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authorGuenter Roeck <linux@roeck-us.net>2016-03-26 12:28:05 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-04-20 15:41:52 +0900
commit63c22e8fe29efe1d03980d5cf933c4d7b9a72d09 (patch)
treea3ebfeb48bdc5dfc326f133d4617aa83f5da1206 /drivers/hwmon
parentb40108b826ed9e1c558f73b9dbabb8d80ded268b (diff)
hwmon: (max1111) Return -ENODEV from max1111_read_channel if not instantiated
commit 3c2e2266a5bd2d1cef258e6e54dca1d99946379f upstream. arm:pxa_defconfig can result in the following crash if the max1111 driver is not instantiated. Unhandled fault: page domain fault (0x01b) at 0x00000000 pgd = c0004000 [00000000] *pgd=00000000 Internal error: : 1b [#1] PREEMPT ARM Modules linked in: CPU: 0 PID: 300 Comm: kworker/0:1 Not tainted 4.5.0-01301-g1701f680407c #10 Hardware name: SHARP Akita Workqueue: events sharpsl_charge_toggle task: c390a000 ti: c391e000 task.ti: c391e000 PC is at max1111_read_channel+0x20/0x30 LR is at sharpsl_pm_pxa_read_max1111+0x2c/0x3c pc : [<c03aaab0>] lr : [<c0024b50>] psr: 20000013 ... [<c03aaab0>] (max1111_read_channel) from [<c0024b50>] (sharpsl_pm_pxa_read_max1111+0x2c/0x3c) [<c0024b50>] (sharpsl_pm_pxa_read_max1111) from [<c00262e0>] (spitzpm_read_devdata+0x5c/0xc4) [<c00262e0>] (spitzpm_read_devdata) from [<c0024094>] (sharpsl_check_battery_temp+0x78/0x110) [<c0024094>] (sharpsl_check_battery_temp) from [<c0024f9c>] (sharpsl_charge_toggle+0x48/0x110) [<c0024f9c>] (sharpsl_charge_toggle) from [<c004429c>] (process_one_work+0x14c/0x48c) [<c004429c>] (process_one_work) from [<c0044618>] (worker_thread+0x3c/0x5d4) [<c0044618>] (worker_thread) from [<c004a238>] (kthread+0xd0/0xec) [<c004a238>] (kthread) from [<c000a670>] (ret_from_fork+0x14/0x24) This can occur because the SPI controller driver (SPI_PXA2XX) is built as module and thus not necessarily loaded. While building SPI_PXA2XX into the kernel would make the problem disappear, it appears prudent to ensure that the driver is instantiated before accessing its data structures. Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r--drivers/hwmon/max1111.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/hwmon/max1111.c b/drivers/hwmon/max1111.c
index 36544c4f653c..303d0c9df907 100644
--- a/drivers/hwmon/max1111.c
+++ b/drivers/hwmon/max1111.c
@@ -85,6 +85,9 @@ static struct max1111_data *the_max1111;
int max1111_read_channel(int channel)
{
+ if (!the_max1111 || !the_max1111->spi)
+ return -ENODEV;
+
return max1111_read(&the_max1111->spi->dev, channel);
}
EXPORT_SYMBOL(max1111_read_channel);
@@ -258,6 +261,9 @@ static int max1111_remove(struct spi_device *spi)
{
struct max1111_data *data = spi_get_drvdata(spi);
+#ifdef CONFIG_SHARPSL_PM
+ the_max1111 = NULL;
+#endif
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);