From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jes Sorensen Subject: Re: [PATCH v16 3/3] Input: new da7280 haptic driver Date: Wed, 22 Jul 2020 11:23:45 -0400 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60252 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728812AbgGVPXt (ORCPT ); Wed, 22 Jul 2020 11:23:49 -0400 In-Reply-To: Content-Language: en-US Sender: linux-pwm-owner@vger.kernel.org List-Id: linux-pwm@vger.kernel.org To: Roy Im , Uwe Kleine-Koenig , Bartosz Golaszewski , Brian Masney , Dmitry Torokhov , Greg KH , Lee Jones , Luca Weiss , Maximilian Luz , Pascal PAILLET-LME , Rob Herring , Samuel Ortiz , Thierry Reding , Thomas Gleixner Cc: Support Opensource , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org On 7/9/20 3:27 AM, Roy Im wrote: > Adds support for the Dialog DA7280 LRA/ERM Haptic Driver with > multiple mode and integrated waveform memory and wideband support. > It communicates via an I2C bus to the device. > > Signed-off-by: Roy Im > --- > v16: > - Corrected some code and updated description in Kconfig. > v15: > - Removed some defines and updated some comments. > v14: > - Updated pwm related code, alignments and comments. > v13: > - Updated some conditions in pwm function and alignments. > v12: No changes. > v11: > - Updated the pwm related code, comments and typo. > v10: > - Updated the pwm related function and added some comments. > v9: > - Removed the header file and put the definitions into the c file. > - Updated the pwm code and error logs with %pE > v8: > - Added changes to support FF_PERIODIC/FF_CUSTOM and FF_CONSTANT. > - Updated the dt-related code. > - Removed memless related functions. > v7: > - Added more attributes to handle one value per file. > - Replaced and updated the dt-related code and functions called. > - Fixed error/functions. > v6: No changes. > v5: Fixed errors in Kconfig file. > v4: Updated code as dt-bindings are changed. > v3: No changes. > v2: Fixed kbuild error/warning > > > drivers/input/misc/Kconfig | 13 + > drivers/input/misc/Makefile | 1 + > drivers/input/misc/da7280.c | 1840 +++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 1854 insertions(+) > create mode 100644 drivers/input/misc/da7280.c Hi Roy, Overall the driver looks pretty good now. I did find one issue, see below. If you fix that I am happy to add a Reviewed-by line. Reviewed-By: Jes Sorensen > diff --git a/drivers/input/misc/da7280.c b/drivers/input/misc/da7280.c > new file mode 100644 > index 0000000..c8c42ac > --- /dev/null > +++ b/drivers/input/misc/da7280.c [snip] > +static int da7280_haptic_set_pwm(struct da7280_haptic *haptics, bool enabled) > +{ > + struct pwm_state state; > + u64 period_mag_multi; > + int error; > + > + if (!haptics->gain && enabled) { > + dev_err(haptics->dev, > + "Please set the gain first for the pwm mode\n"); > + return -EINVAL; > + } > + > + pwm_get_state(haptics->pwm_dev, &state); > + state.enabled = enabled; > + if (enabled) { > + period_mag_multi = state.period * haptics->gain; You are multiplying an unsigned int to a u16 and storing it in a u64. However, C doesn't promote the types, so you'll end up with an unexpected result here. You can fix it by promoting state.period to u64, ie: period_mage_multi = (u64)state.period * haptics->gain; See the following example code which demonstrates the problem. #include #include uint64_t foo(unsigned int a, uint16_t b) { uint64_t tmp = a * b; return tmp; } uint64_t bar(unsigned int a, uint16_t b) { uint64_t tmp = (uint64_t)a * b; return tmp; } int main() { uint64_t val; unsigned int a = 0xff00ff00; uint16_t b = 0x200; val = foo(a, b); printf("result(%0x, %0x) = %0llx\n", a, b, val); val = bar(a, b); printf("result(%0x, %0x) = %0llx\n", a, b, val); } Cheers, Jes