On Sun, Nov 29, 2020 at 06:44:59PM +0000, Jonathan Cameron 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. LGTM now, thanks! Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > 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) > > drivers/iio/gyro/mpu3050-core.c | 28 ++++++++++++++++------------ > 1 file changed, 16 insertions(+), 12 deletions(-) > > diff --git a/drivers/iio/gyro/mpu3050-core.c b/drivers/iio/gyro/mpu3050-core.c > index 00e58060968c..dfa31a23500f 100644 > --- a/drivers/iio/gyro/mpu3050-core.c > +++ b/drivers/iio/gyro/mpu3050-core.c > @@ -13,6 +13,7 @@ > * TODO: add support for setting up the low pass 3dB frequency. > */ > > +#include <linux/bitfield.h> > #include <linux/bitops.h> > #include <linux/delay.h> > #include <linux/err.h> > @@ -784,7 +785,8 @@ static int mpu3050_read_mem(struct mpu3050 *mpu3050, > static int mpu3050_hw_init(struct mpu3050 *mpu3050) > { > int ret; > - u8 otp[8]; > + __le64 otp_le; > + u64 otp; > > /* Reset */ > ret = regmap_update_bits(mpu3050->map, > @@ -815,29 +817,31 @@ static int mpu3050_hw_init(struct mpu3050 *mpu3050) > MPU3050_MEM_USER_BANK | > MPU3050_MEM_OTP_BANK_0), > 0, > - sizeof(otp), > - otp); > + sizeof(otp_le), > + (u8 *)&otp_le); > if (ret) > return ret; > > /* This is device-unique data so it goes into the entropy pool */ > - add_device_randomness(otp, sizeof(otp)); > + add_device_randomness(&otp_le, sizeof(otp_le)); > + > + otp = le64_to_cpu(otp_le); > > dev_info(mpu3050->dev, > - "die ID: %04X, wafer ID: %02X, A lot ID: %04X, " > - "W lot ID: %03X, WP ID: %01X, rev ID: %02X\n", > + "die ID: %04llX, wafer ID: %02llX, A lot ID: %04llX, " > + "W lot ID: %03llX, WP ID: %01llX, rev ID: %02llX\n", > /* Die ID, bits 0-12 */ > - (otp[1] << 8 | otp[0]) & 0x1fff, > + FIELD_GET(GENMASK_ULL(12, 0), otp), > /* Wafer ID, bits 13-17 */ > - ((otp[2] << 8 | otp[1]) & 0x03e0) >> 5, > + FIELD_GET(GENMASK_ULL(17, 13), otp), > /* A lot ID, bits 18-33 */ > - ((otp[4] << 16 | otp[3] << 8 | otp[2]) & 0x3fffc) >> 2, > + FIELD_GET(GENMASK_ULL(33, 18), otp), > /* W lot ID, bits 34-45 */ > - ((otp[5] << 8 | otp[4]) & 0x3ffc) >> 2, > + FIELD_GET(GENMASK_ULL(45, 34), otp), > /* WP ID, bits 47-49 */ > - ((otp[6] << 8 | otp[5]) & 0x0380) >> 7, > + FIELD_GET(GENMASK_ULL(49, 47), otp), > /* rev ID, bits 50-55 */ > - otp[6] >> 2); > + FIELD_GET(GENMASK_ULL(55, 50), otp)); > > return 0; > } > -- > 2.29.2 > -- With Best Regards, Andy Shevchenko
