Re: [PATCH v10 3/5] mfd: Add driver for RAVE Supervisory Processor

[Johan Hovold <johan@kernel.org>]

On Tue, Oct 31, 2017 at 09:36:54AM -0700, Andrey Smirnov wrote:
> Add a driver for RAVE Supervisory Processor, an MCU implementing
> various 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.
> 
> Cc: linux-kernel@vger.kernel.org
> Cc: cphealy@gmail.com
> Cc: Lucas Stach <l.stach@pengutronix.de>
> Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
> Cc: Lee Jones <lee.jones@linaro.org>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Pavel Machek <pavel@ucw.cz>
> Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Johan Hovold <johan@kernel.org>
> Cc: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
> Tested-by: Chris Healy <cphealy@gmail.com>
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> ---

> +int rave_sp_exec(struct rave_sp *sp,
> +		 void *__data,  size_t data_size,
> +		 void *reply_data, size_t reply_data_size)
> +{
> +	struct rave_sp_reply reply = {
> +		.data     = reply_data,
> +		.length   = reply_data_size,
> +		.received = COMPLETION_INITIALIZER_ONSTACK(reply.received),
> +	};
> +	unsigned char *data = __data;
> +	int command, ret = 0;
> +	u8 ackid;
> +
> +	command = sp->variant->cmd.translate(data[0]);
> +	if (command < 0)
> +		return command;
> +
> +	ackid       = atomic_inc_return(&sp->ackid);
> +	reply.ackid = ackid;
> +	reply.code  = rave_sp_reply_code((u8)command),
> +
> +	mutex_lock(&sp->bus_lock);
> +
> +	mutex_lock(&sp->reply_lock);
> +	sp->reply = &reply;
> +	mutex_unlock(&sp->reply_lock);
> +
> +	data[0] = command;
> +	data[1] = ackid;
> +
> +	rave_sp_write(sp, data, data_size);
> +
> +	if (!wait_for_completion_timeout(&reply.received, HZ)) {
> +		dev_err(&sp->serdev->dev, "Command timeout\n");
> +		ret = -ETIMEDOUT;
> +
> +		mutex_lock(&sp->reply_lock);
> +		sp->reply = NULL;
> +		mutex_unlock(&sp->reply_lock);
> +	}
> +
> +	mutex_unlock(&sp->bus_lock);
> +	return ret;
> +}
> +EXPORT_SYMBOL(rave_sp_exec);

EXPORT_SYMBOL_GPL?

> +static int rave_sp_receive_buf(struct serdev_device *serdev,
> +			       const unsigned char *buf, size_t size)
> +{
> +	struct device *dev  = &serdev->dev;
> +	struct rave_sp *sp = dev_get_drvdata(dev);
> +	struct rave_sp_deframer *deframer = &sp->deframer;
> +	const unsigned char *src = buf;
> +	const unsigned char *end = buf + size;
> +	bool reset_framer = false;
> +
> +	while (src < end) {
> +		const unsigned char byte = *src++;
> +
> +		switch (deframer->state) {
> +		case RAVE_SP_EXPECT_SOF:
> +			if (byte == RAVE_SP_STX)
> +				deframer->state = RAVE_SP_EXPECT_DATA;
> +			continue;
> +
> +		case RAVE_SP_EXPECT_DATA:
> +			switch (byte) {
> +			case RAVE_SP_ETX:
> +				rave_sp_receive_frame(sp,
> +						      deframer->data,
> +						      deframer->length);
> +				reset_framer = true;
> +				break;
> +			case RAVE_SP_STX:
> +				dev_warn(dev, "Bad frame: STX before ETX\n");
> +				reset_framer = true;
> +				break;
> +			case RAVE_SP_DLE:
> +				deframer->state = RAVE_SP_EXPECT_ESCAPED_DATA;
> +				continue;
> +			}
> +
> +		case RAVE_SP_EXPECT_ESCAPED_DATA: /* FALLTHROUGH */

The fallthrough comment should precede the case statement (or you will
soon receive a patch from the people working enabling
-Wimplicit-fallthrough).

> +			deframer->data[deframer->length++] = byte;
> +
> +			if (deframer->length == sizeof(deframer->data)) {
> +				dev_warn(dev, "Bad frame: Too long\n");
> +				reset_framer = true;
> +				break;
> +			}
> +
> +			deframer->state = RAVE_SP_EXPECT_DATA;
> +			break;
> +		}
> +	}
> +
> +	if (reset_framer) {
> +		deframer->state  = RAVE_SP_EXPECT_SOF;
> +		deframer->length = 0;
> +	}
> +
> +	return src - buf;
> +}

> +MODULE_LICENSE("GPL v2");

This doesn't match the license text (GPL-2.0+).

> +MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>");
> +MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>");
> +MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
> +MODULE_DESCRIPTION("RAVE SP core driver");
> diff --git a/drivers/platform/Kconfig b/drivers/platform/Kconfig
> index c11db8bceea1..989d38b587bf 100644
> --- a/drivers/platform/Kconfig
> +++ b/drivers/platform/Kconfig
> @@ -8,3 +8,4 @@ endif
>  source "drivers/platform/goldfish/Kconfig"
>  
>  source "drivers/platform/chrome/Kconfig"
> +

This chunk should not be here.

> diff --git a/include/linux/rave-sp.h b/include/linux/rave-sp.h
> new file mode 100644
> index 000000000000..811929afc1a9
> --- /dev/null
> +++ b/include/linux/rave-sp.h

I think this one should live in include/linux/mfd/

> @@ -0,0 +1,54 @@
> +#ifndef _LINUX_RAVE_SP_H_
> +#define _LINUX_RAVE_SP_H_
> +
> +enum rave_sp_command {
> +	RAVE_SP_CMD_GET_FIRMWARE_VERSION	= 0x20,
> +	RAVE_SP_CMD_GET_BOOTLOADER_VERSION	= 0x21,
> +	RAVE_SP_CMD_BOOT_SOURCE			= 0x26,
> +	RAVE_SP_CMD_GET_BOARD_COPPER_REV	= 0x2B,
> +	RAVE_SP_CMD_GET_GPIO_STATE		= 0x2F,
> +
> +	RAVE_SP_CMD_STATUS			= 0xA0,
> +	RAVE_SP_CMD_SW_WDT			= 0xA1,
> +	RAVE_SP_CMD_PET_WDT			= 0xA2,
> +	RAVE_SP_CMD_RESET			= 0xA7,
> +	RAVE_SP_CMD_RESET_REASON		= 0xA8,
> +
> +	RAVE_SP_CMD_REQ_COPPER_REV		= 0xB6,
> +	RAVE_SP_CMD_GET_I2C_DEVICE_STATUS	= 0xBA,
> +	RAVE_SP_CMD_GET_SP_SILICON_REV		= 0xB9,
> +	RAVE_SP_CMD_CONTROL_EVENTS		= 0xBB,
> +
> +	RAVE_SP_EVNT_BASE			= 0xE0,
> +};

Johan