On Wed, 4 Dec 2024 17:05:19 +0800 Yu-Hsian Yang <j2anfernee@xxxxxxxxx> wrote: > Dear Andy Shevchenko, > > Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> 於 2024年12月4日 週三 下午12:27寫道： > > > > On Wed, Dec 04, 2024 at 11:20:20AM +0800, Yu-Hsian Yang wrote: > > > Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> 於 2024年12月3日 週二 下午9:50寫道： > > > > On Tue, Dec 03, 2024 at 05:15:40PM +0800, Eason Yang wrote: > > > > ... > > > > > > Second, why do you need two regmaps? How debugfs is supposed to work on the > > > > registers that are 16-bit if you access them via 8-bit regmap and vice versa? > > > > > > > > Can't you simply use bulk reads/writes when it makes sense and drop 16-bit > > > > regmap completely? > > > > > > Read VIN info can use word read or byte read, and other registers > > > should use byte read. > > > > > > For a reviewer's comment, If the i2c controller allows word read then the > > > right thing is to always use it. > > > > But how does this differ to bulk read of two sequential 8-bit offsets? > > And if there is a difference, shouldn't this be addressed on regmap level for > > all? Like testing for the supported flags and access registers based on the > > controller capability and user request. > > > > We would explain why we use two regmaps. > In the beginning, we declare a property read-vin-data-size for user to > select byte read or word read. > After discuss with reviewers, we don't need this property. > So I get rid of this property and take word read vin data first. > We can't use regmap_bulk_read since the vin data is not sequential. > > For Nuvoton NCT7201/NCT7202 chip, > Take an example as to Vin1: > The VIN reading supports Byte read (One Byte) and Word read (Two Byte) > > For Byte read: > First read Index 00h to get VIN1 MSB, then read Index 0Fh Bit 3~7 to > get VIN1 LSB. > Index 0Fh is a shared LSB for all VINs. > > For Word read: > Read Index 00h and get 2 Byte (VIN1 MSB and VIN1 LSB). Yeah. This is a really weird device. 2 regmaps is probably the best option. The regmap access tables or functions can be used to avoid the debugfs problem Andy mentioned. Jonathan > > > -- > > With Best Regards, > > Andy Shevchenko > > > >
