The MS Surfaces are not directly using the PNP0C40 device for the buttons
but instead a MSHW0028. This one is bound on a I2C bus and so we need to
use a separate driver for it.

One noticeable change is that the original soc_button_array fails
to rmmod and then modprobe when using KBUILD_MODNAME as the gpiod con_id
with the Surface 3. Add this as a parameter of the new API.

Signed-off-by: Benjamin Tissoires <benjamin.tissoi...@redhat.com>
---
new in v2

 drivers/input/misc/soc_button_array.c  | 108 +++++++++++++++++++--------------
 include/linux/input/soc_button_array.h |  37 +++++++++++
 2 files changed, 98 insertions(+), 47 deletions(-)
 create mode 100644 include/linux/input/soc_button_array.h

diff --git a/drivers/input/misc/soc_button_array.c 
b/drivers/input/misc/soc_button_array.c
index 077e06e4..96012f9 100644
--- a/drivers/input/misc/soc_button_array.c
+++ b/drivers/input/misc/soc_button_array.c
@@ -19,23 +19,7 @@
 #include <linux/gpio_keys.h>
 #include <linux/gpio.h>
 #include <linux/platform_device.h>
-
-/*
- * Definition of buttons on the tablet. The ACPI index of each button
- * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
- * Platforms"
- */
-#define MAX_NBUTTONS   5
-
-struct soc_button_info {
-       const char *name;
-       int acpi_index;
-       unsigned int event_type;
-       unsigned int event_code;
-       bool autorepeat;
-       bool wakeup;
-       bool active_low;
-};
+#include <linux/input/soc_button_array.h>
 
 /*
  * Some of the buttons like volume up/down are auto repeat, while others
@@ -51,12 +35,13 @@ struct soc_button_data {
 /*
  * Get the Nth GPIO number from the ACPI object.
  */
-static int soc_button_lookup_gpio(struct device *dev, int acpi_index)
+static int soc_button_lookup_gpio(struct device *dev, const char *con_id,
+                                 int acpi_index)
 {
        struct gpio_desc *desc;
        int gpio;
 
-       desc = gpiod_get_index(dev, KBUILD_MODNAME, acpi_index, GPIOD_ASIS);
+       desc = gpiod_get_index(dev, con_id, acpi_index, GPIOD_ASIS);
        if (IS_ERR(desc))
                return PTR_ERR(desc);
 
@@ -68,7 +53,8 @@ static int soc_button_lookup_gpio(struct device *dev, int 
acpi_index)
 }
 
 static struct platform_device *
-soc_button_device_create(struct platform_device *pdev,
+soc_button_device_create(struct device *dev,
+                        const char *gpiod_con_id,
                         const struct soc_button_info *button_info,
                         bool autorepeat)
 {
@@ -80,7 +66,7 @@ soc_button_device_create(struct platform_device *pdev,
        int gpio;
        int i, error;
 
-       gpio_keys_pdata = devm_kzalloc(&pdev->dev,
+       gpio_keys_pdata = devm_kzalloc(dev,
                                       sizeof(*gpio_keys_pdata) +
                                        sizeof(*gpio_keys) * MAX_NBUTTONS,
                                       GFP_KERNEL);
@@ -93,7 +79,9 @@ soc_button_device_create(struct platform_device *pdev,
                if (info->autorepeat != autorepeat)
                        continue;
 
-               gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
+               gpio = soc_button_lookup_gpio(dev,
+                                             gpiod_con_id,
+                                             info->acpi_index);
                if (!gpio_is_valid(gpio))
                        continue;
 
@@ -142,14 +130,12 @@ soc_button_device_create(struct platform_device *pdev,
 err_free_pdev:
        platform_device_put(pd);
 err_free_mem:
-       devm_kfree(&pdev->dev, gpio_keys_pdata);
+       devm_kfree(dev, gpio_keys_pdata);
        return ERR_PTR(error);
 }
 
-static int soc_button_remove(struct platform_device *pdev)
+int soc_dev_button_remove(struct soc_button_data *priv)
 {
-       struct soc_button_data *priv = platform_get_drvdata(pdev);
-
        int i;
 
        for (i = 0; i < BUTTON_TYPES; i++)
@@ -158,40 +144,28 @@ static int soc_button_remove(struct platform_device *pdev)
 
        return 0;
 }
+EXPORT_SYMBOL_GPL(soc_dev_button_remove);
 
-static int soc_button_probe(struct platform_device *pdev)
+int soc_dev_button_enumerate(struct device *dev, struct soc_button_data *priv,
+                            const char *gpiod_con_id,
+                            struct soc_button_info *button_info)
 {
-       struct device *dev = &pdev->dev;
-       const struct acpi_device_id *id;
-       struct soc_button_info *button_info;
-       struct soc_button_data *priv;
        struct platform_device *pd;
        int i;
        int error;
 
-       id = acpi_match_device(dev->driver->acpi_match_table, dev);
-       if (!id)
-               return -ENODEV;
-
-       button_info = (struct soc_button_info *)id->driver_data;
-
-       if (gpiod_count(&pdev->dev, KBUILD_MODNAME) <= 0) {
-               dev_info(&pdev->dev, "no GPIO attached, ignoring...\n");
+       if (gpiod_count(dev, gpiod_con_id) <= 0) {
+               dev_info(dev, "no GPIO attached, ignoring...\n");
                return -ENODEV;
        }
 
-       priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
-       if (!priv)
-               return -ENOMEM;
-
-       platform_set_drvdata(pdev, priv);
-
        for (i = 0; i < BUTTON_TYPES; i++) {
-               pd = soc_button_device_create(pdev, button_info, i == 0);
+               pd = soc_button_device_create(dev, gpiod_con_id, button_info,
+                                             i == 0);
                if (IS_ERR(pd)) {
                        error = PTR_ERR(pd);
                        if (error != -ENODEV) {
-                               soc_button_remove(pdev);
+                               soc_dev_button_remove(priv);
                                return error;
                        }
                        continue;
@@ -205,6 +179,46 @@ static int soc_button_probe(struct platform_device *pdev)
 
        return 0;
 }
+EXPORT_SYMBOL_GPL(soc_dev_button_enumerate);
+
+struct soc_button_data *soc_dev_button_data_allocate(struct device *dev)
+{
+       return devm_kzalloc(dev, sizeof(struct soc_button_data), GFP_KERNEL);
+}
+EXPORT_SYMBOL_GPL(soc_dev_button_data_allocate);
+
+static int soc_button_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       const struct acpi_device_id *id;
+       struct soc_button_info *button_info;
+       struct soc_button_data *priv;
+       int error;
+
+       id = acpi_match_device(dev->driver->acpi_match_table, dev);
+       if (!id)
+               return -ENODEV;
+
+       button_info = (struct soc_button_info *)id->driver_data;
+
+       priv = soc_dev_button_data_allocate(dev);
+       if (!priv)
+               return -ENOMEM;
+
+       error = soc_dev_button_enumerate(dev, priv, KBUILD_MODNAME,
+                                        button_info);
+       if (error)
+               return error;
+
+       platform_set_drvdata(pdev, priv);
+
+       return 0;
+}
+
+static int soc_button_remove(struct platform_device *pdev)
+{
+       return soc_dev_button_remove(platform_get_drvdata(pdev));
+}
 
 static struct soc_button_info soc_button_PNP0C40[] = {
        { "power", 0, EV_KEY, KEY_POWER, false, true, true },
diff --git a/include/linux/input/soc_button_array.h 
b/include/linux/input/soc_button_array.h
new file mode 100644
index 0000000..634ce90
--- /dev/null
+++ b/include/linux/input/soc_button_array.h
@@ -0,0 +1,37 @@
+/*
+ * Supports for the button array on SoC tablets originally running
+ * Windows 8.
+ *
+ * (C) Copyright 2014 Intel Corporation
+ * (C) Copyright 2016 Red Hat, Inc
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+/*
+ * Definition of buttons on the tablet. The ACPI index of each button
+ * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
+ * Platforms"
+ */
+#define MAX_NBUTTONS   5
+
+struct soc_button_info {
+       const char *name;
+       int acpi_index;
+       unsigned int event_type;
+       unsigned int event_code;
+       bool autorepeat;
+       bool wakeup;
+       bool active_low;
+};
+
+struct soc_button_data;
+
+struct soc_button_data *soc_dev_button_data_allocate(struct device *dev);
+int soc_dev_button_remove(struct soc_button_data *priv);
+int soc_dev_button_enumerate(struct device *dev, struct soc_button_data *priv,
+                            const char *gpiod_con_id,
+                            struct soc_button_info *button_info);
-- 
2.5.0

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