On Sun, Nov 29, 2020 at 7:47 PM Jonathan Cameron <jic23@xxxxxxxxxx> wrote: > From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > > Inspired by Andy Shevchenko's proposal to use get_unaligned_leXX(). > > The whole one time programable memory is treated as a single 64bit > little endian value. Thus we can avoid a lot of messy handling > of fields overlapping byte boundaries by just loading and manipulating > it as an __le64 converted to a u64. That lets us just use FIELD_GET() > and GENMASK() to extract the values desired. > > Note only build tested. We need to use GENMASK_ULL and %llX formatters > to account for the larger types used in computing the various fields. > > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > Cc: Linus Walleij <linus.walleij@xxxxxxxxxx> > Link: https://lore.kernel.org/r/20201128185156.428327-1-jic23@xxxxxxxxxx > --- > > Changes since v1: > * Fix 32 bit builds by using GENMASK_ULL (thanks to Linus + Andy) Easy to test since I'm playing with one of these right now! Before: [ 2.677957] mpu3050-i2c 2-0068: found MPU-3050 part no: 6, version: 14 [ 2.695905] mpu3050-i2c 2-0068: die ID: 05A1, wafer ID: 12, A lot ID: 0000, W lot ID: 662, WP ID: 3, rev ID: 1A After: [ 2.667944] mpu3050-i2c 2-0068: found MPU-3050 part no: 6, version: 14 [ 2.686969] mpu3050-i2c 2-0068: die ID: 05A1, wafer ID: 12, A lot ID: 0000, W lot ID: 662, WP ID: 3, rev ID: 1A And works too. Tested-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx> I used the same approach in the Yamaha driver and it looks good there too. Yours, Linus Walleij
