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Date: Fri, 13 Jan 2017 09:27:10 +0000
From: Ramiro Oliveira <Ramiro.Oliveira@...opsys.com>
To: Philipp Zabel <p.zabel@...gutronix.de>,
Ramiro Oliveira <Ramiro.Oliveira@...opsys.com>
CC: <linux-kernel@...r.kernel.org>,
<laurent.pinchart@...asonboard.com>, <CARLOS.PALMINHA@...opsys.com>
Subject: Re: [PATCH v3 2/2] reset: make optional functions really optional
Hi Philipp
On 1/13/2017 9:11 AM, Philipp Zabel wrote:
> Hi Ramiro,
>
> Am Donnerstag, den 12.01.2017, 18:34 +0000 schrieb Ramiro Oliveira:
>> "The *_get_optional_* functions weren't really optional so this patch
>> makes them really optional.
>>
>> These *_get_optional_* functions will now return NULL instead of an error
>> if no matching reset phandle is found in the DT, and all the
>> reset_control_* functions now accept NULL rstc pointers.
>>
>> Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@...opsys.com>
>> ---
>> drivers/reset/core.c | 59 ++++++++++++++++++++++++++++++++++++++++-----------
>> include/linux/reset.h | 45 ++++++++++++++++++++++-----------------
>> 2 files changed, 73 insertions(+), 31 deletions(-)
>>
>> diff --git a/drivers/reset/core.c b/drivers/reset/core.c
>> index 272c1e4ecb5c..7b679b0bfef8 100644
>> --- a/drivers/reset/core.c
>> +++ b/drivers/reset/core.c
>> @@ -143,12 +143,18 @@ EXPORT_SYMBOL_GPL(devm_reset_controller_register);
>> * a no-op.
>> * Consumers must not use reset_control_(de)assert on shared reset lines when
>> * reset_control_reset has been used.
>> + *
>> + * If rstc is NULL it is an optional reset and the function will just
>> + * return 0.
>> */
>> int reset_control_reset(struct reset_control *rstc)
>> {
>> int ret;
>>
>> - if (WARN_ON(IS_ERR_OR_NULL(rstc)))
>> + if (!rstc)
>> + return 0;
>> +
>> + if (WARN_ON(IS_ERR(rstc)))
>> return -EINVAL;
>>
>> if (!rstc->rcdev->ops->reset)
>> @@ -182,10 +188,17 @@ EXPORT_SYMBOL_GPL(reset_control_reset);
>> * internal state to be reset, but must be prepared for this to happen.
>> * Consumers must not use reset_control_reset on shared reset lines when
>> * reset_control_(de)assert has been used.
>> + * return 0.
>> + *
>> + * If rstc is NULL it is an optional reset and the function will just
>> + * return 0.
>> */
>> int reset_control_assert(struct reset_control *rstc)
>> {
>> - if (WARN_ON(IS_ERR_OR_NULL(rstc)))
>> + if (!rstc)
>> + return 0;
>> +
>> + if (WARN_ON(IS_ERR(rstc)))
>> return -EINVAL;
>>
>> if (!rstc->rcdev->ops->assert)
>> @@ -213,10 +226,17 @@ EXPORT_SYMBOL_GPL(reset_control_assert);
>> * After calling this function, the reset is guaranteed to be deasserted.
>> * Consumers must not use reset_control_reset on shared reset lines when
>> * reset_control_(de)assert has been used.
>> + * return 0.
>> + *
>> + * If rstc is NULL it is an optional reset and the function will just
>> + * return 0.
>> */
>> int reset_control_deassert(struct reset_control *rstc)
>> {
>> - if (WARN_ON(IS_ERR_OR_NULL(rstc)))
>> + if (!rstc)
>> + return 0;
>> +
>> + if (WARN_ON(IS_ERR(rstc)))
>> return -EINVAL;
>>
>> if (!rstc->rcdev->ops->deassert)
>> @@ -237,12 +257,15 @@ EXPORT_SYMBOL_GPL(reset_control_deassert);
>> /**
>> * reset_control_status - returns a negative errno if not supported, a
>> * positive value if the reset line is asserted, or zero if the reset
>> - * line is not asserted.
>> + * line is not asserted or if the desc is NULL (optional reset).
>> * @rstc: reset controller
>> */
>> int reset_control_status(struct reset_control *rstc)
>> {
>> - if (WARN_ON(IS_ERR_OR_NULL(rstc)))
>> + if (!rstc)
>> + return 0;
>> +
>> + if (WARN_ON(IS_ERR(rstc)))
>> return -EINVAL;
>>
>> if (rstc->rcdev->ops->status)
>> @@ -299,7 +322,8 @@ static void __reset_control_put(struct reset_control *rstc)
>> }
>>
>> struct reset_control *__of_reset_control_get(struct device_node *node,
>> - const char *id, int index, bool shared)
>> + const char *id, int index, bool shared,
>> + bool optional)
>> {
>> struct reset_control *rstc;
>> struct reset_controller_dev *r, *rcdev;
>> @@ -313,14 +337,24 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
>> if (id) {
>> index = of_property_match_string(node,
>> "reset-names", id);
>> - if (index < 0)
>> - return ERR_PTR(-ENOENT);
>> + if (index < 0) {
>> + if (optional)
>> + return NULL;
>> + else
>> + return (index == -EILSEQ) ?
>> + ERR_PTR(index) : ERR_PTR(-ENOENT);
>
> That is not what I meant. I think reset_control_get should return an
> error on EILSEQ even if optional is true, since that means there are
> resets specified in the DT, but the reset-names property is broken.
> How about:
> if (index == -EILSEQ)
> return ERR_PTR(index);
> if (index < 0)
> return optional ? NULL : ERR_PTR(-ENOENT);
>
When you first suggested I wasn't entirely sure what you meant, but now it makes
total sense to me.
I should have asked you about it before implementing it.
>> + }
>> }
>>
>> ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
>> index, &args);
>> - if (ret)
>> - return ERR_PTR(ret);
>> + if (ret) {
>> + if (optional)
>> + return NULL;
>> + else
>> + return (index == -EINVAL) ?
>> + ERR_PTR(index) : ERR_PTR(-ENOENT);
>> + }
>
> That is not what I meant either. If the phandle parsing fails with
> of_phandle_iterator_next returning -EINVAL, that should be passed along
> in the optional case: that happens when we've already found a matching
> entry in reset-names, but the resets property is broken.
> How about:
> if (ret == -EINVAL)
> return ERR_PTR(ret);
> if (ret)
> return optional ? NULL : ERR_PTR(ret);
>
Same as above.
> regards
> Philipp
>
I'll refactor the code and send a new patch ASAP.
BRs,
Ramiro
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