Re: [PATCH v4] soc/imx: Add GPCv2 power gating driver

From: Andrey Smirnov
Date: Fri Mar 10 2017 - 00:00:50 EST

On Wed, Mar 8, 2017 at 3:39 AM, Shawn Guo <shawnguo@xxxxxxxxxx> wrote:
> 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?

No, the manual refers to it as GPC. GPCv2 came from already existing
irqchip driver

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/irqchip/irq-imx-gpcv2.c?id=refs/tags/v4.11-rc1

Plus, I think, there were a number of LKML patch submission threads
where that IP block was referred to as as GPCv2 by Freescale devs.

>
>> 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@xxxxxxxxx
>> Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
>> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
>> Cc: Mark Rutland <mark.rutland@xxxxxxx>
>> Cc: Fabio Estevam <fabio.estevam@xxxxxxx>
>> Cc: devicetree@xxxxxxxxxxxxxxx
>> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Acked-by: Rob Herring <robh@xxxxxxxxxx>
>> Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
>> ---
>>
>> 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.

OK, will do in v4.

>
>> 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@303a0000 {
>> + 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@33800000 {
>> + 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@xxxxxxxxx>
>> + *
>> + * Based on the code of analogus driver:
>> + *
>> + * Copyright 2015-2017 Pengutronix, Lucas Stach <kernel@xxxxxxxxxxxxxx>
>> + *
>> + * 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.

Will fix in v4.

>
>> + 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.

Ditto.

>
>> +
>> + regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
>> + domain->bits.map, domain->bits.map);
>
> Have a newline here.

Ditto.

>
>> + 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.

Ditto.

>
>> + regmap_update_bits(domain->regmap, offset,
>> + domain->bits.pxx, domain->bits.pxx);
>
> Have a newline here.

OK.

>
>> + /*
>> + * 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 =.

OK

>
>> + 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 */

OK

>
>> + 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?

Yes for both, will do in v4.

>
>> + },
>> + .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.

OK

>
>> +
>> + if (!IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS))
>> + return 0;
>
> We should probably check the dependency with Kconfig?
>

Agreed. Will fix in v4.

>> +
>> + 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 &&.

OK

>
>> + 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?

I can't think of a reason to continue probing. Will change in v4.

>
>> + 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.

OK

>
>> +
>> + 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.

OK, will do former in v4.

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

OK

>> +
>> + 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.

OK.

>
> 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
>>