Message-ID: <20170308113857.GA12997@x250>
Date:   Wed, 8 Mar 2017 12:39:02 +0100
From:   Shawn Guo <shawnguo@...nel.org>
To:     Andrey Smirnov <andrew.smirnov@...il.com>
Cc:     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: Re: [PATCH v4] soc/imx: Add GPCv2 power gating driver

On Tue, Feb 28, 2017 at 04:09:16PM -0800, Andrey Smirnov wrote:
> Add code allowing for control of various power domains managed by GPCv2

GPCv2, is it the name used in i.MX7 SoC manual?

> 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 +

Please have fsl,imx-gpcv2.txt and imx7-power.h in a separate dt-bindings
patch, and attach Rob's ACK to it.

>  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) ?

Unnecessary parenthesis.

> +		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;

Reverse tree for variable declarations please.

> +
> +	regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
> +			   domain->bits.map, domain->bits.map);

Have a newline here.

> +	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);
> +
> +

One newline is good enough.

> +	regmap_update_bits(domain->regmap, offset,
> +			   domain->bits.pxx, domain->bits.pxx);

Have a newline here.

> +	/*
> +	 * 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;

One space between on and =.

> +			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
> +		 */

/* One line comment */

> +		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,

So we need to do this hook setup for every single power domain, right?
If so, can we do it with for_each_child_of_node() loop in
imx_gpcv2_probe() function?

> +		},
> +		.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;

Reverse tree.

> +
> +	if (!IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS))
> +		return 0;

We should probably check the dependency with Kconfig?

> +
> +	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)  &&

One space before &&.

> +	    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);

Do we want to continue calling regulator_set_voltage() below?  Or should
we stop probing right here?

> +		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;

Reverse tree.

> +
> +	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;

You either want to print 'ret' in error message or you can return
PTR_ERR(regmap) directly.

> +	}
> +
> +	for_each_child_of_node(pgc_np, np) {
> +		u32 domain_index;
> +		struct platform_device *pd_pdev;
> +		struct imx7_pgc_domain *domain;

Reverse tree.

> +
> +		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__

Drop 'ARM' from there.

Shawn

> +
> +#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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