On 10/18/2018 01:49 PM, Slawomir Stepien wrote:
> The custom build function ad7280_crc8_build_table is not needed. The
> crc8_populate_msb function from linux/crc8.h will build the same crc
> table.
>
> Signed-off-by: Slawomir Stepien <sst@xxxxxxxxx>
This looks good, thanks.
Acked-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
I supposed the code could be improved a bit further in a follow up patch by
only having one global table since it will be the same for all instances.
> ---
> Since v1:
> * Fix typo in commit message.
> ---
> drivers/staging/iio/adc/ad7280a.c | 24 +++---------------------
> 1 file changed, 3 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/staging/iio/adc/ad7280a.c b/drivers/staging/iio/adc/ad7280a.c
> index b736275c10f5..c701f07853fa 100644
> --- a/drivers/staging/iio/adc/ad7280a.c
> +++ b/drivers/staging/iio/adc/ad7280a.c
> @@ -6,6 +6,7 @@
> * Licensed under the GPL-2.
> */
>
> +#include <linux/crc8.h>
> #include <linux/device.h>
> #include <linux/kernel.h>
> #include <linux/slab.h>
> @@ -121,8 +122,6 @@ static unsigned int ad7280a_devaddr(unsigned int addr)
> * P(x) = x^8 + x^5 + x^3 + x^2 + x^1 + x^0 = 0b100101111 => 0x2F
> */
> #define POLYNOM 0x2F
> -#define POLYNOM_ORDER 8
> -#define HIGHBIT (1 << (POLYNOM_ORDER - 1))
>
> struct ad7280_state {
> struct spi_device *spi;
> @@ -131,7 +130,7 @@ struct ad7280_state {
> int slave_num;
> int scan_cnt;
> int readback_delay_us;
> - unsigned char crc_tab[256];
> + unsigned char crc_tab[CRC8_TABLE_SIZE];
> unsigned char ctrl_hb;
> unsigned char ctrl_lb;
> unsigned char cell_threshhigh;
> @@ -144,23 +143,6 @@ struct ad7280_state {
> __be32 buf[2] ____cacheline_aligned;
> };
>
> -static void ad7280_crc8_build_table(unsigned char *crc_tab)
> -{
> - unsigned char bit, crc;
> - int cnt, i;
> -
> - for (cnt = 0; cnt < 256; cnt++) {
> - crc = cnt;
> - for (i = 0; i < 8; i++) {
> - bit = crc & HIGHBIT;
> - crc <<= 1;
> - if (bit)
> - crc ^= POLYNOM;
> - }
> - crc_tab[cnt] = crc;
> - }
> -}
> -
> static unsigned char ad7280_calc_crc8(unsigned char *crc_tab, unsigned int val)
> {
> unsigned char crc;
> @@ -857,7 +839,7 @@ static int ad7280_probe(struct spi_device *spi)
> if (!pdata)
> pdata = &ad7793_default_pdata;
>
> - ad7280_crc8_build_table(st->crc_tab);
> + crc8_populate_msb(st->crc_tab, POLYNOM);
>
> st->spi->max_speed_hz = AD7280A_MAX_SPI_CLK_HZ;
> st->spi->mode = SPI_MODE_1;
>
