From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from saturn.retrosnub.co.uk ([178.18.118.26]:44035 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751392AbaLZJXT (ORCPT ); Fri, 26 Dec 2014 04:23:19 -0500 Message-ID: <549D2905.4050801@kernel.org> Date: Fri, 26 Dec 2014 09:23:17 +0000 From: Jonathan Cameron MIME-Version: 1.0 To: Stefan Wahren CC: festevam@gmail.com, kristina.martsenko@gmail.com, knaack.h@gmx.de, marex@denx.de, kernel@pengutronix.de, pawel.moll@arm.com, ijc+devicetree@hellion.org.uk, robh+dt@kernel.org, galak@codeaurora.org, mark.rutland@arm.com, linux-iio@vger.kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH 2/2] iio: mxs-lradc: check ranges of ts properties References: <1419250476-2393-1-git-send-email-stefan.wahren@i2se.com> <1419250476-2393-3-git-send-email-stefan.wahren@i2se.com> In-Reply-To: <1419250476-2393-3-git-send-email-stefan.wahren@i2se.com> Content-Type: text/plain; charset=windows-1252 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org 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 > --- > 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; > } >