| Message ID | 20190214160345.353-1-tony@atomide.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [PATCHv2] mfd: twl6040: Fix device init errors for ACCCTL register | expand |
On Thu, 14 Feb 2019, Tony Lindgren wrote: > I noticed that we can get a -EREMOTEIO errors on at least omap4 duovero: > > twl6040 0-004b: Failed to write 2d = 19: -121 > > And then any following register access will produce errors. > > There 2d offset above is register ACCCTL that gets written on twl6040 > powerup. With error checking added to the related regcache_sync() call, > the -EREMOTEIO error is reproducable on twl6040 powerup at least > duovero. > > To fix the error, we need to wait until twl6040 is accessible after the > powerup. Based on tests on omap4 duovero, we need to wait over 8ms after > powerup before register write will complete without failures. Let's also > make sure we warn about possible errors too. > > Note that we have twl6040_patch[] reg_sequence with the ACCCTL register > configuration and regcache_sync() will write the new value to ACCCTL. > > Cc: Florian Vaussard <florian.vaussard@epfl.ch> > Cc: Peter Ujfalusi <peter.ujfalusi@ti.com> > Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com> > Signed-off-by: Tony Lindgren <tony@atomide.com> > --- > > Changes since v1: > > - Cosmetic change to improve error message as suggested by Lee > > --- > drivers/mfd/twl6040.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) Applied, thanks.
diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c --- a/drivers/mfd/twl6040.c +++ b/drivers/mfd/twl6040.c @@ -322,8 +322,19 @@ int twl6040_power(struct twl6040 *twl6040, int on) } } + /* + * Register access can produce errors after power-up unless we + * wait at least 8ms based on measurements on duovero. + */ + usleep_range(10000, 12000); + /* Sync with the HW */ - regcache_sync(twl6040->regmap); + ret = regcache_sync(twl6040->regmap); + if (ret) { + dev_err(twl6040->dev, "Failed to sync with the HW: %i\n", + ret); + goto out; + } /* Default PLL configuration after power up */ twl6040->pll = TWL6040_SYSCLK_SEL_LPPLL;