On 9/13/2022 4:06 PM, Farber, Eliav wrote:
On 9/8/2022 9:11 PM, Andy Shevchenko wrote:
On Thu, Sep 08, 2022 at 03:24:48PM +0000, Eliav Farber wrote:
This change adds debugfs to read and write temperature sensor
coefficients
- g, h, j and cal5.
The coefficients can vary between product and product, so it can be
very
useful to be able to modify them on the fly during the calibration
process.
e.g.:
cat /sys/kernel/debug/940f23d0000.pvt/ts_coeff_cal5
4096
echo 83000 > sys/kernel/debug/940f23d0000.pvt/ts_coeff_g
...
- Return j coefficient to use debugfs_create_file() instead of
debugfs_create_u32() because j is signed.
You can use
DEFINE_DEBUGFS_ATTRIBUTE(ts_coeff_j, ts_coeff_j_get, ts_coeff_j_set,
"%lld\n");
which still makes code compact.
I tried your suggestion to use DEFINE_DEBUGFS_ATTRIBUTE but I can't set
j to be a negative value:
root@alpine:~# cat /sys/kernel/debug/940f23d0000.pvt/ts_coeff_j
0
root@alpine:~# echo 100 > /sys/kernel/debug/940f23d0000.pvt/ts_coeff_j
root@alpine:~# cat /sys/kernel/debug/940f23d0000.pvt/ts_coeff_j
100
root@alpine:~# echo -100 > /sys/kernel/debug/940f23d0000.pvt/ts_coeff_j
sh: write error: Invalid argument
This is the code I added:
static int ts_coeff_j_set(void *data, u64 val)
{
struct pvt_device *pvt = data;
pvt->ts_coeff.j = val;
return 0;
}
static int ts_coeff_j_get(void *data, u64 *val)
{
struct pvt_device *pvt = data;
*val = pvt->ts_coeff.j;
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(ts_coeff_j_fops, ts_coeff_j_get,
ts_coeff_j_set, "%lld\n");
static void devm_pvt_ts_dbgfs_remove(void *data)
{
struct pvt_device *pvt = (struct pvt_device *)data;
debugfs_remove_recursive(pvt->dbgfs_dir);
pvt->dbgfs_dir = NULL;
}
static int pvt_ts_dbgfs_create(struct pvt_device *pvt, struct device
*dev)
{
...
debugfs_create_file("ts_coeff_j", 0644, pvt->dbgfs_dir, pvt,
&ts_coeff_j_fops);
...
I'm using kernel 5.10.112.
Can you please see if I'm did anything wrong?
It seems like debugfs_attr_write() calls simple_attr_write() and it uses
kstrtoull(), which is why it fails when setting a negative value.
This is the same also in v6.0-rc5.
debugfs_attr_read() on the other hand does show the correct value also
when j is negative.
--
Regards, Eliav
