On 08/15/2016 09:35 AM, Stephen Warren wrote:
On 08/13/2016 09:56 AM, Jagan Teki wrote:
On 13 August 2016 at 02:36, Stephen Warren swarren@wwwdotorg.org wrote:
From: Stephen Warren swarren@nvidia.com
When the set_mode() function runs, the SPI bus is not active, and hence the clocks to the SPI controller are not running. Any register read/write at this time will hang the CPU. Remove the code from set_mode() that does this, and move it to the correct place in claim_bus().
The idea of claim_bus is just to enable the bus for any transaction to start, since set_mode is running before claim (ex: spi_get_bus_and_cs while 'sf probe') it's .probe which actual driver binding responsibility to initialize the SPI bus so-that .set_mode and .set_speed will set the mode and freq for that initialized bus based on the inputs from user, drivers like zynq, exynos will follow the same.
I'd rather not re-structure the driver, and to be honest I see no point in mandating that drivers activate their clocks/resets in probe rather than solely during the actual SPI transaction.
Anyway, if the patch I sent isn't acceptable, please can you simply revert the patch it fixes so that SPI on Tegra works again? Thanks.
It turns out that getting the clocks going in probe() is pretty easy. I've sent a patch to do that, so this patch can be dropped.