From: Armin Wolf <W_Armin@gmx.de>
To: hdegoede@redhat.com
Cc: jdelvare@suse.com, linux@roeck-us.net,
linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] hwmon: (sch5627) Disallow write access if virtual registers are locked
Date: Tue, 15 Aug 2023 18:55:57 +0200 [thread overview]
Message-ID: <20230815165558.4176-1-W_Armin@gmx.de> (raw)
When the lock bit inside SCH5627_REG_CTRL is set, then the virtual
registers become read-only until the next power cycle.
Disallow write access to those registers in such a case.
Tested on a Fujitsu Esprimo P720.
Fixes: aa9f833dfc12 ("hwmon: (sch5627) Add pwmX_auto_channels_temp support")
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
drivers/hwmon/sch5627.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/drivers/hwmon/sch5627.c b/drivers/hwmon/sch5627.c
index 1bbda3b05532..bf408e35e2c3 100644
--- a/drivers/hwmon/sch5627.c
+++ b/drivers/hwmon/sch5627.c
@@ -6,6 +6,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/bits.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/init.h>
@@ -32,6 +33,10 @@
#define SCH5627_REG_PRIMARY_ID 0x3f
#define SCH5627_REG_CTRL 0x40
+#define SCH5627_CTRL_START BIT(0)
+#define SCH5627_CTRL_LOCK BIT(1)
+#define SCH5627_CTRL_VBAT BIT(4)
+
#define SCH5627_NO_TEMPS 8
#define SCH5627_NO_FANS 4
#define SCH5627_NO_IN 5
@@ -147,7 +152,8 @@ static int sch5627_update_in(struct sch5627_data *data)
/* Trigger a Vbat voltage measurement every 5 minutes */
if (time_after(jiffies, data->last_battery + 300 * HZ)) {
- sch56xx_write_virtual_reg(data->addr, SCH5627_REG_CTRL, data->control | 0x10);
+ sch56xx_write_virtual_reg(data->addr, SCH5627_REG_CTRL,
+ data->control | SCH5627_CTRL_VBAT);
data->last_battery = jiffies;
}
@@ -226,6 +232,14 @@ static int reg_to_rpm(u16 reg)
static umode_t sch5627_is_visible(const void *drvdata, enum hwmon_sensor_types type, u32 attr,
int channel)
{
+ const struct sch5627_data *data = drvdata;
+
+ /* Once the lock bit is set, the virtual registers become read-only
+ * until the next power cycle.
+ */
+ if (data->control & SCH5627_CTRL_LOCK)
+ return 0444;
+
if (type == hwmon_pwm && attr == hwmon_pwm_auto_channels_temp)
return 0644;
@@ -483,14 +497,13 @@ static int sch5627_probe(struct platform_device *pdev)
return val;
data->control = val;
- if (!(data->control & 0x01)) {
+ if (!(data->control & SCH5627_CTRL_START)) {
pr_err("hardware monitoring not enabled\n");
return -ENODEV;
}
/* Trigger a Vbat voltage measurement, so that we get a valid reading
the first time we read Vbat */
- sch56xx_write_virtual_reg(data->addr, SCH5627_REG_CTRL,
- data->control | 0x10);
+ sch56xx_write_virtual_reg(data->addr, SCH5627_REG_CTRL, data->control | SCH5627_CTRL_VBAT);
data->last_battery = jiffies;
/*
--
2.39.2
next reply other threads:[~2023-08-15 16:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-15 16:55 Armin Wolf [this message]
2023-08-15 16:55 ` [PATCH 2/2] hwmon: (sch5627) Add support for writing limit registers Armin Wolf
2023-08-15 20:26 ` Guenter Roeck
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