On Mon, Mar 19, 2018 at 4:17 AM, Bjorn Andersson
<bjorn.andersson@xxxxxxxxxx> wrote:
> On Wed 10 Jan 05:17 PST 2018, Anup Patel wrote:
>
>> This patch adds "driver_override" device attribute for rpmsg_device which
>> will allow users to explicitly specify the rpmsg_driver to be used via
>> sysfs entry.
>>
>> The "driver_override" device attribute implemented here is very similar
>> to "driver_override" implemented for platform, pci, and amba bus types.
>>
>> One important use-case of "driver_override" device attribute is to force
>> use of rpmsg_chrdev driver for certain rpmsg_device instances.
>>
>
> I assume you mean specifically for the case where you want to prevent
> some kernel driver to probe for some given channel?
Yes, there are few use-cases where we want to prevent kernel
driver and rather access rpmsg device from user-space using
rpmsg_chrdev driver.
>
> The intention with rpmsg_char is that you through the rpmsg_ctrlX
> interface create and destroy endpoints dynamically, so you wouldn't need
> to use this mechanism to bind some specific channel to rpmsg_char.
>
>
> That said, this does make sense for completeness sake.
>
> [..]
>> diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
>> index dffa3aa..9a25e42 100644
>> --- a/drivers/rpmsg/rpmsg_core.c
>> +++ b/drivers/rpmsg/rpmsg_core.c
>> @@ -321,11 +321,11 @@ struct device *rpmsg_find_device(struct device *parent,
>> }
>> EXPORT_SYMBOL(rpmsg_find_device);
>>
>> -/* sysfs show configuration fields */
>> +/* sysfs configuration fields */
>> #define rpmsg_show_attr(field, path, format_string) \
>> static ssize_t \
>> field##_show(struct device *dev, \
>> - struct device_attribute *attr, char *buf) \
>> + struct device_attribute *attr, char *buf) \
>
> Seems unnecessary.
OK, I will drop these changes.
>
>> { \
>> struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
>> \
>> @@ -333,11 +333,52 @@ field##_show(struct device *dev, \
>> } \
>> static DEVICE_ATTR_RO(field);
>>
>> +#define rpmsg_string_attr(field, path) \
>
> "path" is an odd name for these, I think it's a "member".
>
>> +static ssize_t \
>> +field##_store(struct device *dev, \
>> + struct device_attribute *attr, const char *buf, size_t sz)\
>
> field##_store(struct device *dev, struct device_attribute *attr, \
> const char *buf, size_t sz) \
>
> Is prettier
OK, I will update this.
>
>> +{ \
>> + struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
>> + char *new, *old, *cp; \
>> + \
>> + new = kstrndup(buf, sz, GFP_KERNEL); \
>> + if (!new) \
>> + return -ENOMEM; \
>> + \
>> + cp = strchr(new, '\n'); \
>> + if (cp) \
>> + *cp = '\0'; \
>
> I prefer
>
> new[strcspn(new, "\n")] = '\0';
Sure, I will update this.
Thanks,
Anup
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