| Date | Sat, 25 Jan 2020 19:59:36 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH 4.19 309/639] hwmon: (w83627hf) Use request_muxed_region for Super-IO accesses |
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Hi! > [ Upstream commit e95fd518d05bfc087da6fcdea4900a57cfb083bd ] > > Super-IO accesses may fail on a system with no or unmapped LPC bus. > > Also, other drivers may attempt to access the LPC bus at the same time, > resulting in undefined behavior. > > Use request_muxed_region() to ensure that IO access on the requested > address space is supported, and to ensure that access by multiple drivers > is synchronized. >
> @@ -1644,9 +1654,21 @@ static int w83627thf_read_gpio5(struct platform_device *pdev) > struct w83627hf_sio_data *sio_data = dev_get_platdata(&pdev->dev); > int res = 0xff, sel; > > - superio_enter(sio_data); > + if (superio_enter(sio_data)) { > + /* > + * Some other driver reserved the address space for itself. > + * We don't want to fail driver instantiation because of that, > + * so display a warning and keep going. > + */ > + dev_warn(&pdev->dev, > + "Can not read VID data: Failed to enable SuperIO access\n"); > + return res; > + } > + > superio_select(sio_data, W83627HF_LD_GPIO5); > > + res = 0xff; > +
This is strange. res is not actually assigned in the code above, so we have res = 0xff twice. Can we remove one of the initializations and do 'return 0xff' directly to make code more clear?
> @@ -1677,7 +1699,17 @@ static int w83687thf_read_vid(struct platform_device *pdev) > struct w83627hf_sio_data *sio_data = dev_get_platdata(&pdev->dev); > int res = 0xff; > > - superio_enter(sio_data); > + if (superio_enter(sio_data)) { > + /* > + * Some other driver reserved the address space for itself. > + * We don't want to fail driver instantiation because of that, > + * so display a warning and keep going. > + */ > + dev_warn(&pdev->dev, > + "Can not read VID data: Failed to enable SuperIO access\n"); > + return res; > + }
Direct "return 0xff" would make more sense here, too.
Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html [unhandled content-type:application/pgp-signature] |