The MC13xxx PMIC is mainly used on i.Mx SoC. On those SoC the SPI
hardware will deassert CS line as soon as the SPI FIFO is empty.
The MC13xxx hardware is very sensitive to CS line change as it
corrupts the transfer if CS is deasserted in the middle of a register
read or write.
It is not possible to use the CS line as a GPIO on some SoC, so we
need to workaround this by implementing a single SPI transfer to
access the PMIC.
Reviewed-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: NMarc Reilly <marc@cpdesign.com.au>
Signed-off-by: NPhilippe Rétornaz <philippe.retornaz@epfl.ch>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

This fix the SPI regmap configuration, the wrong write flag was used.
Also, bits_per_word should not be set as the regmap spi implementation
uses a 8bits transfert granularity.
Signed-off-by: NPhilippe Rétornaz <philippe.retornaz@epfl.ch>
Tested-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

All spi specific code is moved into a new module. The mc13xxx struct
moves to a new local include file by necessity.

A new config choice selects the SPI bus type support and by default is
value of SPI_MASTER to remain compatible with existing configs.
Signed-off-by: NMarc Reilly <marc@cpdesign.com.au>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>