| Message ID | 20150224034037.31400.52748.stgit@notabene.brown (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 <neilb@suse.de> > --- > 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...? Does it make sense to change "440k" -> "440KOhm"? Plus I guess you need to update Documentation/ Acked-by: Pavel Machek <pavel@ucw.cz>
On Mon, 2 Mar 2015 22:04:31 +0100 Pavel Machek <pavel@ucw.cz> 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 <neilb@suse.de> > > --- > > 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", 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 <pavel@ucw.cz> > Thanks, NeilBrown
Am 04.03.2015 um 07:35 schrieb NeilBrown <neilb@suse.de>: > On Mon, 2 Mar 2015 22:04:31 +0100 Pavel Machek <pavel@ucw.cz> 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 <neilb@suse.de> >>> --- >>> 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 <pavel@ucw.cz> >> > > Thanks, > NeilBrown > _______________________________________________ > Gta04-owner mailing list > Gta04-owner@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 majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi! > > 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", 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. Does it make sense to use "_ohm" in the attribute name, then? (And yes, I was wrong with the "K", "k" is actually right.) > > Plus I guess you need to update Documentation/ > > I guess I'll need to give in to this eventually :-) Yes please. It was useful in past. Pavel
On Wed, 4 Mar 2015 07:54:41 +0100 "Dr. H. Nikolaus Schaller" <hns@goldelico.com> wrote: > > Am 04.03.2015 um 07:35 schrieb NeilBrown <neilb@suse.de>: > > > On Mon, 2 Mar 2015 22:04:31 +0100 Pavel Machek <pavel@ucw.cz> 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 <neilb@suse.de> > >>> --- > >>> 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
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", + "floating", + "unknown" +}; + +enum twl4030_id_status twl4030_get_id(struct twl4030_usb *twl) +{ + int ret; + + pm_runtime_get_sync(twl->dev); + if (twl->usb_mode == T2_USB_MODE_ULPI) + twl4030_i2c_access(twl, 1); + ret = twl4030_usb_read(twl, ULPI_OTG_CTRL); + if (ret < 0 || !(ret & ULPI_OTG_ID_PULLUP)) { + /* Need pull-up to read ID */ + twl4030_usb_set_bits(twl, ULPI_OTG_CTRL, + ULPI_OTG_ID_PULLUP); + mdelay(50); + } + ret = twl4030_usb_read(twl, ID_STATUS); + if (ret < 0 || (ret & 0x1f) == 0) { + mdelay(50); + ret = twl4030_usb_read(twl, ID_STATUS); + } + + if (twl->usb_mode == T2_USB_MODE_ULPI) + twl4030_i2c_access(twl, 0); + pm_runtime_put_autosuspend(twl->dev); + + if (ret < 0) + return TWL4030_ID_UNKNOWN; + ret = ffs(ret) - 1; + if (ret < TWL4030_GROUND || ret > TWL4030_FLOATING) + return TWL4030_ID_UNKNOWN; + + return ret; +} + static void __twl4030_phy_power(struct twl4030_usb *twl, int on) { u8 pwr = twl4030_usb_read(twl, PHY_PWR_CTRL); @@ -531,6 +581,16 @@ static ssize_t twl4030_usb_vbus_show(struct device *dev, } static DEVICE_ATTR(vbus, 0444, twl4030_usb_vbus_show, NULL); +static ssize_t twl4030_usb_id_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct twl4030_usb *twl = dev_get_drvdata(dev); + return scnprintf(buf, PAGE_SIZE, "%s\n", + twl4030_id_names[twl4030_get_id(twl)]); +} +static DEVICE_ATTR(id, 0444, twl4030_usb_id_show, NULL); + static irqreturn_t twl4030_usb_irq(int irq, void *_twl) { struct twl4030_usb *twl = _twl; @@ -723,6 +783,8 @@ static int twl4030_usb_probe(struct platform_device *pdev) platform_set_drvdata(pdev, twl); if (device_create_file(&pdev->dev, &dev_attr_vbus)) dev_warn(&pdev->dev, "could not create sysfs file\n"); + if (device_create_file(&pdev->dev, &dev_attr_id)) + dev_warn(&pdev->dev, "could not create sysfs file\n"); ATOMIC_INIT_NOTIFIER_HEAD(&twl->phy.notifier); @@ -768,6 +830,7 @@ static int twl4030_usb_remove(struct platform_device *pdev) pm_runtime_get_sync(twl->dev); cancel_delayed_work(&twl->id_workaround_work); device_remove_file(twl->dev, &dev_attr_vbus); + device_remove_file(twl->dev, &dev_attr_id); /* set transceiver mode to power on defaults */ twl4030_usb_set_mode(twl, -1);
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 <neilb@suse.de> --- drivers/phy/phy-twl4030-usb.c | 63 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html