[PATCH 07/12] drm/i915/bxt: Program Tx Rx and Dphy clocks

[Uma Shankar <uma.shankar@intel.com>]

From: Shashank Sharma <shashank.sharma@intel.com>

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

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h      |   51 ++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_dsi.c     |    3 ++
 drivers/gpu/drm/i915/intel_dsi.h     |    1 +
 drivers/gpu/drm/i915/intel_dsi_pll.c |   35 +++++++++++++++++++++++
 4 files changed, 90 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 5eeb2b7..f96f049 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7387,6 +7387,57 @@ enum skl_disp_power_wells {
 #define GEN9_FUSE_PG1_ENABLED                          (1 << 26)
 #define GEN9_FUSE_PG0_ENABLED                          (1 << 27)
 
+/* BXT MIPI clock controls */
+#define BXT_MAX_VAR_OUTPUT_KHZ                  39500
+#define BXT_MIPI_CLOCK_CTL                      0x46090
+#define BXT_MIPI_DIV_SHIFT                      16
+
+/* Var clock divider to generate TX source. Result must be < 39.5 M */
+#define BXT_MIPI1_ESCLK_VAR_DIV_MASK            (0x3F << 26)
+/* BXT MIPI clock controls */
+#define BXT_MAX_VAR_OUTPUT_KHZ                  39500
+#define BXT_MIPI_CLOCK_CTL                      0x46090
+#define BXT_MIPI_DIV_SHIFT                      16
+
+/* Var clock divider to generate TX source. Result must be < 39.5 M */
+#define BXT_MIPI1_ESCLK_VAR_DIV_MASK            (0x3F << 26)
+#define BXT_MIPI2_ESCLK_VAR_DIV_MASK            (0x3F << 10)
+#define BXT_MIPI_ESCLK_VAR_DIV_MASK(check)    \
+		(0x3F << ((!check) * BXT_MIPI_DIV_SHIFT + 10))
+#define BXT_MIPI_ESCLK_VAR_DIV(check, val)            \
+		(val << ((!check) * BXT_MIPI_DIV_SHIFT + 10))
+
+/* TX control divider to select actual TX clock output from (8x/var) */
+#define BXT_MIPI1_TX_ESCLK_FIXDIV_MASK        (3 << 21)
+#define BXT_MIPI2_TX_ESCLK_FIXDIV_MASK        (3 << 5)
+#define BXT_MIPI_TX_ESCLK_FIXDIV_MASK(check)  \
+		(3 << ((!check) * BXT_MIPI_DIV_SHIFT + 5))
+
+#define BXT_MIPI_TX_ESCLK_8XDIV_BY2(check)    \
+		(0x0 << ((!check) * BXT_MIPI_DIV_SHIFT + 5))
+#define BXT_MIPI_TX_ESCLK_8XDIV_BY4(check)    \
+		(0x1 << ((!check) * BXT_MIPI_DIV_SHIFT + 5))
+#define BXT_MIPI_TX_ESCLK_8XDIV_BY8(check)    \
+		(0x2 << ((!check) * BXT_MIPI_DIV_SHIFT + 5))
+
+/* RX control divider to select actual RX clock output from 8x*/
+#define BXT_MIPI1_RX_ESCLK_FIXDIV_MASK        (3 << 19)
+#define BXT_MIPI2_RX_ESCLK_FIXDIV_MASK        (3 << 3)
+#define BXT_MIPI_RX_ESCLK_FIXDIV_MASK(check)  \
+		(3 << ((!check) * BXT_MIPI_DIV_SHIFT + 3))
+#define BXT_MIPI_RX_ESCLK_8X_BY2(check)       \
+		(1 << ((!check) * BXT_MIPI_DIV_SHIFT + 3))
+#define BXT_MIPI_RX_ESCLK_8X_BY3(check)       \
+		(2 << ((!check) * BXT_MIPI_DIV_SHIFT + 3))
+#define BXT_MIPI_RX_ESCLK_8X_BY4(check)       \
+		(3 << ((!check) * BXT_MIPI_DIV_SHIFT + 3))
+
+/* BXT: Always prog DPHY dividers to 00 */
+#define BXT_MIPI_1_DPHY_DIVIDER_MASK          (3 << 16)
+#define BXT_MIPI_2_DPHY_DIVIDER_MASK          (3 << 0)
+#define BXT_MIPI_DPHY_DIVIDER_MASK(check)               \
+		(3 << ((!check) * BXT_MIPI_DIV_SHIFT))
+
 /* BXT MIPI mode configure */
 #define _BXT_MIPIA_TRANS_HACTIVE                       0x6B0F8
 #define _BXT_MIPIC_TRANS_HACTIVE                       0x6B8F8
diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 3a1bb04..729faf6 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -503,6 +503,9 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder)
 		tmp = I915_READ(DSPCLK_GATE_D);
 		tmp |= DPOUNIT_CLOCK_GATE_DISABLE;
 		I915_WRITE(DSPCLK_GATE_D, tmp);
+	} else if (IS_BROXTON(dev)) {
+		/* Program Tx Rx and Dphy clocks */
+		bxt_dsi_program_clocks(dev, intel_dsi->ports);
 	}
 
 	/* put device in ready state */
diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
index 759983e..af5a09f 100644
--- a/drivers/gpu/drm/i915/intel_dsi.h
+++ b/drivers/gpu/drm/i915/intel_dsi.h
@@ -124,6 +124,7 @@ static inline struct intel_dsi *enc_to_intel_dsi(struct drm_encoder *encoder)
 extern void intel_enable_dsi_pll(struct intel_encoder *encoder);
 extern void intel_disable_dsi_pll(struct intel_encoder *encoder);
 extern u32 vlv_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp);
+extern void bxt_dsi_program_clocks(struct drm_device *dev, int pipe);
 
 struct drm_panel *vbt_panel_init(struct intel_dsi *intel_dsi, u16 panel_id);
 
diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c
index 0cbcf32..9a8a35d 100644
--- a/drivers/gpu/drm/i915/intel_dsi_pll.c
+++ b/drivers/gpu/drm/i915/intel_dsi_pll.c
@@ -369,6 +369,41 @@ u32 vlv_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp)
 	return pclk;
 }
 
+/* Program BXT Mipi clocks and dividers */
+void bxt_dsi_program_clocks(struct drm_device *dev, int pipe)
+{
+	u32 tmp = 0;
+	u32 divider = 0;
+	u32 dsi_rate = 0;
+	u32 pll_ratio = 0;
+	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(pipe));
+	tmp &= ~(BXT_MIPI_RX_ESCLK_FIXDIV_MASK(pipe));
+	tmp &= ~(BXT_MIPI_ESCLK_VAR_DIV_MASK(pipe));
+	tmp &= ~(BXT_MIPI_DPHY_DIVIDER_MASK(pipe));
+
+	/* Get the current DSI rate(actual) */
+	pll_ratio = I915_READ(BXT_DSI_PLL_CTL) &
+		BXT_DSI_MASK_PLL_RATIO;
+	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(pipe, divider);
+
+	/* Tx escape clock should be >=20MHz, so select divide by 2 */
+	tmp |= BXT_MIPI_TX_ESCLK_8XDIV_BY2(pipe);
+
+	/* Rx escape clock, select fix divide by 3 clock */
+	tmp |= BXT_MIPI_RX_ESCLK_8X_BY3(pipe);
+
+	/* Do the honors */
+	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;
-- 
1.7.9.5

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