bus: mhi: pci_generic: Implement PCI shutdown callback

Deinit the device on shutdown to halt MHI/PCI operation on device
side. This change fixes floating device state with some hosts that
do not fully shutdown PCIe device when rebooting.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1616169037-7969-1-git-send-email-loic.poulain@linaro.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

drivers/bus/mhi/pci_generic.c

@@ -641,6 +641,12 @@ static void mhi_pci_remove(struct pci_dev *pdev)
 	mhi_unregister_controller(mhi_cntrl);
 }
 
+static void mhi_pci_shutdown(struct pci_dev *pdev)
+{
+	mhi_pci_remove(pdev);
+	pci_set_power_state(pdev, PCI_D3hot);
+}
+
 static void mhi_pci_reset_prepare(struct pci_dev *pdev)
 {
 	struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev);
@@ -857,6 +863,7 @@ static struct pci_driver mhi_pci_driver = {
 	.id_table	= mhi_pci_id_table,
 	.probe		= mhi_pci_probe,
 	.remove		= mhi_pci_remove,
+	.shutdown	= mhi_pci_shutdown,
 	.err_handler	= &mhi_pci_err_handler,
 	.driver.pm	= &mhi_pci_pm_ops
 };