Re: [PATCH v4 0/6] Add Actions Semiconductor Owl S900 I2C support

[Manivannan Sadhasivam]

On Sun, Jul 01, 2018 at 10:52:59PM +0530, Manivannan Sadhasivam wrote:
> This patchset adds I2C controller support for Actions Semiconductor S900 SoC.
> This driver has been structured in a way such that there will be only
> one controller driver for the whole Owl family series (S500, S700 and
> S900 SoCs).
> 
> There are 6 I2C controllers with separate memory mapped register space.
> The I2C controller can handle atmost two messages concatenated by a
> repeated start via its internal address feature. Hence the driver
> uses this feature for messages of length greater than 1. In those cases,
> the first message of the combined message should be a `write` with maximum
> message length 6 and the second message's maximum length should be 240 bytes.
> 
> As far as the bus speed is concerned, this driver only supports
> Standard (100KHz) and High speed (400KHz) for now.
> 
> The pinctrl definitions are only available for I2C0, I2C1 and I2C2.
> With the mux option available only for I2C0.
> 
> For Bubblegum-96 board utilizing the S900 SoC, only I2C1 and I2C2 which
> are exposed on the Low speed expansion connector are enabled.
> 
> This series depends on the pinctrl patch [1] is still not merged by the
> platform maintainer Andreas but it has been reviewed by the pinctrl maintainer
> Linus Walleij. For the reference, I have queued up all reviewed dts patches
> in my tree [2] from which Andreas is picking them for 4.19.
> 
> For this series, since the dts patches will go through the ARM SoC tree,
> Andreas will pick it up once it is reviewed.
> 
> Thanks,
> Mani
> 
> [1] https://patchwork.kernel.org/patch/10322937/
> [2] https://git.linaro.org/people/manivannan.sadhasivam/linux.git/log/?h=s900-for-next
> 

Hi Andy, Peter,

Just a gentle ping on this v4!

Thanks,
Mani

> Changes in v4:
> 
> As per Andy and Peter review:
> 
> * Used spinlock for accessing most of the register access (only parts
>   involved sleep/long-busy-wait has been excluded)
> * Removed returning 0 and added -ENXIO if the msg_ptr not equals to
>   message length
> * Added DIV_ROUND_UP for setting clock frequency
> * Changed one non-atomic mdelay instance to usleep_range
> * Moved pinctrl definition patch before dts patch
> * Fixed the driver to support only 100KHz and 400KHz frequencies
> 
> Changes in v3:
> 
> As per Peter, Andy and Andreas review:
> 
> * Removed owl_i2c_reset function from interrupt handler since it
>   involves the use of delays.
> * Fixed the return path in owl_i2c_master_xfer and added a note
> * Changed "base" parameter to "reg" in owl_i2c_update_reg for better
>   understandability
> * Ordered the includes in alphabetical order
> * Small changes to defines and added comma at the end of struct members
> * Removed rendundant 0 assignment in owl_i2c_master_xfer
> * Changed all OWL naming convention to Owl and also changed Actions Semi
>   naming to Actions Semiconductor
> 
> Changes in v2:
> 
> As per Andy's review:
> * Modified infinite loops to fixed number of retries
> * Used i2c_8bit_addr_from_msg for constructing the slave address
> * Removed unnecessary parenthesis around defines
> * Modified certain dev_warn to dev_dbg
> * Modified the error handling to more generic pattern
> 
> * Fixed the return value in owl_i2c_master_xfer
> * Added MAINTAINERS patch for I2C driver and its binding
> 
> Manivannan Sadhasivam (6):
>   dt-bindings: i2c: Add binding for Actions Semiconductor Owl I2C
>     controller
>   arm64: dts: actions: Add pinctrl definition for S900 I2C controller
>   arm64: dts: actions: Add Actions Semiconductor S900 I2C controller
>     nodes
>   arm64: dts: actions: Enable I2C1 and I2C2 in Bubblegum-96 board
>   i2c: Add Actions Semiconductor Owl family S900 I2C driver
>   MAINTAINERS: Add entry for Actions Semiconductor Owl I2C driver
> 
>  .../devicetree/bindings/i2c/i2c-owl.txt       |  27 +
>  MAINTAINERS                                   |   2 +
>  .../dts/actions/s900-bubblegum-96-pins.dtsi   |  29 +
>  .../boot/dts/actions/s900-bubblegum-96.dts    |  11 +
>  arch/arm64/boot/dts/actions/s900.dtsi         |  60 +++
>  drivers/i2c/busses/Kconfig                    |   7 +
>  drivers/i2c/busses/Makefile                   |   1 +
>  drivers/i2c/busses/i2c-owl.c                  | 504 ++++++++++++++++++
>  8 files changed, 641 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-owl.txt
>  create mode 100644 arch/arm64/boot/dts/actions/s900-bubblegum-96-pins.dtsi
>  create mode 100644 drivers/i2c/busses/i2c-owl.c
> 
> -- 
> 2.17.1
>