Messages in this thread | | | Date | Wed, 8 May 2024 10:16:14 -0500 | Subject | Re: [PATCH v1] hwmon: (ucd90320) Increase delay from 250 to 500us | From | Eddie James <> |
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On 5/7/24 14:46, Lakshmi Yadlapati wrote: > Following the failure observed with a delay of 250us, experiments were > conducted with various delays. It was found that a delay of 350us > effectively mitigated the issue. > > To provide a more optimal solution while still allowing a margin for > stability, the delay is being adjusted to 500us.
Reviewed-by: Eddie James <eajames@linux.ibm.com>
> > Signed-off-by: Lakshmi Yadlapati <lakshmiy@us.ibm.com> > --- > drivers/hwmon/pmbus/ucd9000.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c > index 8d9d422450e5..d817c719b90b 100644 > --- a/drivers/hwmon/pmbus/ucd9000.c > +++ b/drivers/hwmon/pmbus/ucd9000.c > @@ -80,11 +80,11 @@ struct ucd9000_debugfs_entry { > * It has been observed that the UCD90320 randomly fails register access when > * doing another access right on the back of a register write. To mitigate this > * make sure that there is a minimum delay between a write access and the > - * following access. The 250us is based on experimental data. At a delay of > - * 200us the issue seems to go away. Add a bit of extra margin to allow for > + * following access. The 500 is based on experimental data. At a delay of > + * 350us the issue seems to go away. Add a bit of extra margin to allow for > * system to system differences. > */ > -#define UCD90320_WAIT_DELAY_US 250 > +#define UCD90320_WAIT_DELAY_US 500 > > static inline void ucd90320_wait(const struct ucd9000_data *data) > {
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