@@ -655,44 +655,16 @@ static int pvt_write_trim(struct pvt_hwmon *pvt, long val)
static int pvt_read_timeout(struct pvt_hwmon *pvt, long *val)
{
- unsigned long rate;
- ktime_t kt;
- u32 data;
-
- rate = clk_get_rate(pvt->clks[PVT_CLOCK_REF].clk);
- if (!rate)
- return -ENODEV;
-
- /*
- * Don't bother with mutex here, since we just read data from MMIO.
- * We also have to scale the ticks timeout up to compensate the
- * ms-ns-data translations.
- */
- data = readl(pvt->regs + PVT_TTIMEOUT) + 1;
+ int ret;
- /*
- * Calculate ref-clock based delay (Ttotal) between two consecutive
- * data samples of the same sensor. So we first must calculate the
- * delay introduced by the internal ref-clock timer (Tref * Fclk).
- * Then add the constant timeout cuased by each conversion latency
- * (Tmin). The basic formulae for each conversion is following:
- * Ttotal = Tref * Fclk + Tmin
- * Note if alarms are enabled the sensors are polled one after
- * another, so in order to have the delay being applicable for each
- * sensor the requested value must be equally redistirbuted.
- */
-#if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
- kt = ktime_set(PVT_SENSORS_NUM * (u64)data, 0);
- kt = ktime_divns(kt, rate);
- kt = ktime_add_ns(kt, PVT_SENSORS_NUM * PVT_TOUT_MIN);
-#else
- kt = ktime_set(data, 0);
- kt = ktime_divns(kt, rate);
- kt = ktime_add_ns(kt, PVT_TOUT_MIN);
-#endif
+ ret = mutex_lock_interruptible(&pvt->iface_mtx);
+ if (ret)
+ return ret;
/* Return the result in msec as hwmon sysfs interface requires. */
- *val = ktime_to_ms(kt);
+ *val = ktime_to_ms(pvt->timeout);
+
+ mutex_unlock(&pvt->iface_mtx);
return 0;
}
@@ -700,7 +672,7 @@ static int pvt_read_timeout(struct pvt_hwmon *pvt, long *val)
static int pvt_write_timeout(struct pvt_hwmon *pvt, long val)
{
unsigned long rate;
- ktime_t kt;
+ ktime_t kt, cache;
u32 data;
int ret;
@@ -713,7 +685,7 @@ static int pvt_write_timeout(struct pvt_hwmon *pvt, long val)
* between all available sensors to have the requested delay
* applicable to each individual sensor.
*/
- kt = ms_to_ktime(val);
+ cache = kt = ms_to_ktime(val);
#if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
kt = ktime_divns(kt, PVT_SENSORS_NUM);
#endif
@@ -742,6 +714,7 @@ static int pvt_write_timeout(struct pvt_hwmon *pvt, long val)
return ret;
pvt_set_tout(pvt, data);
+ pvt->timeout = cache;
mutex_unlock(&pvt->iface_mtx);
@@ -1018,10 +991,17 @@ static int pvt_check_pwr(struct pvt_hwmon *pvt)
return ret;
}
-static void pvt_init_iface(struct pvt_hwmon *pvt)
+static int pvt_init_iface(struct pvt_hwmon *pvt)
{
+ unsigned long rate;
u32 trim, temp;
+ rate = clk_get_rate(pvt->clks[PVT_CLOCK_REF].clk);
+ if (!rate) {
+ dev_err(pvt->dev, "Invalid reference clock rate\n");
+ return -ENODEV;
+ }
+
/*
* Make sure all interrupts and controller are disabled so not to
* accidentally have ISR executed before the driver data is fully
@@ -1036,12 +1016,37 @@ static void pvt_init_iface(struct pvt_hwmon *pvt)
pvt_set_mode(pvt, pvt_info[pvt->sensor].mode);
pvt_set_tout(pvt, PVT_TOUT_DEF);
+ /*
+ * Preserve the current ref-clock based delay (Ttotal) between the
+ * sensors data samples in the driver data so not to recalculate it
+ * each time on the data requests and timeout reads. It consists of the
+ * delay introduced by the internal ref-clock timer (N / Fclk) and the
+ * constant timeout caused by each conversion latency (Tmin):
+ * Ttotal = N / Fclk + Tmin
+ * If alarms are enabled the sensors are polled one after another and
+ * in order to get the next measurement of a particular sensor the
+ * caller will have to wait for at most until all the others are
+ * polled. In that case the formulae will look a bit different:
+ * Ttotal = 5 * (N / Fclk + Tmin)
+ */
+#if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
+ pvt->timeout = ktime_set(PVT_SENSORS_NUM * PVT_TOUT_DEF, 0);
+ pvt->timeout = ktime_divns(pvt->timeout, rate);
+ pvt->timeout = ktime_add_ns(pvt->timeout, PVT_SENSORS_NUM * PVT_TOUT_MIN);
+#else
+ pvt->timeout = ktime_set(PVT_TOUT_DEF, 0);
+ pvt->timeout = ktime_divns(pvt->timeout, rate);
+ pvt->timeout = ktime_add_ns(pvt->timeout, PVT_TOUT_MIN);
+#endif
+
trim = PVT_TRIM_DEF;
if (!of_property_read_u32(pvt->dev->of_node,
"baikal,pvt-temp-offset-millicelsius", &temp))
trim = pvt_calc_trim(temp);
pvt_set_trim(pvt, trim);
+
+ return 0;
}
static int pvt_request_irq(struct pvt_hwmon *pvt)
@@ -1149,7 +1154,9 @@ static int pvt_probe(struct platform_device *pdev)
if (ret)
return ret;
- pvt_init_iface(pvt);
+ ret = pvt_init_iface(pvt);
+ if (ret)
+ return ret;
ret = pvt_request_irq(pvt);
if (ret)
@@ -10,6 +10,7 @@
#include <linux/completion.h>
#include <linux/hwmon.h>
#include <linux/kernel.h>
+#include <linux/ktime.h>
#include <linux/mutex.h>
#include <linux/seqlock.h>
@@ -201,6 +202,7 @@ struct pvt_cache {
* if alarms are disabled).
* @sensor: current PVT sensor the data conversion is being performed for.
* @cache: data cache descriptor.
+ * @timeout: conversion timeout cache.
*/
struct pvt_hwmon {
struct device *dev;
@@ -214,6 +216,7 @@ struct pvt_hwmon {
struct mutex iface_mtx;
enum pvt_sensor_type sensor;
struct pvt_cache cache[PVT_SENSORS_NUM];
+ ktime_t timeout;
};
/*