scsi: ufs-mediatek: Create reset control device_link

Mediatek UFS reset function relies on Reset Control provided by
reset-ti-syscon. To make Mediatek Reset Control work properly, select
reset-ti-syscon to ensure it is being built.

In addition, establish device_link to wait until reset-ti-syscon
initialization is complete during UFS probing.

Link: https://lore.kernel.org/r/1622601720-22466-1-git-send-email-peter.wang@mediatek.com
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
index 07cf415..2d13795 100644 (file)
--- a/drivers/scsi/ufs/Kconfig
+++ b/drivers/scsi/ufs/Kconfig
@@ -115,6 +115,7 @@ config SCSI_UFS_MEDIATEK
        tristate "Mediatek specific hooks to UFS controller platform driver"
        depends on SCSI_UFSHCD_PLATFORM && ARCH_MEDIATEK
        select PHY_MTK_UFS
+       select RESET_TI_SYSCON
        help
          This selects the Mediatek specific additions to UFSHCD platform driver.
          UFS host on Mediatek needs some vendor specific configuration before

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index bbe0596..e883cab 100644 (file)
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -1068,9 +1068,38 @@ static int ufs_mtk_probe(struct platform_device *pdev)
 {
        int err;
        struct device *dev = &pdev->dev;
+       struct device_node *reset_node;
+       struct platform_device *reset_pdev;
+       struct device_link *link;
+
+       reset_node = of_find_compatible_node(NULL, NULL,
+                                            "ti,syscon-reset");
+       if (!reset_node) {
+               dev_notice(dev, "find ti,syscon-reset fail\n");
+               goto skip_reset;
+       }
+       reset_pdev = of_find_device_by_node(reset_node);
+       if (!reset_pdev) {
+               dev_notice(dev, "find reset_pdev fail\n");
+               goto skip_reset;
+       }
+       link = device_link_add(dev, &reset_pdev->dev,
+               DL_FLAG_AUTOPROBE_CONSUMER);
+       if (!link) {
+               dev_notice(dev, "add reset device_link fail\n");
+               goto skip_reset;
+       }
+       /* supplier is not probed */
+       if (link->status == DL_STATE_DORMANT) {
+               err = -EPROBE_DEFER;
+               goto out;
+       }
 
+skip_reset:
        /* perform generic probe */
        err = ufshcd_pltfrm_init(pdev, &ufs_hba_mtk_vops);
+
+out:
        if (err)
                dev_info(dev, "probe failed %d\n", err);