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HID: ft260: ft260_xfer_status routine cleanup
After clarifying with FTDI's support, it turned out that the error condition (bit 1) in byte 1 of the i2c status HID report is a status bit reflecting all error conditions. When bits 2, 3, or 4 are raised to 1, bit 1 is set to 1 also. Since the ft260_xfer_status routine tests the error condition bit and exits in the case of an error, the program flow never reaches the conditional expressions for 2, 3, and 4 bits when any of them indicates an error state. Though these expressions are never evaluated to true, they are checked several times per IO, increasing the ft260_xfer_status polling cycle duration. The patch removes the conditional expressions for 2, 3, and 4 bits in byte 1 of the i2c status HID report. Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com> Tested-by: Guillaume Champagne <champagne.guillaume.c@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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1 changed files with 10 additions and 20 deletions
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@ -313,27 +313,17 @@ static int ft260_xfer_status(struct ft260_device *dev)
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if (report.bus_status & FT260_I2C_STATUS_CTRL_BUSY)
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return -EAGAIN;
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if (report.bus_status & FT260_I2C_STATUS_BUS_BUSY)
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return -EBUSY;
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if (report.bus_status & FT260_I2C_STATUS_ERROR)
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/*
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* The error condition (bit 1) is a status bit reflecting any
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* error conditions. When any of the bits 2, 3, or 4 are raised
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* to 1, bit 1 is also set to 1.
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*/
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if (report.bus_status & FT260_I2C_STATUS_ERROR) {
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hid_err(hdev, "i2c bus error: %#02x\n", report.bus_status);
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return -EIO;
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}
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ret = -EIO;
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if (report.bus_status & FT260_I2C_STATUS_ADDR_NO_ACK)
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ft260_dbg("unacknowledged address\n");
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if (report.bus_status & FT260_I2C_STATUS_DATA_NO_ACK)
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ft260_dbg("unacknowledged data\n");
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if (report.bus_status & FT260_I2C_STATUS_ARBITR_LOST)
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ft260_dbg("arbitration loss\n");
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if (report.bus_status & FT260_I2C_STATUS_CTRL_IDLE)
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ret = 0;
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return ret;
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return 0;
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}
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static int ft260_hid_output_report(struct hid_device *hdev, u8 *data,
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@ -376,7 +366,7 @@ static int ft260_hid_output_report_check_status(struct ft260_device *dev,
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break;
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} while (--try);
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if (ret == 0 || ret == -EBUSY)
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if (ret == 0)
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return 0;
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ft260_i2c_reset(hdev);
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