platform/x86: x86-android-tablets: Add support for instantiating serdevs

Add support for instantiating serdevs, this is necessary on some boards
where the serdev info in the DSDT has issues.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20211229231431.437982-8-hdegoede@redhat.com

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index b9a73df..833abec 100644 (file)
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1006,7 +1006,7 @@ config TOUCHSCREEN_DMI
 
 config X86_ANDROID_TABLETS
        tristate "X86 Android tablet support"
-       depends on I2C && ACPI && GPIOLIB
+       depends on I2C && SERIAL_DEV_BUS && ACPI && GPIOLIB
        help
          X86 tablets which ship with Android as (part of) the factory image
          typically have various problems with their DSDTs. The factory kernels

diff --git a/drivers/platform/x86/x86-android-tablets.c b/drivers/platform/x86/x86-android-tablets.c
index 4bcad05..5267e57 100644 (file)
--- a/drivers/platform/x86/x86-android-tablets.c
+++ b/drivers/platform/x86/x86-android-tablets.c
@@ -21,6 +21,7 @@
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/platform_device.h>
+#include <linux/serdev.h>
 #include <linux/string.h>
 /* For gpio_get_desc() which is EXPORT_SYMBOL_GPL() */
 #include "../../gpio/gpiolib.h"
@@ -127,11 +128,26 @@ struct x86_i2c_client_info {
        struct x86_acpi_irq_data irq_data;
 };
 
+struct x86_serdev_info {
+       const char *ctrl_hid;
+       const char *ctrl_uid;
+       const char *ctrl_devname;
+       /*
+        * ATM the serdev core only supports of or ACPI matching; and sofar all
+        * Android x86 tablets DSDTs have usable serdev nodes, but sometimes
+        * under the wrong controller. So we just tie the existing serdev ACPI
+        * node to the right controller.
+        */
+       const char *serdev_hid;
+};
+
 struct x86_dev_info {
        const struct x86_i2c_client_info *i2c_client_info;
        const struct platform_device_info *pdev_info;
+       const struct x86_serdev_info *serdev_info;
        int i2c_client_count;
        int pdev_count;
+       int serdev_count;
 };
 
 /*
@@ -273,8 +289,10 @@ MODULE_DEVICE_TABLE(dmi, x86_android_tablet_ids);
 
 static int i2c_client_count;
 static int pdev_count;
+static int serdev_count;
 static struct i2c_client **i2c_clients;
 static struct platform_device **pdevs;
+static struct serdev_device **serdevs;
 
 static __init int x86_instantiate_i2c_client(const struct x86_dev_info *dev_info,
                                             int idx)
@@ -310,10 +328,78 @@ static __init int x86_instantiate_i2c_client(const struct x86_dev_info *dev_info
        return 0;
 }
 
+static __init int x86_instantiate_serdev(const struct x86_serdev_info *info, int idx)
+{
+       struct acpi_device *ctrl_adev, *serdev_adev;
+       struct serdev_device *serdev;
+       struct device *ctrl_dev;
+       int ret = -ENODEV;
+
+       ctrl_adev = acpi_dev_get_first_match_dev(info->ctrl_hid, info->ctrl_uid, -1);
+       if (!ctrl_adev) {
+               pr_err("error could not get %s/%s ctrl adev\n",
+                      info->ctrl_hid, info->ctrl_uid);
+               return -ENODEV;
+       }
+
+       serdev_adev = acpi_dev_get_first_match_dev(info->serdev_hid, NULL, -1);
+       if (!serdev_adev) {
+               pr_err("error could not get %s serdev adev\n", info->serdev_hid);
+               goto put_ctrl_adev;
+       }
+
+       /* get_first_physical_node() returns a weak ref, no need to put() it */
+       ctrl_dev = acpi_get_first_physical_node(ctrl_adev);
+       if (!ctrl_dev)  {
+               pr_err("error could not get %s/%s ctrl physical dev\n",
+                      info->ctrl_hid, info->ctrl_uid);
+               goto put_serdev_adev;
+       }
+
+       /* ctrl_dev now points to the controller's parent, get the controller */
+       ctrl_dev = device_find_child_by_name(ctrl_dev, info->ctrl_devname);
+       if (!ctrl_dev) {
+               pr_err("error could not get %s/%s %s ctrl dev\n",
+                      info->ctrl_hid, info->ctrl_uid, info->ctrl_devname);
+               goto put_serdev_adev;
+       }
+
+       serdev = serdev_device_alloc(to_serdev_controller(ctrl_dev));
+       if (!serdev) {
+               ret = -ENOMEM;
+               goto put_serdev_adev;
+       }
+
+       ACPI_COMPANION_SET(&serdev->dev, serdev_adev);
+       acpi_device_set_enumerated(serdev_adev);
+
+       ret = serdev_device_add(serdev);
+       if (ret) {
+               dev_err(&serdev->dev, "error %d adding serdev\n", ret);
+               serdev_device_put(serdev);
+               goto put_serdev_adev;
+       }
+
+       serdevs[idx] = serdev;
+
+put_serdev_adev:
+       acpi_dev_put(serdev_adev);
+put_ctrl_adev:
+       acpi_dev_put(ctrl_adev);
+       return ret;
+}
+
 static void x86_android_tablet_cleanup(void)
 {
        int i;
 
+       for (i = 0; i < serdev_count; i++) {
+               if (serdevs[i])
+                       serdev_device_remove(serdevs[i]);
+       }
+
+       kfree(serdevs);
+
        for (i = 0; i < pdev_count; i++)
                platform_device_unregister(pdevs[i]);
 
@@ -365,6 +451,21 @@ static __init int x86_android_tablet_init(void)
                }
        }
 
+       serdevs = kcalloc(dev_info->serdev_count, sizeof(*serdevs), GFP_KERNEL);
+       if (!serdevs) {
+               x86_android_tablet_cleanup();
+               return -ENOMEM;
+       }
+
+       serdev_count = dev_info->serdev_count;
+       for (i = 0; i < serdev_count; i++) {
+               ret = x86_instantiate_serdev(&dev_info->serdev_info[i], i);
+               if (ret < 0) {
+                       x86_android_tablet_cleanup();
+                       return ret;
+               }
+       }
+
        return 0;
 }