power: reset: add driver for LinkStation power off

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>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index f07b982c8dff0a722791acd720315677a0cf79d9..0a1fb5c74f83e4856479abc9f2654b77d730002d 100644 (file)
--- 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 5710ca4695170c200f69ec142b3c56ec3d393edd..c51eceba9ea39bdb05e8034e65e8f910c1ebb4f8 100644 (file)
--- 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 (file)
index 0000000..39e89ba
--- /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");