linux-kernel - Re: [RESEND PATCH v4 1/2] platform: Add driver for RAVE Supervisory Processor

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Message-ID: <CAHp75Vd=NdQ_5A4WHsUKUPe_OB_cOt46XqUdHcnLoZ7Es=M9Og@mail.gmail.com>
Date:   Thu, 27 Jul 2017 12:03:03 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Andrey Smirnov <andrew.smirnov@...il.com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Chris Healy <cphealy@...il.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Nikita Yushchenko <nikita.yoush@...entembedded.com>,
        Lee Jones <lee.jones@...aro.org>
Subject: Re: [RESEND PATCH v4 1/2] platform: Add driver for RAVE Supervisory Processor

On Tue, Jul 25, 2017 at 9:44 PM, Andrey Smirnov
<andrew.smirnov@...il.com> wrote:
> Add a driver for RAVE Supervisory Processor, an MCU implementing
> varoius bits of housekeeping functionality (watchdoging, backlight
> control, LED control, etc) on RAVE family of products by Zodiac
> Inflight Innovations.
>
> This driver implementes core MFD/serdev device as well as
> communication subroutines necessary for commanding the device.

Some comments below, and FWIW

Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>

> +#include <asm/unaligned.h>

Usually we put it below linux/* type of headers.

> +#include <linux/atomic.h>

> + * @variant:                   Device variant specific parameters and
> + *                             functions
> + * @event_notifier_list:       Input event notification chain (used with
> + *                             corresponding input MFD cell driver)

Perhaps make them oneliners?

> +static DEVICE_ATTR(boot_source, 0640,
> +                  rave_sp_show_boot_source, rave_sp_store_boot_source);

DEVICE_ATTR_RW() ?
Otherwise a comment is needed here why you can't use it.

> +static void csum_8b2c(const u8 *buf, size_t size, u8 *crc)
> +{
> +       *crc = *buf++;
> +       size--;
> +
> +       while (size--)
> +               *crc += *buf++;

I don't remember the answer to a proposal to convert this like

*crc = 0;

while (size--)
 *crc += *buf++;

> +
> +       *crc = 1 + ~(*crc);
> +}

> +static void csum_ccitt(const u8 *buf, size_t size, u8 *crc)
> +{

> +

Remove this line.

> +       const u16 calculated = crc_ccitt_false(0xffff, buf, size);
> +
> +       /*
> +        * While the rest of the wire protocol is little-endian,
> +        * CCITT-16 CRC in RDU2 device is sent out in big-endian order.
> +        */
> +       put_unaligned_be16(calculated, crc);
> +}

> +static int rave_sp_rdu2_cmd_translate(enum rave_sp_command command)
> +{
> +       if (command >= RAVE_SP_CMD_GET_FIRMWARE_VERSION &&
> +           command <= RAVE_SP_CMD_GET_GPIO_STATE)
> +               return command;
> +
> +       if (command == RAVE_SP_CMD_REQ_COPPER_REV) {
> +               /*
> +                * As per RDU2 ICD 3.4.47 CMD_GET_COPPER_REV code is
> +                * different from that for RDU1 and it is set to 0x28

+ period at the end => "...set to 0x28."

> +                */
> +               return 0x28;
> +       }
> +
> +       return rave_sp_rdu1_cmd_translate(command);
> +}

> +
> +static int rave_sp_default_cmd_translate(enum rave_sp_command command)
> +{
> +       /*
> +        * All of the following command codes were taken from "Table :
> +        * Communications Protocol Message Types" in section 3.3
> +        * "MESSAGE TYPES" of Rave PIC24 ICD

Ditto.

> +        */

> +}

> +static void rave_sp_load_silicon_rev(struct rave_sp *sp)
> +{
> +       struct device *dev = &sp->serdev->dev;
> +       u8 cmd[] = {
> +               [0] = RAVE_SP_CMD_GET_SP_SILICON_REV,
> +               [1] = 0
> +       };
> +       struct {
> +               __le32 devid;
> +               __le32 devrev;
> +       } __packed reply;
> +       int ret;
> +
> +       ret = rave_sp_exec(sp, cmd, sizeof(cmd), &reply, sizeof(reply));
> +       if (ret) {
> +               dev_err(dev, "CMD_GET_SP_SILICON_REV failed %d\n", ret);
> +               return;
> +       }
> +

> +       reply.devid  = le32_to_cpu(reply.devid);
> +       reply.devrev = le32_to_cpu(reply.devrev);

Can you run sparse with endianess check?
I doubt it will be happy about these lines.

> +
> +       sp->silicon_devid  = rave_sp_silicon_to_string(dev, reply.devid);
> +       sp->silicon_devrev = rave_sp_silicon_to_string(dev, reply.devrev);
> +}

> +static int rave_sp_probe(struct serdev_device *serdev)
> +{

> +       /*
> +        * Those strings already have a \n embedded so no need to have
> +        * one in format string.
> +        */
> +       dev_info(dev, "Firmware version: %s", sp->part_number_firmware);
> +       dev_info(dev, "Bootloader version: %s", sp->part_number_bootloader);

\n missed in both cases.

> +}

P.S. Btw, have you consider to use remoteproc framework? Does it suit here?

-- 
With Best Regards,
Andy Shevchenko