PCI: aardvark: Assert PERST# when unbinding driver

Put the PCIe card into reset by asserting PERST# signal when unbinding
driver. It doesn't make sense to leave the card working if it can't
communicate with the host. This should also save some power.

Link: https://lore.kernel.org/r/20211130172913.9727-10-kabel@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index b3d89cb..271ebec 100644 (file)
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -1737,6 +1737,10 @@ static int advk_pcie_remove(struct platform_device *pdev)
        /* Free config space for emulated root bridge */
        pci_bridge_emul_cleanup(&pcie->bridge);
 
+       /* Assert PERST# signal which prepares PCIe card for power down */
+       if (pcie->reset_gpio)
+               gpiod_set_value_cansleep(pcie->reset_gpio, 1);
+
        /* Disable outbound address windows mapping */
        for (i = 0; i < OB_WIN_COUNT; i++)
                advk_pcie_disable_ob_win(pcie, i);