Re: v4.10-rc4 to v4.10-rc5: battery regression on Nokia N900

From: Guenter Roeck
Date: Tue Jan 24 2017 - 09:11:10 EST

On 01/23/2017 11:06 PM, Zhang Rui wrote:
On Mon, Jan 23, 2017 at 03:49:12PM -0800, Guenter Roeck wrote:
On Tue, Jan 24, 2017 at 12:26:54AM +0100, Pavel Machek wrote:

I'll try to revert it on the top of v4.10-rc5 now... and yes, it fixes
the issue.

Any idea what went wrong and how to fix that?

Anyway as we are at -rc5 and this is warning fix that caused a
regression on different hardware... it should be reverted.


What exactly does "stopped working" mean ? That might help understanding
what went wrong.

/sys files related to battery no longer appear. I beieve this has
something to do with it:

[ 2.374877] of_get_named_gpiod_flags: parsed 'reset-gpios' property
of node '/ocp@68000000/spi@48098000/tsc2005@0[0]' - status (0)
[ 2.375946] input: TSC2005 touchscreen as
[ 2.392120] rx51-battery: probe of n900-battery failed with error

Mystery solved:

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index 3932f92..fe5ec82 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -545,8 +545,10 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
int i, j, err, id;

/* Do not accept invalid characters in hwmon name attribute */
- if (name && (!strlen(name) || strpbrk(name, "-* \t\n")))
+ if (name && (!strlen(name) || strpbrk(name, "-* \t\n"))) {
+ printk("hwmon: Invalid character detected: %s\n", name);
return ERR_PTR(-EINVAL);
+ }

id = ida_simple_get(&hwmon_ida, 0, 0, GFP_KERNEL);
if (id < 0)

pavel@n900:~$ dmesg | grep -5 Invalid
[ 0.829650] of_get_named_gpiod_flags: parsed 'gpio-reset' property
of node '/ocp@68000000/i2c@48072000/tlv320aic3x@19[0]' - status (0)
[ 0.833831] tsl2563 2-0029: model 7, rev. 0
[ 0.837768] of_get_named_gpiod_flags: parsed 'enable-gpio' property
of node '/ocp@68000000/i2c@48072000/lp5523@32[0]' - status (0)
[ 1.921417] omap_i2c 48072000.i2c: controller timed out
[ 2.056823] lp5523x 2-0032: lp5523 Programmable led chip found
[ 2.064147] hwmon: Invalid character detected: bq27200-0

So the problem is really that the thermal driver needs to create a valid name.


Before reverting, can you please try if this patch works or not?


From 79320ea3721314ec29ed6cdd6987ff922b11d6f9 Mon Sep 17 00:00:00 2001
From: Zhang Rui <rui.zhang@xxxxxxxxx>
Date: Tue, 24 Jan 2017 14:11:03 +0800
Subject: [PATCH] thermal: fix parameter when registering hwmon

commit 7611fb68062f ("thermal: thermal_hwmon: Convert to
hwmon_device_register_with_info()") converts thermal core to use
hwmon_device_register_with_info() to register to hwmon instead of
deprecated hwmon_device_register().
But at the same time, the name of the hwmon device created is changed to
the thermal zone device name in this commit, which may contain
incompatible characters for hwmon.

Fixes it by using exactly the same parameters as before this commit.

Fixes: 7611fb68062f ("thermal: thermal_hwmon: Convert to hwmon_devce_register_with_info()")
Reported-by: Pavel Machek <pavel@xxxxxx>
Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
drivers/thermal/thermal_hwmon.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/thermal_hwmon.c b/drivers/thermal/thermal_hwmon.c
index c4a508a..0c6789f 100644
--- a/drivers/thermal/thermal_hwmon.c
+++ b/drivers/thermal/thermal_hwmon.c
@@ -157,8 +157,8 @@ int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)

strlcpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
- hwmon->device = hwmon_device_register_with_info(NULL, hwmon->type,
- hwmon, NULL, NULL);
+ hwmon->device = hwmon_device_register_with_info(NULL, NULL, NULL,

This is wrong. The name should be converted to a valid name. Otherwise you would
still have to provide the name attribute yourself, and the resulting name would
still be invalid. A simple fix would be to add
strreplace(hwmon->type, '-', '_');
after strlcpy().


if (IS_ERR(hwmon->device)) {
result = PTR_ERR(hwmon->device);
goto free_mem;