[PATCH] ufs: qcom: Add UFS host regulator support

[Federico Amedeo Izzo via B4 Relay]

From: Federico Amedeo Izzo <federico at izzo.pro>

The qcom UFS driver works without touching the regulators on most platforms
as ABL leaves them already configured and enabled.
On some SC7280 phones with UFS 3.1 like nothing-spacewar, vcc regulator is
not enabled by ABL, so we need to configure and enable it to use the UFS
storage.

Tested on nothing-spacewar and motorola-dubai using Tauchgang U-Boot.

Signed-off-by: Federico Amedeo Izzo <federico at izzo.pro>
---
Add support to qcom-ufs driver for vcc-supply and vccq-supply
regulators to enable UFS support on SC7280 devices with UFS3.1.
SC7280 devices with UFS2.2 were already working.

The root cause was ABL leaving vcc-supply regulator disabled on UFS3.1
devices, and enabled on UFS2.2 devices that worked fine without
regulator support.

The tricky part was enabling the regulator in HPM mode (3), which required
setting LPM mode (1) first, otherwise reg would stay in LPM mode.
I discovered this by changing the regulator settings from U-Boot
console. Enabling the regulator in LPM mode resets the phone.
---
 drivers/ufs/ufs-qcom.c | 22 +++++++++++++++++++++-
 drivers/ufs/ufs-qcom.h |  3 +++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/ufs-qcom.c b/drivers/ufs/ufs-qcom.c
index dc40ee62daf..6c4599a6453 100644
--- a/drivers/ufs/ufs-qcom.c
+++ b/drivers/ufs/ufs-qcom.c
@@ -16,6 +16,7 @@
 #include <generic-phy.h>
 #include <asm/gpio.h>
 #include <interconnect.h>
+#include <power/regulator.h>
 
 #include <linux/bitops.h>
 #include <linux/delay.h>
@@ -557,10 +558,21 @@ static void ufs_qcom_dev_ref_clk_ctrl(struct ufs_hba *hba, bool enable)
 static int ufs_qcom_init(struct ufs_hba *hba)
 {
 	struct ufs_qcom_priv *priv = dev_get_priv(hba->dev);
-	int err;
+	int ret, err;
 
 	priv->hba = hba;
 
+	/* Set regulator to LPM mode first otherwise HPM does not get applied */
+	ret = regulator_set_mode(priv->vcc, 1);
+	ret = regulator_set_mode(priv->vcc, 3);
+	ret = regulator_set_enable(priv->vcc, true);
+	if (ret && ret != -ENOSYS)
+		dev_warn(hba->dev, "failed to enable regulator vcc-supply:%d\n", ret);
+
+	ret = regulator_set_enable(priv->vccq, true);
+	if (ret && ret != -ENOSYS)
+		dev_warn(hba->dev, "failed to enable regulator vccq-supply:%d\n", ret);
+
 	/* setup clocks */
 	ufs_qcom_setup_clocks(hba, true, PRE_CHANGE);
 
@@ -651,6 +663,14 @@ static int ufs_qcom_probe(struct udevice *dev)
 		dev_err(dev, "Warning: cannot get reset GPIO\n");
 	}
 
+	ret = device_get_supply_regulator(dev, "vcc-supply", &priv->vcc);
+	if (ret)
+		dev_warn(dev, "failed to get regulator vcc-supply:%d\n", ret);
+
+	ret = device_get_supply_regulator(dev, "vccq-supply", &priv->vccq);
+	if (ret)
+		dev_warn(dev, "failed to get regulator vccq-supply:%d\n", ret);
+
 	ret = ufshcd_probe(dev, &ufs_qcom_hba_ops);
 	if (ret) {
 		dev_err(dev, "ufshcd_probe() failed, ret:%d\n", ret);
diff --git a/drivers/ufs/ufs-qcom.h b/drivers/ufs/ufs-qcom.h
index de957ae60f3..4e502e7b3ca 100644
--- a/drivers/ufs/ufs-qcom.h
+++ b/drivers/ufs/ufs-qcom.h
@@ -134,6 +134,9 @@ struct ufs_qcom_priv {
 	struct clk_bulk clks;
 	bool is_clks_enabled;
 
+	struct udevice *vcc;
+	struct udevice *vccq;
+
 	struct ufs_hw_version hw_ver;
 
 	/* Reset control of HCI */

---
base-commit: 744cf5d4e398c5f657e5c3eeb44d00fa5175dc85
change-id: 20260521-dpu-add-dspp-gc-driver-0c9ec8b0f127

Best regards,
--  
Federico Amedeo Izzo <federico at izzo.pro>