Re: [PATCH v2] power: reset: add Odroid Go Ultra poweroff driver

[Sebastian Reichel]

Hi,

On Thu, Jan 26, 2023 at 06:11:21PM +0100, Neil Armstrong wrote:
> The Hardkernel Odroid Go Ultra poweroff scheme requires requesting a poweroff
> to its two PMICs in order, this represents the poweroff scheme needed to complete
> a clean poweroff of the system.
> 
> This implement this scheme by implementing a self registering driver to permit
> using probe defer until both pmics are finally probed.
> 
> Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> ---
> Previous submission was at [1], but I converted it to an independent
> platform device with device auto registration to permit waiting for
> both the PMICs drivers to probe.
> 
> [1] https://lore.kernel.org/all/20221031-b4-odroid-go-ultra-initial-v1-2-42e3dbea86d5@xxxxxxxxxx/
> ---
> Changes in v2:
> - Switched to devm_register_sys_off_handler()
> - Link to v1: https://lore.kernel.org/r/20221031-b4-odroid-go-ultra-initial-v1-2-42e3dbea86d5@xxxxxxxxxx
> ---
>  drivers/power/reset/Kconfig                    |   7 ++
>  drivers/power/reset/Makefile                   |   1 +
>  drivers/power/reset/odroid-go-ultra-poweroff.c | 151 +++++++++++++++++++++++++
>  3 files changed, 159 insertions(+)
> 
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index a8c46ba5878f..26860c2e05a9 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -141,6 +141,13 @@ config POWER_RESET_OCELOT_RESET
>  	help
>  	  This driver supports restart for Microsemi Ocelot SoC and similar.
>  
> +config POWER_RESET_ODROID_GO_ULTRA_POWEROFF
> +	bool "Odroid Go Ultra power-off driver"
> +	depends on ARCH_MESON || COMPILE_TEST
> +	depends on MFD_RK808

You are not accessing any symbols from the MFD driver, so you can
append "|| COMPILE_TEST".

It will be fun to coordinate the merging, because of my series
renaming it to MFD_RK8XX :/

https://lore.kernel.org/all/20230127181244.160887-1-sebastian.reichel@xxxxxxxxxxxxx/

> +	help
> +	  This driver supports Power off for Odroid Go Ultra device.
> +
>  config POWER_RESET_OXNAS
>  	bool "OXNAS SoC restart driver"
>  	depends on ARCH_OXNAS
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index 0a39424fc558..d763e6735ee3 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -17,6 +17,7 @@ obj-$(CONFIG_POWER_RESET_MT6323) += mt6323-poweroff.o
>  obj-$(CONFIG_POWER_RESET_OXNAS) += oxnas-restart.o
>  obj-$(CONFIG_POWER_RESET_QCOM_PON) += qcom-pon.o
>  obj-$(CONFIG_POWER_RESET_OCELOT_RESET) += ocelot-reset.o
> +obj-$(CONFIG_POWER_RESET_ODROID_GO_ULTRA_POWEROFF) += odroid-go-ultra-poweroff.o
>  obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o
>  obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
>  obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o
> diff --git a/drivers/power/reset/odroid-go-ultra-poweroff.c b/drivers/power/reset/odroid-go-ultra-poweroff.c
> new file mode 100644
> index 000000000000..51f54e65c927
> --- /dev/null
> +++ b/drivers/power/reset/odroid-go-ultra-poweroff.c
> @@ -0,0 +1,151 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2023 Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> + */
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/of_platform.h>
> +#include <linux/mfd/rk808.h>
> +#include <linux/regmap.h>
> +#include <linux/module.h>
> +#include <linux/reboot.h>
> +#include <linux/i2c.h>
> +
> +/*
> + * The Odroid Go Ultra has 2 PMICs:
> + * - RK818 (manages the battery and USB-C power supply)
> + * - RK817
> + * Both PMICs feeds power to the S922X SoC, so they must be powered-off in sequence.
> + * Vendor does power-off the RK817 first, then the RK818 so here we follow this sequence.
> + */
> +
> +struct odroid_go_ultra_poweroff_data {
> +	struct device *dev;
> +	struct rk808 *rk817;
> +	struct rk808 *rk818;
> +};
> +
> +static int odroid_go_ultra_poweroff_prepare(struct sys_off_data *data)
> +{
> +	struct odroid_go_ultra_poweroff_data *poweroff_data = data->cb_data;
> +	int ret;
> +
> +	dev_info(poweroff_data->dev, "Setting PMICs for power off");
> +
> +	/* RK817 */
> +	ret = regmap_update_bits(poweroff_data->rk817->regmap, RK817_SYS_CFG(3), DEV_OFF, DEV_OFF);
> +	if (ret) {
> +		dev_err(poweroff_data->dev, "failed to poweroff rk817\n");
> +		return notifier_from_errno(ret);
> +	}
> +
> +	/* RK818 */
> +	ret = regmap_update_bits(poweroff_data->rk818->regmap, RK818_DEVCTRL_REG, DEV_OFF, DEV_OFF);
> +	if (ret) {
> +		dev_err(poweroff_data->dev, "failed to poweroff rk818\n");
> +		return notifier_from_errno(ret);
> +	}
> +
> +	return NOTIFY_OK;
> +}
> +
> +static int odroid_go_ultra_poweroff_get_pmic_drvdata(const char *compatible, struct rk808 **pmic)
> +{
> +	struct device_node *pmic_node;
> +	struct i2c_client *pmic_client;
> +
> +	pmic_node = of_find_compatible_node(NULL, NULL, compatible);
> +	if (!pmic_node)
> +		return -ENODEV;
> +
> +	pmic_client = of_find_i2c_device_by_node(pmic_node);
> +	of_node_put(pmic_node);
> +	if (!pmic_client)
> +		return -EPROBE_DEFER;
> +
> +	*pmic = i2c_get_clientdata(pmic_client);

You are only using the regmap, so you can skip the rk808 struct step
and directly get and store the regmap:

*pmic = dev_get_regmap(&pmic_client->dev, NULL);

> +	put_device(&pmic_client->dev);

Technically this allows releasing the PMIC device with the poweroff
driver still probed. I guess it's mostly a theoretical thing in this
case, but people tend to cargo copy. I suggest to store the struct
device handle in odroid_go_ultra_poweroff_data and then use
dev_get_regmap() in the poweroff handler. Finally add a put_device()
via devm_add_action_or_reset().

> +	if (!*pmic)
> +		return -EPROBE_DEFER;
> +
> +	return 0;
> +}
> +
> +static int odroid_go_ultra_poweroff_probe(struct platform_device *pdev)
> +{
> +	struct odroid_go_ultra_poweroff_data *poweroff_data;
> +	int ret;
> +
> +	poweroff_data = devm_kzalloc(&pdev->dev, sizeof(*poweroff_data), GFP_KERNEL);
> +	if (!poweroff_data)
> +		return -ENOMEM;
> +
> +	dev_set_drvdata(&pdev->dev, poweroff_data);
> +
> +	/* RK818 */
> +	ret = odroid_go_ultra_poweroff_get_pmic_drvdata("rockchip,rk818",
> +							&poweroff_data->rk818);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret, "failed to get rk818 mfd data\n");
> +
> +	/* RK817 */
> +	ret = odroid_go_ultra_poweroff_get_pmic_drvdata("rockchip,rk817",
> +							&poweroff_data->rk817);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret, "failed to get rk817 mfd data\n");
> +
> +	/* Register as SYS_OFF_MODE_POWER_OFF_PREPARE because regmap_update_bits may sleep */
> +	ret = devm_register_sys_off_handler(&pdev->dev,
> +					    SYS_OFF_MODE_POWER_OFF_PREPARE,
> +					    SYS_OFF_PRIO_DEFAULT,
> +					    odroid_go_ultra_poweroff_prepare,
> +					    poweroff_data);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret, "failed to register sys-off handler\n");
> +
> +	dev_info(&pdev->dev, "Registered Power-Off handler\n");
> +
> +	return 0;
> +}
> +
> +static struct platform_device *pdev;
> +
> +static struct platform_driver odroid_go_ultra_poweroff_driver = {
> +	.driver = {
> +		.name	= "odroid-go-ultra-poweroff",
> +	},
> +	.probe = odroid_go_ultra_poweroff_probe,
> +};
> +
> +static int __init odroid_go_ultra_poweroff_init(void)
> +{
> +	int ret;
> +
> +	/* Only create when running on the Odroid Go Ultra device */
> +	if (!of_device_is_compatible(of_root, "hardkernel,odroid-go-ultra"))
> +		return -ENODEV;
> +
> +	ret = platform_driver_register(&odroid_go_ultra_poweroff_driver);
> +	if (ret)
> +		return ret;
> +
> +	pdev = platform_device_register_resndata(NULL, "odroid-go-ultra-poweroff", -1,
> +						 NULL, 0, NULL, 0);
> +
> +	return PTR_ERR_OR_ZERO(pdev);

This is missing platform_driver_unregister() in the error path.

> +}
> +
> +static void __exit odroid_go_ultra_poweroff_exit(void)
> +{

if (!of_device_is_compatible(of_root, "hardkernel,odroid-go-ultra"))
		return;

> +	platform_device_unregister(pdev);
> +	platform_driver_unregister(&odroid_go_ultra_poweroff_driver);
> +}
> +
> +module_init(odroid_go_ultra_poweroff_init);
> +module_exit(odroid_go_ultra_poweroff_exit);
> +
> +MODULE_AUTHOR("Neil Armstrong <neil.armstrong@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Odroid Go Ultra poweroff driver");
> +MODULE_LICENSE("GPL");

Thanks,

-- Sebastian

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