[PATCH v3 3/4] HID: google: Add support for vivaldi to hid-hammer

[Stephen Boyd]

Add support to the hammer driver to parse vivaldi keyboard layouts and
expose them to userspace. This allows hammer devices to use vivaldi
function row keys while also supporting the other features this driver
supports, like the CBAS (chrome base attached switch) and a keyboard
backlight.

Cc: Jiri Kosina <jikos@xxxxxxxxxx>
Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Cc: "Sean O'Brien" <seobrien@xxxxxxxxxxxx>
Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Zhengqiao Xia <xiazhengqiao@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
---
 drivers/hid/Kconfig             |  1 +
 drivers/hid/hid-google-hammer.c | 95 +++++++++++++++++++++++++--------
 2 files changed, 75 insertions(+), 21 deletions(-)

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index ea8fa71c9e9c..4bea966e617b 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -413,6 +413,7 @@ config HID_VIVALDI_COMMON
 config HID_GOOGLE_HAMMER
 	tristate "Google Hammer Keyboard"
 	select HID_VIVALDI_COMMON
+	select INPUT_VIVALDIFMAP
 	depends on USB_HID && LEDS_CLASS && CROS_EC
 	help
 	Say Y here if you have a Google Hammer device.
diff --git a/drivers/hid/hid-google-hammer.c b/drivers/hid/hid-google-hammer.c
index 0403beb3104b..e3dd26ddbd43 100644
--- a/drivers/hid/hid-google-hammer.c
+++ b/drivers/hid/hid-google-hammer.c
@@ -15,6 +15,7 @@
 
 #include <linux/acpi.h>
 #include <linux/hid.h>
+#include <linux/input/vivaldi-keymap.h>
 #include <linux/leds.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -22,6 +23,7 @@
 #include <linux/platform_data/cros_ec_proto.h>
 #include <linux/platform_device.h>
 #include <linux/pm_wakeup.h>
+#include <linux/sysfs.h>
 #include <asm/unaligned.h>
 
 #include "hid-ids.h"
@@ -300,6 +302,11 @@ struct hammer_kbd_leds {
 	u8 buf[2] ____cacheline_aligned;
 };
 
+struct hammer_drvdata {
+	struct vivaldi_data vdata;
+	struct hammer_kbd_leds leds;
+};
+
 static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
 		enum led_brightness br)
 {
@@ -337,15 +344,11 @@ static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
 	return ret;
 }
 
-static int hammer_register_leds(struct hid_device *hdev)
+static int hammer_register_leds(struct hammer_drvdata *hdata, struct hid_device *hdev)
 {
 	struct hammer_kbd_leds *kbd_backlight;
-	int error;
-
-	kbd_backlight = kzalloc(sizeof(*kbd_backlight), GFP_KERNEL);
-	if (!kbd_backlight)
-		return -ENOMEM;
 
+	kbd_backlight = &hdata->leds;
 	kbd_backlight->hdev = hdev;
 	kbd_backlight->cdev.name = "hammer::kbd_backlight";
 	kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
@@ -356,26 +359,16 @@ static int hammer_register_leds(struct hid_device *hdev)
 	/* Set backlight to 0% initially. */
 	hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);
 
-	error = led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
-	if (error)
-		goto err_free_mem;
-
-	hid_set_drvdata(hdev, kbd_backlight);
-	return 0;
-
-err_free_mem:
-	kfree(kbd_backlight);
-	return error;
+	return led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
 }
 
 static void hammer_unregister_leds(struct hid_device *hdev)
 {
-	struct hammer_kbd_leds *kbd_backlight = hid_get_drvdata(hdev);
+	struct hammer_drvdata *hdata = hid_get_drvdata(hdev);
+	struct hammer_kbd_leds *kbd_backlight = &hdata->leds;
 
-	if (kbd_backlight) {
+	if (kbd_backlight)
 		led_classdev_unregister(&kbd_backlight->cdev);
-		kfree(kbd_backlight);
-	}
 }
 
 #define HID_UP_GOOGLEVENDOR	0xffd10000
@@ -385,6 +378,58 @@ static void hammer_unregister_leds(struct hid_device *hdev)
 /* HID usage for keyboard backlight (Alphanumeric display brightness) */
 #define HID_AD_BRIGHTNESS	0x00140046
 
+static void hammer_feature_mapping(struct hid_device *hdev,
+				   struct hid_field *field,
+				   struct hid_usage *usage)
+{
+	struct hammer_drvdata *hdata = hid_get_drvdata(hdev);
+
+	vivaldi_hid_feature_mapping(&hdata->vdata, hdev, field, usage);
+}
+
+static ssize_t function_row_physmap_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct hammer_drvdata *hdata = hid_get_drvdata(hdev);
+	struct vivaldi_data *vdata = &hdata->vdata;
+
+	return vivaldi_function_row_physmap_show(vdata, buf);
+}
+
+static DEVICE_ATTR_RO(function_row_physmap);
+static struct attribute *hammer_sysfs_attrs[] = {
+	&dev_attr_function_row_physmap.attr,
+	NULL
+};
+
+static umode_t hammer_attr_is_visible(struct kobject *kobj,
+				      struct attribute *attr, int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct hid_device *hdev = to_hid_device(dev);
+	struct hammer_drvdata *hdata = hid_get_drvdata(hdev);
+	struct vivaldi_data *vdata = &hdata->vdata;
+
+	if (attr == &dev_attr_function_row_physmap.attr &&
+	    !vdata->num_function_row_keys)
+		return 0;
+
+	return attr->mode;
+}
+
+static const struct attribute_group input_attribute_group = {
+	.is_visible = hammer_attr_is_visible,
+	.attrs = hammer_sysfs_attrs,
+};
+
+static int hammer_input_configured(struct hid_device *hdev,
+				   struct hid_input *hidinput)
+{
+	return sysfs_create_group(&hdev->dev.kobj, &input_attribute_group);
+}
+
 static int hammer_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 				struct hid_field *field,
 				struct hid_usage *usage,
@@ -516,6 +561,12 @@ static int hammer_probe(struct hid_device *hdev,
 			const struct hid_device_id *id)
 {
 	int error;
+	struct hammer_drvdata *hdata;
+
+	hdata = devm_kzalloc(&hdev->dev, sizeof(*hdata), GFP_KERNEL);
+	if (!hdata)
+		return -ENOMEM;
+	hid_set_drvdata(hdev, hdata);
 
 	error = hid_parse(hdev);
 	if (error)
@@ -541,7 +592,7 @@ static int hammer_probe(struct hid_device *hdev,
 	}
 
 	if (hammer_has_backlight_control(hdev)) {
-		error = hammer_register_leds(hdev);
+		error = hammer_register_leds(hdata, hdev);
 		if (error)
 			hid_warn(hdev,
 				"Failed to register keyboard backlight: %d\n",
@@ -610,6 +661,8 @@ static struct hid_driver hammer_driver = {
 	.id_table = hammer_devices,
 	.probe = hammer_probe,
 	.remove = hammer_remove,
+	.feature_mapping = hammer_feature_mapping,
+	.input_configured = hammer_input_configured,
 	.input_mapping = hammer_input_mapping,
 	.event = hammer_event,
 };
-- 
https://chromeos.dev