From ca05b38252d7bf6b0d42e80b3d3d98a642f4143b Mon Sep 17 00:00:00 2001 From: Piyush Mehta Date: Wed, 4 May 2022 13:23:09 +0530 Subject: [PATCH] usb: dwc3: xilinx: Add gpio-reset support This patch adds a USB GPIO based reset for dwc3-xilinx driver. The PHY needs to be reset after the completion of phy initialization. As part of the reset, check for gpio-reset binding before toggling the pin. This feature is advantageous when the user toggle GPIO to trigger the ULPI-PHY reset. Delay of milliseconds is added in between low and high to meet the setup and hold time requirement of the reset. The reset-gpio error handling is added for error notification. Some GPIO controllers must be accessed using message-based buses, like I2C or SPI, to address this problem, updates GPIO access with sleep API. This reset is specific to the zynqMp. Signed-off-by: Piyush Mehta Link: https://lore.kernel.org/r/20220504075309.6244-3-piyush.mehta@xilinx.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/dwc3/dwc3-xilinx.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/usb/dwc3/dwc3-xilinx.c b/drivers/usb/dwc3/dwc3-xilinx.c index a6f3a9b..67b237c 100644 --- a/drivers/usb/dwc3/dwc3-xilinx.c +++ b/drivers/usb/dwc3/dwc3-xilinx.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -98,6 +99,7 @@ static int dwc3_xlnx_init_zynqmp(struct dwc3_xlnx *priv_data) { struct device *dev = priv_data->dev; struct reset_control *crst, *hibrst, *apbrst; + struct gpio_desc *reset_gpio; struct phy *usb3_phy; int ret = 0; u32 reg; @@ -201,6 +203,21 @@ static int dwc3_xlnx_init_zynqmp(struct dwc3_xlnx *priv_data) } skip_usb3_phy: + /* ulpi reset via gpio-modepin or gpio-framework driver */ + reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW); + if (IS_ERR(reset_gpio)) { + return dev_err_probe(dev, PTR_ERR(reset_gpio), + "Failed to request reset GPIO\n"); + } + + if (reset_gpio) { + /* Toggle ulpi to reset the phy. */ + gpiod_set_value_cansleep(reset_gpio, 1); + usleep_range(5000, 10000); + gpiod_set_value_cansleep(reset_gpio, 0); + usleep_range(5000, 10000); + } + /* * This routes the USB DMA traffic to go through FPD path instead * of reaching DDR directly. This traffic routing is needed to -- 2.7.4