[PATCH v2 3/5] scsi: ufs-mediatek: Introduce low-power mode for device power supply

From: Stanley Chu
Date: Fri May 29 2020 - 05:23:18 EST


Allow device power supply to enter low-power mode if device will
do nothing to save more power.

Signed-off-by: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
Reviewed-by: Pengshun Zhao <pengshun.zhao@xxxxxxxxxxxx>
---
drivers/scsi/ufs/ufs-mediatek.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index 3c85f5e97dea..5f41b7b7db8f 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -12,6 +12,7 @@
#include <linux/of_address.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
#include <linux/soc/mediatek/mtk_sip_svc.h>

#include "ufshcd.h"
@@ -521,6 +522,19 @@ static int ufs_mtk_link_set_lpm(struct ufs_hba *hba)
return 0;
}

+static void ufs_mtk_vreg_set_lpm(struct ufs_hba *hba, bool lpm)
+{
+ if (!hba->vreg_info.vccq2)
+ return;
+
+ if (lpm & !hba->vreg_info.vcc->enabled)
+ regulator_set_mode(hba->vreg_info.vccq2->reg,
+ REGULATOR_MODE_IDLE);
+ else if (!lpm)
+ regulator_set_mode(hba->vreg_info.vccq2->reg,
+ REGULATOR_MODE_NORMAL);
+}
+
static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
{
int err;
@@ -537,6 +551,12 @@ static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
ufshcd_set_link_off(hba);
return -EAGAIN;
}
+ /*
+ * Make sure no error will be returned to prevent
+ * ufshcd_suspend() re-enabling regulators while vreg is still
+ * in low-power mode.
+ */
+ ufs_mtk_vreg_set_lpm(hba, true);
}

if (!ufshcd_is_link_active(hba))
@@ -554,6 +574,7 @@ static int ufs_mtk_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
phy_power_on(host->mphy);

if (ufshcd_is_link_hibern8(hba)) {
+ ufs_mtk_vreg_set_lpm(hba, false);
err = ufs_mtk_link_set_hpm(hba);
if (err) {
err = ufshcd_link_recovery(hba);
--
2.18.0