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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 <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210109231148.1168104-6-alexandre.belloni@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Alexandre Belloni 2021-01-10 00:11:47 +01:00 committed by Jonathan Cameron
parent 7ae7f75080
commit 9ea7c79097
1 changed files with 59 additions and 11 deletions
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70
drivers/iio/common/ms_sensors/ms_sensors_i2c.c
View File

@ -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;