From efdf6a56a7c73753dd135ed085a223a119b5d805 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 31 Mar 2014 18:26:32 +0200 Subject: tmp105: Read temperature in milli-celsius MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Right now, the temperature property must be written in milli-celsius, but it reads back the value in 8.8 fixed point. Fix this by letting the property read back the original value (possibly rounded). Also simplify the code that does the conversion. Before: (QEMU) qom-set path=/machine/peripheral/sensor property=temperature value=20000 {u'return': {}} (QEMU) qom-get path=sensor property=temperature {u'return': 5120} After: (QEMU) qom-set path=/machine/peripheral/sensor property=temperature value=20000 {u'return': {}} (QEMU) qom-get path=sensor property=temperature {u'return': 20000} Signed-off-by: Paolo Bonzini Signed-off-by: Andreas Färber --- hw/misc/tmp105.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'hw') diff --git a/hw/misc/tmp105.c b/hw/misc/tmp105.c index 155e03d..63aa3d6 100644 --- a/hw/misc/tmp105.c +++ b/hw/misc/tmp105.c @@ -56,12 +56,14 @@ static void tmp105_get_temperature(Object *obj, Visitor *v, void *opaque, const char *name, Error **errp) { TMP105State *s = TMP105(obj); - int64_t value = s->temperature; + int64_t value = s->temperature * 1000 / 256; visit_type_int(v, &value, name, errp); } -/* Units are 0.001 centigrades relative to 0 C. */ +/* Units are 0.001 centigrades relative to 0 C. s->temperature is 8.8 + * fixed point, so units are 1/256 centigrades. A simple ratio will do. + */ static void tmp105_set_temperature(Object *obj, Visitor *v, void *opaque, const char *name, Error **errp) { @@ -78,7 +80,7 @@ static void tmp105_set_temperature(Object *obj, Visitor *v, void *opaque, return; } - s->temperature = ((int16_t) (temp * 0x800 / 128000)) << 4; + s->temperature = (int16_t) (temp * 256 / 1000); tmp105_alarm_update(s); } -- cgit v1.1