linux-kernel - [PATCH v3 02/16] mfd: mfd-core: Don't overwrite the dma

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Date:   Thu, 23 Apr 2020 19:45:29 +0200
From:   Michael Walle <michael@...le.cc>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org,
        linux-pwm@...r.kernel.org, linux-watchdog@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Rob Herring <robh+dt@...nel.org>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Lee Jones <lee.jones@...aro.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Shawn Guo <shawnguo@...nel.org>, Li Yang <leoyang.li@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <maz@...nel.org>, Mark Brown <broonie@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Michael Walle <michael@...le.cc>,
        Robin Murphy <robin.murphy@....com>
Subject: [PATCH v3 02/16] mfd: mfd-core: Don't overwrite the dma_mask of the child device

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.

Signed-off-by: Michael Walle <michael@...le.cc>
Suggested-by: Robin Murphy <robin.murphy@....com>
---
 drivers/mfd/mfd-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index f5a73af60dd4..e735565969b3 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -138,7 +138,7 @@ static int mfd_add_device(struct device *parent, int id,
 
 	pdev->dev.parent = parent;
 	pdev->dev.type = &mfd_dev_type;
-	pdev->dev.dma_mask = parent->dma_mask;
+	pdev->platform_dma_mask = parent->dma_mask ? *parent->dma_mask : 0;
 	pdev->dev.dma_parms = parent->dma_parms;
 	pdev->dev.coherent_dma_mask = parent->coherent_dma_mask;
 
-- 
2.20.1