On 06/20/2016 10:28 AM, Andy Yan wrote:

Hi Krzysztof:

On 2016年06月20日 16:09, Krzysztof Kozlowski wrote:

quoted

On 06/20/2016 08:38 AM, Andy Yan wrote:

quoted

This driver parses the reboot commands like "reboot bootloader"
and "reboot recovery" to get a boot mode described in the
device tree , then call the write interfae to store the boot
mode in some place like special register or sram, which can
be read by the bootloader after system reboot, then the bootloader
can take different action according to the mode stored.

This is commonly used on Android based devices, in order to
reboot the device into fastboot or recovery mode.

Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Moritz Fischer <moritz.fischer@ettus.com>
Tested-by: John Stultz <redacted>
Acked-by: John Stultz <redacted>
Signed-off-by: Andy Yan <andy.yan@rock-chips.com>

---

Changes in v9:
- select MFD_SYSCON when syscon-reboot-mode driver enabled
- refactoring error handling in reboot_mode_register

Changes in v8:
- do some cleanup when driver ubind

Changes in v7:
- address some suggestions from Krzysztof, make syscon-reboot-mode
driver data self-contained.

Changes in v6: None
Changes in v5:
- use two blank space under help in Kconfig
- use unsigned int instead of int for member magic in struct mode_info

Changes in v4:
- make this driver depends on OF to avoid kbuild test error

Changes in v3:
- scan multi properities
- add mask value for some platform which only use some bits of the
register
   to store boot mode magic value

Changes in v2:
- move to dir drivers/power/reset/
- make syscon-reboot-mode a generic driver

Changes in v1:
- fix the embarrassed compile warning
- correct the maskrom magic number
- check for the normal reboot

  drivers/power/reset/Kconfig              |  14 ++++
  drivers/power/reset/Makefile             |   2 +
  drivers/power/reset/reboot-mode.c        | 128
+++++++++++++++++++++++++++++++
  drivers/power/reset/reboot-mode.h        |  14 ++++
  drivers/power/reset/syscon-reboot-mode.c | 100
++++++++++++++++++++++++
  5 files changed, 258 insertions(+)
  create mode 100644 drivers/power/reset/reboot-mode.c
  create mode 100644 drivers/power/reset/reboot-mode.h
  create mode 100644 drivers/power/reset/syscon-reboot-mode.c

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 9bb2622..4ceaf74 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig

@@ -183,5 +183,19 @@ config POWER_RESET_ZX
      help
        Reboot support for ZTE SoCs.
  +config REBOOT_MODE
+    tristate
+
+config SYSCON_REBOOT_MODE
+    bool "Generic SYSCON regmap reboot mode driver"

Why not tristate?

   I see many reset drivers in this directories  use bool, so I follow
them.

+Cc Paul,

I don't mind that although I don't see any particular objections for
making it module-capable. In the same time I just reminded myself about
Paul Gortmaker's long effort (like [1] [2]) about removing module
capability from non-modular drivers.

Following his rationale, I think either this should be a tristate or the
module stuff should be removed.

Best regards,
Krzysztof

[1] https://lkml.org/lkml/2016/2/21/180
[2] https://lkml.org/lkml/2016/6/13/682