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hwmon: epm_adc: Fix incorrect SPI writes

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Incorrect spi write transactions and incorrect readings
are seen. This is because of using incorrect SPI slave
address while initiating the SPI writes to the ADS ADC.
Also fix the incorrect scaling when converting the raw ADC
code to the appropriate physical result.

Change-Id: I0e16f210fa07e1ce1128f39b0f4e1d325ea7e7ef
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
This commit is contained in:
Siddartha Mohanadoss 2012-09-18 16:57:50 -07:00 committed by Stephen Boyd
parent f787fd23f5
commit acd7e22447
1 changed files with 29 additions and 40 deletions
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69
drivers/hwmon/epm_adc.c
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@ -102,8 +102,6 @@
#define EPM_PSOC_BUFFERED_DATA_LENGTH 48
#define EPM_PSOC_BUFFERED_DATA_LENGTH2 54
#define EPM_SPI_NOR_CS_N_GPIO 53
struct epm_adc_drv {
struct platform_device *pdev;
struct device *hwmon;
@ -172,14 +170,6 @@ static int epm_adc_gpio_configure_expander_enable(void)
{
int rc = 0;
rc = gpio_request(EPM_SPI_NOR_CS_N_GPIO, "SPI_NOR_CS_N");
if (!rc)
gpio_direction_output(EPM_SPI_NOR_CS_N_GPIO, 1);
else {
pr_err("Configure spi nor Failed\n");
return -EINVAL;
}
if (epm_adc_first_request) {
rc = gpio_request(GPIO_EPM_GLOBAL_ENABLE, "EPM_GLOBAL_EN");
if (!rc) {
@ -521,27 +511,27 @@ static int epm_adc_ads_scale_result(struct epm_adc_drv *epm_adc,
struct epm_adc_platform_data *pdata = epm_adc->pdev->dev.platform_data;
uint32_t chan_idx = (conv->device_idx * pdata->chan_per_adc) +
conv->channel_idx;
int64_t *adc_scaled_data = 0;
int64_t adc_scaled_data = 0;
/* Get the channel number */
channel_num = (adc_raw_data[0] & EPM_ADC_ADS_CHANNEL_DATA_CHID);
sign_bit = 1;
/* This is the 16-bit raw data */
*adc_scaled_data = ((adc_raw_data[1] << 8) | adc_raw_data[2]);
adc_scaled_data = ((adc_raw_data[1] << 8) | adc_raw_data[2]);
/* Obtain the internal system reading */
if (channel_num == EPM_ADC_ADS_CHANNEL_VCC) {
*adc_scaled_data *= EPM_ADC_SCALE_MILLI;
do_div(*adc_scaled_data, EPM_ADC_SCALE_CODE_VOLTS);
adc_scaled_data *= EPM_ADC_SCALE_MILLI;
do_div(adc_scaled_data, EPM_ADC_SCALE_CODE_VOLTS);
} else if (channel_num == EPM_ADC_ADS_CHANNEL_GAIN) {
do_div(*adc_scaled_data, EPM_ADC_SCALE_CODE_GAIN);
do_div(adc_scaled_data, EPM_ADC_SCALE_CODE_GAIN);
} else if (channel_num == EPM_ADC_ADS_CHANNEL_REF) {
*adc_scaled_data *= EPM_ADC_SCALE_MILLI;
do_div(*adc_scaled_data, EPM_ADC_SCALE_CODE_VOLTS);
adc_scaled_data *= EPM_ADC_SCALE_MILLI;
do_div(adc_scaled_data, EPM_ADC_SCALE_CODE_VOLTS);
} else if (channel_num == EPM_ADC_ADS_CHANNEL_TEMP) {
/* Convert Code to micro-volts */
/* Use this formula to get the temperature reading */
*adc_scaled_data -= EPM_ADC_TEMP_TO_DEGC_COEFF;
do_div(*adc_scaled_data, EPM_ADC_TEMP_SENSOR_COEFF);
adc_scaled_data -= EPM_ADC_TEMP_TO_DEGC_COEFF;
do_div(adc_scaled_data, EPM_ADC_TEMP_SENSOR_COEFF);
} else if (channel_num == EPM_ADC_ADS_CHANNEL_OFFSET) {
/* The offset should be zero */
pr_debug("%s: ADC Channel Offset\n", __func__);
@ -553,31 +543,31 @@ static int epm_adc_ads_scale_result(struct epm_adc_drv *epm_adc,
* mvVRef is in milli-volts and resistorvalue is in micro-ohms.
* Hence, I = V/R gives us current in kilo-amps.
*/
if (*adc_scaled_data & EPM_ADC_MAX_NEGATIVE_SCALE_CODE) {
if (adc_scaled_data & EPM_ADC_MAX_NEGATIVE_SCALE_CODE) {
sign_bit = -1;
*adc_scaled_data = (~*adc_scaled_data
adc_scaled_data = (~adc_scaled_data
& EPM_ADC_NEG_LSB_CODE);
}
if (*adc_scaled_data != 0) {
*adc_scaled_data *= EPM_ADC_SCALE_FACTOR;
if (adc_scaled_data != 0) {
adc_scaled_data *= EPM_ADC_SCALE_FACTOR;
/* Device is calibrated for 1LSB = VREF/7800h.*/
*adc_scaled_data *= EPM_ADC_MILLI_VOLTS_SOURCE;
do_div(*adc_scaled_data, EPM_ADC_VREF_CODE);
adc_scaled_data *= EPM_ADC_MILLI_VOLTS_SOURCE;
do_div(adc_scaled_data, EPM_ADC_VREF_CODE);
/* Data will now be in micro-volts.*/
*adc_scaled_data *= EPM_ADC_SCALE_MILLI;
adc_scaled_data *= EPM_ADC_SCALE_MILLI;
/* Divide by amplifier gain value.*/
do_div(*adc_scaled_data, pdata->channel[chan_idx].gain);
do_div(adc_scaled_data, pdata->channel[chan_idx].gain);
/* Data will now be in nano-volts.*/
do_div(*adc_scaled_data, EPM_ADC_SCALE_FACTOR);
*adc_scaled_data *= EPM_ADC_SCALE_MILLI;
do_div(adc_scaled_data, EPM_ADC_SCALE_FACTOR);
adc_scaled_data *= EPM_ADC_SCALE_MILLI;
/* Data is now in micro-amps.*/
do_div(*adc_scaled_data,
do_div(adc_scaled_data,
pdata->channel[chan_idx].resistorvalue);
/* Set the sign bit for lekage current. */
*adc_scaled_data *= sign_bit;
adc_scaled_data *= sign_bit;
}
}
conv->physical = (int32_t) *adc_scaled_data;
conv->physical = (int32_t) adc_scaled_data;
return 0;
}
@ -1600,16 +1590,15 @@ static int epm_adc_psoc_spi_probe(struct spi_device *spi)
struct device_node *node = spi->dev.of_node;
int rc = 0;
if (!node) {
dev_err(&spi->dev, "no platform data?\n");
pr_info("Error in the probe\n");
return -EINVAL;
}
if (node)
rc = get_device_tree_data(spi);
else
return -ENODEV;
else {
epm_adc = epm_adc_drv;
epm_adc_drv->epm_spi_client = spi;
epm_adc_drv->epm_spi_client->bits_per_word =
EPM_ADC_ADS_SPI_BITS_PER_WORD;
return rc;
}
epm_adc = epm_adc_drv;
epm_adc->misc.name = EPM_ADC_DRIVER_NAME;