[PATCH 1/3 v5] spi: s3c64xx: fix broken "cs_gpios" usage in the driver

Mark or Kukjin,

On Thu, Jun 12, 2014 at 8:59 PM, Naveen Krishna Chatradhi
[off-list ref] wrote:

Since, (3146bee spi: s3c64xx: Added provision for dedicated cs pin)

spi-s3c64xx.c driver expects
1. chip select gpios from "cs-gpio"(singular) under the
   "controller-data" node of the client/slave device of the SPI.

2. "cs-gpio"(singular) entry to be present in the SPI device node.

Eg of current broken usage:
&spi_1 {
        cs-gpio <>;     /* this entry is checked during probe */
        ...
        slave_node {
                controller-data {
                        cs-gpio <&gpioa2 5 0>;
                        /* This field is parsed during .setup() */
                }
        };
};

The following dts files which were using this driver. But,
din't have the "cs-gpio" entry under SPI node.
-- arch/arm/boot/dts/exynos4210-smdkv310.dts
-- arch/arm/boot/dts/exynos4412-trats2.dts
-- arch/arm/boot/dts/exynos5250-smdk5250.dts

Also, the SPI core and many drivers moved on to using "cs-gpios"
from SPI node and removed the gpio handling code from drivers
(including spi-s3c64xx.c).

Hence, spi-s3c64xx.c is broken since "Jun 21 11:26:12 2013" and
considering the time with no compliants about the breakage.

We are assuming it is safe to remove the "cs-gpio"(singular) usage
from device tree binding of spi-samsung.txt and makes appropriate
changes in the driver to use "cs-gpios"(plural) from
SPI device node.

Signed-off-by: Naveen Krishna Chatradhi <redacted>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Javier Martinez Canillas <redacted>
Tested-by: Doug Anderson <dianders@chromium.org>
Cc: Tomasz Figa <redacted>
---
Changes since v4:
1. Added reviewed by from Javier and Tested by from Doug

Changes since v3:
1. Remove the sdd->cs_gpio and use gpio_is_valid(spi->cs_gpio) instead
2. Keep cs->line only for Non-DT platforms and use spi->cs_gpio
   for DT platforms

 .../devicetree/bindings/spi/spi-samsung.txt        |    8 ++--
 drivers/spi/spi-s3c64xx.c                          |   41 ++++++++------------
 2 files changed, 20 insertions(+), 29 deletions(-)

Is one of you two planning to apply (parts 1 and 2)?  I know that
Kukjin needs to handle the part 3 (the .dts files)...

Ideally it seems like it could go to 3.16 since it is a bugfix...

Thanks!

-Doug