From: Jes Sorensen <jes.sorensen@gmail.com>
To: Roy Im <roy.im.opensource@diasemi.com>,
Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Brian Masney <masneyb@onstation.org>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Greg KH <gregkh@linuxfoundation.org>,
Lee Jones <lee.jones@linaro.org>, Luca Weiss <luca@z3ntu.xyz>,
Maximilian Luz <luzmaximilian@gmail.com>,
Pascal PAILLET-LME <p.paillet@st.com>,
Rob Herring <robh@kernel.org>,
Samuel Ortiz <sameo@linux.intel.com>,
Thierry Reding <thierry.reding@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>
Cc: Support Opensource <support.opensource@diasemi.com>,
linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pwm@vger.kernel.org
Subject: Re: [PATCH v16 3/3] Input: new da7280 haptic driver
Date: Wed, 22 Jul 2020 11:23:45 -0400 [thread overview]
Message-ID: <bdc76da9-9223-b6d9-1fc1-2ef6e3b7afa7@gmail.com> (raw)
In-Reply-To: <b02ba5b5dbd3d58f27440ba639d32e4405061df3.1594279649.git.Roy.Im@diasemi.com>
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 <roy.im.opensource@diasemi.com>
> ---
> 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 <Jes.Sorensen@gmail.com>
> 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 <stdio.h>
#include <stdint.h>
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
next prev parent reply other threads:[~2020-07-22 15:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1594279649.git.Roy.Im@diasemi.com>
2020-07-09 7:27 ` [PATCH v16 3/3] Input: new da7280 haptic driver Roy Im
2020-07-22 15:23 ` Jes Sorensen [this message]
2020-07-23 2:23 ` Roy Im
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