[PATCH 2/3] PCI: brcmstb: Add regulator support

[Jaedon Shin <jaedon.shin@gmail.com>]

ARM-based Broadcom STB SoCs have GPIO-based voltage regulator for PCIe
turning off/on power supplies.

Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
---
 drivers/gpio/gpio-brcmstb.c           | 13 ++++-
 drivers/pci/controller/pcie-brcmstb.c | 76 +++++++++++++++++++++++++++
 2 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-brcmstb.c b/drivers/gpio/gpio-brcmstb.c
index 05e3f99ae59c..0cee5fcd2782 100644
--- a/drivers/gpio/gpio-brcmstb.c
+++ b/drivers/gpio/gpio-brcmstb.c
@@ -777,7 +777,18 @@ static struct platform_driver brcmstb_gpio_driver = {
 	.remove = brcmstb_gpio_remove,
 	.shutdown = brcmstb_gpio_shutdown,
 };
-module_platform_driver(brcmstb_gpio_driver);
+
+static int __init brcmstb_gpio_init(void)
+{
+	return platform_driver_register(&brcmstb_gpio_driver);
+}
+subsys_initcall(brcmstb_gpio_init);
+
+static void __exit brcmstb_gpio_exit(void)
+{
+	platform_driver_unregister(&brcmstb_gpio_driver);
+}
+module_exit(brcmstb_gpio_exit);
 
 MODULE_AUTHOR("Gregory Fong");
 MODULE_DESCRIPTION("Driver for Broadcom BRCMSTB SoC UPG GPIO");
diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 34581a6a7313..0e0ca39a680b 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/sizes.h>
 #include <linux/slab.h>
 #include <linux/string.h>
@@ -173,8 +174,79 @@ struct brcm_pcie {
 	int			gen;
 	u64			msi_target_addr;
 	struct brcm_msi		*msi;
+#ifdef CONFIG_REGULATOR
+	int			num_regs;
+	struct regulator	**regs;
+#endif
 };
 
+#ifdef CONFIG_REGULATOR
+static void brcm_pcie_regulator_enable(struct brcm_pcie *pcie)
+{
+	int i, ret;
+
+	for (i = 0; i < pcie->num_regs; i++) {
+		if (!pcie->regs[i])
+			continue;
+
+		ret = regulator_enable(pcie->regs[i]);
+		if (ret)
+			dev_err(pcie->dev, "Failed to enable regulator\n");
+	}
+}
+
+static void brcm_pcie_regulator_disable(struct brcm_pcie *pcie)
+{
+	int i, ret;
+
+	for (i = 0; i < pcie->num_regs; i++) {
+		if (!pcie->regs[i])
+			continue;
+
+		ret = regulator_disable(pcie->regs[i]);
+		if (ret)
+			dev_err(pcie->dev, "Failed to disable regulator\n");
+	}
+}
+
+static void brcm_pcie_regulator_init(struct brcm_pcie *pcie)
+{
+	struct device_node *np = pcie->dev->of_node;
+	struct device *dev = pcie->dev;
+	const char *name;
+	struct regulator *reg;
+	int i;
+
+	pcie->num_regs = of_property_count_strings(np, "supply-names");
+	if (pcie->num_regs <= 0) {
+		pcie->num_regs = 0;
+		return;
+	}
+
+	pcie->regs = devm_kcalloc(dev, pcie->num_regs, sizeof(pcie->regs[0]),
+				  GFP_KERNEL);
+	if (!pcie->regs) {
+		pcie->num_regs = 0;
+		return;
+	}
+
+	for (i = 0; i < pcie->num_regs; i++) {
+		if (of_property_read_string_index(np, "supply-names", i, &name))
+			continue;
+
+		reg = devm_regulator_get_optional(dev, name);
+		if (IS_ERR(reg))
+			continue;
+
+		pcie->regs[i] = reg;
+	}
+}
+#else
+static inline void brcm_pcie_regulator_enable(struct brcm_pcie *pcie) { }
+static inline void brcm_pcie_regulator_disable(struct brcm_pcie *pcie) { }
+static inline void brcm_pcie_regulator_init(struct brcm_pcie *pcie) { }
+#endif
+
 /*
  * 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
@@ -898,6 +970,7 @@ static void __brcm_pcie_remove(struct brcm_pcie *pcie)
 {
 	brcm_msi_remove(pcie);
 	brcm_pcie_turn_off(pcie);
+	brcm_pcie_regulator_disable(pcie);
 	clk_disable_unprepare(pcie->clk);
 	clk_put(pcie->clk);
 }
@@ -955,6 +1028,9 @@ static int brcm_pcie_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	brcm_pcie_regulator_init(pcie);
+	brcm_pcie_regulator_enable(pcie);
+
 	ret = brcm_pcie_setup(pcie);
 	if (ret)
 		goto fail;
-- 
2.21.0