[PATCH v3] phy: cadence-torrent: restore parent clock for refclk during resume

[Thomas Richard (TI.com)]

While suspend and resume, parent clock config for refclk was getting lost.
So save and restore it in suspend and resume operations.

Reviewed-by: Neil Armstrong <neil.armstrong at linaro.org>
Signed-off-by: Thomas Richard (TI.com) <thomas.richard at bootlin.com>
---
Changes in v3:
- catch RB tag.
- Link to v2: https://lore.kernel.org/r/20251126-phy-cadence-torrent-resume-restore-refclk-parent-v2-1-5d2eaa958b06@bootlin.com

Changes in v2:
- store parent configuration in cdns_torrent_refclk_driver.
- add cdns_torrent_refclk_driver_suspend/_resume() functions.
- use get_parent() and set_parent() operations to save and restore the
  configuration.
- Link to v1: https://lore.kernel.org/r/20251110-phy-cadence-torrent-resume-restore-refclk-parent-v1-1-1be87af7d19e@bootlin.com
---
 drivers/phy/cadence/phy-cadence-torrent.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/phy/cadence/phy-cadence-torrent.c b/drivers/phy/cadence/phy-cadence-torrent.c
index 37fa4bad6bd7..877f22177c69 100644
--- a/drivers/phy/cadence/phy-cadence-torrent.c
+++ b/drivers/phy/cadence/phy-cadence-torrent.c
@@ -397,6 +397,7 @@ struct cdns_torrent_refclk_driver {
 	struct clk_hw		hw;
 	struct regmap_field	*cmn_fields[REFCLK_OUT_NUM_CMN_CONFIG];
 	struct clk_init_data	clk_data;
+	u8 parent_index;
 };
 
 #define to_cdns_torrent_refclk_driver(_hw)	\
@@ -3326,11 +3327,29 @@ static const struct cdns_torrent_vals sgmii_qsgmii_xcvr_diag_ln_vals = {
 	.num_regs = ARRAY_SIZE(sgmii_qsgmii_xcvr_diag_ln_regs),
 };
 
+static void cdns_torrent_refclk_driver_suspend(struct cdns_torrent_phy *cdns_phy)
+{
+	struct clk_hw *hw = cdns_phy->clk_hw_data->hws[CDNS_TORRENT_REFCLK_DRIVER];
+	struct cdns_torrent_refclk_driver *refclk_driver = to_cdns_torrent_refclk_driver(hw);
+
+	refclk_driver->parent_index = cdns_torrent_refclk_driver_get_parent(hw);
+}
+
+static int cdns_torrent_refclk_driver_resume(struct cdns_torrent_phy *cdns_phy)
+{
+	struct clk_hw *hw = cdns_phy->clk_hw_data->hws[CDNS_TORRENT_REFCLK_DRIVER];
+	struct cdns_torrent_refclk_driver *refclk_driver = to_cdns_torrent_refclk_driver(hw);
+
+	return cdns_torrent_refclk_driver_set_parent(hw, refclk_driver->parent_index);
+}
+
 static int cdns_torrent_phy_suspend_noirq(struct device *dev)
 {
 	struct cdns_torrent_phy *cdns_phy = dev_get_drvdata(dev);
 	int i;
 
+	cdns_torrent_refclk_driver_suspend(cdns_phy);
+
 	reset_control_assert(cdns_phy->phy_rst);
 	reset_control_assert(cdns_phy->apb_rst);
 	for (i = 0; i < cdns_phy->nsubnodes; i++)
@@ -3352,6 +3371,10 @@ static int cdns_torrent_phy_resume_noirq(struct device *dev)
 	int node = cdns_phy->nsubnodes;
 	int ret, i;
 
+	ret = cdns_torrent_refclk_driver_resume(cdns_phy);
+	if (ret)
+		return ret;
+
 	ret = cdns_torrent_clk(cdns_phy);
 	if (ret)
 		return ret;

---
base-commit: 390f8dfb2f9876eeb827976fa26def5537440249
change-id: 20251110-phy-cadence-torrent-resume-restore-refclk-parent-f59fb5fc69fa

Best regards,
-- 
Thomas Richard (TI.com) <thomas.richard at bootlin.com>