The tegra114 driver wasn't currently handling the cs_change
functionality. cs_change is meant to invert the decisions of whether
or not to deactivate CS after each transfer. Without cs_change, after
every transfer (other than the last in the message) the normal behavior
is to leave CS active. For the last transfer, normally CS is
deactivated when the transfer is complete.
With cs_change set on a transfer (other than last one) CS would be
deactivated and the next transfer would need to activate it again. If
cs_change was set on the last tranfer in a message, then CS would be
left active when the message compeleted.
Also, this builds in logic so that if a different device tries to start
a transfer while CS is active from a different device, it will abort the
previous transfer and start a new one for the new device.
This splits tegra_spi_start_transfer_one into 2 functions, the new one
being tegra_spi_setup_transfer_one. The setup function is safe to call
on all transfers, sets up for the transfer, and handles the special case
of the first transfer in a message. In this special case, it needs to
know whether or not it needs to activate CS.
This work was based on the spi-atmel driver.
Signed-off-by: Rhyland Klein <rklein@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Use devm_spi_register_master() to make cleanup paths simpler.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Check of 'r' and calls to dev_err are already done in devm_ioremap_resource,
so no need to do them twice.
Signed-off-by: Laurent Navet <laurent.navet@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Currently the tegra114 driver acquires a runtime PM reference for the
duration of each transfer. This may result in the IP being powered down
between transfers which would be at best wasteful. Instead it is better
to do this in the callbacks that are generated before and after starting
a series of transfers, keeping the IP powered throughout.
Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
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>
Use the wrapper functions for getting and setting the driver data using
platform_device instead of using dev_{get,set}_drvdata() with &pdev->dev,
so we can directly pass a struct platform_device.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Add SPI driver for NVIDIA's Tegra114 SPI controller. This controller
is different than the older SoCs SPI controller in internal design as
well as register interface.
This driver supports the:
- non DMA based transfer for smaller transfer i.e. less than FIFO depth.
- APB DMA based transfer for larger transfer i.e. more than FIFO depth.
- Clock gating through runtime PM callbacks.
- registration through DT only.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
