Re: [PATCH v6 2/2] soc/imx: Add GPCv2 power gating driver

[Dong Aisheng]

On Thu, Mar 16, 2017 at 06:30:50AM -0700, Andrey Smirnov wrote:
> 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@xxxxxxxxx
> Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> Cc: Fabio Estevam <fabio.estevam@xxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
> ---
>  drivers/soc/Kconfig      |   1 +
>  drivers/soc/imx/Kconfig  |  10 ++
>  drivers/soc/imx/Makefile |   1 +
>  drivers/soc/imx/gpcv2.c  | 385 +++++++++++++++++++++++++++++++++++++++++++++++

Personally i'd like more naming gpc-imx7.c since gpcv2 is too generic,
and actually you also mix using imx7d name below.

And AFAIK only MX7 will use this new driver.

Probably should also change the exist gpc to gpc-imx6.

>  4 files changed, 397 insertions(+)
>  create mode 100644 drivers/soc/imx/Kconfig
>  create mode 100644 drivers/soc/imx/gpcv2.c
> 
> diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
> index f31bceb..55a4eb8 100644
> --- a/drivers/soc/Kconfig
> +++ b/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"
> diff --git a/drivers/soc/imx/Kconfig b/drivers/soc/imx/Kconfig
> new file mode 100644
> index 0000000..bc7f0ee0
> --- /dev/null
> +++ b/drivers/soc/imx/Kconfig
> @@ -0,0 +1,10 @@
> +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
> +
> diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
> index 35861f5..5b6e396 100644
> --- a/drivers/soc/imx/Makefile
> +++ b/drivers/soc/imx/Makefile
> @@ -1 +1,2 @@
>  obj-y += gpc.o
> +obj-$(CONFIG_IMX7_PM_DOMAINS) += gpcv2.o
> diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
> new file mode 100644
> index 0000000..73c58ca
> --- /dev/null
> +++ b/drivers/soc/imx/gpcv2.c
> @@ -0,0 +1,385 @@
> +/*
> + * 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>

Where did you use it?

> +#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)
> +{
> +	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 = domain->pgc_nctrl && !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, 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",
> +		},
> +		.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",
> +		},
> +		.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",
> +		},
> +		.bits  = {
> +			.pxx = USB_OTG1_PHY_SW_Pxx_REQ,
> +			.map = USB_OTG1_PHY_A7_DOMAIN,
> +		},
> +	},
> +
> +	[IMX7_POWER_DOMAIN_PCIE_PHY] = {
> +		.genpd = {
> +			.name      = "pcie-phy",
> +		},
> +		.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",
> +		},
> +		.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)
> +{
> +	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) &&
> +	    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)) {
> +		if (!domain->voltage) {
> +			WARN(1, "No voltage configured for domain's regulator");
> +			return -EINVAL;
> +		}

This is somehow a bit mess.
Not sure if it's regulator API issue or our using issue...

> +
> +		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)

here

> +{
> +	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", },

here

> +	{ },
> +};
> +
> +static struct platform_driver imx7_pgc_domain_driver = {
> +	.driver = {
> +		.name = "imx7-pgc",

here

All you're using imx7, not gpcv2..

That why i prefer gpc-imx7.c

> +	},
> +	.probe    = imx7_pgc_domain_probe,
> +	.remove   = imx7_pgc_domain_remove,
> +	.id_table = imx7_pgc_domain_id,
> +};
> +builtin_platform_driver(imx7_pgc_domain_driver)

I did not understand too much on why we choose this approach to
add a power domain. AFAIK per current power domain design, a provider
can support multiple domains. But with this approach, actually we register
each domain as a provider which is actually a bit violate the real HW.

Lucas, can you please help provide some information on this new approach
decision history?

> +
> +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)
> +{
> +	static const struct regmap_config regmap_config = {

If any special reason to put the structure in this function?

> +		.cache_type	= REGCACHE_FLAT,
> +		.reg_bits	= 32,
> +		.val_bits	= 32,
> +		.reg_stride	= 4,
> +
> +		.readable_reg	= imx_gpcv2_readable_reg,

No really need this.

> +		.volatile_reg	= imx_gpcv2_volatile_reg,

Can you check if you have the same cache issue as GPC which
i just sent out a series to fix?

> +
> +		.max_register	= GPC_MAX_REGISTER,
> +	};
> +	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;

Is imx7_gpc_pu_pgc_sw_pup_req used by all power domains?
The name looks like a bit specific to PU.

> +
> +		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)
> -- 
> 2.9.3
>