diff options
| author | Simon Glass <sjg@chromium.org> | 2016-09-05 11:04:50 -0600 |
|---|---|---|
| committer | Patrick Georgi <pgeorgi@google.com> | 2016-10-04 21:39:51 +0200 |
| commit | 52669fc4dc4ab38e9ca61d65487fdfb809d3dd3d (patch) | |
| tree | c0e40940e7f203741e3245f9fb3f45b0c0a99a86 /src/soc/rockchip/common | |
| parent | 7feb86b26b2b72d21098a90bff0843d8533a7493 (diff) | |
rockchip: spi: Set rxd sample delay when using high speed
At higher SPI bus speeds the SPI RX value is not available in time for
sampling at the normal time. Add a delay to ensure that we read the
correct data.
The value of 40ns is chosen arbitrarily. In my testing I can use a sample
delay of 1 even at 24MHz. But since it is not necessary, I have left that
case alone. It kicks in at 25MHz and up.
BUG=chrome-os-partner:56556
BRANCH=none
TEST=boot on gru and see no change at current speed
Change-Id: I3ef335d9a532eaef1e76034bd02e185acf11176a
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: e9b620c47fc3e39211487507fadb8657afdebee7
Original-Change-Id: I65d66d752cbbbee4d02f475de23a52069a0e9782
Original-Signed-off-by: Simon Glass <sjg@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/381311
Original-Commit-Ready: Julius Werner <jwerner@chromium.org>
Original-Tested-by: Simon Glass <sjg@google.com>
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/16707
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Diffstat (limited to 'src/soc/rockchip/common')
| -rw-r--r-- | src/soc/rockchip/common/include/soc/spi.h | 3 | ||||
| -rw-r--r-- | src/soc/rockchip/common/spi.c | 18 |
2 files changed, 17 insertions, 4 deletions
diff --git a/src/soc/rockchip/common/include/soc/spi.h b/src/soc/rockchip/common/include/soc/spi.h index dcaa4711d2..0e1847c985 100644 --- a/src/soc/rockchip/common/include/soc/spi.h +++ b/src/soc/rockchip/common/include/soc/spi.h @@ -199,4 +199,7 @@ check_member(rockchip_spi, rxdr, 0x800); void rockchip_spi_init(unsigned int bus, unsigned int speed_hz); +/* Set the receive sample delay in nanoseconds */ +void rockchip_spi_set_sample_delay(unsigned int bus, unsigned int delay_ns); + #endif /* ! __COREBOOT_SRC_SOC_ROCKCHIP_COMMON_INCLUDE_SOC_SPI_H */ diff --git a/src/soc/rockchip/common/spi.c b/src/soc/rockchip/common/spi.c index f35f91589f..7dcaaadf19 100644 --- a/src/soc/rockchip/common/spi.c +++ b/src/soc/rockchip/common/spi.c @@ -32,7 +32,7 @@ struct rockchip_spi_slave { }; #define SPI_TIMEOUT_US 1000 -#define SPI_SRCCLK_HZ (99*MHz) +#define SPI_SRCCLK_HZ (198*MHz) #define SPI_FIFO_DEPTH 32 static struct rockchip_spi_slave rockchip_spi_slaves[] = { @@ -152,9 +152,6 @@ void rockchip_spi_init(unsigned int bus, unsigned int speed_hz) /* Byte and Halfword Transform */ ctrlr0 |= (SPI_APB_8BIT << SPI_HALF_WORLD_TX_OFFSET); - /* Rxd Sample Delay */ - ctrlr0 |= (0 << SPI_RXDSD_OFFSET); - /* Frame Format */ ctrlr0 |= (SPI_FRF_SPI << SPI_FRF_OFFSET); @@ -165,6 +162,19 @@ void rockchip_spi_init(unsigned int bus, unsigned int speed_hz) write32(®s->rxftlr, SPI_FIFO_DEPTH / 2 - 1); } +void rockchip_spi_set_sample_delay(unsigned int bus, unsigned int delay_ns) +{ + assert(bus >= 0 && bus < ARRAY_SIZE(rockchip_spi_slaves)); + struct rockchip_spi *regs = rockchip_spi_slaves[bus].regs; + unsigned int rsd; + + /* Rxd Sample Delay */ + rsd = DIV_ROUND_CLOSEST(delay_ns * (SPI_SRCCLK_HZ >> 8), 1*GHz >> 8); + assert(rsd >= 0 && rsd <= 3); + clrsetbits_le32(®s->ctrlr0, SPI_RXDSD_MASK << SPI_RXDSD_OFFSET, + rsd << SPI_RXDSD_OFFSET); +} + int spi_claim_bus(struct spi_slave *slave) { spi_cs_activate(slave); |