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Date: Tue, 25 Nov 2014 16:47:01 +0100
From: Bartosz Golaszewski <bgolaszewski@...libre.com>
To: Guenter Roeck <linux@...ck-us.net>
Cc: LKML <linux-kernel@...r.kernel.org>,
Benoit Cousson <bcousson@...libre.com>,
Patrick Titiano <ptitiano@...libre.com>,
Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: [PATCH 3/5] hwmon: ina2xx: allow to change the averaging rate at run-time
The averaging rate of ina226 is hardcoded to 16 in the driver.
Make it modifiable at run-time via a new sysfs attribute.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
---
drivers/hwmon/ina2xx.c | 115 +++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 106 insertions(+), 9 deletions(-)
diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
index eb66081..0914a72 100644
--- a/drivers/hwmon/ina2xx.c
+++ b/drivers/hwmon/ina2xx.c
@@ -54,6 +54,9 @@
/* shunt resistor sysfs attribute index */
#define INA2XX_RSHUNT 0x8
+/* INA226 averaging sysfs index */
+#define INA226_AVG 0x9
+
/* register count */
#define INA219_REGISTERS 6
#define INA226_REGISTERS 8
@@ -70,6 +73,12 @@
/* default shunt resistance */
#define INA2XX_RSHUNT_DEFAULT 10000
+/* bit masks for the averaging setting in the configuration register */
+#define INA226_AVG_RD_MASK 0x0E00
+#define INA226_AVG_WR_MASK 0xF1FF
+
+#define INA226_READ_AVG(reg) ((reg & INA226_AVG_RD_MASK) >> 9)
+
enum ina2xx_ids { ina219, ina226 };
struct ina2xx_config {
@@ -117,6 +126,13 @@ static const struct ina2xx_config ina2xx_config[] = {
},
};
+/* Available averaging rates for ina226. The indices correspond with
+ * the bit values expected by the chip (according to the ina226 datasheet,
+ * table 3 AVG bit settings, found at
+ * http://www.ti.com/lit/ds/symlink/ina226.pdf.
+ */
+static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
+
static u16 ina2xx_calibration_val(const struct ina2xx_data *data)
{
return (u16)(data->config->calibration_factor / data->rshunt);
@@ -156,6 +172,45 @@ static int ina2xx_calibrate(const struct i2c_client *client, u16 value)
return status;
}
+static int ina226_avg_bits(int avg)
+{
+ int i;
+
+ for (i = 0; i <= ARRAY_SIZE(ina226_avg_tab); i++) {
+ if (avg == ina226_avg_tab[i])
+ return i;
+ }
+
+ /* Invalid value */
+ return -1;
+}
+
+static int ina226_avg_val(int bits)
+{
+ /* Value read from the config register should be correct, but do check
+ * the boundary just in case.
+ */
+ if (bits >= ARRAY_SIZE(ina226_avg_tab)) {
+ WARN_ON_ONCE(1);
+ return -1;
+ }
+
+ return ina226_avg_tab[bits];
+}
+
+static inline int ina226_update_avg(struct ina2xx_data *data, int avg)
+{
+ int status;
+ u16 conf;
+
+ mutex_lock(&data->update_lock);
+ conf = (data->regs[INA2XX_CONFIG] & INA226_AVG_WR_MASK) | (avg << 9);
+ status = ina2xx_configure(data->client, conf);
+ mutex_unlock(&data->update_lock);
+
+ return status;
+}
+
static struct ina2xx_data *ina2xx_update_device(struct device *dev)
{
struct ina2xx_data *data = dev_get_drvdata(dev);
@@ -213,6 +268,10 @@ static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
case INA2XX_RSHUNT:
val = data->rshunt;
break;
+ case INA226_AVG:
+ val = ina226_avg_val(INA226_READ_AVG(
+ data->regs[INA2XX_CONFIG]));
+ break;
default:
/* programmer goofed */
WARN_ON_ONCE(1);
@@ -236,13 +295,25 @@ static ssize_t ina2xx_show_value(struct device *dev,
ina2xx_get_value(data, attr->index));
}
-static ssize_t ina2xx_set_shunt(struct device *dev,
+static ssize_t ina226_show_avg(struct device *dev,
+ struct device_attribute *da, char *buf)
+{
+ struct ina2xx_data *data = dev_get_drvdata(dev);
+
+ if (data->kind != ina226)
+ return -ENXIO;
+
+ return ina2xx_show_value(dev, da, buf);
+}
+
+static ssize_t ina2xx_set_value(struct device *dev,
struct device_attribute *da,
const char *buf, size_t count)
{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ina2xx_data *data = ina2xx_update_device(dev);
long val;
- s32 status;
+ int status;
if (IS_ERR(data))
return PTR_ERR(data);
@@ -250,12 +321,33 @@ static ssize_t ina2xx_set_shunt(struct device *dev,
if ((kstrtol(buf, 10, &val) == -EINVAL) || (val <= 0))
return -EINVAL;
- mutex_lock(&data->update_lock);
- data->rshunt = val;
- status = ina2xx_calibrate(data->client, ina2xx_calibration_val(data));
- mutex_unlock(&data->update_lock);
- if (status < 0)
- return -ENODEV;
+ switch (attr->index) {
+ case INA2XX_RSHUNT:
+ mutex_lock(&data->update_lock);
+ data->rshunt = val;
+ status = ina2xx_calibrate(data->client,
+ ina2xx_calibration_val(data));
+ mutex_unlock(&data->update_lock);
+ if (status < 0)
+ return -ENODEV;
+ break;
+ case INA226_AVG:
+ if (data->kind != ina226)
+ return -ENXIO;
+
+ status = ina226_avg_bits(val);
+ if (status < 0)
+ return -EINVAL;
+
+ if (ina226_update_avg(data, status) < 0)
+ return -ENODEV;
+ break;
+ default:
+ /* programmer goofed */
+ WARN_ON_ONCE(1);
+ val = 0;
+ break;
+ }
return count;
}
@@ -278,7 +370,11 @@ static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
/* shunt resistance */
static SENSOR_DEVICE_ATTR(rshunt, S_IRUGO | S_IWUSR | S_IWGRP,
- ina2xx_show_value, ina2xx_set_shunt, INA2XX_RSHUNT);
+ ina2xx_show_value, ina2xx_set_value, INA2XX_RSHUNT);
+
+/* averaging rate */
+static SENSOR_DEVICE_ATTR(avg, S_IRUGO | S_IWUSR | S_IWGRP,
+ ina226_show_avg, ina2xx_set_value, INA226_AVG);
/* pointers to created device attributes */
static struct attribute *ina2xx_attrs[] = {
@@ -287,6 +383,7 @@ static struct attribute *ina2xx_attrs[] = {
&sensor_dev_attr_curr1_input.dev_attr.attr,
&sensor_dev_attr_power1_input.dev_attr.attr,
&sensor_dev_attr_rshunt.dev_attr.attr,
+ &sensor_dev_attr_avg.dev_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(ina2xx);
--
2.1.3
--
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