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FMC ADC 100M 14b 4cha - Software
Commit 29c4d67d authored by Alessandro Rubini's avatar Alessandro Rubini
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kernel: fix user_offsets and calibration 

Part of the calculation was wrong, so offsets didn't properly work.
This commit fixes the offsets and turns their user-accessible
values from 0..0xfff to -5000..5000 as they are now expressed in millivolts.

Unfortunately the code changes more than strictly necessary.
Signed-off-by: Alessandro Rubini's avatarAlessandro Rubini <rubini@gnudd.com>
parent 0eecd158
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Showing with 78 additions and 35 deletions
kernel/fa-zio-drv.c
View file @ 29c4d67d
......@@ -282,7 +282,7 @@ static int zfad_convert_user_range(uint32_t user_val)
static int zfad_set_range(struct fa_dev *fa, struct zio_channel *chan,
int range)
{
int i, cal_val;
int i, offset, gain;
dev_dbg(&chan->head.dev, "Set offset and gain for range %d\n",
range);
......@@ -291,21 +291,28 @@ static int zfad_set_range(struct fa_dev *fa, struct zio_channel *chan,
i = zfad_get_chx_index(ZFA_CHx_CTL_RANGE, chan);
zfa_common_conf_set(fa, i, zfad_hw_range[range]);
if (range == ZFA_RANGE_OPEN)
return 0;
if (range == ZFA_RANGE_OPEN) {
offset = FA_CAL_NO_OFFSET;
gain = FA_CAL_NO_GAIN;
} else {
if (range < 0 || range > ARRAY_SIZE(fa->calib.adc)) {
dev_info(&fa->fmc->dev, "Invalid range %i or ch %i\n",
range, chan->index);
return -EINVAL;
}
offset = fa->calib.adc[range].offset[chan->index];
gain = fa->calib.adc[range].gain[chan->index];
}
dev_dbg(&fa->fmc->dev, "Chan %i, range %i, offset 0x%x, gain 0x%x\n",
chan->index, range, offset, gain);
/* Apply the ADC calibration value for the offset */
i = zfad_get_chx_index(ZFA_CHx_OFFSET, chan);
cal_val = fa->calib.adc[range].offset[chan->index];
dev_dbg(&chan->head.dev, "offset calibration value 0x%x\n", cal_val);
zfa_common_conf_set(fa, i, cal_val);
/* Apply the ADC calibration value for the gain */
zfa_common_conf_set(fa, i, offset & 0xffff); /* prevent warning */
i = zfad_get_chx_index(ZFA_CHx_GAIN, chan);
cal_val = fa->calib.adc[range].gain[chan->index];
dev_dbg(&chan->head.dev, "gain calibration value 0x%x\n", cal_val);
zfa_common_conf_set(fa, i, cal_val);
zfa_common_conf_set(fa, i, gain);
/* Reset offset */
/* FIXME: recalculate user offset -- this zeroes it*/
zfad_apply_user_offset(fa, chan, 0);
return 0;
......@@ -316,7 +323,7 @@ static int zfad_set_range(struct fa_dev *fa, struct zio_channel *chan,
* zfad_apply_user_offset
* @fa: the fmc-adc descriptor
* @chan: the channel where apply offset
* @usr_val: the offset value to apply
* @usr_val: the offset value to apply, expressed as millivolts (-5000..5000)
*
* Apply user offset to the channel input. Before apply the user offset it must
* be corrected with offset and gain calibration value. An open input does not
......@@ -325,8 +332,12 @@ static int zfad_set_range(struct fa_dev *fa, struct zio_channel *chan,
static int zfad_apply_user_offset(struct fa_dev *fa, struct zio_channel *chan,
uint32_t usr_val)
{
uint32_t tmp, cal_val, offset, gain, range_reg;
int i, range;
uint32_t range_reg;
int32_t uval = (int32_t)usr_val;
int offset, gain, hwval, i, range;
if (uval < -5000 || uval > 5000)
return -EINVAL;
i = zfad_get_chx_index(ZFA_CHx_CTL_RANGE, chan);
zfa_common_info_get(fa, i, &range_reg);
......@@ -335,28 +346,31 @@ static int zfad_apply_user_offset(struct fa_dev *fa, struct zio_channel *chan,
if (range < 0)
return range;
if (range != ZFA_RANGE_OPEN) {
/* Get calibration offset and gain for DAC */
if (range == ZFA_RANGE_OPEN) {
offset = FA_CAL_NO_OFFSET;
gain = FA_CAL_NO_GAIN;
} else {
offset = fa->calib.dac[range].offset[chan->index];
gain = fa->calib.dac[range].gain[chan->index];
} else {
/* open input channel: apply no-conversion values */
gain = 0x8000;
offset = 0;
}
dev_dbg(&chan->head.dev, "Appling offset (%d, 0x%x, 0x%x, 0x%x)\n",
chan->index, range, gain, offset);
/* Calculate value for DAC chip -- FIXME */
cal_val = ((((usr_val - 0x8000 + offset) << 15) * gain) >> 30);
cal_val += 0x8000;
hwval = uval * 0x8000 / 5000;
if (hwval == 0x8000) hwval = 0x7fff; /* -32768 .. 32767 */
dev_dbg(&fa->fmc->dev, "Chan %i: uval %i -> 0x%04x "
"(r %i, o 0x%x, g 0x%x)\n", chan->index, uval, hwval,
range, offset, gain);
if (cal_val > 0xFFFF)
cal_val = 0xFFFF;
hwval = ((hwval + offset) * gain) >> 15; /* signed */
hwval += 0x8000; /* offset binary */
if (hwval < 0)
hwval = 0;
if (hwval > 0xffff)
hwval = 0xffff;
dev_dbg(&chan->head.dev, "DAC offset calibration 0x%x\n", cal_val);
dev_dbg(&chan->head.dev, "DAC offset calibration 0x%x\n", hwval);
/* Apply calibrated offset to DAC */
return fa_spi_xfer(fa, FA_SPI_SS_DAC(chan->index), 16, cal_val, &tmp);
return fa_spi_xfer(fa, FA_SPI_SS_DAC(chan->index), 16, hwval, NULL);
}
......@@ -385,6 +399,7 @@ static int zfad_conf_set(struct device *dev, struct zio_attribute *zattr,
uint32_t usr_val)
{
struct fa_dev *fa = get_zfadc(dev);
struct zio_channel *chan;
int i, range, err, reg_index;
dev_dbg(dev, "Writing %d in the sysfs attribute %s\n",
......@@ -412,17 +427,21 @@ static int zfad_conf_set(struct device *dev, struct zio_attribute *zattr,
i--;
case ZFA_CH4_OFFSET:
i--;
err = zfad_apply_user_offset(fa, &to_zio_cset(dev)->chan[i],
usr_val);
chan = to_zio_cset(dev)->chan + i;
err = zfad_apply_user_offset(fa, chan, usr_val);
if (err)
return err;
fa->user_offset[chan->index] = usr_val;
return 0;
case ZFA_CHx_OFFSET:
err = zfad_apply_user_offset(fa, to_zio_chan(dev), usr_val);
chan = to_zio_chan(dev),
err = zfad_apply_user_offset(fa, chan, usr_val);
if (err)
return err;
fa->user_offset[chan->index] = usr_val;
return 0;
break;
case ZFA_CTL_DAC_CLR_N:
zfad_reset_offset(fa);
return 0;
......@@ -484,15 +503,27 @@ static int zfad_info_get(struct device *dev, struct zio_attribute *zattr,
uint32_t *usr_val)
{
struct fa_dev *fa = get_zfadc(dev);
int reg_index;
int i, reg_index;
i = fa->zdev->cset->n_chan - 1 ; /* -1 because of interleaved channel */
switch (zattr->id) {
/* FIXME temporary until TLV control */
case ZFA_CH1_OFFSET:
i--;
case ZFA_CH2_OFFSET:
i--;
case ZFA_CH3_OFFSET:
i--;
case ZFA_CH4_OFFSET:
i--;
*usr_val = fa->user_offset[i];
return 0;
case ZFA_CHx_OFFSET:
*usr_val = fa->user_offset[to_zio_chan(dev)->index];
return 0;
case ZFA_SW_R_NOADDRES_NBIT:
case ZFA_SW_R_NOADDERS_AUTO:
/* ZIO automatically return the attribute value */
......@@ -504,8 +535,14 @@ static int zfad_info_get(struct device *dev, struct zio_attribute *zattr,
return 0;
case ZFA_CHx_CTL_TERM:
case ZFA_CHx_CTL_RANGE:
reg_index = zfad_get_chx_index(zattr->id, to_zio_chan(dev));
break;
case ZFA_CHx_STA:
reg_index = zfad_get_chx_index(zattr->id, to_zio_chan(dev));
zfa_common_info_get(fa, reg_index, usr_val);
i = (int16_t)(*usr_val); /* now signed integer */
*usr_val = i;
break;
default:
reg_index = zattr->id;
......
kernel/fmc-adc.h
View file @ 29c4d67d
......@@ -54,6 +54,9 @@ struct fa_calib {
#define FA_CAL_OFFSET 0x0100 /* Offset in EEPROM */
#define FA_CAL_NO_OFFSET ((int16_t)0x0000)
#define FA_CAL_NO_GAIN ((uint16_t)0x8000)
/*
* dma_item: The information about a DMA transfer
* @start_addr: pointer where start to retrieve data from device memory
......@@ -105,6 +108,9 @@ struct fa_dev {
/* Statistic informations */
unsigned int n_dma_err;
/* Configuration */
int user_offset[4]; /* one per channel */
/* one-wire */
uint8_t ds18_id[8];
unsigned long next_t;
......
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