Commit 4b3da685 authored by Michael Zaidman's avatar Michael Zaidman Committed by Jiri Kosina
Browse files

HID: ft260: wake up device from power saving mode 



The FT260 can enter a power saving mode after being idle for longer
than 5 seconds.

When being woken up from power saving mode by an I2C write request,
a possible NACK is not correctly reported by the controller. As a
workaround, the driver will issue an I2C status report two times in
ft260_xfer_status() after the chip has been idle for more than 5s.

Co-developed-by: default avatarEnrik Berkhan <Enrik.Berkhan@inka.de>
Signed-off-by: default avatarEnrik Berkhan <Enrik.Berkhan@inka.de>
Signed-off-by: default avatarMichael Zaidman <michael.zaidman@gmail.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 728b117e

drivers/hid/hid-ft260.c

+17 −0
Original line number Diff line number Diff line
@@ -31,6 +31,8 @@ MODULE_PARM_DESC(debug, "Toggle FT260 debugging messages"); 
#define FT260_REPORT_MAX_LENGTH (64)

#define FT260_I2C_DATA_REPORT_ID(len) (FT260_I2C_REPORT_MIN + (len - 1) / 4)



#define FT260_WAKEUP_NEEDED_AFTER_MS (4800) /* 5s minus 200ms margin */



/*

 * The ft260 input report format defines 62 bytes for the data payload, but

 * when requested 62 bytes, the controller returns 60 and 2 in separate input
@@ -237,6 +239,7 @@ struct ft260_device { 
	struct completion wait;

	struct mutex lock;

	u8 write_buf[FT260_REPORT_MAX_LENGTH];

	unsigned long need_wakeup_at;

	u8 *read_buf;

	u16 read_idx;

	u16 read_len;
@@ -306,6 +309,20 @@ static int ft260_xfer_status(struct ft260_device *dev) 
	struct ft260_get_i2c_status_report report;

	int ret;



	if (time_is_before_jiffies(dev->need_wakeup_at)) {

		ret = ft260_hid_feature_report_get(hdev, FT260_I2C_STATUS,

						(u8 *)&report, sizeof(report));

		if (unlikely(ret < 0)) {

			hid_err(hdev, "failed to retrieve status: %d, no wakeup\n",

				ret);

		} else {

			dev->need_wakeup_at = jiffies +

				msecs_to_jiffies(FT260_WAKEUP_NEEDED_AFTER_MS);

			ft260_dbg("bus_status %#02x, wakeup\n",

				  report.bus_status);

		}

	}



	ret = ft260_hid_feature_report_get(hdev, FT260_I2C_STATUS,

					   (u8 *)&report, sizeof(report));

	if (unlikely(ret < 0)) {