[v1,1/1] Support power control driver for BlueField SoCs.

This patch supports handling 2 BlueField power states controlled by GPIO interrupts:
1) chip reset and
2) low power mode

This driver is dependent and should be loaded after the gpio-mlxbf2.c driver,
which is the gpio and interrupt controller.

Signed-off-by: Asmaa Mnebhi <asmaa@nvidia.com>
---
 drivers/power/reset/Kconfig     |   6 ++
 drivers/power/reset/Makefile    |   1 +
 drivers/power/reset/pwr-mlxbf.c | 100 ++++++++++++++++++++++++++++++++
 3 files changed, 107 insertions(+)
 create mode 100644 drivers/power/reset/pwr-mlxbf.c

Hi,

Please find review feedback inline,

On Mon, Apr 18, 2022 at 01:44:50PM -0400, Asmaa Mnebhi wrote:
> This patch supports handling 2 BlueField power states controlled by GPIO interrupts:
> 1) chip reset and
> 2) low power mode
> 
> This driver is dependent and should be loaded after the gpio-mlxbf2.c driver,
> which is the gpio and interrupt controller.
> 
> Signed-off-by: Asmaa Mnebhi <asmaa@nvidia.com>
> ---
>  drivers/power/reset/Kconfig     |   6 ++
>  drivers/power/reset/Makefile    |   1 +
>  drivers/power/reset/pwr-mlxbf.c | 100 ++++++++++++++++++++++++++++++++
>  3 files changed, 107 insertions(+)
>  create mode 100644 drivers/power/reset/pwr-mlxbf.c
> 
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index 4b563db3ab3e..a8c46ba5878f 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -297,4 +297,10 @@ config NVMEM_REBOOT_MODE
>  	  then the bootloader can read it and take different
>  	  action according to the mode.
>  
> +config POWER_MLXBF
> +	tristate "Mellanox BlueField power handling driver"
> +	depends on (GPIO_MLXBF2 && ACPI)
> +	help
> +	  This driver supports reset or low power mode handling for Mellanox BlueField.
> +
>  endif
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index f606a2f60539..0a39424fc558 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -35,3 +35,4 @@ obj-$(CONFIG_REBOOT_MODE) += reboot-mode.o
>  obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o
>  obj-$(CONFIG_POWER_RESET_SC27XX) += sc27xx-poweroff.o
>  obj-$(CONFIG_NVMEM_REBOOT_MODE) += nvmem-reboot-mode.o
> +obj-$(CONFIG_POWER_MLXBF) += pwr-mlxbf.o
> diff --git a/drivers/power/reset/pwr-mlxbf.c b/drivers/power/reset/pwr-mlxbf.c
> new file mode 100644
> index 000000000000..30b3ba13be75
> --- /dev/null
> +++ b/drivers/power/reset/pwr-mlxbf.c
> @@ -0,0 +1,100 @@
> +// SPDX-License-Identifier: GPL-2.0-only or BSD-3-Clause
> +
> +/*
> + *  Copyright (c) 2022 NVIDIA CORPORATION & AFFILIATES.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/device.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm.h>
> +#include <linux/reboot.h>
> +#include <linux/types.h>
> +
> +const char *rst_pwr_hid = "MLNXBF24";
> +const char *low_pwr_hid = "MLNXBF29";
> +
> +struct pwr_mlxbf {
> +	struct work_struct send_work;
> +	const char *hid;
> +};
> +
> +static void pwr_mlxbf_send_work(struct work_struct *work)
> +{
> +	acpi_bus_generate_netlink_event("button/power.*", "Power Button", 0x80, 1);
> +}
> +
> +static irqreturn_t pwr_mlxbf_irq(int irq, void *ptr)
> +{
> +	struct pwr_mlxbf *priv = ptr;
> +
> +	if (!strncmp(priv->hid, rst_pwr_hid, 8))
> +		emergency_restart();
> +
> +	if (!strncmp(priv->hid, low_pwr_hid, 8))
> +		schedule_work(&priv->send_work);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int
> +pwr_mlxbf_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct acpi_device *adev;
> +	struct pwr_mlxbf *priv;
> +	const char *hid;
> +	int irq, err;
> +
> +	priv = devm_kzalloc(dev, sizeof(struct pwr_mlxbf), GFP_KERNEL);

priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);

> +	if (!priv)
> +		return -ENOMEM;
> +
> +	adev = ACPI_COMPANION(dev);
> +	if (!adev)
> +		return -ENXIO;
> +
> +	hid = acpi_device_hid(adev);
> +	priv->hid = hid;
> +
> +	irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(&pdev->dev), 0);
> +	if (irq == -EPROBE_DEFER) {
> +		return -EPROBE_DEFER;
> +	} else if (irq < 0) {
> +		dev_err(&pdev->dev, "Error getting %s irq.\n", priv->hid);
> +		return -ENXIO;
> +	}

if (irq < 0)
    return dev_err_probe(&pdev->dev, irq, "Error getting %s irq.\n", priv->hid);

> +	INIT_WORK(&priv->send_work, pwr_mlxbf_send_work);

err = devm_work_autocancel(dev, &priv->send_work, pwr_mlxbf_send_work);
if (err)
    return err;

Otherwise LGTM,

-- Sebastian

> +	err = devm_request_irq(&pdev->dev, irq, pwr_mlxbf_irq, 0, hid, priv);
> +	if (err)
> +		dev_err(&pdev->dev, "Failed request of %s irq\n", priv->hid);
> +
> +	return err;
> +}
> +
> +static const struct acpi_device_id __maybe_unused pwr_mlxbf_acpi_match[] = {
> +	{ "MLNXBF24", 0 },
> +	{ "MLNXBF29", 0 },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(acpi, pwr_mlxbf_acpi_match);
> +
> +static struct platform_driver pwr_mlxbf_driver = {
> +	.driver = {
> +		.name = "pwr_mlxbf",
> +		.acpi_match_table = pwr_mlxbf_acpi_match,
> +	},
> +	.probe    = pwr_mlxbf_probe,
> +};
> +
> +module_platform_driver(pwr_mlxbf_driver);
> +
> +MODULE_DESCRIPTION("Mellanox BlueField power driver");
> +MODULE_AUTHOR("Asmaa Mnebhi <asmaa@nvidia.com>");
> +MODULE_LICENSE("Dual BSD/GPL");