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From: "Uwe Kleine-König" <>
Subject: Re: [PATCH 1/3] pwm: Add count attribute in sysfs for Intel Keem Bay
Date: Sat, 23 May 2020 23:05:25 +0200
Message-ID: <> (raw)
In-Reply-To: <>

On Sun, May 17, 2020 at 09:52:38PM +0800, wrote:
> From: "Lai, Poey Seng" <>
> In Keem Bay, the number of repetitions for the period/waveform
> can be configured from userspace. This requires addition of a sysfs
> attribute to get/set the repetition count. Setting this value to 0
> will result in continuous repetition of the waveform until the
> channel is disabled or reconfigured.

There is nothing specific for Keem Bay in this patch, the only special
thing here is that this driver is the first implementor.

IMHO all drivers that don't support count should be changed to fail if
a count > 0 is passed and introducing support in the sysfs interface
should be a separate change.

Having said that I'm not convinced this is a good idea given that only
very few driver can support this interface. Also this needs
documentation, e.g. what is expected from .get_state().

You should also motivate what this functionality is used for in the
commit log and I'd prefer to see an in-tree user (apart from sysfs which
I don't count as such).

Best regards

Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | |

  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-17 13:52 [PATCH 0/3] Add PWM support for Intel Keem Bay SoC vineetha.g.jaya.kumaran
2020-05-17 13:52 ` [PATCH 1/3] pwm: Add count attribute in sysfs for Intel Keem Bay vineetha.g.jaya.kumaran
2020-05-23 21:05   ` Uwe Kleine-König [this message]
2020-06-05 13:49     ` G Jaya Kumaran, Vineetha
2020-05-17 13:52 ` [PATCH 2/3] pwm: Add PWM driver " vineetha.g.jaya.kumaran
2020-05-23 21:40   ` Uwe Kleine-König
2020-06-05 13:48     ` G Jaya Kumaran, Vineetha
2020-05-17 13:52 ` [PATCH 3/3] dt-bindings: pwm: keembay: Add bindings for Intel Keem Bay PWM vineetha.g.jaya.kumaran
2020-05-18 14:18   ` Rob Herring
2020-05-20 10:49     ` G Jaya Kumaran, Vineetha
2020-05-18 14:21   ` Rob Herring
2020-05-20 10:52     ` G Jaya Kumaran, Vineetha

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