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Date:   Tue, 10 Oct 2023 21:04:05 +0200
From:   Thomas =?utf-8?Q?Wei=C3=9Fschuh?= <thomas@t-8ch.de>
To:     Anshul Dalal <anshulusr@gmail.com>
Cc:     linux-input@vger.kernel.org, devicetree@vger.kernel.org,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Shuah Khan <skhan@linuxfoundation.org>,
        linux-kernel-mentees@lists.linuxfoundation.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 2/2] input: joystick: driver for Adafruit Seesaw
 Gamepad
Message-ID: <8fbd4f6c-b1cf-4924-9e4b-2b9455b42e41@t-8ch.de>
References: <20231010184827.1213507-1-anshulusr@gmail.com>
 <20231010184827.1213507-2-anshulusr@gmail.com>
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On 2023-10-11 00:18:24+0530, Anshul Dalal wrote:
> Adds a driver for a mini gamepad that communicates over i2c, the gamepad
> has bidirectional thumb stick input and six buttons.
> 
> The gamepad chip utilizes the open framework from Adafruit called 'Seesaw'
> to transmit the ADC data for the joystick and digital pin state for the
> buttons. I have only implemented the functionality required to receive the
> thumb stick and button state.
> 
> Steps in reading the gamepad state over i2c:
>   1. Reset the registers
>   2. Set the pin mode of the pins specified by the `BUTTON_MASK` to input
>       `BUTTON_MASK`: A bit-map for the six digital pins internally
>        connected to the joystick buttons.
>   3. Enable internal pullup resistors for the `BUTTON_MASK`
>   4. Bulk set the pin state HIGH for `BUTTON_MASK`
>   5. Poll the device for button and joystick state done by:
>       `seesaw_read_data(struct i2c_client *client, struct seesaw_data *data)`
> 
> Product page:
>   https://www.adafruit.com/product/5743
> Arduino driver:
>   https://github.com/adafruit/Adafruit_Seesaw
> 
> Driver tested on RPi Zero 2W
> 
> Signed-off-by: Anshul Dalal <anshulusr@gmail.com>

In general:

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>

But one more nitpick below:

> [..]

> +static void seesaw_poll(struct input_dev *input)
> +{
> +	struct seesaw_gamepad *private = input_get_drvdata(input);
> +	struct seesaw_data data;
> +	int err;
> +
> +	err = seesaw_read_data(private->i2c_client, &data);
> +	if (err != 0)
> +		return;

This should be logged at debug level, so the user has some sort of
chance to figure out if something is broken.

> +
> +	input_report_abs(input, ABS_X, data.x);
> +	input_report_abs(input, ABS_Y, data.y);
> +	input_report_key(input, BTN_EAST, data.button_a);
> +	input_report_key(input, BTN_SOUTH, data.button_b);
> +	input_report_key(input, BTN_NORTH, data.button_x);
> +	input_report_key(input, BTN_WEST, data.button_y);
> +	input_report_key(input, BTN_START, data.button_start);
> +	input_report_key(input, BTN_SELECT, data.button_select);
> +	input_sync(input);
> +}

> [..]