linux-kernel - [PATCH v2 1/2] phy: cadence: cdns-dphy: Fix PLL lock and O_CMN

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Message-ID: <20250326152320.3835249-2-devarsht@ti.com>
Date: Wed, 26 Mar 2025 20:53:19 +0530
From: Devarsh Thakkar <devarsht@...com>
To: <vkoul@...nel.org>, <kishon@...nel.org>, <mripard@...nel.org>,
        <linux-phy@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
CC: <sakari.ailus@...ux.intel.com>, <u.kleine-koenig@...libre.com>,
        <vigneshr@...com>, <aradhya.bhatia@...ux.dev>, <s-jain1@...com>,
        <r-donadkar@...com>, <tomi.valkeinen@...asonboard.com>
Subject: [PATCH v2 1/2] phy: cadence: cdns-dphy: Fix PLL lock and O_CMN_READY polling

PLL lockup and O_CMN_READY assertion can only happen after common state
machine gets enabled, but driver was polling them before the common state
machine was enabled. To fix this, add new function callbacks polling on PLL
lock and O_CMN_READY assertion and call them only after common state
machine gets enabled.

Cc: stable@...r.kernel.org
Fixes: 7a343c8bf4b5 ("phy: Add Cadence D-PHY support")
Signed-off-by: Devarsh Thakkar <devarsht@...com>
---
V2: 
- Return error code on polling timeout
- Moved out calibration logic to separate patch

 drivers/phy/cadence/cdns-dphy.c | 57 ++++++++++++++++++++++++++++-----
 1 file changed, 49 insertions(+), 8 deletions(-)

diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
index ed87a3970f83..c4de9e4d3e93 100644
--- a/drivers/phy/cadence/cdns-dphy.c
+++ b/drivers/phy/cadence/cdns-dphy.c
@@ -99,6 +99,8 @@ struct cdns_dphy_ops {
 	void (*set_pll_cfg)(struct cdns_dphy *dphy,
 			    const struct cdns_dphy_cfg *cfg);
 	unsigned long (*get_wakeup_time_ns)(struct cdns_dphy *dphy);
+	int (*wait_for_pll_lock)(struct cdns_dphy *dphy);
+	int (*wait_for_cmn_ready)(struct cdns_dphy *dphy);
 };
 
 struct cdns_dphy {
@@ -191,6 +193,26 @@ static unsigned long cdns_dphy_get_wakeup_time_ns(struct cdns_dphy *dphy)
 	return dphy->ops->get_wakeup_time_ns(dphy);
 }
 
+static int cdns_dphy_wait_for_pll_lock(struct cdns_dphy *dphy)
+{
+	int ret = 0;
+
+	if (dphy->ops->wait_for_pll_lock)
+		ret = dphy->ops->wait_for_pll_lock(dphy);
+
+	return ret;
+}
+
+static int cdns_dphy_wait_for_cmn_ready(struct cdns_dphy *dphy)
+{
+	int ret = 0;
+
+	if (dphy->ops->wait_for_cmn_ready)
+		ret = dphy->ops->wait_for_cmn_ready(dphy);
+
+	return ret;
+}
+
 static unsigned long cdns_dphy_ref_get_wakeup_time_ns(struct cdns_dphy *dphy)
 {
 	/* Default wakeup time is 800 ns (in a simulated environment). */
@@ -232,7 +254,6 @@ static unsigned long cdns_dphy_j721e_get_wakeup_time_ns(struct cdns_dphy *dphy)
 static void cdns_dphy_j721e_set_pll_cfg(struct cdns_dphy *dphy,
 					const struct cdns_dphy_cfg *cfg)
 {
-	u32 status;
 
 	/*
 	 * set the PWM and PLL Byteclk divider settings to recommended values
@@ -249,13 +270,6 @@ static void cdns_dphy_j721e_set_pll_cfg(struct cdns_dphy *dphy,
 
 	writel(DPHY_TX_J721E_WIZ_LANE_RSTB,
 	       dphy->regs + DPHY_TX_J721E_WIZ_RST_CTRL);
-
-	readl_poll_timeout(dphy->regs + DPHY_TX_J721E_WIZ_PLL_CTRL, status,
-			   (status & DPHY_TX_WIZ_PLL_LOCK), 0, POLL_TIMEOUT_US);
-
-	readl_poll_timeout(dphy->regs + DPHY_TX_J721E_WIZ_STATUS, status,
-			   (status & DPHY_TX_WIZ_O_CMN_READY), 0,
-			   POLL_TIMEOUT_US);
 }
 
 static void cdns_dphy_j721e_set_psm_div(struct cdns_dphy *dphy, u8 div)
@@ -263,6 +277,23 @@ static void cdns_dphy_j721e_set_psm_div(struct cdns_dphy *dphy, u8 div)
 	writel(div, dphy->regs + DPHY_TX_J721E_WIZ_PSM_FREQ);
 }
 
+static int cdns_dphy_j721e_wait_for_pll_lock(struct cdns_dphy *dphy)
+{
+	u32 status;
+
+	return readl_poll_timeout(dphy->regs + DPHY_TX_J721E_WIZ_PLL_CTRL, status,
+			       status & DPHY_TX_WIZ_PLL_LOCK, 0, POLL_TIMEOUT_US);
+}
+
+static int cdns_dphy_j721e_wait_for_cmn_ready(struct cdns_dphy *dphy)
+{
+	u32 status;
+
+	return readl_poll_timeout(dphy->regs + DPHY_TX_J721E_WIZ_STATUS, status,
+			       status & DPHY_TX_WIZ_O_CMN_READY, 0,
+			       POLL_TIMEOUT_US);
+}
+
 /*
  * This is the reference implementation of DPHY hooks. Specific integration of
  * this IP may have to re-implement some of them depending on how they decided
@@ -278,6 +309,8 @@ static const struct cdns_dphy_ops j721e_dphy_ops = {
 	.get_wakeup_time_ns = cdns_dphy_j721e_get_wakeup_time_ns,
 	.set_pll_cfg = cdns_dphy_j721e_set_pll_cfg,
 	.set_psm_div = cdns_dphy_j721e_set_psm_div,
+	.wait_for_pll_lock = cdns_dphy_j721e_wait_for_pll_lock,
+	.wait_for_cmn_ready = cdns_dphy_j721e_wait_for_cmn_ready,
 };
 
 static int cdns_dphy_config_from_opts(struct phy *phy,
@@ -373,6 +406,14 @@ static int cdns_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
 	      FIELD_PREP(DPHY_BAND_CFG_RIGHT_BAND, band_ctrl);
 	writel(reg, dphy->regs + DPHY_BAND_CFG);
 
+	ret = cdns_dphy_wait_for_pll_lock(dphy);
+	if (ret)
+		dev_err(&dphy->phy->dev, "Failed to lock PLL with err %d\n", ret);
+
+	ret = cdns_dphy_wait_for_cmn_ready(dphy);
+	if (ret)
+		dev_err(&dphy->phy->dev, "O_CMN_READY signal failed to assert with err %d\n", ret);
+
 	return 0;
 }
 
-- 
2.39.1