From: Artur Rojek <contact@artur-rojek.eu>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Jonathan Cameron <jic23@kernel.org>,
Paul Cercueil <paul@crapouillou.net>,
Heiko Stuebner <heiko@sntech.de>,
Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>,
linux-input <linux-input@vger.kernel.org>,
devicetree <devicetree@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v9 2/2] input: joystick: Add ADC attached joystick driver.
Date: Sun, 06 Sep 2020 14:09:28 +0200 [thread overview]
Message-ID: <2f2047e7ada6fcb70489ea6e5917e20a@artur-rojek.eu> (raw)
In-Reply-To: <CAHp75VfixOwpVSXoG1MqaZR2nmgEKumyKW8etLsRj1g=YjgiKw@mail.gmail.com>
Hi Andy,
thanks for the review, replies inline.
On 2020-09-06 11:22, Andy Shevchenko wrote:
> On Sat, Sep 5, 2020 at 7:34 PM Artur Rojek <contact@artur-rojek.eu>
> wrote:
>>
>> Add a driver for joystick devices connected to ADC controllers
>> supporting the Industrial I/O subsystem.
>
> ...
>
>> +static int adc_joystick_handle(const void *data, void *private)
>> +{
>> + struct adc_joystick *joy = private;
>> + enum iio_endian endianness;
>> + int bytes, msb, val, idx, i;
>> + bool sign;
>> +
>> + bytes = joy->chans[0].channel->scan_type.storagebits >> 3;
>> +
>> + for (i = 0; i < joy->num_chans; ++i) {
>> + idx = joy->chans[i].channel->scan_index;
>> + endianness =
>> joy->chans[i].channel->scan_type.endianness;
>> + msb = joy->chans[i].channel->scan_type.realbits - 1;
>
>> + sign = (tolower(joy->chans[i].channel->scan_type.sign)
>> == 's');
>
> Redundant parentheses.
>
>> + switch (bytes) {
>> + case 1:
>> + val = ((const u8 *)data)[idx];
>> + break;
>> + case 2:
>
>> + if (endianness == IIO_BE)
>> + val = be16_to_cpu(((const __be16
>> *)data)[idx]);
>> + else if (endianness == IIO_LE)
>> + val = le16_to_cpu(((const __le16
>> *)data)[idx]);
>> + else /* IIO_CPU */
>> + val = ((const u16 *)data)[idx];
>> + break;
>
> Hmm... I don't like explicit castings to restricted types. On top of
> that is it guaranteed that pointer to data will be aligned?
The buffer comes from the IIO core, it is aligned to the sample size.
> As a solution for the first two I would recommend to use
> get_unaligned_be16() / get_unaligned_le16().
> The last one is an interesting case and if data can be unaligned needs
> to be fixed.
>
>> + default:
>> + return -EINVAL;
>> + }
>> +
>> + val >>= joy->chans[i].channel->scan_type.shift;
>> + if (sign)
>> + val = sign_extend32(val, msb);
>> + else
>
>> + val &= GENMASK(msb, 0);
>
> It includes msb. Is it expected?
Yes, that's expected as `msb = joy->chans[i].channel->scan_type.realbits
- 1`.
>
>> + input_report_abs(joy->input, joy->axes[i].code, val);
>> + }
>> +
>> + input_sync(joy->input);
>> +
>> + return 0;
>> +}
>
> ...
>
>> +static int adc_joystick_open(struct input_dev *dev)
>
>> +static void adc_joystick_close(struct input_dev *dev)
>
> Just wondering if this is protected against object lifetime cases.
Can you clarify that in more details?
>
> ...
>
>> +err:
>
> err_fwnode_put: ?
>
>> + fwnode_handle_put(child);
>> + return ret;
>
> ...
>
>> + /* Count how many channels we got. NULL terminated. */
>> + for (i = 0; joy->chans[i].indio_dev; ++i) {
>> + bits = joy->chans[i].channel->scan_type.storagebits;
>> + if (!bits || (bits > 16)) {
>> + dev_err(dev, "Unsupported channel storage
>> size\n");
>
>> + return -EINVAL;
>
> -ERANGE?
>
>> + }
>> + if (bits !=
>> joy->chans[0].channel->scan_type.storagebits) {
>> + dev_err(dev, "Channels must have equal storage
>> size\n");
>> + return -EINVAL;
>> + }
>> + }
next prev parent reply other threads:[~2020-09-06 12:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-05 16:34 [PATCH v9 1/2] dt-bindings: input: Add docs for ADC driven joystick Artur Rojek
2020-09-05 16:34 ` [PATCH v9 2/2] input: joystick: Add ADC attached joystick driver Artur Rojek
2020-09-06 9:22 ` Andy Shevchenko
2020-09-06 12:09 ` Artur Rojek [this message]
2020-09-14 20:34 ` Dmitry Torokhov
2020-09-14 20:41 ` Dmitry Torokhov
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