Re: [Gta04-owner] [PATCH 3/4] usb: phy: twl4030: add support for reading restore on ID pin.
On Wed, 4 Mar 2015 07:54:41 +0100 "Dr. H. Nikolaus Schaller" wrote: > > Am 04.03.2015 um 07:35 schrieb NeilBrown : > > > On Mon, 2 Mar 2015 22:04:31 +0100 Pavel Machek wrote: > > > >> Hi! > >> > >>> The twl4030 phy can measure, with low precision, the > >>> resistance-to-ground of the ID pin. > >>> > >>> Add a function to read the value, and export the result > >>> via sysfs. > >>> > >>> If the read fails, which it does sometimes, try again in 50msec. > >>> > >>> Signed-off-by: NeilBrown > >>> --- > >>> drivers/phy/phy-twl4030-usb.c | 63 > >>> + > >>> 1 file changed, 63 insertions(+) > >>> > >>> diff --git a/drivers/phy/phy-twl4030-usb.c b/drivers/phy/phy-twl4030-usb.c > >>> index 023fe150c7a1..759950898df9 100644 > >>> --- a/drivers/phy/phy-twl4030-usb.c > >>> +++ b/drivers/phy/phy-twl4030-usb.c > >>> @@ -374,6 +374,56 @@ static void twl4030_i2c_access(struct twl4030_usb > >>> *twl, int on) > >>> } > >>> } > >>> > >>> +enum twl4030_id_status { > >>> + TWL4030_GROUND, > >>> + TWL4030_102K, > >>> + TWL4030_200K, > >>> + TWL4030_440K, > >>> + TWL4030_FLOATING, > >>> + TWL4030_ID_UNKNOWN, > >>> +}; > >>> +static char *twl4030_id_names[] = { > >>> + "ground", > >>> + "102k", > >>> + "200k", > >>> + "440k", > >> > >> New /sys files should be documented somewhere...? > > > > Preferably with the code... > > > >> > >> Does it make sense to change "440k" -> "440KOhm"? > > > > Interesting question. I prefer to avoid including units in files - bare > > numbers is better. But there is no number to match "floating" unless I > > spell > > it out as "infinity", and wouldn't be helpful. > > > > Certainly "K" would be preferred over "k“, > > The international standard for kilo = 1000 is a lower case k. > While it is (non-standard) to use K for 1024: > > http://en.wikipedia.org/wiki/Kilobyte > > So I would keep the string constants lower case to avoid this potential > confusion. Yes, I got that backwards, didn't I. I think I'll leave it as lower-case. I won't include the word "ohm" - it is very uncommon to have units explicit in sysfs attribute values. Thanks, NeilBrown pgpTfJsV9eFf0.pgp Description: OpenPGP digital signature
Re: [Gta04-owner] [PATCH 3/4] usb: phy: twl4030: add support for reading restore on ID pin.
Am 04.03.2015 um 07:35 schrieb NeilBrown : > On Mon, 2 Mar 2015 22:04:31 +0100 Pavel Machek wrote: > >> Hi! >> >>> The twl4030 phy can measure, with low precision, the >>> resistance-to-ground of the ID pin. >>> >>> Add a function to read the value, and export the result >>> via sysfs. >>> >>> If the read fails, which it does sometimes, try again in 50msec. >>> >>> Signed-off-by: NeilBrown >>> --- >>> drivers/phy/phy-twl4030-usb.c | 63 >>> + >>> 1 file changed, 63 insertions(+) >>> >>> diff --git a/drivers/phy/phy-twl4030-usb.c b/drivers/phy/phy-twl4030-usb.c >>> index 023fe150c7a1..759950898df9 100644 >>> --- a/drivers/phy/phy-twl4030-usb.c >>> +++ b/drivers/phy/phy-twl4030-usb.c >>> @@ -374,6 +374,56 @@ static void twl4030_i2c_access(struct twl4030_usb >>> *twl, int on) >>> } >>> } >>> >>> +enum twl4030_id_status { >>> + TWL4030_GROUND, >>> + TWL4030_102K, >>> + TWL4030_200K, >>> + TWL4030_440K, >>> + TWL4030_FLOATING, >>> + TWL4030_ID_UNKNOWN, >>> +}; >>> +static char *twl4030_id_names[] = { >>> + "ground", >>> + "102k", >>> + "200k", >>> + "440k", >> >> New /sys files should be documented somewhere...? > > Preferably with the code... > >> >> Does it make sense to change "440k" -> "440KOhm"? > > Interesting question. I prefer to avoid including units in files - bare > numbers is better. But there is no number to match "floating" unless I spell > it out as "infinity", and wouldn't be helpful. > > Certainly "K" would be preferred over "k“, The international standard for kilo = 1000 is a lower case k. While it is (non-standard) to use K for 1024: http://en.wikipedia.org/wiki/Kilobyte So I would keep the string constants lower case to avoid this potential confusion. > and given that I have "ground" > and "floating", it is more consistent to include the "Ohm" > > These are really names, not measures of resistance. The data sheet calls > them: > ID_RES_FLOAT (or sometimes ID_FLOAT) > ID_RES_440K > ID_RES_200K > ID_RES_102K > ID_GND(or sometimes ID_RES_GND) > > So using those names is defensible. > > I think I'll change them all to upper case, but leave out the "Ohm". > My justification is consistency with the data sheet. > > > > >> >> Plus I guess you need to update Documentation/ > > I guess I'll need to give in to this eventually :-) > >> >> Acked-by: Pavel Machek >> > > Thanks, > NeilBrown > ___ > Gta04-owner mailing list > gta04-ow...@goldelico.com > http://lists.goldelico.com/mailman/listinfo.cgi/gta04-owner -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html