From de4c2875a5ff2c886df60f2086c6affca83f890a Mon Sep 17 00:00:00 2001 From: Serge Semin Date: Fri, 29 May 2020 16:11:50 +0300 Subject: [PATCH] spi: dw: Set xfer effective_speed_hz 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 to 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 Cc: Georgy Vlasov Cc: Ramil Zaripov Cc: Alexey Malahov Cc: Thomas Bogendoerfer Cc: Arnd Bergmann Cc: Feng Tang Cc: Andy Shevchenko Cc: Rob Herring Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200529131205.31838-2-Sergey.Semin@baikalelectronics.ru Signed-off-by: Mark Brown --- 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 1edb8cd..e6fc0bc 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); -- 2.7.4