_mdss_destroy(struct msm_mdss *msm_mdss) > irq_set_chained_handler_and_data(irq, NULL, NULL); > } > > +static int msm_mdss_reset(struct device *dev) > +{ > + struct reset_control *reset; > + > + reset = reset_control_get_optional_exclusive(dev, NULL); > + if (!reset) { > + /* Optional reset not specified */ > + return 0; > + } else if (IS_ERR(reset)) { > + return dev_err_probe(dev, PTR_ERR(reset), > + "failed to acquire mdss reset\n"); > + } > + > + reset_control_assert(reset); > + /* > + * Tests indicate that reset has to be held for some period of time, > + * make it one frame in a typical system > + */ > + msleep(20); > + reset_control_deassert(reset); > + > + reset_control_put(reset); > + > + return 0; > +} > + > /* > * MDP5 MDSS uses at most three specified clocks. > */ > @@ -229,6 +257,10 @@ static struct msm_mdss *msm_mdss_init(struct platform_device *pdev, bool is_mdp5 > int ret; > int irq; > > + ret = msm_mdss_reset(&pdev->dev); > + if (ret) > + return ERR_PTR(ret); > + > msm_mdss = devm_kzalloc(&pdev->dev, sizeof(*msm_mdss), GFP_KERNEL); > if (!msm_mdss) > return ERR_PTR(-ENOMEM);
diff --git a/Documentation/devicetree/bindings/display/msm/dpu-qcm2290.yaml b/Documentation/devicetree/bindings/display/msm/dpu-qcm2290.yaml index 6fb7e321f011..734d14de966d 100644 --- a/Documentation/devicetree/bindings/display/msm/dpu-qcm2290.yaml +++ b/Documentation/devicetree/bindings/display/msm/dpu-qcm2290.yaml @@ -66,6 +66,10 @@ properties: interconnect-names: const: mdp0-mem + resets: + items: + - description: MDSS_CORE reset + patternProperties: "^display-controller@[0-9a-f]+$": type: object diff --git a/Documentation/devicetree/bindings/display/msm/dpu-sc7180.yaml b/Documentation/devicetree/bindings/display/msm/dpu-sc7180.yaml index 12a86b1ec1bc..b41991eaa454 100644 --- a/Documentation/devicetree/bindings/display/msm/dpu-sc7180.yaml +++ b/Documentation/devicetree/bindings/display/msm/dpu-sc7180.yaml @@ -65,6 +65,10 @@ properties: interconnect-names: const: mdp0-mem + resets: + items: + - description: MDSS_CORE reset + patternProperties: "^display-controller@[0-9a-f]+$": type: object diff --git a/Documentation/devicetree/bindings/display/msm/dpu-sc7280.yaml b/Documentation/devicetree/bindings/display/msm/dpu-sc7280.yaml index fbeb931a026e..6e417d06fc79 100644 --- a/Documentation/devicetree/bindings/display/msm/dpu-sc7280.yaml +++ b/Documentation/devicetree/bindings/display/msm/dpu-sc7280.yaml @@ -64,6 +64,10 @@ properties: interconnect-names: const: mdp0-mem + resets: + items: + - description: MDSS_CORE reset + patternProperties: "^display-controller@[0-9a-f]+$": type: object diff --git a/Documentation/devicetree/bindings/display/msm/dpu-sdm845.yaml b/Documentation/devicetree/bindings/display/msm/dpu-sdm845.yaml index 0dca4b3d66e4..1a42491efdbc 100644 --- a/Documentation/devicetree/bindings/display/msm/dpu-sdm845.yaml +++ b/Documentation/devicetree/bindings/display/msm/dpu-sdm845.yaml @@ -57,6 +57,10 @@ properties: ranges: true + resets: + items: + - description: MDSS_CORE reset + patternProperties: "^display-controller@[0-9a-f]+$": type: object