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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: Enrik Berkhan <Enrik.Berkhan@inka.de>
Signed-off-by: Enrik Berkhan <Enrik.Berkhan@inka.de>
Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Michael Zaidman 2022-11-05 23:11:48 +02:00 committed by Jiri Kosina
parent 728b117e78
commit 4b3da6853a
1 changed files with 17 additions and 0 deletions
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17
drivers/hid/hid-ft260.c
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@ -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)) {