soc: imx: Add GPCv2 power gating driver

Add code allowing for control of various power domains managed by GPCv2
IP block found in i.MX7 series of SoCs. Power domains covered by this
patch are:

    - PCIE PHY
    - MIPI PHY
    - USB HSIC PHY
    - USB OTG1/2 PHY

Support for any other power domain controlled by GPC is not present, and
can be added at some later point.

Testing of this code was done against a PCIe driver.

Cc: yurovsky@gmail.com
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Dong Aisheng <dongas86@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

drivers/soc/Kconfig

@@ -2,6 +2,7 @@ menu "SOC (System On Chip) specific Drivers"
 
 source "drivers/soc/bcm/Kconfig"
 source "drivers/soc/fsl/Kconfig"
+source "drivers/soc/imx/Kconfig"
 source "drivers/soc/mediatek/Kconfig"
 source "drivers/soc/qcom/Kconfig"
 source "drivers/soc/rockchip/Kconfig"

drivers/soc/imx/Kconfig

@@ -0,0 +1,9 @@
+menu "i.MX SoC drivers"
+
+config IMX7_PM_DOMAINS
+	bool "i.MX7 PM domains"
+	select PM_GENERIC_DOMAINS
+	depends on SOC_IMX7D || (COMPILE_TEST && OF)
+	default y if SOC_IMX7D
+
+endmenu

drivers/soc/imx/Makefile

@@ -1 +1,2 @@
 obj-y += gpc.o
+obj-$(CONFIG_IMX7_PM_DOMAINS) += gpcv2.o

drivers/soc/imx/gpcv2.c

@@ -0,0 +1,363 @@
+/*
+ * Copyright 2017 Impinj, Inc
+ * Author: Andrey Smirnov <andrew.smirnov@gmail.com>
+ *
+ * Based on the code of analogus driver:
+ *
+ * Copyright 2015-2017 Pengutronix, Lucas Stach <kernel@pengutronix.de>
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <dt-bindings/power/imx7-power.h>
+
+#define GPC_LPCR_A7_BSC			0x000
+
+#define GPC_PGC_CPU_MAPPING		0x0ec
+#define USB_HSIC_PHY_A7_DOMAIN		BIT(6)
+#define USB_OTG2_PHY_A7_DOMAIN		BIT(5)
+#define USB_OTG1_PHY_A7_DOMAIN		BIT(4)
+#define PCIE_PHY_A7_DOMAIN		BIT(3)
+#define MIPI_PHY_A7_DOMAIN		BIT(2)
+
+#define GPC_PU_PGC_SW_PUP_REQ		0x0f8
+#define GPC_PU_PGC_SW_PDN_REQ		0x104
+#define USB_HSIC_PHY_SW_Pxx_REQ		BIT(4)
+#define USB_OTG2_PHY_SW_Pxx_REQ		BIT(3)
+#define USB_OTG1_PHY_SW_Pxx_REQ		BIT(2)
+#define PCIE_PHY_SW_Pxx_REQ		BIT(1)
+#define MIPI_PHY_SW_Pxx_REQ		BIT(0)
+
+#define GPC_M4_PU_PDN_FLG		0x1bc
+
+
+#define PGC_MIPI			4
+#define PGC_PCIE			5
+#define PGC_USB_HSIC			8
+#define GPC_PGC_CTRL(n)			(0x800 + (n) * 0x40)
+#define GPC_PGC_SR(n)			(GPC_PGC_CTRL(n) + 0xc)
+
+#define GPC_PGC_CTRL_PCR		BIT(0)
+
+struct imx7_pgc_domain {
+	struct generic_pm_domain genpd;
+	struct regmap *regmap;
+	struct regulator *regulator;
+
+	unsigned int pgc;
+
+	const struct {
+		u32 pxx;
+		u32 map;
+	} bits;
+
+	const int voltage;
+	struct device *dev;
+};
+
+static int imx7_gpc_pu_pgc_sw_pxx_req(struct generic_pm_domain *genpd,
+				      bool on)
+{
+	struct imx7_pgc_domain *domain = container_of(genpd,
+						      struct imx7_pgc_domain,
+						      genpd);
+	unsigned int offset = on ?
+		GPC_PU_PGC_SW_PUP_REQ : GPC_PU_PGC_SW_PDN_REQ;
+	const bool enable_power_control = !on;
+	const bool has_regulator = !IS_ERR(domain->regulator);
+	unsigned long deadline;
+	int ret = 0;
+
+	regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
+			   domain->bits.map, domain->bits.map);
+
+	if (has_regulator && on) {
+		ret = regulator_enable(domain->regulator);
+		if (ret) {
+			dev_err(domain->dev, "failed to enable regulator\n");
+			goto unmap;
+		}
+	}
+
+	if (enable_power_control)
+		regmap_update_bits(domain->regmap, GPC_PGC_CTRL(domain->pgc),
+				   GPC_PGC_CTRL_PCR, GPC_PGC_CTRL_PCR);
+
+	regmap_update_bits(domain->regmap, offset,
+			   domain->bits.pxx, domain->bits.pxx);
+
+	/*
+	 * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
+	 * for PUP_REQ/PDN_REQ bit to be cleared
+	 */
+	deadline = jiffies + msecs_to_jiffies(1);
+	while (true) {
+		u32 pxx_req;
+
+		regmap_read(domain->regmap, offset, &pxx_req);
+
+		if (!(pxx_req & domain->bits.pxx))
+			break;
+
+		if (time_after(jiffies, deadline)) {
+			dev_err(domain->dev, "falied to command PGC\n");
+			ret = -ETIMEDOUT;
+			/*
+			 * If we were in a process of enabling a
+			 * domain and failed we might as well disable
+			 * the regulator we just enabled. And if it
+			 * was the opposite situation and we failed to
+			 * power down -- keep the regulator on
+			 */
+			on = !on;
+			break;
+		}
+
+		cpu_relax();
+	}
+
+	if (enable_power_control)
+		regmap_update_bits(domain->regmap, GPC_PGC_CTRL(domain->pgc),
+				   GPC_PGC_CTRL_PCR, 0);
+
+	if (has_regulator && !on) {
+		int err;
+
+		err = regulator_disable(domain->regulator);
+		if (err)
+			dev_err(domain->dev,
+				"failed to disable regulator: %d\n", ret);
+		/* Preserve earlier error code */
+		ret = ret ?: err;
+	}
+unmap:
+	regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
+			   domain->bits.map, 0);
+	return ret;
+}
+
+static int imx7_gpc_pu_pgc_sw_pup_req(struct generic_pm_domain *genpd)
+{
+	return imx7_gpc_pu_pgc_sw_pxx_req(genpd, true);
+}
+
+static int imx7_gpc_pu_pgc_sw_pdn_req(struct generic_pm_domain *genpd)
+{
+	return imx7_gpc_pu_pgc_sw_pxx_req(genpd, false);
+}
+
+static struct imx7_pgc_domain imx7_pgc_domains[] = {
+	[IMX7_POWER_DOMAIN_MIPI_PHY] = {
+		.genpd = {
+			.name      = "mipi-phy",
+		},
+		.bits  = {
+			.pxx = MIPI_PHY_SW_Pxx_REQ,
+			.map = MIPI_PHY_A7_DOMAIN,
+		},
+		.voltage   = 1000000,
+		.pgc	   = PGC_MIPI,
+	},
+
+	[IMX7_POWER_DOMAIN_PCIE_PHY] = {
+		.genpd = {
+			.name      = "pcie-phy",
+		},
+		.bits  = {
+			.pxx = PCIE_PHY_SW_Pxx_REQ,
+			.map = PCIE_PHY_A7_DOMAIN,
+		},
+		.voltage   = 1000000,
+		.pgc	   = PGC_PCIE,
+	},
+
+	[IMX7_POWER_DOMAIN_USB_HSIC_PHY] = {
+		.genpd = {
+			.name      = "usb-hsic-phy",
+		},
+		.bits  = {
+			.pxx = USB_HSIC_PHY_SW_Pxx_REQ,
+			.map = USB_HSIC_PHY_A7_DOMAIN,
+		},
+		.voltage   = 1200000,
+		.pgc	   = PGC_USB_HSIC,
+	},
+};
+
+static int imx7_pgc_domain_probe(struct platform_device *pdev)
+{
+	struct imx7_pgc_domain *domain = pdev->dev.platform_data;
+	int ret;
+
+	domain->dev = &pdev->dev;
+
+	ret = pm_genpd_init(&domain->genpd, NULL, true);
+	if (ret) {
+		dev_err(domain->dev, "Failed to init power domain\n");
+		return ret;
+	}
+
+	domain->regulator = devm_regulator_get_optional(domain->dev, "power");
+	if (IS_ERR(domain->regulator)) {
+		if (PTR_ERR(domain->regulator) != -ENODEV) {
+			dev_err(domain->dev, "Failed to get domain's regulator\n");
+			return PTR_ERR(domain->regulator);
+		}
+	} else {
+		regulator_set_voltage(domain->regulator,
+				      domain->voltage, domain->voltage);
+	}
+
+	ret = of_genpd_add_provider_simple(domain->dev->of_node,
+					   &domain->genpd);
+	if (ret) {
+		dev_err(domain->dev, "Failed to add genpd provider\n");
+		pm_genpd_remove(&domain->genpd);
+	}
+
+	return ret;
+}
+
+static int imx7_pgc_domain_remove(struct platform_device *pdev)
+{
+	struct imx7_pgc_domain *domain = pdev->dev.platform_data;
+
+	of_genpd_del_provider(domain->dev->of_node);
+	pm_genpd_remove(&domain->genpd);
+
+	return 0;
+}
+
+static const struct platform_device_id imx7_pgc_domain_id[] = {
+	{ "imx7-pgc-domain", },
+	{ },
+};
+
+static struct platform_driver imx7_pgc_domain_driver = {
+	.driver = {
+		.name = "imx7-pgc",
+	},
+	.probe    = imx7_pgc_domain_probe,
+	.remove   = imx7_pgc_domain_remove,
+	.id_table = imx7_pgc_domain_id,
+};
+builtin_platform_driver(imx7_pgc_domain_driver)
+
+static int imx_gpcv2_probe(struct platform_device *pdev)
+{
+	static const struct regmap_range yes_ranges[] = {
+		regmap_reg_range(GPC_LPCR_A7_BSC,
+				 GPC_M4_PU_PDN_FLG),
+		regmap_reg_range(GPC_PGC_CTRL(PGC_MIPI),
+				 GPC_PGC_SR(PGC_MIPI)),
+		regmap_reg_range(GPC_PGC_CTRL(PGC_PCIE),
+				 GPC_PGC_SR(PGC_PCIE)),
+		regmap_reg_range(GPC_PGC_CTRL(PGC_USB_HSIC),
+				 GPC_PGC_SR(PGC_USB_HSIC)),
+	};
+	static const struct regmap_access_table access_table = {
+		.yes_ranges	= yes_ranges,
+		.n_yes_ranges	= ARRAY_SIZE(yes_ranges),
+	};
+	static const struct regmap_config regmap_config = {
+		.reg_bits	= 32,
+		.val_bits	= 32,
+		.reg_stride	= 4,
+		.rd_table	= &access_table,
+		.wr_table	= &access_table,
+		.max_register   = SZ_4K,
+	};
+	struct device *dev = &pdev->dev;
+	struct device_node *pgc_np, *np;
+	struct regmap *regmap;
+	struct resource *res;
+	void __iomem *base;
+	int ret;
+
+	pgc_np = of_get_child_by_name(dev->of_node, "pgc");
+	if (!pgc_np) {
+		dev_err(dev, "No power domains specified in DT\n");
+		return -EINVAL;
+	}
+
+	res  = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	regmap = devm_regmap_init_mmio(dev, base, &regmap_config);
+	if (IS_ERR(regmap)) {
+		ret = PTR_ERR(regmap);
+		dev_err(dev, "failed to init regmap (%d)\n", ret);
+		return ret;
+	}
+
+	for_each_child_of_node(pgc_np, np) {
+		struct platform_device *pd_pdev;
+		struct imx7_pgc_domain *domain;
+		u32 domain_index;
+
+		ret = of_property_read_u32(np, "reg", &domain_index);
+		if (ret) {
+			dev_err(dev, "Failed to read 'reg' property\n");
+			of_node_put(np);
+			return ret;
+		}
+
+		if (domain_index >= ARRAY_SIZE(imx7_pgc_domains)) {
+			dev_warn(dev,
+				 "Domain index %d is out of bounds\n",
+				 domain_index);
+			continue;
+		}
+
+		domain = &imx7_pgc_domains[domain_index];
+		domain->regmap = regmap;
+		domain->genpd.power_on  = imx7_gpc_pu_pgc_sw_pup_req;
+		domain->genpd.power_off = imx7_gpc_pu_pgc_sw_pdn_req;
+
+		pd_pdev = platform_device_alloc("imx7-pgc-domain",
+						domain_index);
+		if (!pd_pdev) {
+			dev_err(dev, "Failed to allocate platform device\n");
+			of_node_put(np);
+			return -ENOMEM;
+		}
+
+		pd_pdev->dev.platform_data = domain;
+		pd_pdev->dev.parent = dev;
+		pd_pdev->dev.of_node = np;
+
+		ret = platform_device_add(pd_pdev);
+		if (ret) {
+			platform_device_put(pd_pdev);
+			of_node_put(np);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static const struct of_device_id imx_gpcv2_dt_ids[] = {
+	{ .compatible = "fsl,imx7d-gpc" },
+	{ }
+};
+
+static struct platform_driver imx_gpc_driver = {
+	.driver = {
+		.name = "imx-gpcv2",
+		.of_match_table = imx_gpcv2_dt_ids,
+	},
+	.probe = imx_gpcv2_probe,
+};
+builtin_platform_driver(imx_gpc_driver)