[PATCH v2] pinctrl/nomadik: make independent of prcmu driver
Stephen Warren
swarren at wwwdotorg.org
Fri Nov 9 12:16:03 EST 2012
On 11/09/2012 03:28 AM, Linus Walleij wrote:
> From: Jonas Aaberg <jonas.aberg at stericsson.com>
>
> Currently there are some unnecessary criss-cross
> dependencies between the PRCMU driver in MFD and a lot of
> other drivers, mainly because other drivers need to poke
> around in the PRCM register range.
>
> In cases like this there are actually just a few select
> registers that the pinctrl driver need to read/modify/write,
> and it turns out that no other driver is actually using
> these registers, so there are no concurrency issues
> whatsoever.
>
> So: don't let the location of the register range complicate
> things, just poke into these registers directly and skip
> a layer of indirection.
>
> Take this opportunity to add kerneldoc to the pinctrl
> state container.
> diff --git a/drivers/pinctrl/pinctrl-nomadik.c b/drivers/pinctrl/pinctrl-nomadik.c
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (res) {
> + npct->prcm_base = devm_ioremap(&pdev->dev, res->start,
> + resource_size(res));
> + if (!npct->prcm_base) {
> + dev_err(&pdev->dev,
> + "failed to ioremap PRCM registers\n");
> + return -ENOMEM;
> + }
> + } else {
> + dev_info(&pdev->dev,
> + "No PRCM base, assume no ALT-Cx control is available\n");
> + }
Where is "assume no ALT-Cx control is available" implemented; I don't
see anything that uses npct->prcm_base to conditionally enable/block any
features. Is it just assumed that the DT won't contain any entries that
trigger writes to the PRCM registers? That seems fragile; it could cause
a "user"-triggered kernel crash.
Aside from that, this seems fine. Much smaller than V1:-)
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