Hi maintainers,
Please consider backporting the following patches to the stable trees. These patches fix a significant reading issue with mcp2221 on i2c eeprom.
I have confirmed that the patches applie cleanly and build successfully against v6.6, v6.1, v5.15 and v5.10 stable branches.
I will later come back to you with other patches that might need larger backport changes.
Thanks,
Romain
Hamish Martin (2): HID: mcp2221: Don't set bus speed on every transfer HID: mcp2221: Handle reads greater than 60 bytes
drivers/hid/hid-mcp2221.c | 71 +++++++++++++++++++++++++++------------ 1 file changed, 49 insertions(+), 22 deletions(-)
From: Hamish Martin hamish.martin@alliedtelesis.co.nz
[ Upstream commit 02a46753601a24e1673d9c28173121055e8e6cc9 ]
Since the initial commit of this driver the I2C bus speed has been reconfigured for every single transfer. This is despite the fact that we never change the speed and it is never "lost" by the chip. Upon investigation we find that what was really happening was that the setting of the bus speed had the side effect of cancelling a previous failed command if there was one, thereby freeing the bus. This is the part that was actually required to keep the bus operational in the face of failed commands.
Instead of always setting the speed, we now correctly cancel any failed commands as they are detected. This means we can just set the bus speed at probe time and remove the previous speed sets on each transfer. This has the effect of improving performance and reducing the number of commands required to complete transfers.
Fixes: 67a95c21463d ("HID: mcp2221: add usb to i2c-smbus host bridge") Signed-off-by: Hamish Martin hamish.martin@alliedtelesis.co.nz Signed-off-by: Jiri Kosina jkosina@suse.cz [romain.sioen@microchip.com: backport to stable, up to 6.8. Add "Fixes" tag] Signed-off-by: Romain Sioen romain.sioen@microchip.com --- drivers/hid/hid-mcp2221.c | 41 ++++++++++++++++++++++++++------------- 1 file changed, 27 insertions(+), 14 deletions(-)
diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c index c5bfca8ac5e6..ce4e8e6b3d86 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -187,6 +187,25 @@ static int mcp_cancel_last_cmd(struct mcp2221 *mcp) return mcp_send_data_req_status(mcp, mcp->txbuf, 8); }
+/* Check if the last command succeeded or failed and return the result. + * If the command did fail, cancel that command which will free the i2c bus. + */ +static int mcp_chk_last_cmd_status_free_bus(struct mcp2221 *mcp) +{ + int ret; + + ret = mcp_chk_last_cmd_status(mcp); + if (ret) { + /* The last command was a failure. + * Send a cancel which will also free the bus. + */ + usleep_range(980, 1000); + mcp_cancel_last_cmd(mcp); + } + + return ret; +} + static int mcp_set_i2c_speed(struct mcp2221 *mcp) { int ret; @@ -241,7 +260,7 @@ static int mcp_i2c_write(struct mcp2221 *mcp, usleep_range(980, 1000);
if (last_status) { - ret = mcp_chk_last_cmd_status(mcp); + ret = mcp_chk_last_cmd_status_free_bus(mcp); if (ret) return ret; } @@ -308,7 +327,7 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, if (ret) return ret;
- ret = mcp_chk_last_cmd_status(mcp); + ret = mcp_chk_last_cmd_status_free_bus(mcp); if (ret) return ret;
@@ -328,11 +347,6 @@ static int mcp_i2c_xfer(struct i2c_adapter *adapter,
mutex_lock(&mcp->lock);
- /* Setting speed before every transaction is required for mcp2221 */ - ret = mcp_set_i2c_speed(mcp); - if (ret) - goto exit; - if (num == 1) { if (msgs->flags & I2C_M_RD) { ret = mcp_i2c_smbus_read(mcp, msgs, MCP2221_I2C_RD_DATA, @@ -417,9 +431,7 @@ static int mcp_smbus_write(struct mcp2221 *mcp, u16 addr, if (last_status) { usleep_range(980, 1000);
- ret = mcp_chk_last_cmd_status(mcp); - if (ret) - return ret; + ret = mcp_chk_last_cmd_status_free_bus(mcp); }
return ret; @@ -437,10 +449,6 @@ static int mcp_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
mutex_lock(&mcp->lock);
- ret = mcp_set_i2c_speed(mcp); - if (ret) - goto exit; - switch (size) {
case I2C_SMBUS_QUICK: @@ -1152,6 +1160,11 @@ static int mcp2221_probe(struct hid_device *hdev, if (i2c_clk_freq < 50) i2c_clk_freq = 50; mcp->cur_i2c_clk_div = (12000000 / (i2c_clk_freq * 1000)) - 3; + ret = mcp_set_i2c_speed(mcp); + if (ret) { + hid_err(hdev, "can't set i2c speed: %d\n", ret); + return ret; + }
mcp->adapter.owner = THIS_MODULE; mcp->adapter.class = I2C_CLASS_HWMON;
From: Hamish Martin hamish.martin@alliedtelesis.co.nz
[ Upstream commit 2682468671aa0b4d52ae09779b48212a80d71b91 ]
When a user requests more than 60 bytes of data the MCP2221 must chunk the data in chunks up to 60 bytes long (see command/response code 0x40 in the datasheet). In order to signal that the device has more data the (undocumented) byte at byte index 2 of the Get I2C Data response uses the value 0x54. This contrasts with the case for the final data chunk where the value returned is 0x55 (MCP2221_I2C_READ_COMPL). The fact that 0x55 was not returned in the response was interpreted by the driver as a failure meaning that all reads of more than 60 bytes would fail.
Add support for reads that are split over multiple chunks by looking for the response code indicating that more data is expected and continuing the read as the code intended. Some timing delays are required to ensure the chip has time to refill its FIFO as data is read in from the I2C bus. This timing has been tested in my system when configured for bus speeds of 50KHz, 100KHz, and 400KHz and operates well.
Fixes: 67a95c21463d0 ("HID: mcp2221: add usb to i2c-smbus host bridge") Signed-off-by: Hamish Martin hamish.martin@alliedtelesis.co.nz Signed-off-by: Jiri Kosina jkosina@suse.cz [romain.sioen@microchip.com: backport to stable, up to 6.8. Add "Fixes" tag] Signed-off-by: Romain Sioen romain.sioen@microchip.com --- drivers/hid/hid-mcp2221.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-)
diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c index ce4e8e6b3d86..a985301a4135 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -49,6 +49,7 @@ enum { MCP2221_I2C_MASK_ADDR_NACK = 0x40, MCP2221_I2C_WRADDRL_SEND = 0x21, MCP2221_I2C_ADDR_NACK = 0x25, + MCP2221_I2C_READ_PARTIAL = 0x54, MCP2221_I2C_READ_COMPL = 0x55, MCP2221_ALT_F_NOT_GPIOV = 0xEE, MCP2221_ALT_F_NOT_GPIOD = 0xEF, @@ -297,6 +298,7 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, { int ret; u16 total_len; + int retries = 0;
mcp->txbuf[0] = type; if (msg) { @@ -320,20 +322,31 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, mcp->rxbuf_idx = 0;
do { + /* Wait for the data to be read by the device */ + usleep_range(980, 1000); + memset(mcp->txbuf, 0, 4); mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1); - if (ret) - return ret; - - ret = mcp_chk_last_cmd_status_free_bus(mcp); - if (ret) - return ret; - - usleep_range(980, 1000); + if (ret) { + if (retries < 5) { + /* The data wasn't ready to read. + * Wait a bit longer and try again. + */ + usleep_range(90, 100); + retries++; + } else { + return ret; + } + } else { + retries = 0; + } } while (mcp->rxbuf_idx < total_len);
+ usleep_range(980, 1000); + ret = mcp_chk_last_cmd_status_free_bus(mcp); + return ret; }
@@ -799,7 +812,8 @@ static int mcp2221_raw_event(struct hid_device *hdev, mcp->status = -EIO; break; } - if (data[2] == MCP2221_I2C_READ_COMPL) { + if (data[2] == MCP2221_I2C_READ_COMPL || + data[2] == MCP2221_I2C_READ_PARTIAL) { buf = mcp->rxbuf; memcpy(&buf[mcp->rxbuf_idx], &data[4], data[3]); mcp->rxbuf_idx = mcp->rxbuf_idx + data[3];
linux-stable-mirror@lists.linaro.org
-
Romain Sioen