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.opensou...@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.soren...@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

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