[PATCH 14/26] phy: dphy: add support to calculate the timing based on hs_clk_rate

[Dario Binacchi]

From: Michael Trimarchi <michael at amarulasolutions.com>

Upstream Linux commit 22168675bae7.

For MIPI-CSI sender use-case it is common to specify the allowed
link-frequencies which should be used for the MIPI link and is
half the hs-clock rate.

This commit adds a helper to calculate the D-PHY timing based on the
hs-clock rate so we don't need to calculate the timings within the
driver.

Signed-off-by: Marco Felsch <m.felsch at pengutronix.de>
Acked-by: Vinod Koul <vkoul at kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus at linux.intel.com>
Signed-off-by: Michael Trimarchi <michael at amarulasolutions.com>
Signed-off-by: Dario Binacchi <dario.binacchi at amarulasolutions.com>
---

 drivers/phy/phy-core-mipi-dphy.c | 30 +++++++++++++++++++++++++-----
 include/phy-mipi-dphy.h          |  3 +++
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/drivers/phy/phy-core-mipi-dphy.c b/drivers/phy/phy-core-mipi-dphy.c
index 8fb985a1e682..727c2b040520 100644
--- a/drivers/phy/phy-core-mipi-dphy.c
+++ b/drivers/phy/phy-core-mipi-dphy.c
@@ -13,21 +13,23 @@
 /*
  * Minimum D-PHY timings based on MIPI D-PHY specification. Derived
  * from the valid ranges specified in Section 6.9, Table 14, Page 41
- * of the D-PHY specification (v2.1).
+ * of the D-PHY specification (v1.2).
  */
-int phy_mipi_dphy_get_default_config(unsigned long pixel_clock,
+static int phy_mipi_dphy_calc_config(unsigned long pixel_clock,
 				     unsigned int bpp,
 				     unsigned int lanes,
+				     unsigned long long hs_clk_rate,
 				     struct phy_configure_opts_mipi_dphy *cfg)
 {
-	unsigned long long hs_clk_rate;
 	unsigned long long ui;
 
 	if (!cfg)
 		return -EINVAL;
 
-	hs_clk_rate = pixel_clock * bpp;
-	do_div(hs_clk_rate, lanes);
+	if (!hs_clk_rate) {
+		hs_clk_rate = pixel_clock * bpp;
+		do_div(hs_clk_rate, lanes);
+	}
 
 	ui = ALIGN(PSEC_PER_SEC, hs_clk_rate);
 	do_div(ui, hs_clk_rate);
@@ -74,6 +76,24 @@ int phy_mipi_dphy_get_default_config(unsigned long pixel_clock,
 	return 0;
 }
 
+int phy_mipi_dphy_get_default_config(unsigned long pixel_clock,
+				     unsigned int bpp,
+				     unsigned int lanes,
+				     struct phy_configure_opts_mipi_dphy *cfg)
+{
+	return phy_mipi_dphy_calc_config(pixel_clock, bpp, lanes, 0, cfg);
+}
+
+int phy_mipi_dphy_get_default_config_for_hsclk(unsigned long long hs_clk_rate,
+					       unsigned int lanes,
+					       struct phy_configure_opts_mipi_dphy *cfg)
+{
+	if (!hs_clk_rate)
+		return -EINVAL;
+
+	return phy_mipi_dphy_calc_config(0, 0, lanes, hs_clk_rate, cfg);
+}
+
 /*
  * Validate D-PHY configuration according to MIPI D-PHY specification
  * (v1.2, Section Section 6.9 "Global Operation Timing Parameters").
diff --git a/include/phy-mipi-dphy.h b/include/phy-mipi-dphy.h
index a877ffee845d..1ac128d78dfe 100644
--- a/include/phy-mipi-dphy.h
+++ b/include/phy-mipi-dphy.h
@@ -279,6 +279,9 @@ int phy_mipi_dphy_get_default_config(unsigned long pixel_clock,
 				     unsigned int bpp,
 				     unsigned int lanes,
 				     struct phy_configure_opts_mipi_dphy *cfg);
+int phy_mipi_dphy_get_default_config_for_hsclk(unsigned long long hs_clk_rate,
+					       unsigned int lanes,
+					       struct phy_configure_opts_mipi_dphy *cfg);
 int phy_mipi_dphy_config_validate(struct phy_configure_opts_mipi_dphy *cfg);
 
 #endif /* __PHY_MIPI_DPHY_H_ */
-- 
2.43.0