[PATCH v4 7/7] PCI: mediatek-gen3: Integrate new pwrctrl API

[Chen-Yu Tsai <wenst@chromium.org>]

With the new PCI pwrctrl API and PCI slot binding and power drivers, we
now have a way to describe and power up WiFi/BT adapters connected
through a PCIe or M.2 slot, or exploded onto the mainboard itself.

Integrate the PCI pwrctrl API into the PCIe driver, so that power is
properly enabled before PCIe link training is done, allowing the
card to successfully be detected.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
Changes since v3:
- Adapted changes to movement of existing setup code

Changes since v2:
- Added "select PCI_PWRCTRL_SLOT" to Kconfig to fix kernel test robot
  compilation error

I'm wondering why the two existing uses select PCI_PWRCTRL_SLOT and not
PCI_PWRCTRL though.
---
 drivers/pci/controller/Kconfig              |  1 +
 drivers/pci/controller/pcie-mediatek-gen3.c | 38 ++++++++++++++++-----
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index 5aaed8ac6e44..e72ac6934379 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -222,6 +222,7 @@ config PCIE_MEDIATEK_GEN3
 	depends on ARCH_AIROHA || ARCH_MEDIATEK || COMPILE_TEST
 	depends on PCI_MSI
 	select IRQ_MSI_LIB
+	select PCI_PWRCTRL_SLOT
 	help
 	  Adds support for PCIe Gen3 MAC controller for MediaTek SoCs.
 	  This PCIe controller is compatible with Gen3, Gen2 and Gen1 speed,
diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
index f1a70b92cc9f..3800d0d730f2 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -22,6 +22,7 @@
 #include <linux/of_device.h>
 #include <linux/of_pci.h>
 #include <linux/pci.h>
+#include <linux/pci-pwrctrl.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/pm_domain.h>
@@ -421,15 +422,23 @@ static int mtk_pcie_device_power_up(struct mtk_gen3_pcie *pcie)
 		val |= PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB |
 		       PCIE_PE_RSTB;
 		writel_relaxed(val, pcie->base + PCIE_RST_CTRL_REG);
+	}
 
-		/*
-		 * Described in PCIe CEM specification revision 6.0.
-		 *
-		 * The deassertion of PERST# should be delayed 100ms (TPVPERL)
-		 * for the power and clock to become stable.
-		 */
-		msleep(PCIE_T_PVPERL_MS);
+	err = pci_pwrctrl_power_on_devices(pcie->dev);
+	if (err) {
+		dev_err(pcie->dev, "Failed to power on devices: %pe\n", ERR_PTR(err));
+		return err;
+	}
 
+	/*
+	 * Described in PCIe CEM specification revision 6.0.
+	 *
+	 * The deassertion of PERST# should be delayed 100ms (TPVPERL)
+	 * for the power and clock to become stable.
+	 */
+	msleep(PCIE_T_PVPERL_MS);
+
+	if (!(pcie->soc->flags & SKIP_PCIE_RSTB)) {
 		/* De-assert reset signals */
 		val &= ~(PCIE_MAC_RSTB | PCIE_PHY_RSTB | PCIE_BRG_RSTB |
 			 PCIE_PE_RSTB);
@@ -449,6 +458,8 @@ static void mtk_pcie_device_power_down(struct mtk_gen3_pcie *pcie)
 		val |= PCIE_PE_RSTB;
 		writel_relaxed(val, pcie->base + PCIE_RST_CTRL_REG);
 	}
+
+	pci_pwrctrl_power_off_devices(pcie->dev);
 }
 
 static int mtk_pcie_startup_port(struct mtk_gen3_pcie *pcie)
@@ -1209,9 +1220,15 @@ static int mtk_pcie_probe(struct platform_device *pdev)
 	if (err)
 		return dev_err_probe(dev, err, "Failed to setup IRQ domains\n");
 
+	err = pci_pwrctrl_create_devices(pcie->dev);
+	if (err) {
+		goto err_teardown_irq;
+		dev_err_probe(dev, err, "failed to create pwrctrl devices\n");
+	}
+
 	err = mtk_pcie_setup(pcie);
 	if (err)
-		goto err_tear_down_irq;
+		goto err_destroy_pwrctrl;
 
 	host->ops = &mtk_pcie_ops;
 	host->sysdata = pcie;
@@ -1225,6 +1242,9 @@ static int mtk_pcie_probe(struct platform_device *pdev)
 err_power_down_pcie:
 	mtk_pcie_device_power_down(pcie);
 	mtk_pcie_power_down(pcie);
+err_destroy_pwrctrl:
+	if (err != -EPROBE_DEFER)
+		pci_pwrctrl_destroy_devices(pcie->dev);
 err_tear_down_irq:
 	mtk_pcie_irq_teardown(pcie);
 	return err;
@@ -1240,7 +1260,9 @@ static void mtk_pcie_remove(struct platform_device *pdev)
 	pci_remove_root_bus(host->bus);
 	pci_unlock_rescan_remove();
 
+	pci_pwrctrl_power_off_devices(pcie->dev);
 	mtk_pcie_power_down(pcie);
+	pci_pwrctrl_destroy_devices(pcie->dev);
 	mtk_pcie_irq_teardown(pcie);
 }
 
-- 
2.53.0.473.g4a7958ca14-goog