3 files changed, 152 insertions, 39 deletions

diff --git a/drivers/tty/serdev/Kconfig b/drivers/tty/serdev/Kconfig
index cdc6b820cf93..1dbc8352e027 100644
--- a/drivers/tty/serdev/Kconfig
+++ b/drivers/tty/serdev/Kconfig
@@ -6,11 +6,19 @@ menuconfig SERIAL_DEV_BUS
         help
           Core support for devices connected via a serial port.
 
+          Note that you typically also want to enable TTY port controller support.
+
 if SERIAL_DEV_BUS
 
 config SERIAL_DEV_CTRL_TTYPORT
         bool "Serial device TTY port controller"
+        help
+          Say Y here if you want to use the Serial device bus with common TTY
+          drivers (e.g. serial drivers).
+
+          If unsure, say Y.
         depends on TTY
         depends on SERIAL_DEV_BUS != m
+        default y
 
 endif
diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index c68fb3a8ea1c..1bef39828ca7 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -1,19 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
  *
  * Based on drivers/spmi/spmi.c:
  * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 and
- * only version 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
+#include <linux/acpi.h>
 #include <linux/errno.h>
 #include <linux/idr.h>
 #include <linux/kernel.h>
@@ -49,13 +42,22 @@ static const struct device_type serdev_ctrl_type = {
 
 static int serdev_device_match(struct device *dev, struct device_driver *drv)
 {
-        /* TODO: ACPI and platform matching */
+        /* TODO: platform matching */
+        if (acpi_driver_match_device(dev, drv))
+                return 1;
+
         return of_driver_match_device(dev, drv);
 }
 
 static int serdev_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
-        /* TODO: ACPI and platform modalias */
+        int rc;
+
+        /* TODO: platform modalias */
+        rc = acpi_device_uevent_modalias(dev, env);
+        if (rc != -ENODEV)
+                return rc;
+
         return of_device_uevent_modalias(dev, env);
 }
 
@@ -65,21 +67,32 @@ static int serdev_uevent(struct device *dev, struct kobj_uevent_env *env)
  */
 int serdev_device_add(struct serdev_device *serdev)
 {
+        struct serdev_controller *ctrl = serdev->ctrl;
         struct device *parent = serdev->dev.parent;
         int err;
 
         dev_set_name(&serdev->dev, "%s-%d", dev_name(parent), serdev->nr);
 
+        /* Only a single slave device is currently supported. */
+        if (ctrl->serdev) {
+                dev_err(&serdev->dev, "controller busy\n");
+                return -EBUSY;
+        }
+        ctrl->serdev = serdev;
+
         err = device_add(&serdev->dev);
         if (err < 0) {
                 dev_err(&serdev->dev, "Can't add %s, status %d\n",
                         dev_name(&serdev->dev), err);
-                goto err_device_add;
+                goto err_clear_serdev;
         }
 
         dev_dbg(&serdev->dev, "device %s registered\n", dev_name(&serdev->dev));
 
-err_device_add:
+        return 0;
+
+err_clear_serdev:
+        ctrl->serdev = NULL;
         return err;
 }
 EXPORT_SYMBOL_GPL(serdev_device_add);
@@ -90,7 +103,10 @@ EXPORT_SYMBOL_GPL(serdev_device_add);
  */
 void serdev_device_remove(struct serdev_device *serdev)
 {
+        struct serdev_controller *ctrl = serdev->ctrl;
+
         device_unregister(&serdev->dev);
+        ctrl->serdev = NULL;
 }
 EXPORT_SYMBOL_GPL(serdev_device_remove);
 
@@ -260,6 +276,12 @@ static int serdev_drv_remove(struct device *dev)
 static ssize_t modalias_show(struct device *dev,
                              struct device_attribute *attr, char *buf)
 {
+        int len;
+
+        len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
+        if (len != -ENODEV)
+                return len;
+
         return of_device_modalias(dev, buf, PAGE_SIZE);
 }
 DEVICE_ATTR_RO(modalias);
@@ -295,7 +317,6 @@ struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
                 return NULL;
 
         serdev->ctrl = ctrl;
-        ctrl->serdev = serdev;
         device_initialize(&serdev->dev);
         serdev->dev.parent = &ctrl->dev;
         serdev->dev.bus = &serdev_bus_type;
@@ -329,26 +350,31 @@ struct serdev_controller *serdev_controller_alloc(struct device *parent,
         if (!ctrl)
                 return NULL;
 
-        device_initialize(&ctrl->dev);
-        ctrl->dev.type = &serdev_ctrl_type;
-        ctrl->dev.bus = &serdev_bus_type;
-        ctrl->dev.parent = parent;
-        ctrl->dev.of_node = parent->of_node;
-        serdev_controller_set_drvdata(ctrl, &ctrl[1]);
-
         id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
         if (id < 0) {
                 dev_err(parent,
                         "unable to allocate serdev controller identifier.\n");
-                serdev_controller_put(ctrl);
-                return NULL;
+                goto err_free;
         }
 
         ctrl->nr = id;
+
+        device_initialize(&ctrl->dev);
+        ctrl->dev.type = &serdev_ctrl_type;
+        ctrl->dev.bus = &serdev_bus_type;
+        ctrl->dev.parent = parent;
+        ctrl->dev.of_node = parent->of_node;
+        serdev_controller_set_drvdata(ctrl, &ctrl[1]);
+
         dev_set_name(&ctrl->dev, "serial%d", id);
 
         dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
         return ctrl;
+
+err_free:
+        kfree(ctrl);
+
+        return NULL;
 }
 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
 
@@ -385,6 +411,75 @@ static int of_serdev_register_devices(struct serdev_controller *ctrl)
         return 0;
 }
 
+#ifdef CONFIG_ACPI
+static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
+                                            struct acpi_device *adev)
+{
+        struct serdev_device *serdev = NULL;
+        int err;
+
+        if (acpi_bus_get_status(adev) || !adev->status.present ||
+            acpi_device_enumerated(adev))
+                return AE_OK;
+
+        serdev = serdev_device_alloc(ctrl);
+        if (!serdev) {
+                dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n",
+                        dev_name(&adev->dev));
+                return AE_NO_MEMORY;
+        }
+
+        ACPI_COMPANION_SET(&serdev->dev, adev);
+        acpi_device_set_enumerated(adev);
+
+        err = serdev_device_add(serdev);
+        if (err) {
+                dev_err(&serdev->dev,
+                        "failure adding ACPI serdev device. status %d\n", err);
+                serdev_device_put(serdev);
+        }
+
+        return AE_OK;
+}
+
+static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
+                                       void *data, void **return_value)
+{
+        struct serdev_controller *ctrl = data;
+        struct acpi_device *adev;
+
+        if (acpi_bus_get_device(handle, &adev))
+                return AE_OK;
+
+        return acpi_serdev_register_device(ctrl, adev);
+}
+
+static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
+{
+        acpi_status status;
+        acpi_handle handle;
+
+        handle = ACPI_HANDLE(ctrl->dev.parent);
+        if (!handle)
+                return -ENODEV;
+
+        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+                                     acpi_serdev_add_device, NULL, ctrl, NULL);
+        if (ACPI_FAILURE(status))
+                dev_dbg(&ctrl->dev, "failed to enumerate serdev slaves\n");
+
+        if (!ctrl->serdev)
+                return -ENODEV;
+
+        return 0;
+}
+#else
+static inline int acpi_serdev_register_devices(struct serdev_controller *ctrl)
+{
+        return -ENODEV;
+}
+#endif /* CONFIG_ACPI */
+
 /**
  * serdev_controller_add() - Add an serdev controller
  * @ctrl:       controller to be registered.
@@ -394,7 +489,7 @@ static int of_serdev_register_devices(struct serdev_controller *ctrl)
  */
 int serdev_controller_add(struct serdev_controller *ctrl)
 {
-        int ret;
+        int ret_of, ret_acpi, ret;
 
         /* Can't register until after driver model init */
         if (WARN_ON(!is_registered))
@@ -404,9 +499,14 @@ int serdev_controller_add(struct serdev_controller *ctrl)
         if (ret)
                 return ret;
 
-        ret = of_serdev_register_devices(ctrl);
-        if (ret)
+        ret_of = of_serdev_register_devices(ctrl);
+        ret_acpi = acpi_serdev_register_devices(ctrl);
+        if (ret_of && ret_acpi) {
+                dev_dbg(&ctrl->dev, "no devices registered: of:%d acpi:%d\n",
+                        ret_of, ret_acpi);
+                ret = -ENODEV;
                 goto out_dev_del;
+        }
 
         dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
                 ctrl->nr, &ctrl->dev);
diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
index 302018d67efa..ce7ad0acee7a 100644
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -1,14 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 and
- * only version 2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 #include <linux/kernel.h>
 #include <linux/serdev.h>
@@ -96,16 +88,21 @@ static int ttyport_open(struct serdev_controller *ctrl)
         struct serport *serport = serdev_controller_get_drvdata(ctrl);
         struct tty_struct *tty;
         struct ktermios ktermios;
+        int ret;
 
         tty = tty_init_dev(serport->tty_drv, serport->tty_idx);
         if (IS_ERR(tty))
                 return PTR_ERR(tty);
         serport->tty = tty;
 
-        if (tty->ops->open)
-                tty->ops->open(serport->tty, NULL);
-        else
-                tty_port_open(serport->port, tty, NULL);
+        if (!tty->ops->open || !tty->ops->close) {
+                ret = -ENODEV;
+                goto err_unlock;
+        }
+
+        ret = tty->ops->open(serport->tty, NULL);
+        if (ret)
+                goto err_close;
 
         /* Bring the UART into a known 8 bits no parity hw fc state */
         ktermios = tty->termios;
@@ -122,6 +119,14 @@ static int ttyport_open(struct serdev_controller *ctrl)
 
         tty_unlock(serport->tty);
         return 0;
+
+err_close:
+        tty->ops->close(tty, NULL);
+err_unlock:
+        tty_unlock(tty);
+        tty_release_struct(tty, serport->tty_idx);
+
+        return ret;
 }
 
 static void ttyport_close(struct serdev_controller *ctrl)