If our client is requesting a clock that is above the maximum clock
then the following division will result in 0:
rs->max_freq / rs->speed
We'll then program 0 into the SPI_BAUDR register. The Rockchip TRM
says: "If the value is 0, the serial output clock (sclk_out) is
disabled."
It's much better to end up with the fastest possible clock rather than
a clock that is off, so enforce a minimum value.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Fix to return -EINVAL from the error handling case instead of 0 when
failed to get fifo length.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Mark Brown <broonie@linaro.org>
There is a error message within devm_ioremap_resource
already, so remove the dev_err call to avoid redundant
error message.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Mark Brown <broonie@linaro.org>
In order to facilitate understanding, rockchip SPI controller IP design
looks similar in its registers to designware. But IC implementation
is different from designware, So we need a dedicated driver for Rockchip
RK3XXX SoCs integrated SPI. The main differences:
- dma request line: rockchip SPI controller have two DMA request line
for tx and rx.
- Register offset:
RK3288 dw
SPI_CTRLR0 0x0000 0x0000
SPI_CTRLR1 0x0004 0x0004
SPI_SSIENR 0x0008 0x0008
SPI_MWCR NONE 0x000c
SPI_SER 0x000c 0x0010
SPI_BAUDR 0x0010 0x0014
SPI_TXFTLR 0x0014 0x0018
SPI_RXFTLR 0x0018 0x001c
SPI_TXFLR 0x001c 0x0020
SPI_RXFLR 0x0020 0x0024
SPI_SR 0x0024 0x0028
SPI_IPR 0x0028 NONE
SPI_IMR 0x002c 0x002c
SPI_ISR 0x0030 0x0030
SPI_RISR 0x0034 0x0034
SPI_TXOICR NONE 0x0038
SPI_RXOICR NONE 0x003c
SPI_RXUICR NONE 0x0040
SPI_MSTICR NONE 0x0044
SPI_ICR 0x0038 0x0048
SPI_DMACR 0x003c 0x004c
SPI_DMATDLR 0x0040 0x0050
SPI_DMARDLR 0x0044 0x0054
SPI_TXDR 0x0400 NONE
SPI_RXDR 0x0800 NONE
SPI_IDR NONE 0x0058
SPI_VERSION NONE 0x005c
SPI_DR NONE 0x0060
- register configuration:
such as SPI_CTRLRO in rockchip SPI controller:
cr0 = (CR0_BHT_8BIT << CR0_BHT_OFFSET)
| (CR0_SSD_ONE << CR0_SSD_OFFSET);
cr0 |= (rs->n_bytes << CR0_DFS_OFFSET);
cr0 |= ((rs->mode & 0x3) << CR0_SCPH_OFFSET);
cr0 |= (rs->tmode << CR0_XFM_OFFSET);
cr0 |= (rs->type << CR0_FRF_OFFSET);
For more information, see RK3288 chip manual.
- Wait for idle: Must ensure that the FIFO data has been sent out
before the next transfer.
Signed-off-by: addy ke <addy.ke@rock-chips.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
