Re: [PATCH v4] power: reset: add driver for LinkStation power off

[Sebastian Reichel <sre@kernel.org>]

[-- Attachment #1: Type: text/plain, Size: 7858 bytes --]

Hi,

On Wed, Jul 15, 2020 at 03:35:14PM +0200, Daniel González Cabanelas wrote:
> Some Buffalo LinkStations perform the power off operation, at restart
> time, depending on the state of an output pin (LED2/INTn) at the ethernet
> PHY. This pin is also used to wake the machine when a WoL packet is 
> received by the PHY.
> 
> The driver is required by the Buffalo LinkStation LS421DE (ARM MVEBU),
> and other models. Without it, the board remains forever halted if a 
> power off command is executed, unless the PSU is disconnected and
> connected again.
> 
> Add the driver to provide the power off function and also make the WoL
> feature to be available.
> 
> Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>
> ---

Doing reboot/poweroff via network PHY pin is a really interesting
hardware hack. Considering the circumstances the driver looks good,
so: queued to power-supply's for-next branch.

Thanks,

-- Sebastian

> Changes in v4:
>   - Deleted the power-off binding as suggested by Rob Herring. Therefore
>     the binding patch isn't required. Now the device detection is made
>     using the root node compatible string.
> Changes in v3:
>   - Code for PHY autodectection added, "phy-handle,intn" deleted.
> Changes in v2:
>   - The driver is now compatible with the WoL function, the LED2 pin output
>     is now used as INTn. Added the required code to make INTn work properly.
>   - Code for PHY autodectection deleted, "phy-handle,intn" is now mandatory.
>   - Replace a dev_info with a dev_dbg.
>   - Use phy_device_free in the driver remove.
>   - Cosmetic changes.
> 
>  drivers/power/reset/Kconfig                |  11 ++
>  drivers/power/reset/Makefile               |   1 +
>  drivers/power/reset/linkstation-poweroff.c | 136 +++++++++++++++++++++
>  3 files changed, 148 insertions(+)
>  create mode 100644 drivers/power/reset/linkstation-poweroff.c
> 
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index f07b982c8d..0a1fb5c74f 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -99,6 +99,17 @@ config POWER_RESET_HISI
>  	help
>  	  Reboot support for Hisilicon boards.
>  
> +config POWER_RESET_LINKSTATION
> +	tristate "Buffalo LinkStation power-off driver"
> +	depends on ARCH_MVEBU || COMPILE_TEST
> +	depends on OF_MDIO && PHYLIB
> +	help
> +	  This driver supports turning off some Buffalo LinkStations by
> +	  setting an output pin at the ethernet PHY to the correct state.
> +	  It also makes the device compatible with the WoL function.
> +
> +	  Say Y here if you have a Buffalo LinkStation LS421D/E.
> +
>  config POWER_RESET_MSM
>  	bool "Qualcomm MSM power-off driver"
>  	depends on ARCH_QCOM
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index 5710ca4695..c51eceba9e 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_POWER_RESET_GEMINI_POWEROFF) += gemini-poweroff.o
>  obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
>  obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o
>  obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o
> +obj-${CONFIG_POWER_RESET_LINKSTATION} += linkstation-poweroff.o
>  obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
>  obj-$(CONFIG_POWER_RESET_MT6323) += mt6323-poweroff.o
>  obj-$(CONFIG_POWER_RESET_OXNAS) += oxnas-restart.o
> diff --git a/drivers/power/reset/linkstation-poweroff.c b/drivers/power/reset/linkstation-poweroff.c
> new file mode 100644
> index 0000000000..1d1113d98c
> --- /dev/null
> +++ b/drivers/power/reset/linkstation-poweroff.c
> @@ -0,0 +1,136 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * LinkStation power off restart driver
> + * Copyright (C) 2020 Daniel González Cabanelas <dgcbueu@gmail.com>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/notifier.h>
> +#include <linux/of.h>
> +#include <linux/of_mdio.h>
> +#include <linux/of_platform.h>
> +#include <linux/reboot.h>
> +#include <linux/phy.h>
> +
> +/* Defines from the eth phy Marvell driver */
> +#define MII_MARVELL_COPPER_PAGE		0
> +#define MII_MARVELL_LED_PAGE		3
> +#define MII_MARVELL_WOL_PAGE		17
> +#define MII_MARVELL_PHY_PAGE		22
> +
> +#define MII_PHY_LED_CTRL		16
> +#define MII_88E1318S_PHY_LED_TCR	18
> +#define MII_88E1318S_PHY_WOL_CTRL	16
> +#define MII_M1011_IEVENT		19
> +
> +#define MII_88E1318S_PHY_LED_TCR_INTn_ENABLE		BIT(7)
> +#define MII_88E1318S_PHY_LED_TCR_FORCE_INT		BIT(15)
> +#define MII_88E1318S_PHY_WOL_CTRL_CLEAR_WOL_STATUS	BIT(12)
> +#define LED2_FORCE_ON					(0x8 << 8)
> +#define LEDMASK						GENMASK(11,8)
> +
> +static struct phy_device *phydev;
> +
> +static void mvphy_reg_intn(u16 data)
> +{
> +	int rc = 0, saved_page;
> +
> +	saved_page = phy_select_page(phydev, MII_MARVELL_LED_PAGE);
> +	if (saved_page < 0)
> +		goto err;
> +
> +	/* Force manual LED2 control to let INTn work */
> +	__phy_modify(phydev, MII_PHY_LED_CTRL, LEDMASK, LED2_FORCE_ON);
> +
> +	/* Set the LED[2]/INTn pin to the required state */
> +	__phy_modify(phydev, MII_88E1318S_PHY_LED_TCR,
> +		     MII_88E1318S_PHY_LED_TCR_FORCE_INT,
> +		     MII_88E1318S_PHY_LED_TCR_INTn_ENABLE | data);
> +
> +	if (!data) {
> +		/* Clear interrupts to ensure INTn won't be holded in high state */
> +		__phy_write(phydev, MII_MARVELL_PHY_PAGE, MII_MARVELL_COPPER_PAGE);
> +		__phy_read(phydev, MII_M1011_IEVENT);
> +
> +		/* If WOL was enabled and a magic packet was received before powering
> +		 * off, we won't be able to wake up by sending another magic packet. 
> +		 * Clear WOL status.
> +		 */
> +		__phy_write(phydev, MII_MARVELL_PHY_PAGE, MII_MARVELL_WOL_PAGE);
> +		__phy_set_bits(phydev, MII_88E1318S_PHY_WOL_CTRL,
> +			       MII_88E1318S_PHY_WOL_CTRL_CLEAR_WOL_STATUS);
> +	}
> +err:
> +	rc = phy_restore_page(phydev, saved_page, rc);
> +	if (rc < 0)
> +		dev_err(&phydev->mdio.dev, "Write register failed, %d\n", rc);
> +}
> +
> +static int linkstation_reboot_notifier(struct notifier_block *nb,
> +				       unsigned long action, void *unused)
> +{
> +	if (action == SYS_RESTART)
> +		mvphy_reg_intn(MII_88E1318S_PHY_LED_TCR_FORCE_INT);
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block linkstation_reboot_nb = {
> +	.notifier_call = linkstation_reboot_notifier,
> +};
> +
> +static void linkstation_poweroff(void)
> +{
> +	unregister_reboot_notifier(&linkstation_reboot_nb);
> +	mvphy_reg_intn(0);
> +
> +	kernel_restart("Power off");
> +}
> +
> +static const struct of_device_id ls_poweroff_of_match[] = {
> +	{ .compatible = "buffalo,ls421d" },
> +	{ .compatible = "buffalo,ls421de" },
> +	{ },
> +};
> +
> +static int __init linkstation_poweroff_init(void)
> +{
> +	struct mii_bus *bus;
> +	struct device_node *dn;
> +
> +	dn = of_find_matching_node(NULL, ls_poweroff_of_match);
> +	if (!dn)
> +		return -ENODEV;
> +	of_node_put(dn);
> +
> +	dn = of_find_node_by_name(NULL, "mdio");
> +	if (!dn)
> +		return -ENODEV;
> +
> +	bus = of_mdio_find_bus(dn);
> +	of_node_put(dn);
> +	if (!bus)
> +		return -EPROBE_DEFER;
> +
> +	phydev = phy_find_first(bus);
> +	if (!phydev)
> +		return -EPROBE_DEFER;
> +
> +	register_reboot_notifier(&linkstation_reboot_nb);
> +	pm_power_off = linkstation_poweroff;
> +
> +	return 0;
> +}
> +
> +static void __exit linkstation_poweroff_exit(void)
> +{
> +	pm_power_off = NULL;
> +	unregister_reboot_notifier(&linkstation_reboot_nb);
> +}
> +
> +module_init(linkstation_poweroff_init);
> +module_exit(linkstation_poweroff_exit);
> +
> +MODULE_AUTHOR("Daniel González Cabanelas <dgcbueu@gmail.com>");
> +MODULE_DESCRIPTION("LinkStation power off driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.27.0
> 
> 
> 
> 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]