Add PERST# signal handling via I2C GPIO expander for AMD Versal2
MDB PCIe Root Port.
Signed-off-by: Sai Krishna Musham <sai.krishna.musham@xxxxxxx>
---
drivers/pci/controller/dwc/pcie-amd-mdb.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/drivers/pci/controller/dwc/pcie-amd-mdb.c b/drivers/pci/controller/dwc/pcie-amd-mdb.c
index 4eb2a4e8189d..4eea53e9e197 100644
--- a/drivers/pci/controller/dwc/pcie-amd-mdb.c
+++ b/drivers/pci/controller/dwc/pcie-amd-mdb.c
@@ -18,6 +18,7 @@
#include <linux/resource.h>
#include <linux/types.h>
+#include "../../pci.h"
#include "pcie-designware.h"
#define AMD_MDB_TLP_IR_STATUS_MISC 0x4C0
@@ -408,6 +409,7 @@ static int amd_mdb_add_pcie_port(struct amd_mdb_pcie *pcie,
struct dw_pcie *pci = &pcie->pci;
struct dw_pcie_rp *pp = &pci->pp;
struct device *dev = &pdev->dev;
+ struct gpio_desc *reset_gpio;
int err;
pcie->slcr = devm_platform_ioremap_resource_byname(pdev, "slcr");
@@ -426,6 +428,24 @@ static int amd_mdb_add_pcie_port(struct amd_mdb_pcie *pcie,
pp->ops = &amd_mdb_pcie_host_ops;
+ /* Request the GPIO for PCIe reset signal and assert */
+ reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(reset_gpio)) {
+ if (PTR_ERR(reset_gpio) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ dev_err(dev, "Failed to request reset GPIO\n");
+ return PTR_ERR(reset_gpio);
+ }
+
+ if (reset_gpio) {
+ /* Controller specific delay */
+ udelay(50);
+
+ /* Deassert the reset signal */
+ gpiod_set_value_cansleep(reset_gpio, 0);
+ mdelay(PCIE_T_RRS_READY_MS);
+ }
+
err = dw_pcie_host_init(pp);
if (err) {
dev_err(dev, "Failed to initialize host, err=%d\n", err);
--
2.31.1
