On 22/12/14 12:14, Stefan Wahren wrote:
> 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@xxxxxxxx>
> ---
> drivers/staging/iio/adc/mxs-lradc.c | 44 +++++++++++++++++++++++++++--------
> 1 file changed, 34 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
> index f053535..990e945 100644
> --- a/drivers/staging/iio/adc/mxs-lradc.c
> +++ b/drivers/staging/iio/adc/mxs-lradc.c
> @@ -436,7 +436,13 @@ 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 +1501,38 @@ 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 (%lu)\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) {
please run checkpatch.pl over these. Should be spaces around the +
> + 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;
> }
>
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