drm/sun4i: hdmi: Add support for controller hardware variants

The HDMI controller found in earlier Allwinner SoCs have slight
differences between the A10, A10s, and the A31:

  - Need different initial values for the PLL related registers

  - Different behavior of the DDC and TMDS clocks

  - Different register layout for the DDC portion

  - Separate DDC parent clock on the A31

  - Explicit reset control

For the A31, the HDMI TMDS clock has a different value offset for
the divider. The HDMI DDC block is different from the one in the
other SoCs. As far as the DDC clock goes, it has no pre-divider,
as it is clocked from a slower parent clock, not the TMDS clock.
The divider offset from the register value is different. And the
clock control register is at a different offset.

A new variant data structure is created to store pointers to the
above functions, structures, and the different initial values.
Another flag notates whether there is a separate DDC parent clock.
If not, the TMDS clock is passed to the DDC clock create function,
as before.

Regmap fields are used to deal with the different register layout
of the DDC block.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171010032008.682-8-wens@csie.org

1 files changed, 29 insertions, 9 deletions

diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_ddc_clk.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_ddc_clk.c
index 4692e8c..04f85b1 100644
--- a/drivers/gpu/drm/sun4i/sun4i_hdmi_ddc_clk.c
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_ddc_clk.c
@@ -11,6 +11,7 @@
  */
 
 #include <linux/clk-provider.h>
+#include <linux/regmap.h>
 
 #include "sun4i_tcon.h"
 #include "sun4i_hdmi.h"
@@ -18,6 +19,9 @@
 struct sun4i_ddc {
 	struct clk_hw		hw;
 	struct sun4i_hdmi	*hdmi;
+	struct regmap_field	*reg;
+	u8			pre_div;
+	u8			m_offset;
 };
 
 static inline struct sun4i_ddc *hw_to_ddc(struct clk_hw *hw)
@@ -27,6 +31,8 @@ static inline struct sun4i_ddc *hw_to_ddc(struct clk_hw *hw)
 
 static unsigned long sun4i_ddc_calc_divider(unsigned long rate,
 					    unsigned long parent_rate,
+					    const u8 pre_div,
+					    const u8 m_offset,
 					    u8 *m, u8 *n)
 {
 	unsigned long best_rate = 0;
@@ -36,7 +42,8 @@ static unsigned long sun4i_ddc_calc_divider(unsigned long rate,
 		for (_n = 0; _n < 8; _n++) {
 			unsigned long tmp_rate;
 
-			tmp_rate = (((parent_rate / 2) / 10) >> _n) / (_m + 1);
+			tmp_rate = (((parent_rate / pre_div) / 10) >> _n) /
+				(_m + m_offset);
 
 			if (tmp_rate > rate)
 				continue;
@@ -60,21 +67,25 @@ static unsigned long sun4i_ddc_calc_divider(unsigned long rate,
 static long sun4i_ddc_round_rate(struct clk_hw *hw, unsigned long rate,
 				 unsigned long *prate)
 {
-	return sun4i_ddc_calc_divider(rate, *prate, NULL, NULL);
+	struct sun4i_ddc *ddc = hw_to_ddc(hw);
+
+	return sun4i_ddc_calc_divider(rate, *prate, ddc->pre_div,
+				      ddc->m_offset, NULL, NULL);
 }
 
 static unsigned long sun4i_ddc_recalc_rate(struct clk_hw *hw,
 					    unsigned long parent_rate)
 {
 	struct sun4i_ddc *ddc = hw_to_ddc(hw);
-	u32 reg;
+	unsigned int reg;
 	u8 m, n;
 
-	reg = readl(ddc->hdmi->base + SUN4I_HDMI_DDC_CLK_REG);
-	m = (reg >> 3) & 0x7;
+	regmap_field_read(ddc->reg, &reg);
+	m = (reg >> 3) & 0xf;
 	n = reg & 0x7;
 
-	return (((parent_rate / 2) / 10) >> n) / (m + 1);
+	return (((parent_rate / ddc->pre_div) / 10) >> n) /
+	       (m + ddc->m_offset);
 }
 
 static int sun4i_ddc_set_rate(struct clk_hw *hw, unsigned long rate,
@@ -83,10 +94,12 @@ static int sun4i_ddc_set_rate(struct clk_hw *hw, unsigned long rate,
 	struct sun4i_ddc *ddc = hw_to_ddc(hw);
 	u8 div_m, div_n;
 
-	sun4i_ddc_calc_divider(rate, parent_rate, &div_m, &div_n);
+	sun4i_ddc_calc_divider(rate, parent_rate, ddc->pre_div,
+			       ddc->m_offset, &div_m, &div_n);
 
-	writel(SUN4I_HDMI_DDC_CLK_M(div_m) | SUN4I_HDMI_DDC_CLK_N(div_n),
-	       ddc->hdmi->base + SUN4I_HDMI_DDC_CLK_REG);
+	regmap_field_write(ddc->reg,
+			   SUN4I_HDMI_DDC_CLK_M(div_m) |
+			   SUN4I_HDMI_DDC_CLK_N(div_n));
 
 	return 0;
 }
@@ -111,6 +124,11 @@ int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *parent)
 	if (!ddc)
 		return -ENOMEM;
 
+	ddc->reg = devm_regmap_field_alloc(hdmi->dev, hdmi->regmap,
+					   hdmi->variant->ddc_clk_reg);
+	if (IS_ERR(ddc->reg))
+		return PTR_ERR(ddc->reg);
+
 	init.name = "hdmi-ddc";
 	init.ops = &sun4i_ddc_ops;
 	init.parent_names = &parent_name;
@@ -118,6 +136,8 @@ int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *parent)
 
 	ddc->hdmi = hdmi;
 	ddc->hw.init = &init;
+	ddc->pre_div = hdmi->variant->ddc_clk_pre_divider;
+	ddc->m_offset = hdmi->variant->ddc_clk_m_offset;
 
 	hdmi->ddc_clk = devm_clk_register(hdmi->dev, &ddc->hw);
 	if (IS_ERR(hdmi->ddc_clk))