Commit 951d21de authored May 22, 2017 by Tony Lindgren Committed by Jonathan Cameron Jun 03, 2017

iio: adc: cpcap: Fix die temperature



It seems that "MC13783 Power Management and Audio Ciruit User's Guide"
MC1378UG.pdf documents several similar components as in the CPCAP PMIC.

Chapter "9.5.5 Die Temperature and UID" says that the die temperature
value is 282 at 25C with LSB of -1.14C. Converting CPCAP PMIC channel3
values with following seems to produce values that make sense for a
PMIC die:

temperature = 25000 + ((regval - 282) * 114)

As we don't have any other documentation, let's assume the die
temperature is unconfigured in the Motorola mapphone Linux kernel
and the current temperature conversion table should be only used
for the battery thermistor and not for the die temperature.

Cc: Marcel Partap <mpartap@gmx.net>
Cc: Michael Scott <michael.scott@linaro.org>
Cc: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

parent 3f9f3a1a

drivers/iio/adc/cpcap-adc.c

+28 −3

Original line number	Diff line number	Diff line
		@@ -874,6 +874,22 @@ static int cpcap_adc_init_request(struct cpcap_adc_request *req,
		return 0;
		}

		static int cpcap_adc_read_st_die_temp(struct cpcap_adc *ddata,
		int addr, int *val)
		{
		int error;

		error = regmap_read(ddata->reg, addr, val);
		if (error)
		return error;

		*val -= 282;
		val = 114;
		*val += 25000;

		return 0;
		}

		static int cpcap_adc_read(struct iio_dev *indio_dev,
		struct iio_chan_spec const *chan,
		int val, int val2, long mask)
		@@ -905,9 +921,18 @@ static int cpcap_adc_read(struct iio_dev *indio_dev,
		error = cpcap_adc_start_bank(ddata, &req);
		if (error)
		goto err_unlock;
		if ((ddata->vendor == CPCAP_VENDOR_ST) &&
		(chan->channel == CPCAP_ADC_AD3)) {
		error = cpcap_adc_read_st_die_temp(ddata,
		chan->address,
		&req.result);
		if (error)
		goto err_unlock;
		} else {
		error = cpcap_adc_read_bank_scaled(ddata, &req);
		if (error)
		goto err_unlock;
		}
		error = cpcap_adc_stop_bank(ddata);
		if (error)
		goto err_unlock;

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