Date:   Tue, 28 Feb 2017 16:09:16 -0800
From:   Andrey Smirnov <andrew.smirnov@...il.com>
To:     Shawn Guo <shawnguo@...nel.org>
Cc:     Andrey Smirnov <andrew.smirnov@...il.com>, yurovsky@...il.com,
        Lucas Stach <l.stach@...gutronix.de>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Fabio Estevam <fabio.estevam@....com>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4] 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@...il.com
Cc: Lucas Stach <l.stach@...gutronix.de>
Cc: Rob Herring <robh+dt@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Fabio Estevam <fabio.estevam@....com>
Cc: devicetree@...r.kernel.org
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Acked-by: Rob Herring <robh@...nel.org>
Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
---

Changes since v3 (see [v3]):

	- Minor device tree bindings documentation fixes as per
          feedback from Rob Herring
	- Collect Acked-by from Rob

Changes since v2 (see [v2]):

	- Fix a critical bug where incorrect state of a bit was
          expected in a busy wait loop (bit set instead of bit
          cleared) imx7_gpc_pu_pgc_sw_pxx_req()

	- Add missing step (setting of PCR in GPC_PGC_nCTRL) in power
          down procedure

Changes since v1 (see [v1]):

	- Various small DT bindings description fixes as per feedback
          from Rob Herring


[v1] https://lkml.org/lkml/2017/2/6/554
[v2] https://lkml.org/lkml/2017/2/13/489
[v3] https://lkml.org/lkml/2017/2/20/338

 .../devicetree/bindings/power/fsl,imx-gpcv2.txt    |  71 ++++
 drivers/soc/imx/Makefile                           |   2 +-
 drivers/soc/imx/gpcv2.c                            | 397 +++++++++++++++++++++
 include/dt-bindings/power/imx7-power.h             |  18 +
 4 files changed, 487 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt
 create mode 100644 drivers/soc/imx/gpcv2.c
 create mode 100644 include/dt-bindings/power/imx7-power.h

diff --git a/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt b/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt
new file mode 100644
index 0000000..02f45c6
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt
@@ -0,0 +1,71 @@
+Freescale i.MX General Power Controller v2
+==========================================
+
+The i.MX7S/D General Power Control (GPC) block contains Power Gating
+Control (PGC) for various power domains.
+
+Required properties:
+
+- compatible: Should be "fsl,imx7d-gpc"
+
+- reg: should be register base and length as documented in the
+  datasheet
+
+- interrupts: Should contain GPC interrupt request 1
+
+Power domains contained within GPC node are generic power domain
+providers, documented in
+Documentation/devicetree/bindings/power/power_domain.txt, which are
+described as subnodes of the power gating controller 'pgc' node,
+which, in turn, is expected to contain the following:
+
+Required properties:
+
+- reg: Power domain index. Valid values are defined in
+  include/dt-bindings/power/imx7-power.h
+
+- #power-domain-cells: Should be 0
+
+Optional properties:
+
+- power-supply: Power supply used to power the domain
+
+Example:
+
+	gpc: gpc@...a0000 {
+		compatible = "fsl,imx7d-gpc";
+		reg = <0x303a0000 0x1000>;
+		interrupt-controller;
+		interrupts = <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
+		#interrupt-cells = <3>;
+		interrupt-parent = <&intc>;
+
+		pgc {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			pgc_pcie_phy: power-domain@3 {
+				#power-domain-cells = <0>;
+
+				reg = <IMX7_POWER_DOMAIN_PCIE_PHY>;
+				power-supply = <&reg_1p0d>;
+			};
+		};
+	};
+
+
+Specifying power domain for IP modules
+======================================
+
+IP cores belonging to a power domain should contain a 'power-domains'
+property that is a phandle for PGC node representing the domain.
+
+Example of a device that is part of the PCIE_PHY power domain:
+
+	pcie: pcie@...00000 {
+	      reg = <0x33800000 0x4000>,
+	            <0x4ff00000 0x80000>;
+		/* ... */
+		power-domains = <&pgc_pcie_phy>;
+		/* ... */
+	};
diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
index 35861f5..7bcc933 100644
--- a/drivers/soc/imx/Makefile
+++ b/drivers/soc/imx/Makefile
@@ -1 +1 @@
-obj-y += gpc.o
+obj-y += gpc.o gpcv2.o
diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
new file mode 100644
index 0000000..20f0515
--- /dev/null
+++ b/drivers/soc/imx/gpcv2.c
@@ -0,0 +1,397 @@
+/*
+ * Copyright 2017 Impinj, Inc
+ * Author: Andrey Smirnov <andrew.smirnov@...il.com>
+ *
+ * Based on the code of analogus driver:
+ *
+ * Copyright 2015-2017 Pengutronix, Lucas Stach <kernel@...gutronix.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/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/of_device.h>
+#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_PGC_CPU_MAPPING	0xec
+#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	0xf8
+#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_MAX_REGISTER	0x1000
+
+#define GPC_PGC_nCTRL_PCR	BIT(0)
+
+struct imx7_pgc_domain {
+	struct generic_pm_domain genpd;
+	struct regmap *regmap;
+	struct regulator *regulator;
+
+	unsigned int pgc_nctrl;
+
+	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)
+{
+	int ret = 0;
+	unsigned long deadline;
+	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 has_regulator = !IS_ERR(domain->regulator);
+	const bool enable_power_control = domain->pgc_nctrl && !on;
+
+	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, domain->pgc_nctrl,
+				   GPC_PGC_nCTRL_PCR, GPC_PGC_nCTRL_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, domain->pgc_nctrl,
+				   GPC_PGC_nCTRL_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_USB_HSIC_PHY] = {
+		.genpd = {
+			.name      = "usb-hsic-phy",
+			.power_on  = imx7_gpc_pu_pgc_sw_pup_req,
+			.power_off = imx7_gpc_pu_pgc_sw_pdn_req,
+		},
+		.bits  = {
+			.pxx = USB_HSIC_PHY_SW_Pxx_REQ,
+			.map = USB_HSIC_PHY_A7_DOMAIN,
+		},
+		.voltage   = 1200000,
+		.pgc_nctrl = 0x0d00,
+	},
+
+	[IMX7_POWER_DOMAIN_USB_OTG2_PHY] = {
+		.genpd = {
+			.name      = "usb-otg2-phy",
+			.power_on  = imx7_gpc_pu_pgc_sw_pup_req,
+			.power_off = imx7_gpc_pu_pgc_sw_pdn_req,
+		},
+		.bits  = {
+			.pxx = USB_OTG2_PHY_SW_Pxx_REQ,
+			.map = USB_OTG2_PHY_A7_DOMAIN,
+		},
+	},
+
+	[IMX7_POWER_DOMAIN_USB_OTG1_PHY] = {
+		.genpd = {
+			.name      = "usb-otg1-phy",
+			.power_on  = imx7_gpc_pu_pgc_sw_pup_req,
+			.power_off = imx7_gpc_pu_pgc_sw_pdn_req,
+		},
+		.bits  = {
+			.pxx = USB_OTG1_PHY_SW_Pxx_REQ,
+			.map = USB_OTG1_PHY_A7_DOMAIN,
+		},
+	},
+
+	[IMX7_POWER_DOMAIN_PCIE_PHY] = {
+		.genpd = {
+			.name      = "pcie-phy",
+			.power_on  = imx7_gpc_pu_pgc_sw_pup_req,
+			.power_off = imx7_gpc_pu_pgc_sw_pdn_req,
+		},
+		.bits  = {
+			.pxx = PCIE_PHY_SW_Pxx_REQ,
+			.map = PCIE_PHY_A7_DOMAIN,
+		},
+		.voltage   = 1000000,
+		.pgc_nctrl = 0x0c40,
+	},
+
+	[IMX7_POWER_DOMAIN_MIPI_PHY] = {
+		.genpd = {
+			.name      = "mipi-phy",
+			.power_on  = imx7_gpc_pu_pgc_sw_pup_req,
+			.power_off = imx7_gpc_pu_pgc_sw_pdn_req,
+		},
+		.bits  = {
+			.pxx = MIPI_PHY_SW_Pxx_REQ,
+			.map = MIPI_PHY_A7_DOMAIN,
+		},
+		.voltage   = 1000000,
+		.pgc_nctrl = 0x0c00,
+	},
+};
+
+static int imx7_pgc_domain_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct imx7_pgc_domain *domain = pdev->dev.platform_data;
+
+	if (!IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS))
+		return 0;
+
+	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)  &&
+	    PTR_ERR(domain->regulator) != -ENODEV) {
+		dev_err(domain->dev, "Failed to get domain's regulator\n");
+		return PTR_ERR(domain->regulator);
+	}
+
+	if (!IS_ERR(domain->regulator)) {
+		WARN_ON(!domain->voltage);
+		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;
+
+	if (IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS)) {
+		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 bool imx_gpcv2_readable_reg(struct device *dev, unsigned int reg)
+{
+	return reg % 4 == 0 &&
+	       reg <= GPC_MAX_REGISTER;
+}
+
+static bool imx_gpcv2_volatile_reg(struct device *dev, unsigned int reg)
+{
+	return reg == GPC_PU_PGC_SW_PUP_REQ ||
+	       reg == GPC_PU_PGC_SW_PDN_REQ;
+}
+
+static int imx_gpcv2_probe(struct platform_device *pdev)
+{
+	int ret;
+	void __iomem *base;
+	struct resource *res;
+	struct regmap *regmap;
+	struct device *dev = &pdev->dev;
+	struct device_node *pgc_np, *np;
+
+	static const struct regmap_config regmap_config = {
+		.cache_type	= REGCACHE_FLAT,
+		.reg_bits	= 32,
+		.val_bits	= 32,
+		.reg_stride	= 4,
+
+		.readable_reg	= imx_gpcv2_readable_reg,
+		.volatile_reg	= imx_gpcv2_volatile_reg,
+
+		.max_register	= GPC_MAX_REGISTER,
+	};
+
+	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\n");
+		return ret;
+	}
+
+	for_each_child_of_node(pgc_np, np) {
+		u32 domain_index;
+		struct platform_device *pd_pdev;
+		struct imx7_pgc_domain *domain;
+
+		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;
+
+		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)
diff --git a/include/dt-bindings/power/imx7-power.h b/include/dt-bindings/power/imx7-power.h
new file mode 100644
index 0000000..24dde62
--- /dev/null
+++ b/include/dt-bindings/power/imx7-power.h
@@ -0,0 +1,18 @@
+/*
+ *  Copyright © 2017 Impinj
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __DT_BINDINGS_ARM_IMX7_POWER_H__
+#define __DT_BINDINGS_ARM_IMX7_POWER_H__
+
+#define IMX7_POWER_DOMAIN_USB_HSIC_PHY	0
+#define IMX7_POWER_DOMAIN_USB_OTG2_PHY	1
+#define IMX7_POWER_DOMAIN_USB_OTG1_PHY	2
+#define IMX7_POWER_DOMAIN_PCIE_PHY	3
+#define IMX7_POWER_DOMAIN_MIPI_PHY	4
+
+#endif
-- 
2.9.3

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