Messages in this thread | | | Date | Mon, 14 Oct 2019 23:20:24 +0200 | From | Thomas Bogendoerfer <> | Subject | Re: [PATCH 3/3] rtc: ds1685: add indirect access method and remove plat_read/plat_write |
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On Sat, 12 Oct 2019 19:22:01 -0400 Joshua Kinard <kumba@gentoo.org> wrote:
> On 10/11/2019 11:05, Thomas Bogendoerfer wrote: > > +static void > > +ds1685_indir_write(struct ds1685_priv *rtc, int reg, u8 value) > > +{ > > + writeb(reg, rtc->regs); > > + writeb(value, rtc->data); > > +} > > IP30 applied a mask of 0x7f on the 'reg' parameter on both of its > read/write functions, which was from Stan's original code. Is this mask > not needed any more with the other changes you made to the IP30 code?
reg is always < 0x80, so I didn't see a point in masking it.
> > + switch (pdata->access_type) { > > + case ds1685_reg_direct: > > + rtc->regs = devm_platform_ioremap_resource(pdev, 0); > > + if (IS_ERR(rtc->regs)) > > + return PTR_ERR(rtc->regs); > > + rtc->read = ds1685_read; > > + rtc->write = ds1685_write; > > + break; > > + case ds1685_reg_indirect: > > rtc->regs = devm_platform_ioremap_resource(pdev, 0); > > if (IS_ERR(rtc->regs)) > > return PTR_ERR(rtc->regs); > > + rtc->data = devm_platform_ioremap_resource(pdev, 1); > > + if (IS_ERR(rtc->data)) > > + return PTR_ERR(rtc->data); > > + rtc->read = ds1685_indir_read; > > + rtc->write = ds1685_indir_write; > > + break; > > } > > I believe there should be a default case in the switch statement to catch > and return -ENXIO so that we don't wind up with rtc->{read,write} being > NULL.
access_type is an enum and all possible values are covered with cases. But I'll add a safe guart to check that read/write is set to cover garbled platform_data. If you want to keep plat_read/plat_write I could add an additional access_type (which could also be done later, when there is a real use case).
> I also think the "indir" name isn't really descriptive of why IP32 and > IP30 effectively have different read/write mechanisms.
IP32 accesses register directly and IP30 indirectly via an address register. I'll use indirect in function name and some comment to explain.
> Might want to add > some comments to explain that IP32 uses MMIO and can just directly > read/write the registers, while IP30 uses PIO and has to go the route of
what's PIO here for you ? RTC address and data register are mapped MMIO as part of the IOC3 register bar on IP30.
Thomas.
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