linux-kernel - [PATCH v2 2/3] phy: cdns-dphy: Add band config for dphy tx

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Date:   Wed, 22 Jun 2022 13:23:39 +0530
From:   Rahul T R <r-ravikumar@...com>
To:     <linux-phy@...ts.infradead.org>, <kishon@...com>,
        <vkoul@...nel.org>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>
CC:     <p.yadav@...com>, <tomi.valkeinen@...asonboard.com>,
        <laurent.pinchart@...asonboard.com>,
        <linux-kernel@...r.kernel.org>, <jpawar@...ence.com>,
        <sjakhade@...ence.com>, <mparab@...ence.com>,
        <devicetree@...r.kernel.org>, <vigneshr@...com>,
        <lee.jones@...aro.org>, Rahul T R <r-ravikumar@...com>
Subject: [PATCH v2 2/3] phy: cdns-dphy: Add band config for dphy tx

Add support for band ctrl config for dphy tx.

Signed-off-by: Rahul T R <r-ravikumar@...com>
---
 drivers/phy/cadence/cdns-dphy.c | 52 ++++++++++++++++++++++++++++++++-
 1 file changed, 51 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
index ba042e39cfaf..ddfa524d8ce7 100644
--- a/drivers/phy/cadence/cdns-dphy.c
+++ b/drivers/phy/cadence/cdns-dphy.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/bitops.h>
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/module.h>
@@ -45,6 +46,10 @@
 #define DPHY_CMN_OPDIV_FROM_REG		BIT(6)
 #define DPHY_CMN_OPDIV(x)		((x) << 7)
 
+#define DPHY_BAND_CFG			DPHY_PCS(0x0)
+#define DPHY_BAND_CFG_LEFT_BAND		GENMASK(4, 0)
+#define DPHY_BAND_CFG_RIGHT_BAND	GENMASK(9, 5)
+
 #define DPHY_PSM_CFG			DPHY_PCS(0x4)
 #define DPHY_PSM_CFG_FROM_REG		BIT(0)
 #define DPHY_PSM_CLK_DIV(x)		((x) << 1)
@@ -92,6 +97,22 @@ struct cdns_dphy {
 	struct phy *phy;
 };
 
+struct cdns_dphy_band {
+	unsigned int min_rate;
+	unsigned int max_rate;
+};
+
+/* Order of bands is important since the index is the band number. */
+static struct cdns_dphy_band tx_bands[] = {
+	{80, 100}, {100, 120}, {120, 160}, {160, 200}, {200, 240},
+	{240, 320}, {320, 390}, {390, 450}, {450, 510}, {510, 560},
+	{560, 640}, {640, 690}, {690, 770}, {770, 870}, {870, 950},
+	{950, 1000}, {1000, 1200}, {1200, 1400}, {1400, 1600}, {1600, 1800},
+	{1800, 2000}, {2000, 2200}, {2200, 2500}
+};
+
+static int num_tx_bands = ARRAY_SIZE(tx_bands);
+
 static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy,
 				     struct cdns_dphy_cfg *cfg,
 				     struct phy_configure_opts_mipi_dphy *opts,
@@ -232,6 +253,26 @@ static int cdns_dphy_config_from_opts(struct phy *phy,
 	return 0;
 }
 
+static int cdns_dphy_tx_get_band_ctrl(unsigned long hs_clk_rate)
+{
+	unsigned int rate;
+	int i;
+
+	rate = hs_clk_rate / 1000000UL;
+
+	if (rate < tx_bands[0].min_rate || rate >= tx_bands[num_tx_bands - 1].max_rate)
+		return -EOPNOTSUPP;
+
+	for (i = 0; i < num_tx_bands; i++) {
+		if (rate >= tx_bands[i].min_rate && rate < tx_bands[i].max_rate)
+			return i;
+	}
+
+	/* Unreachable. */
+	WARN(1, "Reached unreachable code.");
+	return -EINVAL;
+}
+
 static int cdns_dphy_validate(struct phy *phy, enum phy_mode mode, int submode,
 			      union phy_configure_opts *opts)
 {
@@ -247,7 +288,8 @@ static int cdns_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
 {
 	struct cdns_dphy *dphy = phy_get_drvdata(phy);
 	struct cdns_dphy_cfg cfg = { 0 };
-	int ret;
+	int ret, band_ctrl;
+	unsigned int reg;
 
 	ret = cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
 	if (ret)
@@ -276,6 +318,14 @@ static int cdns_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
 	 */
 	cdns_dphy_set_pll_cfg(dphy, &cfg);
 
+	band_ctrl = cdns_dphy_tx_get_band_ctrl(opts->mipi_dphy.hs_clk_rate);
+	if (band_ctrl < 0)
+		return band_ctrl;
+
+	reg = FIELD_PREP(DPHY_BAND_CFG_LEFT_BAND, band_ctrl) |
+	      FIELD_PREP(DPHY_BAND_CFG_RIGHT_BAND, band_ctrl);
+	writel(reg, dphy->regs + DPHY_BAND_CFG);
+
 	return 0;
 }
 
-- 
2.36.1