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

From: Andrey Smirnov
Date: Mon Mar 20 2017 - 16:42:39 EST

On Mon, Mar 20, 2017 at 12:03 AM, Dong Aisheng <dongas86@xxxxxxxxx> wrote:
> 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.
>

This IP block is already referenced as GPCv2 in
drivers/irqchip/irq-imx-gpcv2.c, so IMHO re-naming it to gpc-imx7
would be confusing.

> 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?

Not sure, I'll double check and drop it if it's unused.

>
>> +#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...
>

You are going to have to give me something to work with. If you think
this code can be improved please provide concrete suggestions.

>> +
>> + 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
>

I am fine with this inconsistency and I am going to let Shawn decide.

Shawn, please let me know if you want me to do any renaming.


>> + },
>> + .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.
>

OK, I'll drop it.

>> + .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?
>

It probably does. I'll adopt your fix from GPC driver.

>> +
>> + .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.
>

All power domains currently supported by the driver, which is limited
to domains controlled by GPC_PU_PGC_SW_PUP_REQ register, hence the
name.

>> +
>> + 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
>>