[PATCH v8 0/3] ARM: mediatek: Add driver for Mediatek I2C

[Eddie Huang]

This series is for Mediatek SoCs I2C controller common bus driver.

Earlier MTK SoC (for example, MT6589, MT8135) I2C HW has some limitations.
New generation SoC like MT8173 fix following limitations:

1. Only support one i2c_msg number. One exception is WRRD (write then read)
mode. WRRD can have two i2c_msg numbers.

2. Mediatek I2C controller support WRRD(write then read) mode, in WRRD
mode the Repeat Start will be issued between 2 messages.
In this driver if 2 messages is first write then read, the driver will
combine 2 messages using Write-Read mode so the RS will be issued between
the 2 messages.

3. The max transfer data length is 255 in one message. In WRRD mode, the
max data length of second msg is 31.

MT8135 and MT6589 can control I2C pins on PMIC(MT6397) by setting the i2c
registers in MT8135 side. In this case, driver should set OFFSET_PATH_DIR
bit first, the operation on other registers are still the same.
For now MT6589/MT8135 support this, MT6577/MT6595/MT8127 do not support.
For example, If want to use I2C4/5/6 pins on MT8135 just need to enable
the pinmux, else if want to use I2C pins on PMIC(MT6397) need to add
"mediatek,have-pmic" property in the .dts file of each platform.

This driver is based on 4.1-rc1.

Change in v8:
Fix Wolfram's review comments like sort include file order, remove thin
wrapper functions, remove define number that only use once, and revise
error return value.

Change in v7:
Fix mtk_i2c_of_match in wrong patch bug.

Change in v6:
1. Update binding document not use default clock-frequency as example.
2. Add mtk_i2c_compatible struct and pass hardware capabilities
   through of_device_id
3. Remove some hardware setting in mtk_i2c_do_transfer to mtk_i2c_init_hw
   so just init one time.
4. Correct mtk_i2c_parse_dt don't set default clock bug.

Change in v5:
Apply new i2c_adapter_quirks patch [2]. Change to use dam_map_single to map
dma buffer. Add spinlock to fix race condition. Check of_property_read_u32
return value. Remove I2C_FUNC_10BIT_ADDR capability due to driver not implement.
Add MT8173 I2C driver.

Change in v4:
Modify to support i2c_adapter_quirks base on Wolfram's patch [1].
Remove check transfer size and WRRD combine code. Instead, fill quirk
property and let i2c_check_for_quirks to do the filter.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-January/314804.html
[2] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-February/325744.html

Eddie Huang (1):
  I2C: mediatek: Add driver for MediaTek MT8173 I2C controller

Xudong Chen (2):
  dt-bindings: Add I2C bindings for mt65xx/mt81xx.
  I2C: mediatek: Add driver for MediaTek I2C controller

 .../devicetree/bindings/i2c/i2c-mt6577.txt         |  41 ++
 drivers/i2c/busses/Kconfig                         |   9 +
 drivers/i2c/busses/Makefile                        |   1 +
 drivers/i2c/busses/i2c-mt65xx.c                    | 715 +++++++++++++++++++++
 4 files changed, 766 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mt6577.txt
 create mode 100644 drivers/i2c/busses/i2c-mt65xx.c

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1.8.1.1.dirty