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[RESEND,v10,0/3] Support pwm/tach driver for aspeed ast26xx

Message ID 20231107105025.1480561-1-billy_tsai@aspeedtech.com
Headers show
Series Support pwm/tach driver for aspeed ast26xx | expand

Message

Billy Tsai Nov. 7, 2023, 10:50 a.m. UTC 
Unlike the old design that the register setting of the TACH should based
on the configure of the PWM. In ast26xx, the dependency between pwm and
tach controller is eliminated and becomes a separate hardware block. One
is used to provide pwm output and another is used to monitor the frequency
of the input. This driver implements them by exposing two kernel
subsystems: PWM and HWMON. The PWM subsystem can be utilized alongside
existing drivers for controlling elements such as fans (pwm-fan.c),
beepers (pwm-beeper.c) and so on. Through the HWMON subsystem, the driver
provides sysfs interfaces for fan.

Changes since v9:
Change the type of fan-driving-mode to string
Fix some typos and formatting issues.

Changes since v8:
Fix the fail of fan div register setting. (FIELD_GET -> FIELD_PREP)
Change the type of tach-ch from uint32_t to uint8-array
Add additional properties and apply constraints to certain properties.

Changes since v7:
Cherry-pick the fan-common.yaml and add the following properties:
- min-rpm
- div
- mode
- tach-ch
Fix the warning which is reported by the kernel test robot.

Changes since v6:
Consolidate the PWM and TACH functionalities into a unified driver.

Changes since v5:
- pwm/tach:
  - Remove the utilization of common resources from the parent node.
  - Change the concept to 16 PWM/TACH controllers, each with one channel,
  instead of 1 PWM/TACH controller with 16 channels.
- dt-binding:
  - Eliminate the usage of simple-mfd.

Changes since v4:
- pwm:
  - Fix the return type of get_status function.
- tach:
  - read clk source once and re-use it
  - Remove the constants variables
  - Allocate tach_channel as array
  - Use dev->parent
- dt-binding:
  - Fix the order of the patches
  - Add example and description for tach child node
  - Remove pwm extension property

Changes since v3:
- pwm:
  - Remove unnecessary include header
  - Fix warning Prefer "GPL" over "GPL v2"
- tach:
  - Remove the paremeter min_rpm and max_rpm and return the tach value 
  directly without any polling or delay.
  - Fix warning Prefer "GPL" over "GPL v2"
- dt-binding:
  - Replace underscore in node names with dashes
  - Split per subsystem

Changes since v2:
- pwm:
  - Use devm_* api to simplify the error cleanup
  - Fix the multi-line alignment problem
- tach:
  - Add tach-aspeed-ast2600 to index.rst
  - Fix the multi-line alignment problem
  - Remove the tach enable/disable when read the rpm
  - Fix some coding format issue

Changes since v1:
- tach:
  - Add the document tach-aspeed-ast2600.rst
  - Use devm_* api to simplify the error cleanup.
  - Change hwmon register api to devm_hwmon_device_register_with_info

Billy Tsai (2):
  dt-bindings: hwmon: Support Aspeed g6 PWM TACH Control
  hwmon: (aspeed-g6-pwm-tacho): Support for ASPEED g6 PWM/Fan tach

Naresh Solanki (1):
  dt-bindings: hwmon: fan: Add fan binding to schema

 .../bindings/hwmon/aspeed,g6-pwm-tach.yaml    |  69 +++
 .../devicetree/bindings/hwmon/fan-common.yaml |  78 +++
 Documentation/hwmon/aspeed-g6-pwm-tach.rst    |  26 +
 Documentation/hwmon/index.rst                 |   1 +
 drivers/hwmon/Kconfig                         |  11 +
 drivers/hwmon/Makefile                        |   1 +
 drivers/hwmon/aspeed-g6-pwm-tach.c            | 539 ++++++++++++++++++
 7 files changed, 725 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/aspeed,g6-pwm-tach.yaml
 create mode 100644 Documentation/devicetree/bindings/hwmon/fan-common.yaml
 create mode 100644 Documentation/hwmon/aspeed-g6-pwm-tach.rst
 create mode 100644 drivers/hwmon/aspeed-g6-pwm-tach.c

Comments

Rob Herring Nov. 8, 2023, 6:16 p.m. UTC | #1 
On Tue, Nov 07, 2023 at 06:50:23PM +0800, Billy Tsai wrote:
> From: Naresh Solanki <naresh.solanki@9elements.com>
> 
> Add common fan properties bindings to a schema.
> 
> Bindings for fan controllers can reference the common schema for the
> fan
> 
> child nodes:
> 
>   patternProperties:
>     "^fan@[0-2]":
>       type: object
>       $ref: fan-common.yaml#
>       unevaluatedProperties: false
> 
> Signed-off-by: Naresh Solanki <naresh.solanki@9elements.com>
> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
> ---
>  .../devicetree/bindings/hwmon/fan-common.yaml | 78 +++++++++++++++++++
>  1 file changed, 78 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/hwmon/fan-common.yaml

Looking pretty good to me. It's disappointing that no one else 
interested in upstreaming their fan controller can be bothered to 
comment.

> 
> diff --git a/Documentation/devicetree/bindings/hwmon/fan-common.yaml b/Documentation/devicetree/bindings/hwmon/fan-common.yaml
> new file mode 100644
> index 000000000000..be4ce3bd7f22
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/fan-common.yaml
> @@ -0,0 +1,78 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/hwmon/fan-common.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Common Fan Properties
> +
> +maintainers:
> +  - Naresh Solanki <naresh.solanki@9elements.com>
> +  - Billy Tsai <billy_tsai@aspeedtech.com>
> +
> +properties:
> +  max-rpm:
> +    description:
> +      Max RPM supported by fan.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    maximum: 100000
> +
> +  min-rpm:
> +    description:
> +      Min RPM supported by fan.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    maximum: 1000
> +
> +  pulses-per-revolution:
> +    description:
> +      The number of pulse from fan sensor per revolution.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    maximum: 4
> +
> +  tach-div:
> +    description:
> +      Divisor for the tach sampling clock, which determines the sensitivity of the tach pin.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +  target-rpm:
> +    description:
> +      The default desired fan speed in RPM.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +  fan-driving-mode:
> +    description:
> +      Select the driving mode of the fan.(DC, PWM and so on)
> +    $ref: /schemas/types.yaml#/definitions/string

You need to define the possible values. I assume it's:

enum:
  - dc
  - pwm
  - anything else???

With that,

Reviewed-by: Rob Herring <robh@kernel.org>
Guenter Roeck Nov. 8, 2023, 6:38 p.m. UTC | #2 
On 11/8/23 10:16, Rob Herring wrote:
> On Tue, Nov 07, 2023 at 06:50:23PM +0800, Billy Tsai wrote:
>> From: Naresh Solanki <naresh.solanki@9elements.com>
>>
>> Add common fan properties bindings to a schema.
>>
>> Bindings for fan controllers can reference the common schema for the
>> fan
>>
>> child nodes:
>>
>>    patternProperties:
>>      "^fan@[0-2]":
>>        type: object
>>        $ref: fan-common.yaml#
>>        unevaluatedProperties: false
>>
>> Signed-off-by: Naresh Solanki <naresh.solanki@9elements.com>
>> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
>> ---
>>   .../devicetree/bindings/hwmon/fan-common.yaml | 78 +++++++++++++++++++
>>   1 file changed, 78 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/hwmon/fan-common.yaml
> 
> Looking pretty good to me. It's disappointing that no one else
> interested in upstreaming their fan controller can be bothered to
> comment.
> 

FWIW, I declined to comment since it basically looks ok to me
and because at this point I'd rather have something (whatever it is)
instead of nothing.

>>
>> diff --git a/Documentation/devicetree/bindings/hwmon/fan-common.yaml b/Documentation/devicetree/bindings/hwmon/fan-common.yaml
>> new file mode 100644
>> index 000000000000..be4ce3bd7f22
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/hwmon/fan-common.yaml
>> @@ -0,0 +1,78 @@
>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/hwmon/fan-common.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Common Fan Properties
>> +
>> +maintainers:
>> +  - Naresh Solanki <naresh.solanki@9elements.com>
>> +  - Billy Tsai <billy_tsai@aspeedtech.com>
>> +
>> +properties:
>> +  max-rpm:
>> +    description:
>> +      Max RPM supported by fan.
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    maximum: 100000
>> +
>> +  min-rpm:
>> +    description:
>> +      Min RPM supported by fan.
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    maximum: 1000
>> +
>> +  pulses-per-revolution:
>> +    description:
>> +      The number of pulse from fan sensor per revolution.
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    maximum: 4
>> +
>> +  tach-div:
>> +    description:
>> +      Divisor for the tach sampling clock, which determines the sensitivity of the tach pin.
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +
>> +  target-rpm:
>> +    description:
>> +      The default desired fan speed in RPM.
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +
>> +  fan-driving-mode:
>> +    description:
>> +      Select the driving mode of the fan.(DC, PWM and so on)
>> +    $ref: /schemas/types.yaml#/definitions/string
> 
> You need to define the possible values. I assume it's:
> 
> enum:
>    - dc
>    - pwm
>    - anything else???
> 

I am not aware of any other possible method. dc and pwm is all
I have ever seen.

Guenter

> With that,
> 
> Reviewed-by: Rob Herring <robh@kernel.org>
Uwe Kleine-König Dec. 6, 2023, 5:48 p.m. UTC | #3 
On Tue, Nov 07, 2023 at 11:02:43AM -0800, Guenter Roeck wrote:
> On 11/7/23 02:50, Billy Tsai wrote:
> > Unlike the old design that the register setting of the TACH should based
> > on the configure of the PWM. In ast26xx, the dependency between pwm and
> > tach controller is eliminated and becomes a separate hardware block. One
> > is used to provide pwm output and another is used to monitor the frequency
> > of the input. This driver implements them by exposing two kernel
> > subsystems: PWM and HWMON. The PWM subsystem can be utilized alongside
> > existing drivers for controlling elements such as fans (pwm-fan.c),
> > beepers (pwm-beeper.c) and so on. Through the HWMON subsystem, the driver
> > provides sysfs interfaces for fan.
> > 
> > Changes since v9:
> > Change the type of fan-driving-mode to string
> > Fix some typos and formatting issues.
> > 
> 
> What is the resend about ?

And to the original v10 there is a reply by Krzysztof;
see https://lore.kernel.org/linux-pwm/3d9e50db-19f0-43b3-8042-2f80a1e7b79e@linaro.org/ .

I'll mark the original and this resend as "changes-requested" in our
patchwork. Probably the most cooperative way to object is to send a v11
and point out the changes compared to v10.

Best regards
Uwe