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scsi: ufs: core: Add quirks for VCC ramp-up delay

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On some platforms, the VCC regulator has a slow ramp-up time. Add a delay
after enabling VCC to ensure voltage has fully stabilized before we enable
the clocks.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ed Tsai <ed.tsai@mediatek.com>
Link: https://patch.msgid.link/20260310005230.4001904-4-ed.tsai@mediatek.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Ed Tsai
2026-03-10 08:52:28 +08:00
committed by Martin K. Petersen
parent 096cd6b7ad
commit 6ab94d0194
2 changed files with 18 additions and 0 deletions
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12
drivers/ufs/core/ufshcd.c
View File

@@ -9952,11 +9952,13 @@ static void ufshcd_vreg_set_lpm(struct ufs_hba *hba)
#ifdef CONFIG_PM
static int ufshcd_vreg_set_hpm(struct ufs_hba *hba)
{
bool vcc_on = false;
int ret = 0;
if (ufshcd_is_ufs_dev_poweroff(hba) && ufshcd_is_link_off(hba) &&
!hba->dev_info.is_lu_power_on_wp) {
ret = ufshcd_setup_vreg(hba, true);
vcc_on = true;
} else if (!ufshcd_is_ufs_dev_active(hba)) {
if (!ufshcd_is_link_active(hba)) {
ret = ufshcd_config_vreg_hpm(hba, hba->vreg_info.vccq);
@@ -9967,6 +9969,7 @@ static int ufshcd_vreg_set_hpm(struct ufs_hba *hba)
goto vccq_lpm;
}
ret = ufshcd_toggle_vreg(hba->dev, hba->vreg_info.vcc, true);
vcc_on = true;
}
goto out;
@@ -9975,6 +9978,15 @@ static int ufshcd_vreg_set_hpm(struct ufs_hba *hba)
vcc_disable:
ufshcd_toggle_vreg(hba->dev, hba->vreg_info.vcc, false);
out:
/*
* On platforms with a slow VCC ramp-up, a delay is needed after
* turning on VCC to ensure the voltage is stable before the
* reference clock is enabled.
*/
if (hba->quirks & UFSHCD_QUIRK_VCC_ON_DELAY && !ret && vcc_on &&
hba->vreg_info.vcc && !hba->vreg_info.vcc->always_on)
usleep_range(1000, 1100);
return ret;
}
#endif /* CONFIG_PM */

6
include/ufs/ufshcd.h
View File

@@ -690,6 +690,12 @@ enum ufshcd_quirks {
* because it causes link startup to become unreliable.
*/
UFSHCD_QUIRK_PERFORM_LINK_STARTUP_ONCE = 1 << 26,
/*
* On some platforms, the VCC regulator has a slow ramp-up time. Add a
* delay after enabling VCC to ensure it's stable.
*/
UFSHCD_QUIRK_VCC_ON_DELAY = 1 << 27,
};
enum ufshcd_caps {