From 9ea7c79097fb3907d7bc587f70963dba7c95658c Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Sun, 10 Jan 2021 00:11:47 +0100 Subject: iio:common:ms_sensors:ms_sensors_i2c: add support for alternative PROM layout Currently, only the 112bit PROM with 7 words is supported. However the ms58xx family also have devices with a 128bit PROM on 8 words. See AN520: C-CODE EXAMPLE FOR MS56XX, MS57XX (EXCEPT ANALOG SENSOR), AND MS58XX SERIES PRESSURE SENSORS and the various device datasheets. The difference is that the CRC is the 4 LSBs of word7 instead of being the 4 MSBs of word0. Signed-off-by: Alexandre Belloni Link: https://lore.kernel.org/r/20210109231148.1168104-6-alexandre.belloni@bootlin.com Signed-off-by: Jonathan Cameron --- drivers/iio/common/ms_sensors/ms_sensors_i2c.c | 70 ++++++++++++++++++++++---- 1 file changed, 59 insertions(+), 11 deletions(-) (limited to 'drivers/iio') diff --git a/drivers/iio/common/ms_sensors/ms_sensors_i2c.c b/drivers/iio/common/ms_sensors/ms_sensors_i2c.c index 872f90459e2e..16ea697e945c 100644 --- a/drivers/iio/common/ms_sensors/ms_sensors_i2c.c +++ b/drivers/iio/common/ms_sensors/ms_sensors_i2c.c @@ -488,21 +488,18 @@ int ms_sensors_ht_read_humidity(struct ms_ht_dev *dev_data, EXPORT_SYMBOL(ms_sensors_ht_read_humidity); /** - * ms_sensors_tp_crc_valid() - CRC check function for + * ms_sensors_tp_crc4() - Calculate PROM CRC for * Temperature and pressure devices. * This function is only used when reading PROM coefficients * * @prom: pointer to PROM coefficients array * - * Return: True if CRC is ok. + * Return: CRC. */ -static bool ms_sensors_tp_crc_valid(u16 *prom) +static u8 ms_sensors_tp_crc4(u16 *prom) { unsigned int cnt, n_bit; - u16 n_rem = 0x0000, crc_read = prom[0], crc = (*prom & 0xF000) >> 12; - - prom[MS_SENSORS_TP_PROM_WORDS_NB - 1] = 0; - prom[0] &= 0x0FFF; /* Clear the CRC computation part */ + u16 n_rem = 0x0000; for (cnt = 0; cnt < MS_SENSORS_TP_PROM_WORDS_NB * 2; cnt++) { if (cnt % 2 == 1) @@ -517,10 +514,55 @@ static bool ms_sensors_tp_crc_valid(u16 *prom) n_rem <<= 1; } } - n_rem >>= 12; - prom[0] = crc_read; - return n_rem == crc; + return n_rem >> 12; +} + +/** + * ms_sensors_tp_crc_valid_112() - CRC check function for + * Temperature and pressure devices for 112bit PROM. + * This function is only used when reading PROM coefficients + * + * @prom: pointer to PROM coefficients array + * + * Return: True if CRC is ok. + */ +static bool ms_sensors_tp_crc_valid_112(u16 *prom) +{ + u16 w0 = prom[0], crc_read = (w0 & 0xF000) >> 12; + u8 crc; + + prom[0] &= 0x0FFF; /* Clear the CRC computation part */ + prom[MS_SENSORS_TP_PROM_WORDS_NB - 1] = 0; + + crc = ms_sensors_tp_crc4(prom); + + prom[0] = w0; + + return crc == crc_read; +} + +/** + * ms_sensors_tp_crc_valid_128() - CRC check function for + * Temperature and pressure devices for 128bit PROM. + * This function is only used when reading PROM coefficients + * + * @prom: pointer to PROM coefficients array + * + * Return: True if CRC is ok. + */ +static bool ms_sensors_tp_crc_valid_128(u16 *prom) +{ + u16 w7 = prom[7], crc_read = w7 & 0x000F; + u8 crc; + + prom[7] &= 0xFF00; /* Clear the CRC and LSB part */ + + crc = ms_sensors_tp_crc4(prom); + + prom[7] = w7; + + return crc == crc_read; } /** @@ -535,6 +577,7 @@ static bool ms_sensors_tp_crc_valid(u16 *prom) int ms_sensors_tp_read_prom(struct ms_tp_dev *dev_data) { int i, ret; + bool valid; for (i = 0; i < dev_data->hw->prom_len; i++) { ret = ms_sensors_read_prom_word( @@ -546,7 +589,12 @@ int ms_sensors_tp_read_prom(struct ms_tp_dev *dev_data) return ret; } - if (!ms_sensors_tp_crc_valid(dev_data->prom)) { + if (dev_data->hw->prom_len == 8) + valid = ms_sensors_tp_crc_valid_128(dev_data->prom); + else + valid = ms_sensors_tp_crc_valid_112(dev_data->prom); + + if (!valid) { dev_err(&dev_data->client->dev, "Calibration coefficients crc check error\n"); return -ENODEV; -- cgit v1.2.3