On 06/25/2016 09:40 PM, Guenter Roeck wrote: > By concerting the driver to regmap, we can use regmap to cache non-volatile > registers. Stop caching the temperature register; while potentially reading > it more often can result in reading it more often than necessary, this is > offset by the gain due to not re-reading the limit registers. > > Cc: Mark Brown <[email protected]> > Signed-off-by: Guenter Roeck <[email protected]> > --- > v2: Set use_single_rw to indicate that the chip can not perform > read operations crossing register boundaries. > Use REGCACHE_RBTREE instead REGCACHE_FLAT. REGCACHE_FLAT does not > initialize the cache from the chip unless num_reg_defaults_raw is > provided. If it is provided without actual cache values, it complains > with 'No cache defaults, reading back from HW'. REGCACHE_RBTREE > automatically initializes register values from the chip if no > defaults are provided, and does not complain about it. > > Note: I'll drop the Cc: to Mark later. > > drivers/hwmon/tmp102.c | 156 > +++++++++++++++++++++++++------------------------ > 1 file changed, 79 insertions(+), 77 deletions(-) > > diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c > index 487b4ef5992c..e4a2314a2c49 100644 > --- a/drivers/hwmon/tmp102.c > +++ b/drivers/hwmon/tmp102.c > @@ -24,6 +24,7 @@ > #include <linux/mutex.h> > #include <linux/device.h> > #include <linux/jiffies.h> > +#include <linux/regmap.h> > #include <linux/thermal.h> > #include <linux/of.h> > > @@ -61,13 +62,9 @@ > #define CONVERSION_TIME_MS 35 /* in milli-seconds */ > > struct tmp102 { > - struct i2c_client *client; > - struct mutex lock; > + struct regmap *regmap; > u16 config_orig; > - unsigned long last_update; > unsigned long ready_time; > - bool valid; > - int temp[3]; > }; > > /* convert left adjusted 13-bit TMP102 register value to milliCelsius */ > @@ -82,16 +79,11 @@ static inline u16 tmp102_mC_to_reg(int val) > return (val * 128) / 1000; > } > > -static const u8 tmp102_reg[] = { > - TMP102_TEMP_REG, > - TMP102_TLOW_REG, > - TMP102_THIGH_REG, > -}; > - > -static struct tmp102 *tmp102_update_device(struct device *dev) > +static int tmp102_read_temp(void *dev, int *temp) > { > struct tmp102 *tmp102 = dev_get_drvdata(dev); > - struct i2c_client *client = tmp102->client; > + unsigned int reg; > + int ret; > > /* Is it too early to return a conversion ? */ > if (time_before(jiffies, tmp102->ready_time)) { > @@ -100,28 +92,11 @@ static struct tmp102 *tmp102_update_device(struct device > *dev) > msleep(jiffies_to_msecs(sleeptime)); > }
Note, at this point: We have set CR0=0, CR1=1 (4HZ conversion rate). we do indeed have a 26typical (worst case 35ms) conversion time, but if we read register before 250 ms, we are not getting a new data, instead, we are just reading the same old register data. for lowering potential i2c ops, I suggest: if < conversion_rate + CONVERSION_TIME_MS, provide a cached data, if after that, do a read. we could do a patch over this ofcourse -> best will be to let us do a configurable conversion rate. We could get upto 8Hz conversion rate with this chip (CR0,1=1). Otherwise, this series worked just fine.. http://pastebin.ubuntu.com/17907605/ -- Regards, Nishanth Menon
