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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>
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1 changed files with 17 additions and 0 deletions
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@ -31,6 +31,8 @@ MODULE_PARM_DESC(debug, "Toggle FT260 debugging messages");
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#define FT260_REPORT_MAX_LENGTH (64)
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#define FT260_I2C_DATA_REPORT_ID(len) (FT260_I2C_REPORT_MIN + (len - 1) / 4)
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#define FT260_WAKEUP_NEEDED_AFTER_MS (4800) /* 5s minus 200ms margin */
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/*
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* The ft260 input report format defines 62 bytes for the data payload, but
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* when requested 62 bytes, the controller returns 60 and 2 in separate input
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@ -237,6 +239,7 @@ struct ft260_device {
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struct completion wait;
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struct mutex lock;
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u8 write_buf[FT260_REPORT_MAX_LENGTH];
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unsigned long need_wakeup_at;
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u8 *read_buf;
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u16 read_idx;
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u16 read_len;
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@ -306,6 +309,20 @@ static int ft260_xfer_status(struct ft260_device *dev)
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struct ft260_get_i2c_status_report report;
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int ret;
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if (time_is_before_jiffies(dev->need_wakeup_at)) {
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ret = ft260_hid_feature_report_get(hdev, FT260_I2C_STATUS,
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(u8 *)&report, sizeof(report));
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if (unlikely(ret < 0)) {
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hid_err(hdev, "failed to retrieve status: %d, no wakeup\n",
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ret);
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} else {
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dev->need_wakeup_at = jiffies +
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msecs_to_jiffies(FT260_WAKEUP_NEEDED_AFTER_MS);
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ft260_dbg("bus_status %#02x, wakeup\n",
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report.bus_status);
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}
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}
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ret = ft260_hid_feature_report_get(hdev, FT260_I2C_STATUS,
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(u8 *)&report, sizeof(report));
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if (unlikely(ret < 0)) {
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