2016-07-12 12:13 GMT+02:00 Daniel Vetter daniel@ffwll.ch:
On Wed, Jun 29, 2016 at 6:31 AM, Daniel Kurtz djkurtz@chromium.org wrote:
On Fri, Jun 17, 2016 at 3:14 AM, Emil Velikov emil.l.velikov@gmail.com wrote:
+static ssize_t ps8640_update_fw_store(struct device *dev,
struct device_attribute *attr,const char *buf, size_t count)+{
struct i2c_client *client = to_i2c_client(dev);struct ps8640 *ps_bridge = i2c_get_clientdata(client);const struct firmware *fw;int error;error = request_firmware(&fw, PS_FW_NAME, dev);Can the device operate without a firmware ? If not, why is the firmware loaded so later/after user interaction (via sysfs) ? I don't recall any other driver in DRM to use such an approach.
The PS8640 has internal flash, so it should always already have a working firmware. This sysfs interface is useful for user space initiated field firmware updates.
Might be better to just do a request_firmware on driver load, and simply proceed if it's not there. Adding a sysfs interface (which is abi) seems way too much overkill for this imo. If you want to upgrade the firmware you can then just drop it into the right directory, with no further interaction needed.
IMHO I'm not sure if for this use case request_firmware on driver load is a good idea. Flash the non-volatile internal chip can be a slow operation and if you forget to remove the firmware after drop it into the right directory apart from slow down the driver probe you can damage the chip depending on the write endurance of the chip.
This sysfs interface is used on other subsystems when there is a non-volatile memory, as example you can see at [1], [2]. Unfortunately not all are using the same sysfs interface and maybe this should be standardized (maybe it's an opportunity to define it)
Regards, Enric
[1] http://lxr.free-electrons.com/source/drivers/input/touchscreen/wdt87xx_i2c.c... [2] http://lxr.free-electrons.com/source/drivers/scsi/pm8001/pm8001_ctl.c#L732
-Daniel
Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel