HID: i2c-hid: add DT bindings
Add device tree based support for HID over I2C devices. Tested on an Odroid-X board with a Synaptics touchpad. Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Documentation/devicetree/bindings/hid/hid-over-i2c.txt
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28
Documentation/devicetree/bindings/hid/hid-over-i2c.txt
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* HID over I2C Device-Tree bindings
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HID over I2C provides support for various Human Interface Devices over the
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I2C bus. These devices can be for example touchpads, keyboards, touch screens
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or sensors.
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The specification has been written by Microsoft and is currently available here:
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http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
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If this binding is used, the kernel module i2c-hid will handle the communication
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with the device and the generic hid core layer will handle the protocol.
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Required properties:
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- compatible: must be "hid-over-i2c"
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- reg: i2c slave address
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- hid-descr-addr: HID descriptor address
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- interrupt-parent: the phandle for the interrupt controller
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- interrupts: interrupt line
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Example:
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i2c-hid-dev@2c {
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compatible = "hid-over-i2c";
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reg = <0x2c>;
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hid-descr-addr = <0x0020>;
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interrupt-parent = <&gpx3>;
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interrupts = <3 2>;
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};
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@ -35,6 +35,7 @@
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#include <linux/hid.h>
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#include <linux/mutex.h>
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#include <linux/acpi.h>
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#include <linux/of.h>
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#include <linux/i2c/i2c-hid.h>
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@ -933,6 +934,42 @@ static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
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}
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#endif
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#ifdef CONFIG_OF
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static int i2c_hid_of_probe(struct i2c_client *client,
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struct i2c_hid_platform_data *pdata)
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{
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struct device *dev = &client->dev;
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u32 val;
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int ret;
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ret = of_property_read_u32(dev->of_node, "hid-descr-addr", &val);
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if (ret) {
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dev_err(&client->dev, "HID register address not provided\n");
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return -ENODEV;
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}
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if (val >> 16) {
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dev_err(&client->dev, "Bad HID register address: 0x%08x\n",
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val);
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return -EINVAL;
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}
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pdata->hid_descriptor_address = val;
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return 0;
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}
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static const struct of_device_id i2c_hid_of_match[] = {
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{ .compatible = "hid-over-i2c" },
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{},
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};
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MODULE_DEVICE_TABLE(of, i2c_hid_of_match);
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#else
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static inline int i2c_hid_of_probe(struct i2c_client *client,
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struct i2c_hid_platform_data *pdata)
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{
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return -ENODEV;
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}
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#endif
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static int i2c_hid_probe(struct i2c_client *client,
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const struct i2c_device_id *dev_id)
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{
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if (!ihid)
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return -ENOMEM;
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if (!platform_data) {
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if (client->dev.of_node) {
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ret = i2c_hid_of_probe(client, &ihid->pdata);
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if (ret)
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goto err;
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} else if (!platform_data) {
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ret = i2c_hid_acpi_pdata(client, &ihid->pdata);
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if (ret) {
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dev_err(&client->dev,
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@ -1095,6 +1136,7 @@ static struct i2c_driver i2c_hid_driver = {
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.owner = THIS_MODULE,
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.pm = &i2c_hid_pm,
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.acpi_match_table = ACPI_PTR(i2c_hid_acpi_match),
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.of_match_table = of_match_ptr(i2c_hid_of_match),
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},
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.probe = i2c_hid_probe,
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@ -19,7 +19,8 @@
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* @hid_descriptor_address: i2c register where the HID descriptor is stored.
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*
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* Note that it is the responsibility of the platform driver (or the acpi 5.0
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* driver) to setup the irq related to the gpio in the struct i2c_board_info.
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* driver, or the flattened device tree) to setup the irq related to the gpio in
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* the struct i2c_board_info.
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* The platform driver should also setup the gpio according to the device:
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*
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* A typical example is the following:
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