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HID: ft260: missed NACK from busy device

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When writing into a slow device like an EEPROM chip, the
controller may exit the busy state before the device releases
the bus. In this case, the ft260_xfer_status returns success
before the data transfer completion.

The patch fixes it by returning from the ft260_xfer_status()
with the "-EAGAIN" on both controller and bus busy status when
appropriate.

It does not apply to the i2c combined transactions when after
the write IO, the controller keeps the bus busy until the read
IO and then between reading IOs to ensure an atomic operation.

Co-developed-by: Germain Hebert <germain.hebert@ca.abb.com>
Signed-off-by: Germain Hebert <germain.hebert@ca.abb.com>
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 23:11:50 +02:00 committed by Jiri Kosina
parent c2500bdffe
commit 5afac727de
1 changed files with 22 additions and 5 deletions
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27
drivers/hid/hid-ft260.c
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@ -303,7 +303,7 @@ static int ft260_i2c_reset(struct hid_device *hdev)
return ret;
}
static int ft260_xfer_status(struct ft260_device *dev)
static int ft260_xfer_status(struct ft260_device *dev, u8 bus_busy)
{
struct hid_device *hdev = dev->hdev;
struct ft260_get_i2c_status_report report;
@ -334,7 +334,7 @@ static int ft260_xfer_status(struct ft260_device *dev)
ft260_dbg("bus_status %#02x, clock %u\n", report.bus_status,
dev->clock);
if (report.bus_status & FT260_I2C_STATUS_CTRL_BUSY)
if (report.bus_status & (FT260_I2C_STATUS_CTRL_BUSY | bus_busy))
return -EAGAIN;
/*
@ -369,8 +369,11 @@ static int ft260_hid_output_report(struct hid_device *hdev, u8 *data,
static int ft260_hid_output_report_check_status(struct ft260_device *dev,
u8 *data, int len)
{
u8 bus_busy;
int ret, usec, try = 100;
struct hid_device *hdev = dev->hdev;
struct ft260_i2c_write_request_report *rep =
(struct ft260_i2c_write_request_report *)data;
ret = ft260_hid_output_report(hdev, data, len);
if (ret < 0) {
@ -388,8 +391,18 @@ static int ft260_hid_output_report_check_status(struct ft260_device *dev,
ft260_dbg("wait %d usec, len %d\n", usec, len);
}
/*
* Do not check the busy bit for combined transactions
* since the controller keeps the bus busy between writing
* and reading IOs to ensure an atomic operation.
*/
if (rep->flag == FT260_FLAG_START)
bus_busy = 0;
else
bus_busy = FT260_I2C_STATUS_BUS_BUSY;
do {
ret = ft260_xfer_status(dev);
ret = ft260_xfer_status(dev, bus_busy);
if (ret != -EAGAIN)
break;
} while (--try);
@ -488,6 +501,7 @@ static int ft260_i2c_read(struct ft260_device *dev, u8 addr, u8 *data,
int timeout, ret = 0;
struct ft260_i2c_read_request_report rep;
struct hid_device *hdev = dev->hdev;
u8 bus_busy = 0;
if ((flag & FT260_FLAG_START_REPEATED) == FT260_FLAG_START_REPEATED)
flag = FT260_FLAG_START_REPEATED;
@ -531,7 +545,10 @@ static int ft260_i2c_read(struct ft260_device *dev, u8 addr, u8 *data,
dev->read_buf = NULL;
ret = ft260_xfer_status(dev);
if (flag & FT260_FLAG_STOP)
bus_busy = FT260_I2C_STATUS_BUS_BUSY;
ret = ft260_xfer_status(dev, bus_busy);
if (ret < 0) {
ret = -EIO;
ft260_i2c_reset(hdev);
@ -1003,7 +1020,7 @@ static int ft260_probe(struct hid_device *hdev, const struct hid_device_id *id)
mutex_init(&dev->lock);
init_completion(&dev->wait);
ret = ft260_xfer_status(dev);
ret = ft260_xfer_status(dev, FT260_I2C_STATUS_BUS_BUSY);
if (ret)
ft260_i2c_reset(hdev);