[PATCH v5 0/6] bcm2835: auxiliar device support for spi

kernel at martin.sperl.org kernel at martin.sperl.org
Fri Sep 4 02:41:44 PDT 2015

From: Martin Sperl <kernel at martin.sperl.org>

The BCM2835 contains 3 auxiliar devices:
* spi1
* spi2
* uart1

All of those 3 devices are enabled/disabled via a shared register,
which is set by default to be disabled.

Access to this register needs to get serialized.

So after several iterations of discussions with the following ideas:
* syscon - device tree should describe HW not drivers to use -
           'compatiblity = "brcm,bcm2835-aux-enable", "syscon";'
           is not acceptable
* regulator - it is not necessarily a regulator or a power gate
              that is implemented in HW, so it is not valid to use
              this framework

The recommendation was made to create a new minimal API in soc
just for access to this shared enable/disable register.

This patch-series implements:
* the bcm2835-auxiliar device enable/disable api in soc.
* the bcm2835-auxiliar spi device driver

The uart1 device driver (ns16550 based) is not implemented so far
but would be using the same API.

Both spi and uart drivers can run with shared interrupts,
so there is no need for an interrupt-controller to get implemented.

Martin Sperl (6):
  soc: bcm2835: auxiliar devices enable infrastructure
  ARM: bcm2835: add DT for the bcm2835 auxiliar devices
  dt/bindings: bcm2835: add binding documentation for bcm2835-aux
  spi: bcm2835: new driver implementing auxiliar spi1/spi2 on the
    bcm2835 soc
  ARM: bcm2835: enable building of spi-bcm2835aux driver in default
  dt/bindings: bcm2835: Add binding documentation for auxiliar spi

 .../bindings/soc/bcm/brcm,bcm2835-aux.txt          |   27 +
 .../bindings/spi/brcm,bcm2835-aux-spi.txt          |   47 ++
 arch/arm/boot/dts/bcm2835.dtsi                     |   37 ++
 arch/arm/configs/bcm2835_defconfig                 |    1 +
 drivers/soc/Kconfig                                |    1 +
 drivers/soc/Makefile                               |    1 +
 drivers/soc/bcm/Kconfig                            |   11 +
 drivers/soc/bcm/Makefile                           |    1 +
 drivers/soc/bcm/bcm2835-aux.c                      |  154 ++++++
 drivers/spi/Kconfig                                |   12 +
 drivers/spi/Makefile                               |    1 +
 drivers/spi/spi-bcm2835aux.c                       |  514 ++++++++++++++++++++
 include/linux/soc/bcm/bcm2835-aux.h                |   23 +
 13 files changed, 830 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/bcm/brcm,bcm2835-aux.txt
 create mode 100644 Documentation/devicetree/bindings/spi/brcm,bcm2835-aux-spi.txt
 create mode 100644 drivers/soc/bcm/Kconfig
 create mode 100644 drivers/soc/bcm/Makefile
 create mode 100644 drivers/soc/bcm/bcm2835-aux.c
 create mode 100644 drivers/spi/spi-bcm2835aux.c
 create mode 100644 include/linux/soc/bcm/bcm2835-aux.h


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