From 7ae7f75080733d1d0e7c32156725c5729b02404d Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Sun, 10 Jan 2021 00:11:46 +0100 Subject: [PATCH] iio:common:ms_sensors:ms_sensors_i2c: rework CRC calculation helper The CRC calculation always happens on 8 words which is why there is an extra element in the prom array of struct ms_tp_dev. However, on ms5637 and similar, only 7 words are readable. Then, set MS_SENSORS_TP_PROM_WORDS_NB to 8 and stop passing a len parameter to ms_sensors_tp_crc_valid as this simply hide the fact that it is hardcoded. Finally, use the newly introduced hw->prom_len to know how many words can be read. Signed-off-by: Alexandre Belloni Link: https://lore.kernel.org/r/20210109231148.1168104-5-alexandre.belloni@bootlin.com Signed-off-by: Jonathan Cameron --- drivers/iio/common/ms_sensors/ms_sensors_i2c.c | 12 +++++------- drivers/iio/common/ms_sensors/ms_sensors_i2c.h | 4 ++-- 2 files changed, 7 insertions(+), 9 deletions(-) diff --git a/drivers/iio/common/ms_sensors/ms_sensors_i2c.c b/drivers/iio/common/ms_sensors/ms_sensors_i2c.c index b9e2038..872f904 100644 --- a/drivers/iio/common/ms_sensors/ms_sensors_i2c.c +++ b/drivers/iio/common/ms_sensors/ms_sensors_i2c.c @@ -493,19 +493,18 @@ EXPORT_SYMBOL(ms_sensors_ht_read_humidity); * This function is only used when reading PROM coefficients * * @prom: pointer to PROM coefficients array - * @len: length of PROM coefficients array * * Return: True if CRC is ok. */ -static bool ms_sensors_tp_crc_valid(u16 *prom, u8 len) +static bool ms_sensors_tp_crc_valid(u16 *prom) { unsigned int cnt, n_bit; u16 n_rem = 0x0000, crc_read = prom[0], crc = (*prom & 0xF000) >> 12; - prom[len - 1] = 0; + prom[MS_SENSORS_TP_PROM_WORDS_NB - 1] = 0; prom[0] &= 0x0FFF; /* Clear the CRC computation part */ - for (cnt = 0; cnt < len * 2; cnt++) { + for (cnt = 0; cnt < MS_SENSORS_TP_PROM_WORDS_NB * 2; cnt++) { if (cnt % 2 == 1) n_rem ^= prom[cnt >> 1] & 0x00FF; else @@ -537,7 +536,7 @@ int ms_sensors_tp_read_prom(struct ms_tp_dev *dev_data) { int i, ret; - for (i = 0; i < MS_SENSORS_TP_PROM_WORDS_NB; i++) { + for (i = 0; i < dev_data->hw->prom_len; i++) { ret = ms_sensors_read_prom_word( dev_data->client, MS_SENSORS_TP_PROM_READ + (i << 1), @@ -547,8 +546,7 @@ int ms_sensors_tp_read_prom(struct ms_tp_dev *dev_data) return ret; } - if (!ms_sensors_tp_crc_valid(dev_data->prom, - MS_SENSORS_TP_PROM_WORDS_NB + 1)) { + if (!ms_sensors_tp_crc_valid(dev_data->prom)) { dev_err(&dev_data->client->dev, "Calibration coefficients crc check error\n"); return -ENODEV; diff --git a/drivers/iio/common/ms_sensors/ms_sensors_i2c.h b/drivers/iio/common/ms_sensors/ms_sensors_i2c.h index f4a8814..f15b973 100644 --- a/drivers/iio/common/ms_sensors/ms_sensors_i2c.h +++ b/drivers/iio/common/ms_sensors/ms_sensors_i2c.h @@ -11,7 +11,7 @@ #include #include -#define MS_SENSORS_TP_PROM_WORDS_NB 7 +#define MS_SENSORS_TP_PROM_WORDS_NB 8 /** * struct ms_ht_dev - Humidity/Temperature sensor device structure @@ -47,7 +47,7 @@ struct ms_tp_dev { struct i2c_client *client; struct mutex lock; const struct ms_tp_hw_data *hw; - u16 prom[MS_SENSORS_TP_PROM_WORDS_NB + 1]; + u16 prom[MS_SENSORS_TP_PROM_WORDS_NB]; u8 res_index; }; -- 2.7.4