I've added a BME280 driver in the kernel and enabled this driver as built in kernel module.
Can anybody help me to add sysfs entry for this?
SYSFS entry should be like i've to see pressure and temperature values.
Related
I am learing the loading process of Windows Driver.
But I cannot understand a part of the following article.
https://learn.microsoft.com/ja-jp/windows-hardware/drivers/install/step-3--the-driver-for-the-device-is-installed
In this article, there is the following description.
"4. The PnP manager loads the appropriate function driver and any optional filter drivers for the device."
I have a question about above description.
How does the PnP manager determine the appropriate function driver?
For example,
when a USB memory is plugged into a Windows PC then PnP manager will load disk.sys after loading a driver relating USB.
In this case, I want to know why PnP manager could judge that the device corresponds to disk.sys.
(seeing somewhere in registry? sending some requests to bus driver? and so on.. )
when bus driver detect and report PDO device PnP manager send several IRP_MJ_PNP to PDO device. including IRP_MN_QUERY_ID for get Device Identification Strings
then formated registry key path in form
\REGISTRY\MACHINE\SYSTEM\CurrentControlSet\Enum\<BusQueryDeviceID>\<BusQueryInstanceID>
in place <BusQueryDeviceID> string returned by device for BusQueryDeviceID and in place <BusQueryInstanceID> string returned by device for BusQueryInstanceID (Parameters.QueryId.IdType)
this key opened or created. then was query for BusQueryHardwareIDs and BusQueryCompatibleIDs. result of this query saved in HardwareID and CompatibleIDs REG_MULTI_SZ values.
and then PnP manager look for Service REG_SZ value under this key - if it already exist - the driver ( \REGISTRY\MACHINE\SYSTEM\CurrentControlSet\Services\<Service>) loaded and it AddDevice called with this PDO. if this value yet not set - was search via installed inf files in system - for best match HardwareID and CompatibleIDs. if found driver - result saved under Service REG_SZ value, for not search next time
I created a filter driver and I just want to install it for the Serial port. I know that the existing driver class is "Ports" so I changed inf file as follows:
[Version]
Signature="$Windows NT$"
Class=Ports
ClassGUID={4D36E978-E325-11CE-BFC1-08002BE10318}
Provider=%Provider%
DriverVer=03/17/2001,1.0.0.1
CatalogFile=KmdfSamples.cat
Note that the classguid is the same as in system for serial port. So I does not know how to install it for specyfic class, I have to manally edit "UpperFilter" field in registry?
I also can not find out from the microsoft documentation if I have to specyfi device in such a way (I do not know the device name, but i know whole class id).
So the questions are:
How to install upper filter for existing class?
Have I specyfi the device hardware id that I do not know?
Any repsonses will be greatly appreciated ;)
Latest kernel 4.1 supports MPLS datapath.
IpRoute2 is also adding commands to add mpls routes in kernel.
What are the iproutes command to create FTN(Fec to NHLFE), ILM(Incoming Label Map) and NHLFE(Next hop label forwarding entry) ?
What are the commands to see above tables ?
Thanks in advance.
I want to write a test driver for mcspi and want to give all configuration in my driver file (instead of using user space application I want to use driver as a test driver and want to create .ko) and want to pass all configuration to the mcspi controller.
The configurations like chip_select, mode, speed, bits etc., Basically all these configurations I want to use for my test driver to check functionality of FIFO mode in the mcspi. I have already enabled FIFO in the mcspi but I want to check its functionality.
Can anyone please give me some suggestions?
I don't really know why cant you do something you want. I think you can pass the configuration by set up parameters using module_param
Adding on what #sunnyleevip suggested: another "standard" way to configure your driver would be to expose the params of interest via the /proc or the /sys filesystems.
You can find all the details in Linux Device Driver
Expanding on #sergico and #sunnyleevip, you could also use device tree to pass configuration data to the driver. The SPI bus master driver (since the 2.6.30s and all of the 3.x kernels) already are pretty devicetree supportive, so there might not be much more to do to get it to work.
I have an array in my kernel mode driver. Is it possible for the driver to save the array data and on load restore the same?
Assuming your array is not incredibly large you can use the registry to store this type of information.
You can set your driver to open a specific registry location relative to your driver instance. If it's missing your driver should contain a default value (you can also set your INF file to put this value in the registry on install). Then, as your data changes and your device unloads rewrite the data to the registry to be looked up the next time your device loads.