The patch increases the read buffer size to 128 bytes. It reduces the number of ft260_i2c_read calls by three and improves the large data chunks' read performance by about 10%. Before: $ sudo ./i2cperf -d 2 -o 2 -s 128 -r 0-0xff 13 0x51 -S Read block via i2ctransfer by chunks ------------------------------------------------------------------- data rate(bps) efficiency(%) data size(B) total IOs IO size(B) ------------------------------------------------------------------- 43990 85 256 2 128 [ +1.464346] ft260_i2c_write_read: off 0x0 rlen 128 wlen 2 [ +0.000002] ft260_i2c_write: rep 0xd0 addr 0x51 off 0 len 2 wlen 2 flag 0x2 d[0] 0x0 [ +0.001653] ft260_xfer_status: bus_status 0x41, clock 100 [ +0.000188] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000002] ft260_i2c_read: rep 0xc2 addr 0x51 len 128 rlen 60 flag 0x3 [ +0.008609] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000157] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000002] ft260_i2c_read: rep 0xc2 addr 0x51 len 68 rlen 60 flag 0x0 [ +0.008840] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000203] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000002] ft260_i2c_read: rep 0xc2 addr 0x51 len 8 rlen 8 flag 0x4 [ +0.002794] ft260_raw_event: i2c resp: rep 0xd1 len 8 [ +0.000201] ft260_xfer_status: bus_status 0x20, clock 100 [ +0.015171] ft260_i2c_write_read: off 0x80 rlen 128 wlen 2 [ +0.000002] ft260_i2c_write: rep 0xd0 addr 0x51 off 0 len 2 wlen 2 flag 0x2 d[0] 0x0 [ +0.000764] ft260_xfer_status: bus_status 0x41, clock 100 [ +0.000231] ft260_xfer_status: bus_status 0x41, clock 100 [ +0.000148] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000002] ft260_i2c_read: rep 0xc2 addr 0x51 len 128 rlen 60 flag 0x3 [ +0.008488] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000205] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000002] ft260_i2c_read: rep 0xc2 addr 0x51 len 68 rlen 60 flag 0x0 [ +0.008795] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000176] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000001] ft260_i2c_read: rep 0xc2 addr 0x51 len 8 rlen 8 flag 0x4 [ +0.002819] ft260_raw_event: i2c resp: rep 0xd1 len 8 [ +0.000167] ft260_xfer_status: bus_status 0x20, clock 100 After: $ sudo ./i2cperf -d 2 -o 2 -s 128 -r 0-0xff 13 0x51 -S Read block via i2ctransfer by chunks ------------------------------------------------------------------- data rate(bps) efficiency(%) data size(B) total IOs IO size(B) ------------------------------------------------------------------- 49316 85 256 2 128 [ +1.447360] ft260_i2c_write_read: off 0x0 rlen 128 wlen 2 [ +0.000002] ft260_i2c_write: rep 0xd0 addr 0x51 off 0 len 2 wlen 2 flag 0x2 d[0] 0x0 [ +0.001633] ft260_xfer_status: bus_status 0x41, clock 100 [ +0.000190] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000001] ft260_i2c_read: rep 0xc2 addr 0x51 len 128 rlen 128 flag 0x7 [ +0.008617] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.008033] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.000954] ft260_raw_event: i2c resp: rep 0xd1 len 8 [ +0.000208] ft260_xfer_status: bus_status 0x20, clock 100 [ +0.015853] ft260_i2c_write_read: off 0x80 rlen 128 wlen 2 [ +0.000002] ft260_i2c_write: rep 0xd0 addr 0x51 off 0 len 2 wlen 2 flag 0x2 d[0] 0x0 [ +0.001182] ft260_xfer_status: bus_status 0x41, clock 100 [ +0.000180] ft260_xfer_status: bus_status 0x40, clock 100 [ +0.000001] ft260_i2c_read: rep 0xc2 addr 0x51 len 128 rlen 128 flag 0x7 [ +0.008575] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.008014] ft260_raw_event: i2c resp: rep 0xde len 60 [ +0.001001] ft260_raw_event: i2c resp: rep 0xd1 len 8 [ +0.000223] ft260_xfer_status: bus_status 0x20, clock 100 Signed-off-by: Michael Zaidman <michael.zaidman@xxxxxxxxx> --- drivers/hid/hid-ft260.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c index cb8f1782d1f0..c7c3a9d395a2 100644 --- a/drivers/hid/hid-ft260.c +++ b/drivers/hid/hid-ft260.c @@ -30,12 +30,8 @@ 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) -/* - * The input report format assigns 62 bytes for the data payload, but ft260 - * returns 60 and 2 in two separate transactions. To minimize transfer time - * in reading chunks mode, set the maximum read payload length to 60 bytes. - */ -#define FT260_RD_DATA_MAX (60) + +#define FT260_RD_DATA_MAX (128) #define FT260_WR_DATA_MAX (60) /* -- 2.25.1
