This is a note to let you know that I've just added the patch titled

iio: adc: xilinx-xadc: Don't clobber preset voltage/temperature

to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 8d6b3ea4d9eaca80982442b68a292ce50ce0a135 Mon Sep 17 00:00:00 2001 From: Robert Hancock robert.hancock@calian.com Date: Thu, 14 Sep 2023 18:10:18 -0600 Subject: iio: adc: xilinx-xadc: Don't clobber preset voltage/temperature thresholds

In the probe function, the driver was reading out the thresholds already set in the core, which can be configured by the user in the Vivado tools when the FPGA image is built. However, it later clobbered those values with zero or maximum values. In particular, the overtemperature shutdown threshold register was overwritten with the max value, which effectively prevents the FPGA from shutting down when the desired threshold was eached, potentially risking hardware damage in that case.

Remove this code to leave the preconfigured default threshold values intact.

The code was also disabling all alarms regardless of what enable state they were left in by the FPGA image, including the overtemperature shutdown feature. Leave these bits in their original state so they are not unconditionally disabled.

Fixes: bdc8cda1d010 ("iio:adc: Add Xilinx XADC driver") Signed-off-by: Robert Hancock robert.hancock@calian.com Acked-by: O'Griofa, Conall conall.ogriofa@amd.com Tested-by: O'Griofa, Conall conall.ogriofa@amd.com Link: https://lore.kernel.org/r/20230915001019.2862964-2-robert.hancock@calian.com Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com --- drivers/iio/adc/xilinx-xadc-core.c | 22 ---------------------- 1 file changed, 22 deletions(-)

diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c index dba73300f894..d4d0d184a172 100644 --- a/drivers/iio/adc/xilinx-xadc-core.c +++ b/drivers/iio/adc/xilinx-xadc-core.c @@ -1423,28 +1423,6 @@ static int xadc_probe(struct platform_device *pdev) if (ret) return ret;

- /* Disable all alarms */ - ret = xadc_update_adc_reg(xadc, XADC_REG_CONF1, XADC_CONF1_ALARM_MASK, - XADC_CONF1_ALARM_MASK); - if (ret) - return ret; - - /* Set thresholds to min/max */ - for (i = 0; i < 16; i++) { - /* - * Set max voltage threshold and both temperature thresholds to - * 0xffff, min voltage threshold to 0. - */ - if (i % 8 < 4 || i == 7) - xadc->threshold[i] = 0xffff; - else - xadc->threshold[i] = 0; - ret = xadc_write_adc_reg(xadc, XADC_REG_THRESHOLD(i), - xadc->threshold[i]); - if (ret) - return ret; - } - /* Go to non-buffered mode */ xadc_postdisable(indio_dev);