Messages in this thread | | | Date | Wed, 29 Aug 2018 21:20:11 +0300 | From | Andy Shevchenko <> | Subject | Re: [PATCH] platform/x86: Add Intel ISP dummy driver |
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On Wed, Aug 29, 2018 at 03:57:44PM +0200, Hans de Goede wrote: > The Image Signal Processor found on Cherry Trail devices is brought up in > D0 state on devices which have camera sensors attached to it. The ISP will > not enter D3 state again without some massaging of its registers beforehand > and the ISP not being in D3 state blocks the SoC from entering S0ix modes. > > There was a driver for the ISP in drivers/staging but that got removed > again because it never worked. It does not seem likely that a real > driver for the ISP will be added to the mainline kernel anytime soon. > > This commit adds a dummy driver which contains the necessary magic from > the staging driver to powerdown the ISP, so that Cherry Trail devices where > the ISP is used will properly use S0ix modes when suspended. > > Together with other recent S0ix related fixes this allows S0ix modes to > be entered on e.g. a Chuwi Hi8 Pro and a HP x2 210. >
Thanks for the patch, my comments below.
> drivers/platform/x86/intel_isp_dummy.c | 119 +++++++++++++++++++++++++
First of all, I would like to see that this is about pm and pm only, so, perhaps
intel_isp_pm ?
OTOH, it would be nice to have less confusing of what ISP we are talking about, so,
intel_atomisp2_pm ?
> +config INTEL_ISP_DUMMY > + tristate "Intel ISP dummy driver"
> + depends on PCI && IOSF_MBI && PM
If someone decides to port this to kernels where ATOMISP driver is still available, it might be a conflict here. I dunno if it's a good idea to put something like depends !ATOMISP here taking into consideration that it would be staled option.
> + while (1) {
A nit: I would rather put it like
do { ... } while (time_after(...));
> + /* Wait until ISPSSPM0 bit[25:24] shows 0x3 */ > + iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, ISPSSPM0, &val); > + val = (val & ISPSSPM0_ISPSSS_MASK) >> ISPSSPM0_ISPSSS_OFFSET; > + if (val == ISPSSPM0_IUNIT_POWER_OFF) > + break; > + > + if (time_after(jiffies, timeout)) { > + dev_err(&dev->dev, "IUNIT power-off timeout.\n"); > + return -EBUSY; > + } > + usleep_range(1000, 2000); > + }
-- With Best Regards, Andy Shevchenko
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