When not all LED channels of the device are configured in OF, the
array size of pdata->led_config is smaller than the max number of
channels on the device. Subsequent accesses to pdata->led_config[i]
are going beyond the bounds of the allocated array. The check on
the configured led_current is also invalid, resulting in erroneous
test results for this function.
There is a potential for LED overcurrent conditions since the
test current will be set to values from these out-of-bound regions.
For the test, the PWM is set to 100%, although for a short amount
of time.
Instead of iterating over all the physical channels of the device,
loop over the available LED configurations and use led->chan_nr to
access the correct i2c registers. Keep the zero-check for the LED
current as existing configurations might depend on this to disable
a channel.
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: <dmurphy@xxxxxx>
Cc: <milo.kim@xxxxxx>
Reported-by: Arne Staessen <a.staessen@xxxxxxxxxxx>
Signed-off-by: Maarten Zanders <maarten.zanders@xxxxxxx>
---
drivers/leds/leds-lp5523.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/leds/leds-lp5523.c b/drivers/leds/leds-lp5523.c
index b1590cb4a188..f3782759c8d8 100644
--- a/drivers/leds/leds-lp5523.c
+++ b/drivers/leds/leds-lp5523.c
@@ -581,8 +581,8 @@ static ssize_t lp5523_selftest(struct device *dev,
struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
struct lp55xx_chip *chip = led->chip;
struct lp55xx_platform_data *pdata = chip->pdata;
- int i, ret, pos = 0;
- u8 status, adc, vdd;
+ int ret, pos = 0;
+ u8 status, adc, vdd, i;
mutex_lock(&chip->lock);
@@ -612,20 +612,20 @@ static ssize_t lp5523_selftest(struct device *dev,
vdd--; /* There may be some fluctuation in measurement */
- for (i = 0; i < LP5523_MAX_LEDS; i++) {
- /* Skip non-existing channels */
+ for (i = 0; i < pdata->num_channels; i++) {
+ /* Skip disabled channels */
if (pdata->led_config[i].led_current == 0)
continue;
/* Set default current */
- lp55xx_write(chip, LP5523_REG_LED_CURRENT_BASE + i,
+ lp55xx_write(chip, LP5523_REG_LED_CURRENT_BASE + led->chan_nr,
pdata->led_config[i].led_current);
- lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + i, 0xff);
+ lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + led->chan_nr, 0xff);
/* let current stabilize 2 - 4ms before measurements start */
usleep_range(2000, 4000);
lp55xx_write(chip, LP5523_REG_LED_TEST_CTRL,
- LP5523_EN_LEDTEST | i);
+ LP5523_EN_LEDTEST | led->chan_nr);
/* ADC conversion time is 2.7 ms typically */
usleep_range(3000, 6000);
ret = lp55xx_read(chip, LP5523_REG_STATUS, &status);
@@ -640,12 +640,12 @@ static ssize_t lp5523_selftest(struct device *dev,
goto fail;
if (adc >= vdd || adc < LP5523_ADC_SHORTCIRC_LIM)
- pos += sprintf(buf + pos, "LED %d FAIL\n", i);
+ pos += sprintf(buf + pos, "LED %d FAIL\n", led->chan_nr);
- lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + i, 0x00);
+ lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + led->chan_nr, 0x00);
/* Restore current */
- lp55xx_write(chip, LP5523_REG_LED_CURRENT_BASE + i,
+ lp55xx_write(chip, LP5523_REG_LED_CURRENT_BASE + led->chan_nr,
led->led_current);
led++;
}
--
2.31.1
