From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Michael Walle <michael@walle.cc>
Cc: linux-kernel@vger.kernel.org, Lee Jones <lee.jones@linaro.org>,
Mark Brown <broonie@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Gene Chen <gene.chen.richtek@gmail.com>
Subject: Re: [PATCH] mfd: mfd-core: Don't overwrite the dma_mask of the child device
Date: Fri, 5 Jun 2020 16:16:22 +0300 [thread overview]
Message-ID: <20200605131622.GL2428291@smile.fi.intel.com> (raw)
In-Reply-To: <20200604213037.17254-1-michael@walle.cc>
On Thu, Jun 04, 2020 at 11:30:37PM +0200, Michael Walle wrote:
> Commit cdfee5623290 ("driver core: initialize a default DMA mask for
> platform device") initialize the DMA of a platform device. But if the
> parent doesn't have a dma_mask set, for example if it's an I2C device,
> the dma_mask of the child platform device will be set to zero again.
> Which leads to many "DMA mask not set" warnings, if the MFD cell has the
> of_compatible property set.
>
> [ 1.877937] sl28cpld-pwm sl28cpld-pwm: DMA mask not set
> [ 1.883282] sl28cpld-pwm sl28cpld-pwm.0: DMA mask not set
> [ 1.888795] sl28cpld-gpio sl28cpld-gpio: DMA mask not set
>
> Thus don't overwrite the dma_mask of the children. Instead set the
> dma_mask of the platform device.
> ---
> Former discussion was here:
> https://lore.kernel.org/lkml/20200423174543.17161-3-michael@walle.cc/
>
> Because my MFD driver now uses of_platform_populate() it doesn't trigger
> this anymore. But it may be useful for others, e.g. if I'm not mistaken it
> should apply to the mt6360 sub devices.
Yeah, I'm not sure it's right thing to do, but let maintainers and more
experienced in topic developers to speak up.
--
With Best Regards,
Andy Shevchenko
prev parent reply other threads:[~2020-06-05 13:16 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-04 21:30 [PATCH] mfd: mfd-core: Don't overwrite the dma_mask of the child device Michael Walle
2020-06-05 13:16 ` Andy Shevchenko [this message]
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