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staging: ti-soc-thermal:Introduce ti_bandgap_get_trend function for OMAP5

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The patch adds ti_bandgap_get_trend function. This is specific
to OMAP5 for now it computes the trend from the temp values stored
in the hardware history buffer.

Formula: (T1 - T2) / P.

Where:
                T1: Last read valid temperature.
                T2: Last but one read valid temperature.
                P:  Update Interval.

Signed-off-by: J Keerthy <j-keerthy@ti.com>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
J Keerthy 2013-04-01 12:04:45 -04:00 committed by Greg Kroah-Hartman
parent 54b59c9224
commit 2f440b0622
2 changed files with 68 additions and 0 deletions
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67
drivers/staging/ti-soc-thermal/ti-bandgap.c
View file

@ -961,6 +961,73 @@ static int ti_bandgap_set_continuous_mode(struct ti_bandgap *bgp)
return 0;
}
/**
* ti_bandgap_get_trend() - To fetch the temperature trend of a sensor
* @bgp: pointer to struct ti_bandgap
* @id: id of the individual sensor
* @trend: Pointer to trend.
*
* This function needs to be called to fetch the temperature trend of a
* Particular sensor. The function computes the difference in temperature
* w.r.t time. For the bandgaps with built in history buffer the temperatures
* are read from the buffer and for those without the Buffer -ENOTSUPP is
* returned.
*
* Return: 0 if no error, else return corresponding error. If no
* error then the trend value is passed on to trend parameter
*/
int ti_bandgap_get_trend(struct ti_bandgap *bgp, int id, int *trend)
{
struct temp_sensor_registers *tsr;
u32 temp1, temp2, reg1, reg2;
int t1, t2, interval, ret = 0;
ret = ti_bandgap_validate(bgp, id);
if (ret)
goto exit;
if (!TI_BANDGAP_HAS(bgp, HISTORY_BUFFER) ||
!TI_BANDGAP_HAS(bgp, FREEZE_BIT)) {
ret = -ENOTSUPP;
goto exit;
}
tsr = bgp->conf->sensors[id].registers;
/* Freeze and read the last 2 valid readings */
reg1 = tsr->ctrl_dtemp_1;
reg2 = tsr->ctrl_dtemp_2;
/* read temperature from history buffer */
temp1 = ti_bandgap_readl(bgp, reg1);
temp1 &= tsr->bgap_dtemp_mask;
temp2 = ti_bandgap_readl(bgp, reg2);
temp2 &= tsr->bgap_dtemp_mask;
/* Convert from adc values to mCelsius temperature */
ret = ti_bandgap_adc_to_mcelsius(bgp, temp1, &t1);
if (ret)
goto exit;
ret = ti_bandgap_adc_to_mcelsius(bgp, temp2, &t2);
if (ret)
goto exit;
/* Fetch the update interval */
ret = ti_bandgap_read_update_interval(bgp, id, &interval);
if (ret || !interval)
goto exit;
*trend = (t1 - t2) / interval;
dev_dbg(bgp->dev, "The temperatures are t1 = %d and t2 = %d and trend =%d\n",
t1, t2, *trend);
exit:
return ret;
}
/**
* ti_bandgap_tshut_init() - setup and initialize tshut handling
* @bgp: pointer to struct ti_bandgap

1
drivers/staging/ti-soc-thermal/ti-bandgap.h
View file

@ -382,6 +382,7 @@ int ti_bandgap_read_temperature(struct ti_bandgap *bgp, int id,
int *temperature);
int ti_bandgap_set_sensor_data(struct ti_bandgap *bgp, int id, void *data);
void *ti_bandgap_get_sensor_data(struct ti_bandgap *bgp, int id);
int ti_bandgap_get_trend(struct ti_bandgap *bgp, int id, int *trend);
#ifdef CONFIG_OMAP4_THERMAL
extern const struct ti_bandgap_data omap4430_data;