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From: Guenter Roeck <linux@roeck-us.net>
To: Hardware Monitoring <linux-hwmon@vger.kernel.org>
Cc: Jean Delvare <jdelvare@suse.com>,
	Guenter Roeck <linux@roeck-us.net>,
	Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Subject: [PATCH 06/11] hwmon: (max6650) Simplify alarm handling
Date: Tue, 23 Apr 2019 06:33:06 -0700
Message-ID: <1556026391-15360-6-git-send-email-linux@roeck-us.net> (raw)
In-Reply-To: <1556026391-15360-1-git-send-email-linux@roeck-us.net>

Instead of re-reading the alarm register after reporting an alarm,
mark cached values as invalid. While this results in always reading all
data on subsequent reads, it is quite unlikely that such reads will
actually happen before the cache times out. The upside is avoiding
unnecessary unconditional i2c read operations.

Cc: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/hwmon/max6650.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/hwmon/max6650.c b/drivers/hwmon/max6650.c
index cf051f3acf26..c02694d70eee 100644
--- a/drivers/hwmon/max6650.c
+++ b/drivers/hwmon/max6650.c
@@ -526,15 +526,12 @@ static ssize_t alarm_show(struct device *dev,
 {
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 	struct max6650_data *data = max6650_update_device(dev);
-	struct i2c_client *client = data->client;
-	int alarm = 0;
+	bool alarm = data->alarm & attr->index;
 
-	if (data->alarm & attr->index) {
+	if (alarm) {
 		mutex_lock(&data->update_lock);
-		alarm = 1;
 		data->alarm &= ~attr->index;
-		data->alarm |= i2c_smbus_read_byte_data(client,
-							MAX6650_REG_ALARM);
+		data->valid = false;
 		mutex_unlock(&data->update_lock);
 	}
 
-- 
2.7.4


  parent reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-23 13:33 [PATCH 01/11] hwmon: (max6650) Use devm_add_action to unregister thermal device Guenter Roeck
2019-04-23 13:33 ` [PATCH 02/11] hwmon: (max6650) Introduce pwm_to_dac and dac_to_pwm Guenter Roeck
2019-04-23 15:23   ` Jean-Francois Dagenais
2019-04-23 17:02     ` Guenter Roeck
2019-04-23 13:33 ` [PATCH 03/11] hwmon: (max6650) Improve error handling in max6650_init_client Guenter Roeck
2019-04-23 13:33 ` [PATCH 04/11] hwmon: (max6650) Declare valid as boolean Guenter Roeck
2019-04-23 13:33 ` [PATCH 05/11] hwmon: (max6650) Cache alarm_en register Guenter Roeck
2019-04-23 13:33 ` Guenter Roeck [this message]
2019-04-23 13:33 ` [PATCH 07/11] hwmon: (max6650) Convert to use devm_hwmon_device_register_with_info Guenter Roeck
2019-04-24 13:42   ` Guenter Roeck
2019-04-23 13:33 ` [PATCH 08/11] hwmon: (max6650) Read non-volatile registers only once Guenter Roeck
2019-04-23 13:33 ` [PATCH 09/11] hwmon: (max6650) Improve error handling in max6650_update_device Guenter Roeck
2019-04-23 13:33 ` [PATCH 10/11] hwmon: (max6650) Use SPDX license identifier Guenter Roeck
2019-04-23 13:33 ` [PATCH 11/11] hwmon: (max6650) Fix minor formatting issues Guenter Roeck
2019-04-23 14:38   ` Jean-Francois Dagenais
2019-04-23 15:18     ` Guenter Roeck

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