Seeing DW APB SSI controller doesn't support setting the exactly requested SPI bus frequency, but only a rounded frequency determined by means of the odd-numbered half-worded reference clock divider, it would be good tune the SPI core up and initialize the current transfer effective_speed_hz. By doing so the core will be able to execute the xfer-related delays with better accuracy.
Signed-off-by: Serge Semin <[email protected]> Cc: Georgy Vlasov <[email protected]> Cc: Ramil Zaripov <[email protected]> Cc: Alexey Malahov <[email protected]> Cc: Thomas Bogendoerfer <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Feng Tang <[email protected]> Cc: Andy Shevchenko <[email protected]> Cc: Rob Herring <[email protected]> Cc: [email protected] Cc: [email protected] --- drivers/spi/spi-dw.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c index 9d6904d30104..050cb2ea0812 100644 --- a/drivers/spi/spi-dw.c +++ b/drivers/spi/spi-dw.c @@ -352,6 +352,7 @@ static int dw_spi_transfer_one(struct spi_controller *master, spi_set_clk(dws, chip->clk_div); } + transfer->effective_speed_hz = dws->max_freq / chip->clk_div; dws->n_bytes = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE); cr0 = dws->update_cr0(master, spi, transfer); -- 2.26.2
