Re: [PATCH v8 16/17] PCI/pwrctl: add a PCI power control driver for power sequenced devices

[Bjorn Helgaas <helgaas@kernel.org>]

On Tue, May 28, 2024 at 09:03:24PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> Add a PCI power control driver that's capable of correctly powering up
> devices using the power sequencing subsystem. The first users of this
> driver are the ath11k module on QCA6390 and ath12k on WCN7850.
> 
> Tested-by: Amit Pundir <amit.pundir@linaro.org>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

With s/add/Add/ in subject,

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

> ---
>  drivers/pci/pwrctl/Kconfig             |  9 ++++
>  drivers/pci/pwrctl/Makefile            |  2 +
>  drivers/pci/pwrctl/pci-pwrctl-pwrseq.c | 89 ++++++++++++++++++++++++++++++++++
>  3 files changed, 100 insertions(+)
> 
> diff --git a/drivers/pci/pwrctl/Kconfig b/drivers/pci/pwrctl/Kconfig
> index 96195395af69..f1b824955d4b 100644
> --- a/drivers/pci/pwrctl/Kconfig
> +++ b/drivers/pci/pwrctl/Kconfig
> @@ -5,4 +5,13 @@ menu "PCI Power control drivers"
>  config PCI_PWRCTL
>  	tristate
>  
> +config PCI_PWRCTL_PWRSEQ
> +	tristate "PCI Power Control driver using the Power Sequencing subsystem"
> +	select POWER_SEQUENCING
> +	select PCI_PWRCTL
> +	default m if ((ATH11K_PCI || ATH12K) && ARCH_QCOM)
> +	help
> +	  Enable support for the PCI power control driver for device
> +	  drivers using the Power Sequencing subsystem.
> +
>  endmenu
> diff --git a/drivers/pci/pwrctl/Makefile b/drivers/pci/pwrctl/Makefile
> index 52ae0640ef7b..d308aae4800c 100644
> --- a/drivers/pci/pwrctl/Makefile
> +++ b/drivers/pci/pwrctl/Makefile
> @@ -2,3 +2,5 @@
>  
>  obj-$(CONFIG_PCI_PWRCTL)		+= pci-pwrctl-core.o
>  pci-pwrctl-core-y			:= core.o
> +
> +obj-$(CONFIG_PCI_PWRCTL_PWRSEQ)		+= pci-pwrctl-pwrseq.o
> diff --git a/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c b/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c
> new file mode 100644
> index 000000000000..c7a113a76c0c
> --- /dev/null
> +++ b/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c
> @@ -0,0 +1,89 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2024 Linaro Ltd.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/pci-pwrctl.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwrseq/consumer.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +
> +struct pci_pwrctl_pwrseq_data {
> +	struct pci_pwrctl ctx;
> +	struct pwrseq_desc *pwrseq;
> +};
> +
> +static void devm_pci_pwrctl_pwrseq_power_off(void *data)
> +{
> +	struct pwrseq_desc *pwrseq = data;
> +
> +	pwrseq_power_off(pwrseq);
> +}
> +
> +static int pci_pwrctl_pwrseq_probe(struct platform_device *pdev)
> +{
> +	struct pci_pwrctl_pwrseq_data *data;
> +	struct device *dev = &pdev->dev;
> +	int ret;
> +
> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->pwrseq = devm_pwrseq_get(dev, of_device_get_match_data(dev));
> +	if (IS_ERR(data->pwrseq))
> +		return dev_err_probe(dev, PTR_ERR(data->pwrseq),
> +				     "Failed to get the power sequencer\n");
> +
> +	ret = pwrseq_power_on(data->pwrseq);
> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +				     "Failed to power-on the device\n");
> +
> +	ret = devm_add_action_or_reset(dev, devm_pci_pwrctl_pwrseq_power_off,
> +				       data->pwrseq);
> +	if (ret)
> +		return ret;
> +
> +	data->ctx.dev = dev;
> +
> +	ret = devm_pci_pwrctl_device_set_ready(dev, &data->ctx);
> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +				     "Failed to register the pwrctl wrapper\n");
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id pci_pwrctl_pwrseq_of_match[] = {
> +	{
> +		/* ATH11K in QCA6390 package. */
> +		.compatible = "pci17cb,1101",
> +		.data = "wlan",
> +	},
> +	{
> +		/* ATH12K in WCN7850 package. */
> +		.compatible = "pci17cb,1107",
> +		.data = "wlan",
> +	},
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, pci_pwrctl_pwrseq_of_match);
> +
> +static struct platform_driver pci_pwrctl_pwrseq_driver = {
> +	.driver = {
> +		.name = "pci-pwrctl-pwrseq",
> +		.of_match_table = pci_pwrctl_pwrseq_of_match,
> +	},
> +	.probe = pci_pwrctl_pwrseq_probe,
> +};
> +module_platform_driver(pci_pwrctl_pwrseq_driver);
> +
> +MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@linaro.org>");
> +MODULE_DESCRIPTION("Generic PCI Power Control module for power sequenced devices");
> +MODULE_LICENSE("GPL");
> 
> -- 
> 2.43.0
>