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 <redacted>
---
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>

[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