[PATCH 25/30] PCI: tegra: Put PEX CLK & BIAS pads in DPD mode

[Manikanta Maddireddy <mmaddireddy@nvidia.com>]

In Tegra210 AFI design has clamp value for the BIAS pad as 0, which keeps
the bias pad in non power down mode. This is leading to power consumption
of 2 mW in BIAS pad, even if the PCIe partition is power gated. To avoid
unnecessary power consumption, put PEX CLK & BIAS pads in deep power down
mode when PCIe partition is power gated.

Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
---
 drivers/pci/controller/pci-tegra.c | 65 +++++++++++++++++++++++++++++-
 1 file changed, 64 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
index c050687020f0..92c6daa0de84 100644
--- a/drivers/pci/controller/pci-tegra.c
+++ b/drivers/pci/controller/pci-tegra.c
@@ -30,6 +30,7 @@
 #include <linux/of_platform.h>
 #include <linux/pci.h>
 #include <linux/phy/phy.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/reset.h>
 #include <linux/sizes.h>
@@ -323,6 +324,7 @@ struct tegra_pcie_soc {
 	bool program_deskew_time;
 	bool raw_violation_fixup;
 	bool update_fc_threshold;
+	bool config_pex_io_dpd;
 	struct {
 		struct {
 			u32 rp_ectl_2_r1;
@@ -385,6 +387,10 @@ struct tegra_pcie {
 
 	const struct tegra_pcie_soc *soc;
 	struct dentry *debugfs;
+
+	struct pinctrl *pex_pinctrl;
+	struct pinctrl_state *pex_dpd_enable;
+	struct pinctrl_state *pex_dpd_disable;
 };
 
 struct tegra_pcie_port {
@@ -2154,6 +2160,37 @@ static int tegra_pcie_get_regulators(struct tegra_pcie *pcie, u32 lane_mask)
 	return tegra_pcie_get_legacy_regulators(pcie);
 }
 
+static int tegra_pcie_parse_pinctrl(struct tegra_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+	int err = 0;
+
+	pcie->pex_pinctrl = devm_pinctrl_get(dev);
+	if (IS_ERR(pcie->pex_pinctrl)) {
+		err = PTR_ERR(pcie->pex_pinctrl);
+		dev_err(dev, "failed to get pinctrl handle: %d\n", err);
+		return err;
+	}
+
+	pcie->pex_dpd_enable = pinctrl_lookup_state(pcie->pex_pinctrl,
+						    "pex-dpd-enable");
+	if (IS_ERR(pcie->pex_dpd_enable)) {
+		err = PTR_ERR(pcie->pex_dpd_enable);
+		dev_err(dev, "missing pex-dpd-enable state: %d\n", err);
+		return err;
+	}
+
+	pcie->pex_dpd_disable = pinctrl_lookup_state(pcie->pex_pinctrl,
+						     "pex-dpd-disable");
+	if (IS_ERR(pcie->pex_dpd_disable)) {
+		err = PTR_ERR(pcie->pex_dpd_disable);
+		dev_err(dev, "missing pex-dpd-disable state: %d\n", err);
+		return err;
+	}
+
+	return err;
+}
+
 static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
 {
 	struct device *dev = pcie->dev;
@@ -2496,6 +2533,7 @@ static const struct tegra_pcie_soc tegra20_pcie = {
 	.program_deskew_time = false,
 	.raw_violation_fixup = false,
 	.update_fc_threshold = false,
+	.config_pex_io_dpd = false,
 	.ectl.enable = false,
 };
 
@@ -2524,6 +2562,7 @@ static const struct tegra_pcie_soc tegra30_pcie = {
 	.program_deskew_time = false,
 	.raw_violation_fixup = false,
 	.update_fc_threshold = false,
+	.config_pex_io_dpd = false,
 	.ectl.enable = false,
 };
 
@@ -2547,6 +2586,7 @@ static const struct tegra_pcie_soc tegra124_pcie = {
 	.program_deskew_time = false,
 	.raw_violation_fixup = true,
 	.update_fc_threshold = false,
+	.config_pex_io_dpd = false,
 	.ectl.enable = false,
 };
 
@@ -2570,6 +2610,7 @@ static const struct tegra_pcie_soc tegra210_pcie = {
 	.program_deskew_time = true,
 	.raw_violation_fixup = false,
 	.update_fc_threshold = true,
+	.config_pex_io_dpd = true,
 	.ectl.regs.rp_ectl_2_r1 = 0x0000000f,
 	.ectl.regs.rp_ectl_4_r1 = 0x00000067,
 	.ectl.regs.rp_ectl_5_r1 = 0x55010000,
@@ -2607,6 +2648,7 @@ static const struct tegra_pcie_soc tegra186_pcie = {
 	.program_deskew_time = false,
 	.raw_violation_fixup = false,
 	.update_fc_threshold = false,
+	.config_pex_io_dpd = false,
 	.ectl.enable = false,
 };
 
@@ -2753,6 +2795,12 @@ static int tegra_pcie_probe(struct platform_device *pdev)
 	INIT_LIST_HEAD(&pcie->ports);
 	pcie->dev = dev;
 
+	if (pcie->soc->config_pex_io_dpd) {
+		err = tegra_pcie_parse_pinctrl(pcie);
+		if (err < 0)
+			return err;
+	}
+
 	err = tegra_pcie_parse_dt(pcie);
 	if (err < 0)
 		return err;
@@ -2866,6 +2914,8 @@ static int __maybe_unused tegra_pcie_pm_suspend(struct device *dev)
 		tegra_pcie_disable_msi(pcie);
 
 	tegra_pcie_disable_controller(pcie);
+	if (pcie->soc->config_pex_io_dpd)
+		pinctrl_select_state(pcie->pex_pinctrl, pcie->pex_dpd_enable);
 	tegra_pcie_power_off(pcie);
 
 	return 0;
@@ -2881,10 +2931,20 @@ static int __maybe_unused tegra_pcie_pm_resume(struct device *dev)
 		dev_err(dev, "tegra pcie power on fail: %d\n", err);
 		return err;
 	}
+
+	if (pcie->soc->config_pex_io_dpd) {
+		err = pinctrl_select_state(pcie->pex_pinctrl,
+					   pcie->pex_dpd_disable);
+		if (err < 0) {
+			dev_err(dev, "disabling PCIe IO DPD failed: %d\n", err);
+			goto poweroff;
+		}
+	}
+
 	err = tegra_pcie_enable_controller(pcie);
 	if (err) {
 		dev_err(dev, "tegra pcie controller enable fail: %d\n", err);
-		goto poweroff;
+		goto pex_dpd_enable;
 	}
 	tegra_pcie_setup_translations(pcie);
 
@@ -2904,6 +2964,9 @@ static int __maybe_unused tegra_pcie_pm_resume(struct device *dev)
 
 disable_controller:
 	tegra_pcie_disable_controller(pcie);
+pex_dpd_enable:
+	if (pcie->soc->config_pex_io_dpd)
+		pinctrl_select_state(pcie->pex_pinctrl, pcie->pex_dpd_enable);
 poweroff:
 	tegra_pcie_power_off(pcie);
 
-- 
2.17.1