Re: [PATCH V2] net: phy: tja11xx: Add TJA11xx PHY driver

On 22.12.2018 00:22, Marek Vasut wrote:

On 12/15/2018 06:38 PM, Heiner Kallweit wrote:

quoted

On 15.12.2018 18:01, Andrew Lunn wrote:

quoted

quoted

+static struct tja11xx_phy_stats tja11xx_hw_stats[] = {
+	{ "phy_symbol_error_count", 20, 0, 0xffff },
+	{ "phy_overtemp_error", 21, 1, BIT(1) },
+	{ "phy_undervolt_error", 21, 3, BIT(3) },
+	{ "phy_polarity_detect", 25, 6, BIT(6) },
+	{ "phy_open_detect", 25, 7, BIT(7) },
+	{ "phy_short_detect", 25, 8, BIT(8) },

Hi Marek

You have a number of one bit counters here, which is pretty unusual.
The names also don't really suggest they are counters.

Apart from few counters the values seem to be flags. I just think
it could be done in a little bit more readable form, e.g. instead of
{ "phy_short_detect", 25, 8, BIT(8) } use
{ "phy_short_detect", 25, BIT(8) } and in tja11xx_get_stats() then
use FIELD_GET (see linux/bitfield.h).

This doesn't work with the counters, it only works with flags. The array
contains both.

Maybe we have a misunderstanding here, but FIELD_GET would work also
with the counters. FIELD_GET calculates the field offset, so you don't
need to specify it. Let's say you would have an entry in your array like
this: { "phy_xxx_error_count", 20, 4, 0xfff0 }

Then you would do:
#define XXX_ERROR_CNT_MASK GENMASK(15, 4)
{ "phy_xxx_error_count", 20, XXX_ERROR_CNT_MASK }
and access the value by
val = FIELD_GET(XXX_ERROR_CNT_MASK, reg)

quoted

The idea of HWMON attributes sounds good to me because it allows
to use the flags to trigger actions in a structured way. And I
assume in case of e.g. "PHY undervolt" some monitoring system
would like to be informed (especially because we talk about
automotive here).

I added HWMON_T_CRIT_ALARM and HWMON_I_LCRIT_ALARM for
phy_overtemp_error and phy_undervolt_error respectively.
Are there any other hwmon attributes I can use to replace the flags in
the tja11xx_hw_stats array ?

I think that's it.