[PATCH linux v3 3/3] drivers: w1: add hwmon temp support for w1_therm

From: Jaghathiswari Rankappagounder Natarajan
Date: Thu Jul 13 2017 - 17:07:10 EST


This change adds hwmon temp support for w1_therm.

Signed-off-by: Jaghathiswari Rankappagounder Natarajan <jaghu@xxxxxxxxxx>
Acked-by: Evgeniy Polyakov <zbr@xxxxxxxxxxx>
---
v2
- make changes to support hwmon_device_register_with_info mentioned by Guenter.

v3
- used IS_REACHABLE()
- rearranged the code to not require forward declarations
- used family_data
- incremented the reference count with the bus mutex locked
- corrected indentation
- removed dev_warn message
- simplified returning mode
- removed write function

drivers/w1/slaves/w1_therm.c | 91 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 91 insertions(+)

diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c
index 64e6a8f38410..b7d13220dd8f 100644
--- a/drivers/w1/slaves/w1_therm.c
+++ b/drivers/w1/slaves/w1_therm.c
@@ -29,6 +29,7 @@
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/delay.h>
+#include <linux/hwmon.h>

#include "../w1.h"
#include "../w1_int.h"
@@ -118,19 +119,77 @@ static struct attribute *w1_ds28ea00_attrs[] = {
&dev_attr_w1_seq.attr,
NULL,
};
+
ATTRIBUTE_GROUPS(w1_therm);
ATTRIBUTE_GROUPS(w1_ds28ea00);

+#if IS_REACHABLE(CONFIG_HWMON)
+static int w1_read_temp(struct device *dev, u32 attr, int channel,
+ long *val);
+
+static umode_t w1_is_visible(const void *_data, enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ return attr == hwmon_temp_input ? 0444 : 0;
+}
+
+static int w1_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ switch (type) {
+ case hwmon_temp:
+ return w1_read_temp(dev, attr, channel, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static const u32 w1_temp_config[] = {
+ HWMON_T_INPUT,
+ 0
+};
+
+static const struct hwmon_channel_info w1_temp = {
+ .type = hwmon_temp,
+ .config = w1_temp_config,
+};
+
+static const struct hwmon_channel_info *w1_info[] = {
+ &w1_temp,
+ NULL
+};
+
+static const struct hwmon_ops w1_hwmon_ops = {
+ .is_visible = w1_is_visible,
+ .read = w1_read,
+};
+
+static const struct hwmon_chip_info w1_chip_info = {
+ .ops = &w1_hwmon_ops,
+ .info = w1_info,
+};
+#endif
+
static struct w1_family_ops w1_therm_fops = {
.add_slave = w1_therm_add_slave,
.remove_slave = w1_therm_remove_slave,
.groups = w1_therm_groups,
+#if IS_REACHABLE(CONFIG_HWMON)
+ .chip_info = &w1_chip_info,
+#else
+ .chip_info = NULL,
+#endif
};

static struct w1_family_ops w1_ds28ea00_fops = {
.add_slave = w1_therm_add_slave,
.remove_slave = w1_therm_remove_slave,
.groups = w1_ds28ea00_groups,
+#if IS_REACHABLE(CONFIG_HWMON)
+ .chip_info = &w1_chip_info,
+#else
+ .chip_info = NULL,
+#endif
};

static struct w1_family w1_therm_family_DS18S20 = {
@@ -559,6 +618,38 @@ static ssize_t w1_slave_show(struct device *device,
return ret;
}

+#if IS_REACHABLE(CONFIG_HWMON)
+static int w1_read_temp(struct device *device, u32 attr, int channel,
+ long *val)
+{
+ struct w1_slave *sl = dev_get_drvdata(device);
+ struct therm_info info;
+ u8 fid = sl->family->fid;
+ int ret;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ ret = read_therm(device, sl, &info);
+ if (ret)
+ return ret;
+
+ if (!info.verdict) {
+ ret = -EIO;
+ return ret;
+ }
+
+ *val = w1_convert_temp(info.rom, fid);
+ ret = 0;
+ break;
+ default:
+ ret = -EOPNOTSUPP;
+ break;
+ }
+
+ return ret;
+}
+#endif
+
#define W1_42_CHAIN 0x99
#define W1_42_CHAIN_OFF 0x3C
#define W1_42_CHAIN_OFF_INV 0xC3
--
2.13.2.932.g7449e964c-goog