linux-kernel - Re: [PATCH 4/8] pinctrl: qcom: sdm845: Provide ACPI support

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Message-ID: <20190605061721.GK22737@tuxbook-pro>
Date:   Tue, 4 Jun 2019 23:17:21 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     alokc@...eaurora.org, kramasub@...eaurora.org,
        andy.gross@...aro.org, david.brown@...aro.org,
        wsa+renesas@...g-engineering.com, linus.walleij@...aro.org,
        balbi@...nel.org, gregkh@...uxfoundation.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        jlhugo@...il.com, linux-i2c@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-usb@...r.kernel.org
Subject: Re: [PATCH 4/8] pinctrl: qcom: sdm845: Provide ACPI support

On Tue 04 Jun 03:44 PDT 2019, Lee Jones wrote:

> This patch provides basic support for booting with ACPI instead
> of the currently supported Device Tree.  When doing so there are a
> couple of differences which we need to taken into consideration.
> 
> Firstly, the SDM850 ACPI tables omit information pertaining to the
> 4 reserved GPIOs on the platform.  If Linux attempts to touch/
> initialise any of these lines, the firmware will restart the
> platform.
> 
> Secondly, when booting with ACPI, it is expected that the firmware
> will set-up things like; Regulators, Clocks, Pin Functions, etc in
> their ideal configuration.  Thus, the possible Pin Functions
> available to this platform are not advertised when providing the
> higher GPIOD/Pinctrl APIs with pin information.
> 
> Signed-off-by: Lee Jones <lee.jones@...aro.org>
> ---
>  drivers/pinctrl/qcom/Kconfig          |  2 +-
>  drivers/pinctrl/qcom/pinctrl-sdm845.c | 35 ++++++++++++++++++++++++++-
>  2 files changed, 35 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pinctrl/qcom/Kconfig b/drivers/pinctrl/qcom/Kconfig
> index 2e66ab72c10b..aafbe932424f 100644
> --- a/drivers/pinctrl/qcom/Kconfig
> +++ b/drivers/pinctrl/qcom/Kconfig
> @@ -168,7 +168,7 @@ config PINCTRL_SDM660
>  
>  config PINCTRL_SDM845
>         tristate "Qualcomm Technologies Inc SDM845 pin controller driver"
> -       depends on GPIOLIB && OF
> +       depends on GPIOLIB && (OF || ACPI)
>         select PINCTRL_MSM
>         help
>           This is the pinctrl, pinmux, pinconf and gpiolib driver for the
> diff --git a/drivers/pinctrl/qcom/pinctrl-sdm845.c b/drivers/pinctrl/qcom/pinctrl-sdm845.c
> index c97f20fca5fd..7188bee3cf3e 100644
> --- a/drivers/pinctrl/qcom/pinctrl-sdm845.c
> +++ b/drivers/pinctrl/qcom/pinctrl-sdm845.c
> @@ -3,6 +3,7 @@
>   * Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
>   */
>  
> +#include <linux/acpi.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
> @@ -1277,6 +1278,10 @@ static const struct msm_pingroup sdm845_groups[] = {
>  	UFS_RESET(ufs_reset, 0x99f000),
>  };
>  
> +static const int sdm845_acpi_reserved_gpios[] = {
> +	0, 1, 2, 3, 81, 82, 83, 84, -1
> +};
> +
>  static const struct msm_pinctrl_soc_data sdm845_pinctrl = {
>  	.pins = sdm845_pins,
>  	.npins = ARRAY_SIZE(sdm845_pins),
> @@ -1284,14 +1289,41 @@ static const struct msm_pinctrl_soc_data sdm845_pinctrl = {
>  	.nfunctions = ARRAY_SIZE(sdm845_functions),
>  	.groups = sdm845_groups,
>  	.ngroups = ARRAY_SIZE(sdm845_groups),
> +	.reserved_gpios = sdm845_acpi_reserved_gpios,

The reason why put these in DT is because the list is board/firmware
dependent. E.g. the firmware on db845c does not support the peripherals
that sits on these 8 pins and as such these are not reserved.

But given that the two structs looks identical now, did you perhaps not
intend to add.reserved_gpios for the non-ACPI case?

Regards,
Bjorn

> +	.ngpios = 150,
> +};
> +
> +static const struct msm_pinctrl_soc_data sdm845_acpi_pinctrl = {
> +	.pins = sdm845_pins,
> +	.npins = ARRAY_SIZE(sdm845_pins),
> +	.groups = sdm845_groups,
> +	.ngroups = ARRAY_SIZE(sdm845_groups),
> +	.reserved_gpios = sdm845_acpi_reserved_gpios,
>  	.ngpios = 150,
>  };
>  
>  static int sdm845_pinctrl_probe(struct platform_device *pdev)
>  {
> -	return msm_pinctrl_probe(pdev, &sdm845_pinctrl);
> +	int ret;
> +
> +	if (pdev->dev.of_node) {
> +		ret = msm_pinctrl_probe(pdev, &sdm845_pinctrl);
> +	} else if (ACPI_HANDLE(&pdev->dev)) {
> +		ret = msm_pinctrl_probe(pdev, &sdm845_acpi_pinctrl);
> +	} else {
> +		dev_err(&pdev->dev, "DT and ACPI disabled\n");
> +		return -EINVAL;
> +	}
> +
> +	return ret;
>  }
>  
> +static const struct acpi_device_id sdm845_pinctrl_acpi_match[] = {
> +	{ "QCOM0217"},
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(acpi, sdm845_pinctrl_acpi_match);
> +
>  static const struct of_device_id sdm845_pinctrl_of_match[] = {
>  	{ .compatible = "qcom,sdm845-pinctrl", },
>  	{ },
> @@ -1302,6 +1334,7 @@ static struct platform_driver sdm845_pinctrl_driver = {
>  		.name = "sdm845-pinctrl",
>  		.pm = &msm_pinctrl_dev_pm_ops,
>  		.of_match_table = sdm845_pinctrl_of_match,
> +		.acpi_match_table = ACPI_PTR(sdm845_pinctrl_acpi_match),
>  	},
>  	.probe = sdm845_pinctrl_probe,
>  	.remove = msm_pinctrl_remove,
> -- 
> 2.17.1
>