From 4e71d926abbe9ec23415f2ec8685a7bc26c1ceed Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 19 Aug 2020 14:59:01 +0200 Subject: spi: rspi: Increase bit rate range for RSPI on SH Increase bit rate range for RSPI on legacy SH by making use of the Bit Rate Frequency Division Setting field in Command Registers, just like is already done on RZ/A. This decreases the lower limit by a factor of 8. Signed-off-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/20200819125904.20938-5-geert+renesas@glider.be Signed-off-by: Mark Brown --- drivers/spi/spi-rspi.c | 35 ++++++++++++++++++----------------- 1 file changed, 18 insertions(+), 17 deletions(-) (limited to 'drivers/spi/spi-rspi.c') diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c index ad4ac867170b..ea3f2680d3c1 100644 --- a/drivers/spi/spi-rspi.c +++ b/drivers/spi/spi-rspi.c @@ -248,19 +248,32 @@ struct spi_ops { u8 num_hw_ss; }; +static void rspi_set_rate(struct rspi_data *rspi) +{ + unsigned long clksrc; + int brdv = 0, spbr; + + clksrc = clk_get_rate(rspi->clk); + spbr = DIV_ROUND_UP(clksrc, 2 * rspi->speed_hz) - 1; + while (spbr > 255 && brdv < 3) { + brdv++; + spbr = DIV_ROUND_UP(spbr + 1, 2) - 1; + } + + rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR); + rspi->spcmd |= SPCMD_BRDV(brdv); +} + /* * functions for RSPI on legacy SH */ static int rspi_set_config_register(struct rspi_data *rspi, int access_size) { - int spbr; - /* Sets output mode, MOSI signal, and (optionally) loopback */ rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR); /* Sets transfer bit rate */ - spbr = DIV_ROUND_UP(clk_get_rate(rspi->clk), 2 * rspi->speed_hz) - 1; - rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR); + rspi_set_rate(rspi); /* Disable dummy transmission, set 16-bit word access, 1 frame */ rspi_write8(rspi, 0, RSPI_SPDCR); @@ -290,23 +303,11 @@ static int rspi_set_config_register(struct rspi_data *rspi, int access_size) */ static int rspi_rz_set_config_register(struct rspi_data *rspi, int access_size) { - int spbr; - int brdv = 0; - unsigned long clksrc; - /* Sets output mode, MOSI signal, and (optionally) loopback */ rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR); - clksrc = clk_get_rate(rspi->clk); - spbr = DIV_ROUND_UP(clksrc, 2 * rspi->speed_hz) - 1; - while (spbr > 255 && brdv < 3) { - brdv++; - spbr = DIV_ROUND_UP(spbr + 1, 2) - 1; - } - /* Sets transfer bit rate */ - rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR); - rspi->spcmd |= SPCMD_BRDV(brdv); + rspi_set_rate(rspi); /* Disable dummy transmission, set byte access */ rspi_write8(rspi, SPDCR_SPLBYTE, RSPI_SPDCR); -- cgit v1.2.3