drm/i915/bxt: Program Tx Rx and Dphy clocks
BXT DSI clocks are different than previous platforms. So adding a
new function to program following clocks and dividers:
1. Program variable divider to generate input to Tx clock divider
(Output value must be < 39.5Mhz)
2. Select divide by 2 option to get < 20Mhz for Tx clock
3. Program 8by3 divider to generate Rx clock
v2: Fixed Jani's review comments. Adjusted the Macro definition as
per convention. Simplified the logic for bit definitions for
MIPI PORT A and PORT C in same registers.
v3: Refactored the macros for TX, RX Escape and DPHY clocks as per
Jani's suggestion.
v4: Addressed Jani's review comments.
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c
index f335e6c..3863362 100644
--- a/drivers/gpu/drm/i915/intel_dsi_pll.c
+++ b/drivers/gpu/drm/i915/intel_dsi_pll.c
@@ -384,6 +384,42 @@
return pclk;
}
+/* Program BXT Mipi clocks and dividers */
+static void bxt_dsi_program_clocks(struct drm_device *dev, enum port port)
+{
+ u32 tmp;
+ u32 divider;
+ u32 dsi_rate;
+ u32 pll_ratio;
+ struct drm_i915_private *dev_priv = dev->dev_private;
+
+ /* Clear old configurations */
+ tmp = I915_READ(BXT_MIPI_CLOCK_CTL);
+ tmp &= ~(BXT_MIPI_TX_ESCLK_FIXDIV_MASK(port));
+ tmp &= ~(BXT_MIPI_RX_ESCLK_FIXDIV_MASK(port));
+ tmp &= ~(BXT_MIPI_ESCLK_VAR_DIV_MASK(port));
+ tmp &= ~(BXT_MIPI_DPHY_DIVIDER_MASK(port));
+
+ /* Get the current DSI rate(actual) */
+ pll_ratio = I915_READ(BXT_DSI_PLL_CTL) &
+ BXT_DSI_PLL_RATIO_MASK;
+ dsi_rate = (BXT_REF_CLOCK_KHZ * pll_ratio) / 2;
+
+ /* Max possible output of clock is 39.5 MHz, program value -1 */
+ divider = (dsi_rate / BXT_MAX_VAR_OUTPUT_KHZ) - 1;
+ tmp |= BXT_MIPI_ESCLK_VAR_DIV(port, divider);
+
+ /*
+ * Tx escape clock must be as close to 20MHz possible, but should
+ * not exceed it. Hence select divide by 2
+ */
+ tmp |= BXT_MIPI_TX_ESCLK_8XDIV_BY2(port);
+
+ tmp |= BXT_MIPI_RX_ESCLK_8X_BY3(port);
+
+ I915_WRITE(BXT_MIPI_CLOCK_CTL, tmp);
+}
+
static bool bxt_configure_dsi_pll(struct intel_encoder *encoder)
{
struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
@@ -435,6 +471,8 @@
static void bxt_enable_dsi_pll(struct intel_encoder *encoder)
{
struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
+ struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
+ enum port port;
u32 val;
DRM_DEBUG_KMS("\n");
@@ -453,6 +491,10 @@
return;
}
+ /* Program TX, RX, Dphy clocks */
+ for_each_dsi_port(port, intel_dsi->ports)
+ bxt_dsi_program_clocks(encoder->base.dev, port);
+
/* Enable DSI PLL */
val = I915_READ(BXT_DSI_PLL_ENABLE);
val |= BXT_DSI_PLL_DO_ENABLE;