[PATCH v4 2/2] PCI: tegra: Support per-lane PHYs

[Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

From: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

The current XUSB pad controller bindings are insufficient to describe
PHY devices attached to USB controllers. New bindings have been created
to overcome these restrictions. As a side-effect each root port now is
assigned a set of PHY devices, one for each lane associated with the
root port. This has the benefit of allowing fine-grained control of the
power management for each lane.

Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
Changes in v4:
- propagate failure from PHY power on
- refactor PHY power off sequence

Changes in v3:
- cache result of check for new PHY bindings usage (Stephen Warren)

Changes in v2:
- rework commit message to more accurately describe this change

 drivers/pci/host/pci-tegra.c | 243 ++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 226 insertions(+), 17 deletions(-)

diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index 68d1f41b3cbf..d50568bf93c5 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -295,6 +295,7 @@ struct tegra_pcie {
 	struct reset_control *afi_rst;
 	struct reset_control *pcie_xrst;
 
+	bool legacy_phy;
 	struct phy *phy;
 
 	struct tegra_msi msi;
@@ -311,11 +312,14 @@ struct tegra_pcie {
 
 struct tegra_pcie_port {
 	struct tegra_pcie *pcie;
+	struct device_node *np;
 	struct list_head list;
 	struct resource regs;
 	void __iomem *base;
 	unsigned int index;
 	unsigned int lanes;
+
+	struct phy **phys;
 };
 
 struct tegra_pcie_bus {
@@ -860,6 +864,128 @@ static int tegra_pcie_phy_enable(struct tegra_pcie *pcie)
 	return 0;
 }
 
+static int tegra_pcie_phy_disable(struct tegra_pcie *pcie)
+{
+	const struct tegra_pcie_soc_data *soc = pcie->soc_data;
+	u32 value;
+
+	/* disable TX/RX data */
+	value = pads_readl(pcie, PADS_CTL);
+	value &= ~(PADS_CTL_TX_DATA_EN_1L | PADS_CTL_RX_DATA_EN_1L);
+	pads_writel(pcie, value, PADS_CTL);
+
+	/* override IDDQ */
+	value = pads_readl(pcie, PADS_CTL);
+	value |= PADS_CTL_IDDQ_1L;
+	pads_writel(pcie, PADS_CTL, value);
+
+	/* reset PLL */
+	value = pads_readl(pcie, soc->pads_pll_ctl);
+	value &= ~PADS_PLL_CTL_RST_B4SM;
+	pads_writel(pcie, value, soc->pads_pll_ctl);
+
+	usleep_range(20, 100);
+
+	return 0;
+}
+
+static int tegra_pcie_port_phy_power_on(struct tegra_pcie_port *port)
+{
+	struct device *dev = port->pcie->dev;
+	unsigned int i;
+	int err;
+
+	for (i = 0; i < port->lanes; i++) {
+		err = phy_power_on(port->phys[i]);
+		if (err < 0) {
+			dev_err(dev, "failed to power on PHY#%u: %d\n", i,
+				err);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static int tegra_pcie_port_phy_power_off(struct tegra_pcie_port *port)
+{
+	struct device *dev = port->pcie->dev;
+	unsigned int i;
+	int err;
+
+	for (i = 0; i < port->lanes; i++) {
+		err = phy_power_off(port->phys[i]);
+		if (err < 0) {
+			dev_err(dev, "failed to power off PHY#%u: %d\n", i,
+				err);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static int tegra_pcie_phy_power_on(struct tegra_pcie *pcie)
+{
+	struct tegra_pcie_port *port;
+	int err;
+
+	if (pcie->legacy_phy) {
+		if (pcie->phy)
+			err = phy_power_on(pcie->phy);
+		else
+			err = tegra_pcie_phy_enable(pcie);
+
+		if (err < 0)
+			dev_err(pcie->dev, "failed to power on PHY: %d\n", err);
+
+		return err;
+	}
+
+	list_for_each_entry(port, &pcie->ports, list) {
+		err = tegra_pcie_port_phy_power_on(port);
+		if (err < 0) {
+			dev_err(pcie->dev,
+				"failed to power on PCIe port %u PHY: %d\n",
+				port->index, err);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static int tegra_pcie_phy_power_off(struct tegra_pcie *pcie)
+{
+	struct tegra_pcie_port *port;
+	int err;
+
+	if (pcie->legacy_phy) {
+		if (pcie->phy)
+			err = phy_power_on(pcie->phy);
+		else
+			err = tegra_pcie_phy_disable(pcie);
+
+		if (err < 0)
+			dev_err(pcie->dev, "failed to power off PHY: %d\n",
+				err);
+
+		return err;
+	}
+
+	list_for_each_entry(port, &pcie->ports, list) {
+		err = tegra_pcie_port_phy_power_off(port);
+		if (err < 0) {
+			dev_err(pcie->dev,
+				"failed to power off PCIe port %u PHY: %d\n",
+				port->index, err);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
 static int tegra_pcie_enable_controller(struct tegra_pcie *pcie)
 {
 	const struct tegra_pcie_soc_data *soc = pcie->soc_data;
@@ -899,13 +1025,9 @@ static int tegra_pcie_enable_controller(struct tegra_pcie *pcie)
 		afi_writel(pcie, value, AFI_FUSE);
 	}
 
-	if (!pcie->phy)
-		err = tegra_pcie_phy_enable(pcie);
-	else
-		err = phy_power_on(pcie->phy);
-
+	err = tegra_pcie_phy_power_on(pcie);
 	if (err < 0) {
-		dev_err(pcie->dev, "failed to power on PHY: %d\n", err);
+		dev_err(pcie->dev, "failed to power off PHY(s): %d\n", err);
 		return err;
 	}
 
@@ -942,9 +1064,9 @@ static void tegra_pcie_power_off(struct tegra_pcie *pcie)
 
 	/* TODO: disable and unprepare clocks? */
 
-	err = phy_power_off(pcie->phy);
+	err = tegra_pcie_phy_power_off(pcie);
 	if (err < 0)
-		dev_warn(pcie->dev, "failed to power off PHY: %d\n", err);
+		dev_err(pcie->dev, "failed to power off PHY(s): %d\n", err);
 
 	reset_control_assert(pcie->pcie_xrst);
 	reset_control_assert(pcie->afi_rst);
@@ -1049,6 +1171,99 @@ static int tegra_pcie_resets_get(struct tegra_pcie *pcie)
 	return 0;
 }
 
+static int tegra_pcie_phys_get_legacy(struct tegra_pcie *pcie)
+{
+	int err;
+
+	pcie->phy = devm_phy_optional_get(pcie->dev, "pcie");
+	if (IS_ERR(pcie->phy)) {
+		err = PTR_ERR(pcie->phy);
+		dev_err(pcie->dev, "failed to get PHY: %d\n", err);
+		return err;
+	}
+
+	err = phy_init(pcie->phy);
+	if (err < 0) {
+		dev_err(pcie->dev, "failed to initialize PHY: %d\n", err);
+		return err;
+	}
+
+	pcie->legacy_phy = true;
+
+	return 0;
+}
+
+static struct phy *devm_of_phy_optional_get_index(struct device *dev,
+						  struct device_node *np,
+						  const char *consumer,
+						  unsigned int index)
+{
+	struct phy *phy;
+	char *name;
+
+	name = kasprintf(GFP_KERNEL, "%s-%u", consumer, index);
+	if (!name)
+		return ERR_PTR(-ENOMEM);
+
+	phy = devm_of_phy_get(dev, np, name);
+	kfree(name);
+
+	if (IS_ERR(phy) && PTR_ERR(phy) == -ENODEV)
+		phy = NULL;
+
+	return phy;
+}
+
+static int tegra_pcie_port_get_phys(struct tegra_pcie_port *port)
+{
+	struct device *dev = port->pcie->dev;
+	struct phy *phy;
+	unsigned int i;
+	int err;
+
+	port->phys = devm_kcalloc(dev, sizeof(phy), port->lanes, GFP_KERNEL);
+	if (!port->phys)
+		return -ENOMEM;
+
+	for (i = 0; i < port->lanes; i++) {
+		phy = devm_of_phy_optional_get_index(dev, port->np, "pcie", i);
+		if (IS_ERR(phy)) {
+			dev_err(dev, "failed to get PHY#%u: %ld\n", i,
+				PTR_ERR(phy));
+			return PTR_ERR(phy);
+		}
+
+		err = phy_init(phy);
+		if (err < 0) {
+			dev_err(dev, "failed to initialize PHY#%u: %d\n", i,
+				err);
+			return err;
+		}
+
+		port->phys[i] = phy;
+	}
+
+	return 0;
+}
+
+static int tegra_pcie_phys_get(struct tegra_pcie *pcie)
+{
+	struct tegra_pcie_port *port;
+	int err;
+
+	if (of_get_property(pcie->dev->of_node, "phys", NULL) != NULL)
+		return tegra_pcie_phys_get_legacy(pcie);
+
+	list_for_each_entry(port, &pcie->ports, list) {
+		err = tegra_pcie_port_get_phys(port);
+		if (err < 0) {
+			return err;
+		}
+	}
+
+	return 0;
+}
+
 static int tegra_pcie_get_resources(struct tegra_pcie *pcie)
 {
 	struct platform_device *pdev = to_platform_device(pcie->dev);
@@ -1067,16 +1282,9 @@ static int tegra_pcie_get_resources(struct tegra_pcie *pcie)
 		return err;
 	}
 
-	pcie->phy = devm_phy_optional_get(pcie->dev, "pcie");
-	if (IS_ERR(pcie->phy)) {
-		err = PTR_ERR(pcie->phy);
-		dev_err(&pdev->dev, "failed to get PHY: %d\n", err);
-		return err;
-	}
-
-	err = phy_init(pcie->phy);
+	err = tegra_pcie_phys_get(pcie);
 	if (err < 0) {
-		dev_err(&pdev->dev, "failed to initialize PHY: %d\n", err);
+		dev_err(&pdev->dev, "failed to get PHYs: %d\n", err);
 		return err;
 	}
 
@@ -1752,6 +1960,7 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
 		rp->index = index;
 		rp->lanes = value;
 		rp->pcie = pcie;
+		rp->np = port;
 
 		rp->base = devm_ioremap_resource(pcie->dev, &rp->regs);
 		if (IS_ERR(rp->base))
-- 
2.8.0