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From:   Dmitry Torokhov <dmitry.torokhov@gmail.com>
To:     linux-input@vger.kernel.org, Benson Leung <bleung@chromium.org>
Cc:     Nick Dyer <nick@shmanahar.org>, linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] platform/chrome: chromeos_laptop - supply properties for ACPI devices
Date:   Thu,  3 May 2018 17:41:34 -0700
Message-Id: <20180504004135.67554-1-dmitry.torokhov@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

BayTrail-based and newer Chromebooks describe their peripherals in ACPI;
unfortunately their description is not complete, and peripherals
drivers, such as driver for Atmel Touch controllers, has to resort to
DMI-matching to configure the peripherals properly. To avoid polluting
peripheral driver code, let's teach chromeos_laptop driver to supply
missing data via generic device properties.

Note we supply "compatible" string for Atmel peripherals not because it is
needed for matching devices and driver (matching is still done on ACPI HID
entries), but because peripherals driver will be using presence of
"compatible" property to determine if device properties have been attached
to the device, and fail to bind if they are absent.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/platform/chrome/chromeos_laptop.c | 307 ++++++++++++++++++++--
 1 file changed, 278 insertions(+), 29 deletions(-)

diff --git a/drivers/platform/chrome/chromeos_laptop.c b/drivers/platform/chrome/chromeos_laptop.c
index 5c47f451e43b1..3cecf7933f751 100644
--- a/drivers/platform/chrome/chromeos_laptop.c
+++ b/drivers/platform/chrome/chromeos_laptop.c
@@ -6,6 +6,7 @@
 
 #define pr_fmt(fmt)		KBUILD_MODNAME ": " fmt
 
+#include <linux/acpi.h>
 #include <linux/dmi.h>
 #include <linux/i2c.h>
 #include <linux/input.h>
@@ -54,6 +55,11 @@ struct i2c_peripheral {
 	struct i2c_client *client;
 };
 
+struct acpi_peripheral {
+	char hid[ACPI_ID_LEN];
+	const struct property_entry *properties;
+};
+
 struct chromeos_laptop {
 	/*
 	 * Note that we can't mark this pointer as const because
@@ -61,6 +67,9 @@ struct chromeos_laptop {
 	 */
 	struct i2c_peripheral *i2c_peripherals;
 	unsigned int num_i2c_peripherals;
+
+	const struct acpi_peripheral *acpi_peripherals;
+	unsigned int num_acpi_peripherals;
 };
 
 static const struct chromeos_laptop *cros_laptop;
@@ -148,6 +157,38 @@ static void chromeos_laptop_check_adapter(struct i2c_adapter *adapter)
 	}
 }
 
+static bool chromeos_laptop_adjust_client(struct i2c_client *client)
+{
+	const struct acpi_peripheral *acpi_dev;
+	struct acpi_device_id acpi_ids[2] = { };
+	int i;
+	int error;
+
+	if (!has_acpi_companion(&client->dev))
+		return false;
+
+	for (i = 0; i < cros_laptop->num_acpi_peripherals; i++) {
+		acpi_dev = &cros_laptop->acpi_peripherals[i];
+
+		memcpy(acpi_ids[0].id, acpi_dev->hid, ACPI_ID_LEN);
+
+		if (acpi_match_device(acpi_ids, &client->dev)) {
+			error = device_add_properties(&client->dev,
+						      acpi_dev->properties);
+			if (error) {
+				dev_err(&client->dev,
+					"failed to add properties: %d\n",
+					error);
+				break;
+			}
+
+			return true;
+		}
+	}
+
+	return false;
+}
+
 static void chromeos_laptop_detach_i2c_client(struct i2c_client *client)
 {
 	struct i2c_peripheral *i2c_dev;
@@ -170,6 +211,8 @@ static int chromeos_laptop_i2c_notifier_call(struct notifier_block *nb,
 	case BUS_NOTIFY_ADD_DEVICE:
 		if (dev->type == &i2c_adapter_type)
 			chromeos_laptop_check_adapter(to_i2c_adapter(dev));
+		else if (dev->type == &i2c_client_type)
+			chromeos_laptop_adjust_client(to_i2c_client(dev));
 		break;
 
 	case BUS_NOTIFY_REMOVED_DEVICE:
@@ -191,6 +234,12 @@ static const struct chromeos_laptop _name __initconst = {		\
 	.num_i2c_peripherals	= ARRAY_SIZE(_name##_peripherals),	\
 }
 
+#define DECLARE_ACPI_CROS_LAPTOP(_name)					\
+static const struct chromeos_laptop _name __initconst = {		\
+	.acpi_peripherals	= _name##_peripherals,			\
+	.num_acpi_peripherals	= ARRAY_SIZE(_name##_peripherals),	\
+}
+
 static struct i2c_peripheral samsung_series_5_550_peripherals[] __initdata = {
 	/* Touchpad. */
 	{
@@ -234,16 +283,25 @@ static const int chromebook_pixel_tp_keys[] __initconst = {
 
 static const struct property_entry
 chromebook_pixel_trackpad_props[] __initconst = {
+	PROPERTY_ENTRY_STRING("compatible", "atmel,maxtouch"),
 	PROPERTY_ENTRY_U32_ARRAY("linux,gpio-keymap", chromebook_pixel_tp_keys),
 	{ }
 };
 
+static const struct property_entry
+chromebook_atmel_touchscreen_props[] __initconst = {
+	PROPERTY_ENTRY_STRING("compatible", "atmel,maxtouch"),
+	{ }
+};
+
 static struct i2c_peripheral chromebook_pixel_peripherals[] __initdata = {
 	/* Touch Screen. */
 	{
 		.board_info	= {
 			I2C_BOARD_INFO("atmel_mxt_ts",
 					ATMEL_TS_I2C_ADDR),
+			.properties	=
+				chromebook_atmel_touchscreen_props,
 			.flags		= I2C_CLIENT_WAKE,
 		},
 		.dmi_name	= "touchscreen",
@@ -354,6 +412,8 @@ static struct i2c_peripheral acer_c720_peripherals[] __initdata = {
 		.board_info	= {
 			I2C_BOARD_INFO("atmel_mxt_ts",
 					ATMEL_TS_I2C_ADDR),
+			.properties	=
+				chromebook_atmel_touchscreen_props,
 			.flags		= I2C_CLIENT_WAKE,
 		},
 		.dmi_name	= "touchscreen",
@@ -419,6 +479,47 @@ static struct i2c_peripheral cr48_peripherals[] __initdata = {
 };
 DECLARE_CROS_LAPTOP(cr48);
 
+static const u32 samus_touchpad_buttons[] __initconst = {
+	KEY_RESERVED,
+	KEY_RESERVED,
+	KEY_RESERVED,
+	BTN_LEFT
+};
+
+static const struct property_entry samus_trackpad_props[] __initconst = {
+	PROPERTY_ENTRY_STRING("compatible", "atmel,maxtouch"),
+	PROPERTY_ENTRY_U32_ARRAY("linux,gpio-keymap", samus_touchpad_buttons),
+	{ }
+};
+
+static struct acpi_peripheral samus_peripherals[] __initdata = {
+	/* Touchpad */
+	{
+		.hid		= "ATML0000",
+		.properties	= samus_trackpad_props,
+	},
+	/* Touchsceen */
+	{
+		.hid		= "ATML0001",
+		.properties	= chromebook_atmel_touchscreen_props,
+	},
+};
+DECLARE_ACPI_CROS_LAPTOP(samus);
+
+static struct acpi_peripheral generic_atmel_peripherals[] __initdata = {
+	/* Touchpad */
+	{
+		.hid		= "ATML0000",
+		.properties	= chromebook_pixel_trackpad_props,
+	},
+	/* Touchsceen */
+	{
+		.hid		= "ATML0001",
+		.properties	= chromebook_atmel_touchscreen_props,
+	},
+};
+DECLARE_ACPI_CROS_LAPTOP(generic_atmel);
+
 static const struct dmi_system_id chromeos_laptop_dmi_table[] __initconst = {
 	{
 		.ident = "Samsung Series 5 550",
@@ -502,17 +603,64 @@ static const struct dmi_system_id chromeos_laptop_dmi_table[] __initconst = {
 		},
 		.driver_data = (void *)&cr48,
 	},
+	/* Devices with peripherals incompletely described in ACPI */
+	{
+		.ident = "Chromebook Pro",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Google"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Caroline"),
+		},
+		.driver_data = (void *)&samus,
+	},
+	{
+		.ident = "Google Pixel 2 (2015)",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Samus"),
+		},
+		.driver_data = (void *)&samus,
+	},
+	{
+		/*
+		 * Other Chromebooks with Atmel touch controllers:
+		 * - Celes, Winky (touchpad)
+		 * - Clapper, Expresso, Rambi, Glimmer (touchscreen)
+		 */
+		.ident = "Other Chromebook",
+		.matches = {
+			/*
+			 * This will match all Google devices, not only devices
+			 * with Atmel, but we will validate that the device
+			 * actually has matching peripherals.
+			 */
+			DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
+		},
+		.driver_data = (void *)&generic_atmel,
+	},
 	{ }
 };
 MODULE_DEVICE_TABLE(dmi, chromeos_laptop_dmi_table);
 
-static int __init chromeos_laptop_scan_adapter(struct device *dev, void *data)
+static int __init chromeos_laptop_scan_peripherals(struct device *dev, void *data)
 {
-	struct i2c_adapter *adapter;
+	int error;
 
-	adapter = i2c_verify_adapter(dev);
-	if (adapter)
-		chromeos_laptop_check_adapter(adapter);
+	if (dev->type == &i2c_adapter_type) {
+		chromeos_laptop_check_adapter(to_i2c_adapter(dev));
+	} else if (dev->type == &i2c_client_type) {
+		if (chromeos_laptop_adjust_client(to_i2c_client(dev))) {
+			/*
+			 * Now that we have needed properties re-trigger
+			 * driver probe in case driver was initialized
+			 * earlier and probe failed.
+			 */
+			error = device_attach(dev);
+			if (error < 0)
+				dev_warn(dev,
+					 "%s: device_attach() failed: %d\n",
+					 __func__, error);
+		}
+	}
 
 	return 0;
 }
@@ -556,27 +704,24 @@ static int __init chromeos_laptop_setup_irq(struct i2c_peripheral *i2c_dev)
 	return 0;
 }
 
-static struct chromeos_laptop * __init
-chromeos_laptop_prepare(const struct chromeos_laptop *src)
+static int __init
+chromeos_laptop_prepare_i2c_peripherals(struct chromeos_laptop *cros_laptop,
+					const struct chromeos_laptop *src)
 {
-	struct chromeos_laptop *cros_laptop;
 	struct i2c_peripheral *i2c_dev;
 	struct i2c_board_info *info;
-	int error;
 	int i;
+	int error;
 
-	cros_laptop = kzalloc(sizeof(*cros_laptop), GFP_KERNEL);
-	if (!cros_laptop)
-		return ERR_PTR(-ENOMEM);
+	if (!src->num_i2c_peripherals)
+		return 0;
 
 	cros_laptop->i2c_peripherals = kmemdup(src->i2c_peripherals,
 					       src->num_i2c_peripherals *
 						sizeof(*src->i2c_peripherals),
 					       GFP_KERNEL);
-	if (!cros_laptop->i2c_peripherals) {
-		error = -ENOMEM;
-		goto err_free_cros_laptop;
-	}
+	if (!cros_laptop->i2c_peripherals)
+		return -ENOMEM;
 
 	cros_laptop->num_i2c_peripherals = src->num_i2c_peripherals;
 
@@ -586,7 +731,7 @@ chromeos_laptop_prepare(const struct chromeos_laptop *src)
 
 		error = chromeos_laptop_setup_irq(i2c_dev);
 		if (error)
-			goto err_destroy_cros_peripherals;
+			goto err_out;
 
 		/* We need to deep-copy properties */
 		if (info->properties) {
@@ -594,14 +739,14 @@ chromeos_laptop_prepare(const struct chromeos_laptop *src)
 				property_entries_dup(info->properties);
 			if (IS_ERR(info->properties)) {
 				error = PTR_ERR(info->properties);
-				goto err_destroy_cros_peripherals;
+				goto err_out;
 			}
 		}
 	}
 
-	return cros_laptop;
+	return 0;
 
-err_destroy_cros_peripherals:
+err_out:
 	while (--i >= 0) {
 		i2c_dev = &cros_laptop->i2c_peripherals[i];
 		info = &i2c_dev->board_info;
@@ -609,13 +754,74 @@ chromeos_laptop_prepare(const struct chromeos_laptop *src)
 			property_entries_free(info->properties);
 	}
 	kfree(cros_laptop->i2c_peripherals);
-err_free_cros_laptop:
-	kfree(cros_laptop);
-	return ERR_PTR(error);
+	return error;
+}
+
+static int __init
+chromeos_laptop_prepare_acpi_peripherals(struct chromeos_laptop *cros_laptop,
+					const struct chromeos_laptop *src)
+{
+	struct acpi_peripheral *acpi_peripherals;
+	struct acpi_peripheral *acpi_dev;
+	const struct acpi_peripheral *src_dev;
+	int n_peripherals = 0;
+	int i;
+	int error;
+
+	for (i = 0; i < src->num_acpi_peripherals; i++) {
+		if (acpi_dev_present(src->acpi_peripherals[i].hid, NULL, -1))
+			n_peripherals++;
+	}
+
+	if (!n_peripherals)
+		return 0;
+
+	acpi_peripherals = kcalloc(n_peripherals,
+				   sizeof(*src->acpi_peripherals),
+				   GFP_KERNEL);
+	if (!acpi_peripherals)
+		return -ENOMEM;
+
+	acpi_dev = acpi_peripherals;
+	for (i = 0; i < src->num_acpi_peripherals; i++) {
+		src_dev = &src->acpi_peripherals[i];
+		if (!acpi_dev_present(src_dev->hid, NULL, -1))
+			continue;
+
+		*acpi_dev = *src_dev;
+
+		/* We need to deep-copy properties */
+		if (src_dev->properties) {
+			acpi_dev->properties =
+				property_entries_dup(src_dev->properties);
+			if (IS_ERR(acpi_dev->properties)) {
+				error = PTR_ERR(acpi_dev->properties);
+				goto err_out;
+			}
+		}
+
+		acpi_dev++;
+	}
+
+	cros_laptop->acpi_peripherals = acpi_peripherals;
+	cros_laptop->num_acpi_peripherals = n_peripherals;
+
+	return 0;
+
+err_out:
+	while (--i >= 0) {
+		acpi_dev = &acpi_peripherals[i];
+		if (acpi_dev->properties)
+			property_entries_free(acpi_dev->properties);
+	}
+
+	kfree(acpi_peripherals);
+	return error;
 }
 
 static void chromeos_laptop_destroy(const struct chromeos_laptop *cros_laptop)
 {
+	const struct acpi_peripheral *acpi_dev;
 	struct i2c_peripheral *i2c_dev;
 	struct i2c_board_info *info;
 	int i;
@@ -631,10 +837,41 @@ static void chromeos_laptop_destroy(const struct chromeos_laptop *cros_laptop)
 			property_entries_free(info->properties);
 	}
 
+	for (i = 0; i < cros_laptop->num_acpi_peripherals; i++) {
+		acpi_dev = &cros_laptop->acpi_peripherals[i];
+
+		if (acpi_dev->properties)
+			property_entries_free(acpi_dev->properties);
+	}
+
 	kfree(cros_laptop->i2c_peripherals);
+	kfree(cros_laptop->acpi_peripherals);
 	kfree(cros_laptop);
 }
 
+static struct chromeos_laptop * __init
+chromeos_laptop_prepare(const struct chromeos_laptop *src)
+{
+	struct chromeos_laptop *cros_laptop;
+	int error;
+
+	cros_laptop = kzalloc(sizeof(*cros_laptop), GFP_KERNEL);
+	if (!cros_laptop)
+		return ERR_PTR(-ENOMEM);
+
+	error = chromeos_laptop_prepare_i2c_peripherals(cros_laptop, src);
+	if (!error)
+		error = chromeos_laptop_prepare_acpi_peripherals(cros_laptop,
+								 src);
+
+	if (error) {
+		chromeos_laptop_destroy(cros_laptop);
+		return ERR_PTR(error);
+	}
+
+	return cros_laptop;
+}
+
 static int __init chromeos_laptop_init(void)
 {
 	const struct dmi_system_id *dmi_id;
@@ -652,21 +889,33 @@ static int __init chromeos_laptop_init(void)
 	if (IS_ERR(cros_laptop))
 		return PTR_ERR(cros_laptop);
 
+	if (!cros_laptop->num_i2c_peripherals &&
+	    !cros_laptop->num_acpi_peripherals) {
+		pr_debug("no relevant devices detected\n");
+		error = -ENODEV;
+		goto err_destroy_cros_laptop;
+	}
+
 	error = bus_register_notifier(&i2c_bus_type,
 				      &chromeos_laptop_i2c_notifier);
 	if (error) {
-		pr_err("failed to register i2c bus notifier: %d\n", error);
-		chromeos_laptop_destroy(cros_laptop);
-		return error;
+		pr_err("failed to register i2c bus notifier: %d\n",
+		       error);
+		goto err_destroy_cros_laptop;
 	}
 
 	/*
-	 * Scan adapters that have been registered before we installed
-	 * the notifier to make sure we do not miss any devices.
+	 * Scan adapters that have been registered and clients that have
+	 * been created before we installed the notifier to make sure
+	 * we do not miss any devices.
 	 */
-	i2c_for_each_dev(NULL, chromeos_laptop_scan_adapter);
+	i2c_for_each_dev(NULL, chromeos_laptop_scan_peripherals);
 
 	return 0;
+
+err_destroy_cros_laptop:
+	chromeos_laptop_destroy(cros_laptop);
+	return error;
 }
 
 static void __exit chromeos_laptop_exit(void)
-- 
2.17.0.441.gb46fe60e1d-goog