[PATCH v4 1/2] phy: rockchip: inno-hdmi: Add configure() and validate() ops

[Jonas Karlman]

The commit 10ed34d6eaaf ("phy: Add HDMI configuration options")
introduced a way for HDMI PHYs to be configured through the generic
phy_configure() function.

This driver derives the TMDS character rate from the pixel clock and the
PHY bus width setting. However, no in-tree consumer of this PHY has ever
called phy_set_bus_width() to change the TMDS character rate as only
8-bit RGB output is supported by the HDMI display driver.

Add configure() and validate() ops to allow consumers to configure the
TMDS character rate using phy_configure(). Fallback to the deprecated
way of using the PHY bus width to configure the TMDS character rate.

A typical call chain during DRM modeset on a RK3328 device:

  dw_hdmi_rockchip_encoder_atomic_check():
  - inno_hdmi_phy_validate(): pixclock 148500000 tmdsclock 594000000

  dw_hdmi_rockchip_encoder_atomic_mode_set():
  - inno_hdmi_phy_configure(): pixclock 148500000
    - inno_hdmi_phy_validate(): pixclock 148500000 tmdsclock 594000000

  vop_crtc_atomic_enable():
  - inno_hdmi_phy_rk3328_clk_set_rate(): rate 594000000 tmdsclk 594000000
    inno_hdmi_phy_rk3328_clk_set_rate(): pixclock 594000000 tmdsclock 594000000
  - inno_hdmi_phy_rk3328_clk_recalc_rate(): pixclock 594000000 vco 594000000

  dw_hdmi_rockchip_encoder_enable():
  - inno_hdmi_phy_power_on(): Inno HDMI PHY Power On
    - inno_hdmi_phy_rk3328_clk_set_rate(): rate 594000000 tmdsclk 594000000

Signed-off-by: Jonas Karlman <jonas at kwiboo.se>
---
Changes in v4:
- Add NULL opts check in validate()
- Only store the opts->hdmi.tmds_char_rate value for later use
- Move comments about expected consumer usage from inline to above the
  functions
- Indent a set_rate() sub-call in the commit message call chain
Changes in v3:
- Change validate() ops to only validate tmdsclock
- Add comments about expected consumer usage
- Update commit message with a typical call chain
Changes in v2:
- Add validate() ops to validate that the TMDS rate is supported
- Split out parts that remove the old workaround into a separate patch

Patch "drm/rockchip: dw_hdmi: Configure HDMI PHY in atomic_mode_set()"
at [1] adds phy_validate() and phy_configure() calls for this HDMI PHY.

[1] https://lore.kernel.org/dri-devel/20260510183114.1248840-10-jonas@kwiboo.se/
---
 drivers/phy/rockchip/phy-rockchip-inno-hdmi.c | 62 ++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/rockchip/phy-rockchip-inno-hdmi.c b/drivers/phy/rockchip/phy-rockchip-inno-hdmi.c
index 1483907413fa..1c43ea700f0e 100644
--- a/drivers/phy/rockchip/phy-rockchip-inno-hdmi.c
+++ b/drivers/phy/rockchip/phy-rockchip-inno-hdmi.c
@@ -245,6 +245,7 @@ struct inno_hdmi_phy {
 	struct clk *phyclk;
 	unsigned long pixclock;
 	unsigned long tmdsclock;
+	unsigned long opts_tmds_char_rate;
 };
 
 struct pre_pll_config {
@@ -554,7 +555,12 @@ static inline void inno_update_bits(struct inno_hdmi_phy *inno, u8 reg,
 static unsigned long inno_hdmi_phy_get_tmdsclk(struct inno_hdmi_phy *inno,
 					       unsigned long rate)
 {
-	int bus_width = phy_get_bus_width(inno->phy);
+	int bus_width;
+
+	if (inno->opts_tmds_char_rate)
+		return inno->opts_tmds_char_rate;
+
+	bus_width = phy_get_bus_width(inno->phy);
 
 	switch (bus_width) {
 	case 4:
@@ -602,6 +608,57 @@ static irqreturn_t inno_hdmi_phy_rk3328_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+/*
+ * phy_validate() is expected to be called from encoder atomic_check(), before
+ * the hdmiphy pixel clock is known. Without knowing the actual pixel clock, we
+ * cannot do full validation of the configuration. Instead, we do a simple check
+ * that the pre-pll table contains an entry for the requested TMDS char rate.
+ */
+static int inno_hdmi_phy_validate(struct phy *phy, enum phy_mode mode,
+				  int submode, union phy_configure_opts *opts)
+{
+	const struct pre_pll_config *cfg = pre_pll_cfg_table;
+	unsigned long tmdsclock;
+
+	if (!(mode == PHY_MODE_HDMI && submode == PHY_HDMI_MODE_TMDS))
+		return -EINVAL;
+
+	if (!opts)
+		return -EINVAL;
+
+	if (!opts->hdmi.tmds_char_rate || opts->hdmi.tmds_char_rate > 594000000)
+		return -EINVAL;
+
+	tmdsclock = opts->hdmi.tmds_char_rate;
+	for (; cfg->pixclock != 0; cfg++)
+		if (cfg->tmdsclock == tmdsclock)
+			return 0;
+
+	return -EINVAL;
+}
+
+/*
+ * phy_configure() is expected to be called from encoder atomic_set_mode(),
+ * before the hdmiphy pixel clock is known. Store the requested TMDS character
+ * rate, so that it can be used later in power_on() and/or set_rate() when the
+ * pixel clock is known.
+ */
+static int inno_hdmi_phy_configure(struct phy *phy,
+				   union phy_configure_opts *opts)
+{
+	struct inno_hdmi_phy *inno = phy_get_drvdata(phy);
+	int ret;
+
+	ret = inno_hdmi_phy_validate(phy, phy_get_mode(phy),
+				     PHY_HDMI_MODE_TMDS, opts);
+	if (ret)
+		return ret;
+
+	inno->opts_tmds_char_rate = opts->hdmi.tmds_char_rate;
+
+	return 0;
+}
+
 static int inno_hdmi_phy_power_on(struct phy *phy)
 {
 	struct inno_hdmi_phy *inno = phy_get_drvdata(phy);
@@ -670,6 +727,8 @@ static const struct phy_ops inno_hdmi_phy_ops = {
 	.owner = THIS_MODULE,
 	.power_on = inno_hdmi_phy_power_on,
 	.power_off = inno_hdmi_phy_power_off,
+	.configure = inno_hdmi_phy_configure,
+	.validate = inno_hdmi_phy_validate,
 };
 
 static const
@@ -1392,6 +1451,7 @@ static int inno_hdmi_phy_probe(struct platform_device *pdev)
 	}
 
 	phy_set_drvdata(inno->phy, inno);
+	phy_set_mode_ext(inno->phy, PHY_MODE_HDMI, PHY_HDMI_MODE_TMDS);
 	phy_set_bus_width(inno->phy, 8);
 
 	if (inno->plat_data->ops->init) {
-- 
2.54.0