Without this i.e. the m25p driver is not working properly.
Its used to calculate the return value of the read/write function of
some devices. If the value is missing, barebox would always
miscalculate the next transfer sizes.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
The Linux kernel says (spi.h) :
* All SPI transfers start with the relevant chipselect active. Normally
* it stays selected until after the last transfer in a message. Drivers
* can affect the chipselect signal using cs_change.
*
* (i) If the transfer isn't the last one in the message, this flag is
* used to make the chipselect briefly go inactive in the middle of the
* message. Toggling chipselect in this way may be needed to terminate
* a chip command, letting a single spi_message perform all of group of
* chip transactions together.
*
* (ii) When the transfer is the last one in the message, the chip may
* stay selected until the next transfer. On multi-device SPI busses
* with nothing blocking messages going to other devices, this is just
* a performance hint; starting a message to another device deselects
* this one. But in other cases, this can be used to ensure correctness.
* Some devices need protocol transactions to be built from a series of
* spi_message submissions, where the content of one message is
* determined by the results of previous messages and where the whole
* transaction
* ends when the chipselect goes intactive.
In other words, cs_change changes the default chipselect *behavior*.
Support of cs_change is necessary to implement the mci spi driver.
This patch also fix few things:
Passing the bus number to the brand new master device.
Disable chipselect during master->setup.
Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Documentation says it should default to 8 when not specified
explicitly by the device data.
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Call setup() before registering the device because registering leads
to a probe routine of the slave device and that requires an
initialised master.
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
To allow for some generic io accessors introduce io.h and use
this instead of asm/io.h throughout the tree.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Based on the Linux driver. Tested with m25p80 with CS in GPIO mode.
Clock setting support is ad-hoc as the corresponding mach is not using
the generic clock infrastructure.
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This code was tested barely with m25p80 driver, reading jedec id and some data
from the chip worked fine.
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
If the device setup executed by the spi master fails,
unregister the created device.
Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
During the creation of a new spi device, we need to
have the possiblility to give the bits_per_word value
to master->setup.
As a matter of fact, spi master could check the spi
device bits_per_word and compare this value against its
capabilities.
Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit adds the following spi transfer functions:
- spi_write
- spi_read
- spi_write_then_read
- spi_w8r8
The code has been ported from the linux kernel.
Signed-off-by: Hubert Feurstein <h.feurstein@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
In the spi layer this pointer will be assigned to the
platform_data pointer of the new spi device, thus it can
be accessed in the drivers 'probe' handler.
Signed-off-by: Hubert Feurstein <h.feurstein@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Sascha Hauer
Michael Grzeschik
Franck Jullien
Paul Fertser
Hubert Feurstein
Marc Kleine-Budde
Juergen Beisert
Jean-Christophe PLAGNIOL-VILLARD
Menon, Nishanth