[PATCHv2 3/7] thermal: ti-soc-thermal: freeze FSM while computing trend

From: Eduardo Valentin
Date: Fri Jun 07 2013 - 15:13:25 EST


In order to read the history buffer, it is required to
freeze BG FSM. This patch adds the missing piece of code
to freeze the FSM and also a contention area to avoid
other parts of the code to access the DTEMPs.

Cc: Zhang Rui <rui.zhang@xxxxxxxxx>
Cc: linux-pm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Eduardo Valentin <eduardo.valentin@xxxxxx>
---
drivers/thermal/ti-soc-thermal/ti-bandgap.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
---

v2: Removed unused label 'unlock:'.

diff --git a/drivers/thermal/ti-soc-thermal/ti-bandgap.c b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
index f20c1cf..219c051 100644
--- a/drivers/thermal/ti-soc-thermal/ti-bandgap.c
+++ b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
@@ -992,9 +992,12 @@ int ti_bandgap_get_trend(struct ti_bandgap *bgp, int id, int *trend)
goto exit;
}

+ spin_lock(&bgp->lock);
+
tsr = bgp->conf->sensors[id].registers;

/* Freeze and read the last 2 valid readings */
+ RMW_BITS(bgp, id, bgap_mask_ctrl, mask_freeze_mask, 1);
reg1 = tsr->ctrl_dtemp_1;
reg2 = tsr->ctrl_dtemp_2;

@@ -1008,22 +1011,25 @@ int ti_bandgap_get_trend(struct ti_bandgap *bgp, int id, int *trend)
/* Convert from adc values to mCelsius temperature */
ret = ti_bandgap_adc_to_mcelsius(bgp, temp1, &t1);
if (ret)
- goto exit;
+ goto unfreeze;

ret = ti_bandgap_adc_to_mcelsius(bgp, temp2, &t2);
if (ret)
- goto exit;
+ goto unfreeze;

/* Fetch the update interval */
ret = ti_bandgap_read_update_interval(bgp, id, &interval);
if (ret || !interval)
- goto exit;
+ goto unfreeze;

*trend = (t1 - t2) / interval;

dev_dbg(bgp->dev, "The temperatures are t1 = %d and t2 = %d and trend =%d\n",
t1, t2, *trend);

+unfreeze:
+ RMW_BITS(bgp, id, bgap_mask_ctrl, mask_freeze_mask, 0);
+ spin_unlock(&bgp->lock);
exit:
return ret;
}
--
1.8.2.1.342.gfa7285d

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