Re: [PATCH v1 2/5] rtc: isl12022: Explicitly use __le16 type for ISL12022_REG_TEMP_L

Rasmus Villemoes
2022-11-29T14:15:50Z

On 26/11/2022 15.18, Andy Shevchenko wrote:
> We are reading 10-bit value in a 16-bit register in LE format.
> Make this explicit by using __le16 type for it and corresponding
> conversion function.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> drivers/rtc/rtc-isl12022.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/rtc/rtc-isl12022.c b/drivers/rtc/rtc-isl12022.c
> index 44058fa27277..bf1aa6f6560d 100644
> --- a/drivers/rtc/rtc-isl12022.c
> +++ b/drivers/rtc/rtc-isl12022.c
> @@ -19,6 +19,8 @@
> #include <linux/regmap.h>
> #include <linux/hwmon.h>
>
> +#include <asm/byteorder.h>
> +
> /* ISL register offsets */
> #define ISL12022_REG_SC 0x00
> #define ISL12022_REG_MN 0x01
> @@ -63,17 +65,16 @@ static umode_t isl12022_hwmon_is_visible(const void *data,
> static int isl12022_hwmon_read_temp(struct device *dev, long *mC)
> {
> struct regmap *regmap = dev_get_drvdata(dev);
> - u8 temp_buf[2];
> int temp, ret;
> + __le16 buf;
>
> - ret = regmap_bulk_read(regmap, ISL12022_REG_TEMP_L,
> - temp_buf, sizeof(temp_buf));
> + ret = regmap_bulk_read(regmap, ISL12022_REG_TEMP_L, &buf, sizeof(buf));
> if (ret)
> return ret;
> /*
> * Temperature is represented as a 10-bit number, unit half-Kelvins.
> */
> - temp = (temp_buf[1] << 8) | temp_buf[0];
> + temp = le16_to_cpu(buf);

Makes sense. Perhaps we should throw in "& 0x3ff" just in case there
were ever any garbage bits set in the temp_h register.

With or without that,

Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>