Re: [PATCH 2/6] iommu/arm-smmu: add support for specifying regulators

Mitchel Humpherys
2014-08-13T21:17:21Z

On Tue, Aug 12 2014 at 05:51:35 PM, Mitchel Humpherys <mitchelh-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> wrote:
> On some power-constrained platforms it's useful to disable power when a
> device is not in use. Add support for specifying regulators for SMMUs
> and only leave power on as long as the SMMU is in use (attached).
>
> Signed-off-by: Mitchel Humpherys <mitchelh-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
> ---
> .../devicetree/bindings/iommu/arm,smmu.txt | 3 +
> drivers/iommu/arm-smmu.c | 102 ++++++++++++++++++---
> 2 files changed, 93 insertions(+), 12 deletions(-)

[...]

> @@ -2124,13 +2192,19 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
> }
> dev_notice(dev, "registered %d master devices\n", i);
>
> + err = arm_smmu_init_regulators(smmu);
> + if (err)
> + goto out_put_masters;
> +
> err = arm_smmu_init_clocks(smmu);
> if (err)
> goto out_put_masters;
>
> + arm_smmu_enable_regulators(smmu);
> arm_smmu_enable_clocks(smmu);
> -
> err = arm_smmu_device_cfg_probe(smmu);
> + arm_smmu_disable_clocks(smmu);
> + arm_smmu_disable_regulators(smmu);
> if (err)
> goto out_disable_clocks;

The out_disable_clocks label can go away now that arm_smmu_device_reset
is done in arm_smmu_attach_dev.

>
> @@ -2163,8 +2237,6 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
> list_add(&smmu->list, &arm_smmu_devices);
> spin_unlock(&arm_smmu_devices_lock);
>
> - arm_smmu_device_reset(smmu);
> - arm_smmu_disable_clocks(smmu);
> return 0;
>
> out_free_irqs:
> @@ -2173,6 +2245,7 @@ out_free_irqs:
>
> out_disable_clocks:
> arm_smmu_disable_clocks(smmu);
> + arm_smmu_disable_regulators(smmu);
>
> out_put_masters:
> for (node = rb_first(&smmu->masters); node; node = rb_next(node)) {

-Mitch