[v4,4/5] PCI: imx6: Convert to agnostic GPIO API

The of_gpio.h is going to be removed. In preparation of that convert
the driver to the agnostic API.

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 36 ++++++++-------------------
 1 file changed, 10 insertions(+), 26 deletions(-)

On Mon, May 06, 2024 at 05:20:40PM +0300, Andy Shevchenko wrote:
> The of_gpio.h is going to be removed. In preparation of that convert
> the driver to the agnostic API.
> 
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---

Can I include your patch in my imx6 pci improvement patches
https://lore.kernel.org/linux-pci/20240507-pci2_upstream-v4-0-e8c80d874057@nxp.com/T/#t

There is patch, which rename function from imx6 -> imx. That will avoid
conflict.

Frank Li


>  drivers/pci/controller/dwc/pci-imx6.c | 36 ++++++++-------------------
>  1 file changed, 10 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 917c69edee1d..62a4994c5501 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -11,14 +11,13 @@
>  #include <linux/bitfield.h>
>  #include <linux/clk.h>
>  #include <linux/delay.h>
> -#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
>  #include <linux/kernel.h>
>  #include <linux/mfd/syscon.h>
>  #include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
>  #include <linux/mfd/syscon/imx7-iomuxc-gpr.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> -#include <linux/of_gpio.h>
>  #include <linux/of_address.h>
>  #include <linux/pci.h>
>  #include <linux/platform_device.h>
> @@ -107,8 +106,7 @@ struct imx6_pcie_drvdata {
>  
>  struct imx6_pcie {
>  	struct dw_pcie		*pci;
> -	int			reset_gpio;
> -	bool			gpio_active_high;
> +	struct gpio_desc	*reset_gpiod;
>  	bool			link_is_up;
>  	struct clk_bulk_data	clks[IMX6_PCIE_MAX_CLKS];
>  	struct regmap		*iomuxc_gpr;
> @@ -721,9 +719,7 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
>  	}
>  
>  	/* Some boards don't have PCIe reset GPIO. */
> -	if (gpio_is_valid(imx6_pcie->reset_gpio))
> -		gpio_set_value_cansleep(imx6_pcie->reset_gpio,
> -					imx6_pcie->gpio_active_high);
> +	gpiod_set_value_cansleep(imx6_pcie->reset_gpiod, 1);
>  }
>  
>  static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
> @@ -771,10 +767,9 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
>  	}
>  
>  	/* Some boards don't have PCIe reset GPIO. */
> -	if (gpio_is_valid(imx6_pcie->reset_gpio)) {
> +	if (imx6_pcie->reset_gpiod) {
>  		msleep(100);
> -		gpio_set_value_cansleep(imx6_pcie->reset_gpio,
> -					!imx6_pcie->gpio_active_high);
> +		gpiod_set_value_cansleep(imx6_pcie->reset_gpiod, 0);
>  		/* Wait for 100ms after PERST# deassertion (PCIe r5.0, 6.6.1) */
>  		msleep(100);
>  	}
> @@ -1285,22 +1280,11 @@ static int imx6_pcie_probe(struct platform_device *pdev)
>  		return PTR_ERR(pci->dbi_base);
>  
>  	/* Fetch GPIOs */
> -	imx6_pcie->reset_gpio = of_get_named_gpio(node, "reset-gpio", 0);
> -	imx6_pcie->gpio_active_high = of_property_read_bool(node,
> -						"reset-gpio-active-high");
> -	if (gpio_is_valid(imx6_pcie->reset_gpio)) {
> -		ret = devm_gpio_request_one(dev, imx6_pcie->reset_gpio,
> -				imx6_pcie->gpio_active_high ?
> -					GPIOF_OUT_INIT_HIGH :
> -					GPIOF_OUT_INIT_LOW,
> -				"PCIe reset");
> -		if (ret) {
> -			dev_err(dev, "unable to get reset gpio\n");
> -			return ret;
> -		}
> -	} else if (imx6_pcie->reset_gpio == -EPROBE_DEFER) {
> -		return imx6_pcie->reset_gpio;
> -	}
> +	imx6_pcie->reset_gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(imx6_pcie->reset_gpiod))
> +		return dev_err_probe(dev, PTR_ERR(imx6_pcie->reset_gpiod),
> +				     "unable to get reset gpio\n");
> +	gpiod_set_consumer_name(imx6_pcie->reset_gpiod, "PCIe reset");
>  
>  	if (imx6_pcie->drvdata->clks_cnt >= IMX6_PCIE_MAX_CLKS)
>  		return dev_err_probe(dev, -ENOMEM, "clks_cnt is too big\n");
> -- 
> 2.43.0.rc1.1336.g36b5255a03ac
>

Tue, May 07, 2024 at 03:22:33PM -0400, Frank Li kirjoitti:
> On Mon, May 06, 2024 at 05:20:40PM +0300, Andy Shevchenko wrote:
> > The of_gpio.h is going to be removed. In preparation of that convert
> > the driver to the agnostic API.

...

> Can I include your patch in my imx6 pci improvement patches
> https://lore.kernel.org/linux-pci/20240507-pci2_upstream-v4-0-e8c80d874057@nxp.com/T/#t
> 
> There is patch, which rename function from imx6 -> imx. That will avoid
> conflict.

You can, of course, but it will be not my decision to make. Ask PCI maintainers
who is supposed to take this series.

Thu, May 09, 2024 at 01:24:45AM +0000, Hongxing Zhu kirjoitti:
> > -----Original Message-----
> > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Sent: 2024年5月6日 22:21

...

> > -	imx6_pcie->gpio_active_high = of_property_read_bool(node,
> > -						"reset-gpio-active-high");
> > -	if (gpio_is_valid(imx6_pcie->reset_gpio)) {
> > -		ret = devm_gpio_request_one(dev, imx6_pcie->reset_gpio,
> > -				imx6_pcie->gpio_active_high ?
> > -					GPIOF_OUT_INIT_HIGH :
> > -					GPIOF_OUT_INIT_LOW,
> > -				"PCIe reset");
> > -		if (ret) {
> > -			dev_err(dev, "unable to get reset gpio\n");
> > -			return ret;
> > -		}
> > -	} else if (imx6_pcie->reset_gpio == -EPROBE_DEFER) {
> > -		return imx6_pcie->reset_gpio;
> > -	}

> Please correct me if my understand is wrong.
> The "reset-gpio-active-high" property is added for some buggy board designs.
> On these buggy boards, the reset gpio is active high.

This is my understanding too.

> In the other words, the PERST# is active and remote endpoint device would
> be in reset stat when this gpio is high on these buggy boards.

Yes.

> I'm afraid that the PCIe would be broken on these boards, If these codes
>  are removed totally,

No. Linus W. explained in the previous version review round how it's supposed
to work.

> and toggle the reset GPIO pin like below.
> ...
> gpio_set_value_cansleep(imx6_pcie->reset_gpio, 0);
> msleep(100);
> gpio_set_value_cansleep(imx6_pcie->reset_gpio, 1);
> ...

It's not the code that this patch adds. I'm not sure if I understand starting
from here what you mean.

> By the way, this reset GPIO pin should be high at end in
> imx6_pcie_deassert_core_reset() if the imx6_pcie->gpio_active_high is zero. 

This seems a terminology mixup. You probably meant "inactive".
And this is exactly the case with this patch.

If you start thinking in terms of "active"/"inactive" you will see that there
is no contradiction and no behaviour change. The quirk itself is located in
gpiolib-of.c..