linux-kernel - [PATCH v1 2/6] PCI: brcmstb: Add control of EP voltage regulator(s)

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Message-Id: <20201125192424.14440-3-james.quinlan@broadcom.com>
Date:   Wed, 25 Nov 2020 14:24:19 -0500
From:   Jim Quinlan <james.quinlan@...adcom.com>
To:     linux-pci@...r.kernel.org,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        bcm-kernel-feedback-list@...adcom.com, james.quinlan@...adcom.com
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        linux-rpi-kernel@...ts.infradead.org (moderated list:BROADCOM
        BCM2711/BCM2835 ARM ARCHITECTURE),
        linux-arm-kernel@...ts.infradead.org (moderated list:BROADCOM
        BCM2711/BCM2835 ARM ARCHITECTURE),
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v1 2/6] PCI: brcmstb: Add control of EP voltage regulator(s)

Control of EP regulators by the RC is needed because of the chicken-and-egg
situation: although the regulator is "owned" by the EP and would be best
handled on its driver, the EP cannot be discovered and probed unless its
regulator is already turned on.

Signed-off-by: Jim Quinlan <james.quinlan@...adcom.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 66 +++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index bea86899bd5d..34d6bad07b66 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -23,6 +23,7 @@
 #include <linux/of_platform.h>
 #include <linux/pci.h>
 #include <linux/printk.h>
+#include <linux/regulator/consumer.h>
 #include <linux/reset.h>
 #include <linux/sizes.h>
 #include <linux/slab.h>
@@ -210,6 +211,18 @@ enum pcie_type {
 	BCM2711,
 };
 
+enum pcie_regulators {
+	VPCIE12V,
+	VPCIE3V3,
+	VPCIE1V8,
+	VPCIE0V9,
+	PCIE_REGULATORS_MAX,
+};
+
+static const char *ep_regulator_names[PCIE_REGULATORS_MAX] = {
+	"vpcie12v", "vpcie3v3", "vpcie1v8", "vpcie0v9",
+};
+
 struct pcie_cfg_data {
 	const int *offsets;
 	const enum pcie_type type;
@@ -287,8 +300,53 @@ struct brcm_pcie {
 	u32			hw_rev;
 	void			(*perst_set)(struct brcm_pcie *pcie, u32 val);
 	void			(*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
+	struct regulator	*regulators[PCIE_REGULATORS_MAX];
+	int			num_regulators;
 };
 
+static int brcm_parse_regulators(struct brcm_pcie *pcie)
+{
+	struct device *dev = pcie->dev;
+	struct regulator *ep_reg;
+	int i;
+
+	for (i = 0; i < PCIE_REGULATORS_MAX; i++) {
+		ep_reg = devm_regulator_get_optional(dev, ep_regulator_names[i]);
+		if (IS_ERR(ep_reg)) {
+			if (PTR_ERR(ep_reg) == -ENODEV)
+				continue;
+			dev_err(dev, "failed to get regulator %s\n", ep_regulator_names[i]);
+			return PTR_ERR(ep_reg);
+		}
+		pcie->regulators[i] = ep_reg;
+		pcie->num_regulators++;
+	}
+	return 0;
+}
+
+static void brcm_set_regulators(struct brcm_pcie *pcie, bool on)
+{
+	struct device *dev = pcie->dev;
+	int ret, i;
+
+	if (pcie->num_regulators == 0)
+		return;
+
+	for (i = 0; i < PCIE_REGULATORS_MAX; i++) {
+		if (!pcie->regulators[i])
+			continue;
+		if (on) {
+			ret = regulator_enable(pcie->regulators[i]);
+			dev_dbg(dev, "enable regulator %s (%s)\n",
+				ep_regulator_names[i], ret ? "fail" : "pass");
+		} else {
+			ret = regulator_disable(pcie->regulators[i]);
+			dev_dbg(dev, "disable regulator %s (%s)\n",
+				ep_regulator_names[i], ret ? "fail" : "pass");
+		}
+	}
+}
+
 /*
  * This is to convert the size of the inbound "BAR" region to the
  * non-linear values of PCIE_X_MISC_RC_BAR[123]_CONFIG_LO.SIZE
@@ -1139,6 +1197,7 @@ static int brcm_pcie_suspend(struct device *dev)
 	brcm_pcie_turn_off(pcie);
 	ret = brcm_phy_stop(pcie);
 	clk_disable_unprepare(pcie->clk);
+	brcm_set_regulators(pcie, false);
 
 	return ret;
 }
@@ -1151,6 +1210,7 @@ static int brcm_pcie_resume(struct device *dev)
 	int ret;
 
 	base = pcie->base;
+	brcm_set_regulators(pcie, true);
 	clk_prepare_enable(pcie->clk);
 
 	ret = brcm_phy_start(pcie);
@@ -1189,6 +1249,7 @@ static void __brcm_pcie_remove(struct brcm_pcie *pcie)
 	brcm_phy_stop(pcie);
 	reset_control_assert(pcie->rescal);
 	clk_disable_unprepare(pcie->clk);
+	brcm_set_regulators(pcie, false);
 }
 
 static int brcm_pcie_remove(struct platform_device *pdev)
@@ -1238,6 +1299,10 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 	pcie->perst_set = data->perst_set;
 	pcie->bridge_sw_init_set = data->bridge_sw_init_set;
 
+	ret = brcm_parse_regulators(pcie);
+	if (ret)
+		return ret;
+
 	pcie->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(pcie->base))
 		return PTR_ERR(pcie->base);
@@ -1273,6 +1338,7 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	brcm_set_regulators(pcie, true);
 	ret = brcm_pcie_setup(pcie);
 	if (ret)
 		goto fail;
-- 
2.17.1


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