On Thu, 19 Jan 2017, Vidya Srinivas <vidya.srinivas@xxxxxxxxx> wrote:
> From: Uma Shankar <uma.shankar@xxxxxxxxx>
>
> Enable MIPI IO WA for BXT DSI as per bspec and
> program the DSI regulators.
>
> v2: Moved IO enable to pre-enable as per Mika's
> review comments. Also reused the existing register
> definition for BXT_P_CR_GT_DISP_PWRON.
>
> v3: Added Programming the DSI regulators as per disable/enable
> sequences.
>
> v4: Restricting regulator changes to BXT as suggested by
> Jani/Mika
This applies to BXT_P_CR_GT_DISP_PWRON changes as well.
One other question inline.
>
> Signed-off-by: Uma Shankar <uma.shankar@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 7 +++++++
> drivers/gpu/drm/i915/intel_dsi.c | 25 +++++++++++++++++++++++++
> 2 files changed, 32 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 00970aa..0a9ad44 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -1553,6 +1553,7 @@ enum skl_disp_power_wells {
> _MMIO(_BXT_PHY_CH(phy, ch, reg_ch0, reg_ch1))
>
> #define BXT_P_CR_GT_DISP_PWRON _MMIO(0x138090)
> +#define MIPIO_RST_CTRL (1 << 2)
>
> #define _BXT_PHY_CTL_DDI_A 0x64C00
> #define _BXT_PHY_CTL_DDI_B 0x64C10
> @@ -8301,6 +8302,12 @@ enum {
> #define _BXT_MIPIC_PORT_CTRL 0x6B8C0
> #define BXT_MIPI_PORT_CTRL(tc) _MMIO_MIPI(tc, _BXT_MIPIA_PORT_CTRL, _BXT_MIPIC_PORT_CTRL)
>
> +#define BXT_P_DSI_REGULATOR_CFG _MMIO(0x160020)
> +#define STAP_SELECT (1 << 0)
> +
> +#define BXT_P_DSI_REGULATOR_TX_CTRL _MMIO(0x160054)
> +#define HS_IO_CTRL_SELECT (1 << 0)
> +
> #define DPI_ENABLE (1 << 31) /* A + C */
> #define MIPIA_MIPI4DPHY_DELAY_COUNT_SHIFT 27
> #define MIPIA_MIPI4DPHY_DELAY_COUNT_MASK (0xf << 27)
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index 16732e7..4dc1293 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -548,6 +548,7 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder,
> struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> enum port port;
> + u32 val;
>
> DRM_DEBUG_KMS("\n");
>
> @@ -558,6 +559,11 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder,
> intel_disable_dsi_pll(encoder);
> intel_enable_dsi_pll(encoder, pipe_config);
>
> + /* Add MIPI IO reset programming for modeset */
> + val = I915_READ(BXT_P_CR_GT_DISP_PWRON);
> + I915_WRITE(BXT_P_CR_GT_DISP_PWRON,
> + val | MIPIO_RST_CTRL);
> +
> intel_dsi_prepare(encoder, pipe_config);
>
> /* Panel Enable over CRC PMIC */
> @@ -575,6 +581,14 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder,
> I915_WRITE(DSPCLK_GATE_D, val);
> }
>
> + /* Power up DSI regulator */
> + if (IS_BROXTON(dev_priv)) {
> + I915_WRITE(BXT_P_DSI_REGULATOR_CFG, STAP_SELECT);
> + val = I915_READ(BXT_P_DSI_REGULATOR_TX_CTRL);
> + val &= ~HS_IO_CTRL_SELECT;
> + I915_WRITE(BXT_P_DSI_REGULATOR_TX_CTRL, val);
Why does this specific change warrant a read-modify-write when the other
regulator changes in this patch do a full register write?
Also, the enable and disable sequences seem a bit asymmetric with these
changes, i.e. you enable and disable things in different steps of the
sequences. That's a bit surprising.
(These might have an answer in bspec, but I don't seem to be able to
access that right now.)
BR,
Jani.
> + }
> +
> /* put device in ready state */
> intel_dsi_device_ready(encoder);
>
> @@ -707,6 +721,7 @@ static void intel_dsi_post_disable(struct intel_encoder *encoder,
> {
> struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> + u32 val;
>
> DRM_DEBUG_KMS("\n");
>
> @@ -714,8 +729,18 @@ static void intel_dsi_post_disable(struct intel_encoder *encoder,
>
> intel_dsi_clear_device_ready(encoder);
>
> + val = I915_READ(BXT_P_CR_GT_DISP_PWRON);
> + I915_WRITE(BXT_P_CR_GT_DISP_PWRON,
> + val & ~MIPIO_RST_CTRL);
> +
> intel_disable_dsi_pll(encoder);
>
> + if (IS_BROXTON(dev_priv)) {
> + /* Power down DSI regulator to save power */
> + I915_WRITE(BXT_P_DSI_REGULATOR_CFG, STAP_SELECT);
> + I915_WRITE(BXT_P_DSI_REGULATOR_TX_CTRL, HS_IO_CTRL_SELECT);
> + }
> +
> if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
> u32 val;
--
Jani Nikula, Intel Open Source Technology Center
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