Re: [PATCH v3 04/11] thermal: armada: Rationalize register accesses

Baruch Siach
2017-12-16T22:18:38Z

Hi Miquèl,

On Thu, Dec 14, 2017 at 11:30:04AM +0100, Miquel Raynal wrote:
> Bindings were incomplete for a long time by only exposing one of the two
> available control registers. To ease the migration to the full bindings
> (already in use for the Armada 375 SoC), rename the pointers for
> clarification. This way, it will only be needed to add another pointer
> to access the other control register when the time comes.
>
> This avoids dangerous situations where the offset 0 of the control
> area can be either one register or the other depending on the bindings
> used. After this change, device trees of other SoCs could be migrated to
> the "full" bindings if they may benefit from features from the
> unaccessible register, without any change in the driver.
>
> Signed-off-by: Miquel Raynal <miquel.raynal-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> ---

[...]

> + /*
> + * Legacy DT bindings only described "control1" register (also referred
> + * as "control MSB" on old documentation). New bindings cover
> + * "control0/control LSB" and "control1/control MSB" registers within
> + * the same resource, which is then of size 8 instead of 4.
> + */
> + if ((res->end - res->start) == LEGACY_CONTROL_MEM_LEN) {
> + /* ->control0 unavailable in this configuration */
> + priv->control1 = control + LEGACY_CONTROL1_OFFSET;
> + } else {
> + priv->control0 = control + CONTROL0_OFFSET;
> + priv->control1 = control + CONTROL1_OFFSET;
> + }

I think we need to add a check here that the control registers area size
matches the expected value given the compatible string. In case of mismatch
probe should fail.

> priv->data = (struct armada_thermal_data *)match->data;
> priv->data->init_sensor(pdev, priv);

baruch

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