[PATCH v3 4/5] ufs: rockchip: Add device reset support

[Alexey Charkov]

Wire up the GPIO line which Rockchip RK3576 UFS controller uses to reset
the connected UFS device.

This seems necessary at least for some UFS modules and fixes the following
error while enumerating UFS storage:

ufshcd-rockchip ufshc at 2a2d0000: ufshcd_link_startup: Device not present
ufshcd-rockchip ufshc at 2a2d0000: link startup failed -6
ufshcd-rockchip ufshc at 2a2d0000: ufshcd_pltfrm_init() failed -6

Fixes: 76465ce21ee4 ("ufs: rockchip: Add initial support")
Reviewed-by: Neil Armstrong <neil.armstrong at linaro.org>
Reviewed-by: Shawn Lin <shawn.lin at rock-chips.com>
Signed-off-by: Alexey Charkov <alchark at gmail.com>
---
 drivers/ufs/Kconfig        |  1 +
 drivers/ufs/ufs-rockchip.c | 25 +++++++++++++++++++++++++
 drivers/ufs/ufs-rockchip.h |  1 +
 3 files changed, 27 insertions(+)

diff --git a/drivers/ufs/Kconfig b/drivers/ufs/Kconfig
index 2543b5d47c04..e9b22acb262f 100644
--- a/drivers/ufs/Kconfig
+++ b/drivers/ufs/Kconfig
@@ -77,6 +77,7 @@ config UFS_ROCKCHIP
 	bool "Rockchip specific hooks to UFS controller platform driver"
 	depends on UFS
 	select BOUNCE_BUFFER
+	select DM_GPIO
 	help
 	  This selects the Rockchip specific additions to UFSHCD platform driver.
 
diff --git a/drivers/ufs/ufs-rockchip.c b/drivers/ufs/ufs-rockchip.c
index 699460fc4d15..20ad78d5f558 100644
--- a/drivers/ufs/ufs-rockchip.c
+++ b/drivers/ufs/ufs-rockchip.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2025 Rockchip Electronics Co.Ltd.
  */
 
+#include <asm/gpio.h>
 #include <asm/io.h>
 #include <clk.h>
 #include <dm.h>
@@ -153,12 +154,35 @@ static int ufs_rockchip_common_init(struct ufs_hba *hba)
 		return err;
 	}
 
+	err = gpio_request_by_name(dev, "reset-gpios", 0, &host->device_reset,
+				   GPIOD_IS_OUT | GPIOD_ACTIVE_LOW);
+	if (err) {
+		dev_err(dev, "Warning: cannot get reset GPIO\n");
+		return err;
+	}
+
 	hba->quirks |= UFSHCD_QUIRK_DMA_SDRAM_ONLY;
 	host->hba = hba;
 
 	return 0;
 }
 
+static int ufs_rockchip_device_reset(struct ufs_hba *hba)
+{
+	struct ufs_rockchip_host *host = dev_get_priv(hba->dev);
+
+	if (!dm_gpio_is_valid(&host->device_reset))
+		return 0;
+
+	dm_gpio_set_value(&host->device_reset, true);
+	udelay(20);
+
+	dm_gpio_set_value(&host->device_reset, false);
+	udelay(20);
+
+	return 0;
+}
+
 static int ufs_rockchip_rk3576_init(struct ufs_hba *hba)
 {
 	int ret = 0;
@@ -176,6 +200,7 @@ static struct ufs_hba_ops ufs_hba_rk3576_vops = {
 	.init = ufs_rockchip_rk3576_init,
 	.phy_initialization = ufs_rockchip_rk3576_phy_init,
 	.hce_enable_notify = ufs_rockchip_hce_enable_notify,
+	.device_reset = ufs_rockchip_device_reset,
 };
 
 static const struct udevice_id ufs_rockchip_of_match[] = {
diff --git a/drivers/ufs/ufs-rockchip.h b/drivers/ufs/ufs-rockchip.h
index 3dcb80f57020..50c2539da78a 100644
--- a/drivers/ufs/ufs-rockchip.h
+++ b/drivers/ufs/ufs-rockchip.h
@@ -72,6 +72,7 @@ struct ufs_rockchip_host {
 	void __iomem *ufs_sys_ctrl;
 	void __iomem *mphy_base;
 	struct reset_ctl_bulk rsts;
+	struct gpio_desc device_reset;
 	struct clk ref_out_clk;
 	uint64_t caps;
 	uint32_t phy_config_mode;

-- 
2.51.2