Messages in this thread | | | Subject | Re: [PATCH 4.19 309/639] hwmon: (w83627hf) Use request_muxed_region for Super-IO accesses | From | Guenter Roeck <> | Date | Sat, 25 Jan 2020 11:14:57 -0800 |
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On 1/25/20 10:59 AM, Pavel Machek wrote: > 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. >
Please feel free to submit a patch to improve the upstream code.
Thanks, Guenter
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