Re: [PATCH v3 1/2] phy: cadence: cdns-dphy: Fix PLL lock and O_CMN_READY polling

From: Devarsh Thakkar
Date: Fri Jun 20 2025 - 10:42:45 EST

Hi Vinod,

Thanks for the review.

On 14/05/25 15:59, Vinod Koul wrote:
On 02-05-25, 09:04, Devarsh Thakkar wrote:
PLL lockup and O_CMN_READY assertion can only happen after common state
machine gets enabled (by programming DPHY_CMN_SSM register), but driver was
polling them before the common state machine was enabled. To fix this :

- Add new function callbacks for polling on PLL lock and O_CMN_READY
assertion.
- As state machine and clocks get enabled in power_on callback only, move
the clock related programming part from configure callback to power_on
callback and poll for the PLL lockup and O_CMN_READY assertion after
state machine gets enabled.
- The configure callback only saves the PLL configuration received from the
client driver which will be applied later on in power_on callback.
- Add checks to ensure configure is called before power_on and state
machine is in disabled state before power_on callback is called.
- Disable state machine in power_off so that client driver can
re-configure the PLL by following up a power_off, configure, power_on
sequence.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 7a343c8bf4b5 ("phy: Add Cadence D-PHY support")
Signed-off-by: Devarsh Thakkar <devarsht@xxxxxx>
---
V3:
- Move out clock programming logic to power_on as PLL polling and enable
can happen only after SSM enable
- Disable state machine on power off

V2:
- Return error code on polling timeout
- Moved out calibration logic to separate patch

drivers/phy/cadence/cdns-dphy.c | 109 +++++++++++++++++++++++++-------
1 file changed, 85 insertions(+), 24 deletions(-)

diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
index ed87a3970f83..a94109a63788 100644
--- a/drivers/phy/cadence/cdns-dphy.c
+++ b/drivers/phy/cadence/cdns-dphy.c
@@ -79,6 +79,7 @@ struct cdns_dphy_cfg {
u8 pll_ipdiv;
u8 pll_opdiv;
u16 pll_fbdiv;
+ u64 hs_clk_rate;
unsigned int nlanes;
};
@@ -99,6 +100,8 @@ 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 {
@@ -108,6 +111,8 @@ struct cdns_dphy {
struct clk *pll_ref_clk;
const struct cdns_dphy_ops *ops;
struct phy *phy;
+ bool is_configured;
+ bool is_powered;
};
/* Order of bands is important since the index is the band number. */
@@ -191,6 +196,26 @@ 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;

We can drop ret from both, also it is called only once, so maybe open
code this one line?


Agreed.

+}
+
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 +257,6 @@ 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 +273,6 @@ 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 +280,23 @@ 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 +312,8 @@ 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,
@@ -298,6 +334,7 @@ static int cdns_dphy_config_from_opts(struct phy *phy,
return ret;
opts->wakeup = cdns_dphy_get_wakeup_time_ns(dphy) / 1000;
+ cfg->hs_clk_rate = opts->hs_clk_rate;
return 0;
}
@@ -334,13 +371,23 @@ static int cdns_dphy_validate(struct phy *phy, enum phy_mode mode, int submode,
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, band_ctrl;
- unsigned int reg;
+ int ret = 0;

Superfluous init


Agreed. I will do the fixups in next revision.

Thanks,
Devarsh