Re: [PATCH V2 4/6] PCI: tegra: Add support to enable slot regulators
From: Thierry Reding <hidden>
Date: 2019-08-28 16:24:28
Also in:
linux-devicetree, linux-pci, linux-tegra, lkml
On Wed, Aug 28, 2019 at 06:45:03PM +0530, Vidya Sagar wrote:
quoted hunk ↗ jump to hunk
Add support to get regulator information of 3.3V and 12V supplies of a PCIe slot from the respective controller's device-tree node and enable those supplies. This is required in platforms like p2972-0000 where the supplies to x16 slot owned by C5 controller need to be enabled before attempting to enumerate the devices. Signed-off-by: Vidya Sagar <redacted> --- V2: * Addressed review comments from Thierry Reding and Andrew Murray * Handled failure case of devm_regulator_get_optional() for -ENODEV cleanly drivers/pci/controller/dwc/pcie-tegra194.c | 80 ++++++++++++++++++++++ 1 file changed, 80 insertions(+)diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c index 057ba4f9fbcd..6a66101ec83d 100644 --- a/drivers/pci/controller/dwc/pcie-tegra194.c +++ b/drivers/pci/controller/dwc/pcie-tegra194.c@@ -278,6 +278,8 @@ struct tegra_pcie_dw { u32 aspm_l0s_enter_lat; struct regulator *pex_ctl_supply; + struct regulator *slot_ctl_3v3; + struct regulator *slot_ctl_12v; unsigned int phy_count; struct phy **phys;@@ -1047,6 +1049,72 @@ static void tegra_pcie_downstream_dev_to_D0(struct tegra_pcie_dw *pcie) } } +static int tegra_pcie_get_slot_regulators(struct tegra_pcie_dw *pcie) +{ + pcie->slot_ctl_3v3 = devm_regulator_get_optional(pcie->dev, "vpcie3v3"); + if (IS_ERR(pcie->slot_ctl_3v3)) { + if (PTR_ERR(pcie->slot_ctl_3v3) != -ENODEV) + return PTR_ERR(pcie->slot_ctl_3v3); + + pcie->slot_ctl_3v3 = NULL; + } + + pcie->slot_ctl_12v = devm_regulator_get_optional(pcie->dev, "vpcie12v"); + if (IS_ERR(pcie->slot_ctl_12v)) { + if (PTR_ERR(pcie->slot_ctl_12v) != -ENODEV) + return PTR_ERR(pcie->slot_ctl_12v); + + pcie->slot_ctl_12v = NULL; + } + + return 0; +} + +static int tegra_pcie_enable_slot_regulators(struct tegra_pcie_dw *pcie) +{ + int ret; + + if (pcie->slot_ctl_3v3) { + ret = regulator_enable(pcie->slot_ctl_3v3); + if (ret < 0) { + dev_err(pcie->dev, + "Failed to enable 3V3 slot supply: %d\n", ret);
Nit: perhaps make this error message "Failed to enable 3.3V slot supply"? Seems somewhat more user-friendly than 3V3.
+ return ret;
+ }
+ }
+
+ if (pcie->slot_ctl_12v) {
+ ret = regulator_enable(pcie->slot_ctl_12v);
+ if (ret < 0) {
+ dev_err(pcie->dev,
+ "Failed to enable 12V slot supply: %d\n", ret);
+ goto fail_12v_enable;
+ }
+ }
+
+ /*
+ * According to PCI Express Card Electromechanical Specification
+ * Revision 1.1, Table-2.4, T_PVPERL (Power stable to PERST# inactive)
+ * should be a minimum of 100ms.
+ */
+ msleep(100);Do you perhaps want to guard this with something like: if (pcie->slot_ctl_3v3 || pcie->slot_ctl_12v) ? Doesn't seem useful to me to sleep 100 ms here if there are no regulators being enabled to begin with. Thierry
quoted hunk ↗ jump to hunk
+ + return 0; + +fail_12v_enable: + if (pcie->slot_ctl_3v3) + regulator_disable(pcie->slot_ctl_3v3); + return ret; +} + +static void tegra_pcie_disable_slot_regulators(struct tegra_pcie_dw *pcie) +{ + if (pcie->slot_ctl_12v) + regulator_disable(pcie->slot_ctl_12v); + if (pcie->slot_ctl_3v3) + regulator_disable(pcie->slot_ctl_3v3); +} + static int tegra_pcie_config_controller(struct tegra_pcie_dw *pcie, bool en_hw_hot_rst) {@@ -1060,6 +1128,10 @@ static int tegra_pcie_config_controller(struct tegra_pcie_dw *pcie, return ret; } + ret = tegra_pcie_enable_slot_regulators(pcie); + if (ret < 0) + goto fail_slot_reg_en; + ret = regulator_enable(pcie->pex_ctl_supply); if (ret < 0) { dev_err(pcie->dev, "Failed to enable regulator: %d\n", ret);@@ -1142,6 +1214,8 @@ static int tegra_pcie_config_controller(struct tegra_pcie_dw *pcie, fail_core_clk: regulator_disable(pcie->pex_ctl_supply); fail_reg_en: + tegra_pcie_disable_slot_regulators(pcie); +fail_slot_reg_en: tegra_pcie_bpmp_set_ctrl_state(pcie, false); return ret;@@ -1174,6 +1248,8 @@ static int __deinit_controller(struct tegra_pcie_dw *pcie) return ret; } + tegra_pcie_disable_slot_regulators(pcie); + ret = tegra_pcie_bpmp_set_ctrl_state(pcie, false); if (ret) { dev_err(pcie->dev, "Failed to disable controller %d: %d\n",@@ -1373,6 +1449,10 @@ static int tegra_pcie_dw_probe(struct platform_device *pdev) return ret; } + ret = tegra_pcie_get_slot_regulators(pcie); + if (ret < 0) + return ret; + pcie->pex_ctl_supply = devm_regulator_get(dev, "vddio-pex-ctl"); if (IS_ERR(pcie->pex_ctl_supply)) { dev_err(dev, "Failed to get regulator: %ld\n",-- 2.17.1