* [PATCH V2 1/2] DT: mxs-lradc: fix ranges of ts properties
2014-12-29 10:27 [PATCH V2 0/2] iio: mxs-lradc: check ranges of ts properties Stefan Wahren
@ 2014-12-29 10:27 ` Stefan Wahren
2015-01-04 11:14 ` Jonathan Cameron
2014-12-29 10:27 ` [PATCH V2 2/2] iio: mxs-lradc: check " Stefan Wahren
1 sibling, 1 reply; 4+ messages in thread
From: Stefan Wahren @ 2014-12-29 10:27 UTC (permalink / raw)
To: jic23
Cc: festevam, kristina.martsenko, knaack.h, marex, kernel, pawel.moll,
ijc+devicetree, robh+dt, galak, mark.rutland, linux-iio,
devicetree, Stefan Wahren
This patch fixes off-by-one issues in the devicetree binding of
mxs-lradc.
According to the i.MX23 and i.MX28 reference manuals [1][2] the range of
NUM_SAMPLES is 0..31, but property ave-ctrl is substracted by 1 before used.
Considering all limitations the range of DELAY is 1..2047, but also
property ave-delay is substracted by 1 before used.
The patch has been suggested by Hartmut Knaack and Kristina Martsenko.
[1] - http://cache.freescale.com/files/dsp/doc/ref_manual/IMX23RM.pdf
[2] - http://cache.freescale.com/files/dsp/doc/ref_manual/MCIMX28RM.pdf
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
---
.../bindings/staging/iio/adc/mxs-lradc.txt | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
index ee05dc3..3075377 100644
--- a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
+++ b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
@@ -12,9 +12,9 @@ Optional properties:
property is not present, then the touchscreen is
disabled. 5 wires is valid for i.MX28 SoC only.
- fsl,ave-ctrl: number of samples per direction to calculate an average value.
- Allowed value is 1 ... 31, default is 4
+ Allowed value is 1 ... 32, default is 4
- fsl,ave-delay: delay between consecutive samples. Allowed value is
- 1 ... 2047. It is used if 'fsl,ave-ctrl' > 1, counts at
+ 2 ... 2048. It is used if 'fsl,ave-ctrl' > 1, counts at
2 kHz and its default is 2 (= 1 ms)
- fsl,settling: delay between plate switch to next sample. Allowed value is
1 ... 2047. It counts at 2 kHz and its default is
--
1.7.9.5
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH V2 2/2] iio: mxs-lradc: check ranges of ts properties
2014-12-29 10:27 [PATCH V2 0/2] iio: mxs-lradc: check ranges of ts properties Stefan Wahren
2014-12-29 10:27 ` [PATCH V2 1/2] DT: mxs-lradc: fix " Stefan Wahren
@ 2014-12-29 10:27 ` Stefan Wahren
1 sibling, 0 replies; 4+ messages in thread
From: Stefan Wahren @ 2014-12-29 10:27 UTC (permalink / raw)
To: jic23
Cc: festevam, kristina.martsenko, knaack.h, marex, kernel, pawel.moll,
ijc+devicetree, robh+dt, galak, mark.rutland, linux-iio,
devicetree, Stefan Wahren
The devicetree binding for mxs-lradc defines ranges for the
touchscreen properties. In order to avoid unexpected behavior like
division by zero, we better check these ranges during probe and
abort in error case.
Additionally this patch adds an important note from the reference
manual about the range of sample delay.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Marek Vasut <marex@denx.de>
---
drivers/staging/iio/adc/mxs-lradc.c | 45 +++++++++++++++++++++++++++--------
1 file changed, 35 insertions(+), 10 deletions(-)
diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index f053535..d9d6fad 100644
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -436,7 +436,14 @@ static void mxs_lradc_setup_ts_channel(struct mxs_lradc *lradc, unsigned ch)
*/
mxs_lradc_reg_clear(lradc, LRADC_CH_VALUE_MASK, LRADC_CH(ch));
- /* prepare the delay/loop unit according to the oversampling count */
+ /*
+ * prepare the delay/loop unit according to the oversampling count
+ *
+ * from the datasheet:
+ * "The DELAY fields in HW_LRADC_DELAY0, HW_LRADC_DELAY1,
+ * HW_LRADC_DELAY2, and HW_LRADC_DELAY3 must be non-zero; otherwise,
+ * the LRADC will not trigger the delay group."
+ */
mxs_lradc_reg_wrt(lradc, LRADC_DELAY_TRIGGER(1 << ch) |
LRADC_DELAY_TRIGGER_DELAYS(0) |
LRADC_DELAY_LOOP(lradc->over_sample_cnt - 1) |
@@ -1495,20 +1502,38 @@ static int mxs_lradc_probe_touchscreen(struct mxs_lradc *lradc,
return -EINVAL;
}
- lradc->over_sample_cnt = 4;
- ret = of_property_read_u32(lradc_node, "fsl,ave-ctrl", &adapt);
- if (ret == 0)
+ if (of_property_read_u32(lradc_node, "fsl,ave-ctrl", &adapt)) {
+ lradc->over_sample_cnt = 4;
+ } else {
+ if (adapt < 1 || adapt > 32) {
+ dev_err(lradc->dev, "Invalid sample count (%u)\n",
+ adapt);
+ return -EINVAL;
+ }
lradc->over_sample_cnt = adapt;
+ }
- lradc->over_sample_delay = 2;
- ret = of_property_read_u32(lradc_node, "fsl,ave-delay", &adapt);
- if (ret == 0)
+ if (of_property_read_u32(lradc_node, "fsl,ave-delay", &adapt)) {
+ lradc->over_sample_delay = 2;
+ } else {
+ if (adapt < 2 || adapt > LRADC_DELAY_DELAY_MASK + 1) {
+ dev_err(lradc->dev, "Invalid sample delay (%u)\n",
+ adapt);
+ return -EINVAL;
+ }
lradc->over_sample_delay = adapt;
+ }
- lradc->settling_delay = 10;
- ret = of_property_read_u32(lradc_node, "fsl,settling", &adapt);
- if (ret == 0)
+ if (of_property_read_u32(lradc_node, "fsl,settling", &adapt)) {
+ lradc->settling_delay = 10;
+ } else {
+ if (adapt < 1 || adapt > LRADC_DELAY_DELAY_MASK) {
+ dev_err(lradc->dev, "Invalid settling delay (%u)\n",
+ adapt);
+ return -EINVAL;
+ }
lradc->settling_delay = adapt;
+ }
return 0;
}
--
1.7.9.5
^ permalink raw reply related [flat|nested] 4+ messages in thread