On Tue, Mar 25, 2025 at 08:18:27AM +0100, Mike Looijmans wrote:
> Support providing the PERST# reset signal through a devicetree binding.
> Thus the system no longer relies on external components to perform the
> bus reset.
>
> Signed-off-by: Mike Looijmans <mike.looijmans@xxxxxxxx>
> ---
>
> Changes in v2:
> Split into "reset GPIO" and "wait for link" patches
> Handle GPIO defer and/or errors
>
> drivers/pci/controller/pcie-xilinx.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/pci/controller/pcie-xilinx.c b/drivers/pci/controller/pcie-xilinx.c
> index 2e59b91f43e0..e191ab95d669 100644
> --- a/drivers/pci/controller/pcie-xilinx.c
> +++ b/drivers/pci/controller/pcie-xilinx.c
> @@ -18,6 +18,7 @@
> #include <linux/iopoll.h>
> #include <linux/msi.h>
> #include <linux/of_address.h>
> +#include <linux/of_gpio.h>
Correct header is:
#include <linux/gpio/consumer.h>
> #include <linux/of_pci.h>
> #include <linux/of_platform.h>
> #include <linux/of_irq.h>
> @@ -577,11 +578,17 @@ static int xilinx_pcie_probe(struct platform_device *pdev)
> struct device *dev = &pdev->dev;
> struct xilinx_pcie *pcie;
> struct pci_host_bridge *bridge;
> + struct gpio_desc *perst_gpio;
> int err;
>
> if (!dev->of_node)
> return -ENODEV;
>
> + perst_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> + if (IS_ERR(perst_gpio))
> + return dev_err_probe(dev, PTR_ERR(perst_gpio),
> + "reset-gpios request failed\n");
'Failed to request reset GPIO'
> +
> bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
> if (!bridge)
> return -ENODEV;
> @@ -596,6 +603,13 @@ static int xilinx_pcie_probe(struct platform_device *pdev)
> return err;
> }
>
> + if (perst_gpio) {
> + usleep_range(10, 20); /* Assert the reset for ~10 us */
Delay should be PCIE_T_PVPERL_MS.
> + gpiod_set_value_cansleep(perst_gpio, 0);
> + /* Initial delay to provide endpoint time to restart */
s/restart/initialize
- Mani
--
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