Re: [PATCH 2/7] drivers: mfd: Add a driver for iEi WT61P803 PUZZLE MCU

Lee Jones
2020-09-09T09:40:35Z

On Sat, 05 Sep 2020, Luka Kovacic wrote:

> Add a driver for the iEi WT61P803 PUZZLE microcontroller, used in some
> iEi Puzzle series devices. The microcontroller controls system power,
> temperature sensors, fans and LEDs.
>
> This driver implements the core functionality for device communication
> over the system serial (serdev bus). It handles MCU messages and the
> internal MCU properties. Some properties can be managed over sysfs.

Do you provide documentation for the new sysfs entries?

> Signed-off-by: Luka Kovacic <luka.kovacic@sartura.hr>
> Cc: Luka Perkov <luka.perkov@sartura.hr>
> ---
> drivers/mfd/Kconfig | 8 +
> drivers/mfd/Makefile | 1 +
> drivers/mfd/iei-wt61p803-puzzle.c | 1242 +++++++++++++++++++++++
> include/linux/mfd/iei-wt61p803-puzzle.h | 27 +
> 4 files changed, 1278 insertions(+)
> create mode 100644 drivers/mfd/iei-wt61p803-puzzle.c
> create mode 100644 include/linux/mfd/iei-wt61p803-puzzle.h
>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 33df0837ab41..3fcda95f07a3 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -2118,5 +2118,13 @@ config SGI_MFD_IOC3
> If you have an SGI Origin, Octane, or a PCI IOC3 card,
> then say Y. Otherwise say N.
>
> +config MFD_IEI_WT61P803_PUZZLE
> + tristate "iEi WT61P803 PUZZLE MCU driver"
> + depends on SERIAL_DEV_BUS
> + help
> + iEi WT61P803 PUZZLE is a system power management microcontroller
> + used for fan control, temperature sensor reading, led control
> + and system identification.
> +
> endmenu
> endif
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index a60e5f835283..33b88023a68d 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -236,6 +236,7 @@ obj-$(CONFIG_MFD_HI655X_PMIC) += hi655x-pmic.o
> obj-$(CONFIG_MFD_DLN2) += dln2.o
> obj-$(CONFIG_MFD_RT5033) += rt5033.o
> obj-$(CONFIG_MFD_SKY81452) += sky81452.o
> +obj-$(CONFIG_MFD_IEI_WT61P803_PUZZLE) += iei-wt61p803-puzzle.o
>
> intel-soc-pmic-objs := intel_soc_pmic_core.o intel_soc_pmic_crc.o
> obj-$(CONFIG_INTEL_SOC_PMIC) += intel-soc-pmic.o
> diff --git a/drivers/mfd/iei-wt61p803-puzzle.c b/drivers/mfd/iei-wt61p803-puzzle.c
> new file mode 100644
> index 000000000000..110ea1b84c53
> --- /dev/null
> +++ b/drivers/mfd/iei-wt61p803-puzzle.c
> @@ -0,0 +1,1242 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +

Please remove this line.

> +/* iEi WT61P803 PUZZLE MCU Driver
> + *
> + * Copyright (C) 2020 Sartura Ltd.
> + * Author: Luka Kovacic <luka.kovacic@sartura.hr>
> + */
> +
> +#include <linux/atomic.h>
> +#include <linux/delay.h>
> +#include <linux/export.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/iei-wt61p803-puzzle.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/sched.h>
> +#include <linux/serdev.h>
> +#include <asm/unaligned.h>
> +#include <linux/delay.h>
> +#include <linux/sysfs.h>

Alphabetical.

> +#define IEI_WT61P803_PUZZLE_MAX_COMMAND_LENGTH (20 + 2)
> +#define IEI_WT61P803_PUZZLE_RESP_BUF_SIZE 512
> +#define IEI_WT61P803_PUZZLE_GENERAL_TIMEOUT HZ

Can you tab align the values please.

Comment required for the use of 'HZ'.

> +/**
> + * struct iei_wt61p803_puzzle_mcu_status - MCU flags state
> + *
> + * @ac_recovery_status_flag: AC Recovery Status Flag
> + * @power_loss_recovery: System recovery after power loss
> + * @power_status: System Power-on Method
> + */

Please tab out the descriptions.

> +struct iei_wt61p803_puzzle_mcu_status {
> + u8 ac_recovery_status_flag;
> + u8 power_loss_recovery;
> + u8 power_status;
> +};
> +
> +/**
> + * enum iei_wt61p803_puzzle_reply_state - State of the reply
> + * @FRAME_OK: The frame was completely processed/received
> + * @FRAME_PROCESSING: First bytes were received, but the frame isn't complete
> + * @FRAME_STRUCT_EMPTY: The frame struct is empty, no data was received
> + * @FRAME_TIMEOUT: The frame processing timed out, communication failed

As above. Just makes it easier on the eye IMHO.

> + * The enum iei_wt61p803_puzzle_reply_state is used to describe the general state

s/The enum iei_wt61p803_puzzle_reply_state is used to describe/Describes/

> + * of the frame that is currently being received.
> + */
> +enum iei_wt61p803_puzzle_reply_state {
> + FRAME_OK = 0x00,
> + FRAME_PROCESSING = 0x01,
> + FRAME_STRUCT_EMPTY = 0xFF,
> + FRAME_TIMEOUT = 0xFE
> +};
> +
> +/**
> + * struct iei_wt61p803_puzzle_reply - MCU reply
> + *
> + * @size: Size of the MCU reply
> + * @data: Full MCU reply buffer
> + * @state: Current state of the packet
> + * @received: Was the response fullfilled
> + */
> +struct iei_wt61p803_puzzle_reply {
> + size_t size;
> + unsigned char *data;
> + u8 state;
> + struct completion received;
> +};
> +
> +/**
> + * struct iei_wt61p803_puzzle_mcu_version - MCU version status
> + *
> + * @version: Primary firmware version
> + * @build_info: Build date and time
> + * @bootloader_mode: Status of the MCU operation
> + * @protocol_version: MCU communication protocol version
> + * @serial_number: Device factory serial number
> + * @mac_address: Device factory MAC addresses
> + */
> +struct iei_wt61p803_puzzle_mcu_version {
> + const char *version;
> + const char *build_info;
> + bool bootloader_mode;
> + const char *protocol_version;
> + const char *serial_number;
> + const char *mac_address[8];
> +};
> +
> +/**
> + * struct iei_wt61p803_puzzle - iEi WT61P803 PUZZLE MCU Driver
> + *
> + * @serdev: Pointer to underlying serdev device
> + * @kobj: Pointer to kobject (sysfs)
> + * @reply_lock: Reply mutex lock
> + * @bus_lock: Bus mutex lock
> + * @reply: Pointer to the iei_wt61p803_puzzle_reply struct
> + * @version_lock: Version R/W mutex lock
> + * @version: Pointer to the iei_wt61p803_puzzle_mcu_version struct
> + * @status_lock: Status R/W mutex lock
> + * @status: Pointer to the iei_wt61p803_puzzle_mcu_status struct
> + */
> +struct iei_wt61p803_puzzle {
> + struct serdev_device *serdev;
> + struct kobject *kobj;
> +
> + struct mutex reply_lock;
> + struct mutex bus_lock;
> +
> + struct iei_wt61p803_puzzle_reply *reply;
> +
> + struct mutex version_lock;
> + struct iei_wt61p803_puzzle_mcu_version *version;
> +
> + struct mutex status_lock;
> + struct iei_wt61p803_puzzle_mcu_status *status;
> +};

Why do you need so many locks?

Are they intertwined?

Any reason why you can't just use one?

> +static const struct of_device_id iei_wt61p803_puzzle_dt_ids[] = {
> + { .compatible = "iei,wt61p803-puzzle" },
> + { /* sentinel */ }

Please remove this comment.

> +};

Move this to just above 'struct serdev_device_driver'.

> +unsigned char iei_wt61p803_puzzle_add_xor_checksum(unsigned char *buf,

'iei_wt61p803_puzzle_checksum' will be fine.

> + unsigned char xor_len)

'len'

> +{
> + unsigned char xor_sum = 0;

'checksum'

> + unsigned int i;
> +
> + for (i = 0; i < xor_len; i++)
> + xor_sum ^= buf[i];
> +
> + return xor_sum;
> +}
> +
> +static int iei_wt61p803_puzzle_process_resp(struct iei_wt61p803_puzzle *mcu,

Could you change all instances of 'mcu' to 'ddata' please.

> + unsigned char *raw_resp_data, size_t size)
> +{
> + struct device *dev = &mcu->serdev->dev;
> +
> + unsigned char xor_checksum;
> +
> + /*
> + * Start receiving the frame/Continue receiving the frame

* Start/continue receiving the frame

> + *
> + * The code below determines whether:

"the code below" is assumed.

> + * * we are receiving a new frame
> + * * appending data to an existing frame
> + *
> + */

Is this comment really required?

> + /* Lock the reply struct mutex */

This comment is definitely not required.

> + mutex_lock(&mcu->reply_lock);
> +
> + /* Check the incoming frame header */
> + if (!(raw_resp_data[0] == '@' || raw_resp_data[0] == '%' ||
> + (raw_resp_data[0] == 0xF7 && raw_resp_data[1] == 0xA1))) {

Please define *all* magic numbers.

> + /* Frame header is not correct, check whether to append */
> + if (mcu->reply->state != FRAME_PROCESSING) {
> + /* The incoming frame should be discarded */

Again, this really isn't required. We can see the error return.

> + dev_err(dev, "Invalid frame header and state (0x%x)",
> + mcu->reply->state);
> +
> + mutex_unlock(&mcu->reply_lock);
> + return -1;

Are you sure you want to return -EPERM? I suggest not.

Please use properly defined Linux error codes throughout:

https://www-numi.fnal.gov/offline_software/srt_public_context/WebDocs/Errors/unix_system_errors.html

> + }
> +
> + /* The frame should be appended to the existing data */

Tell the code what to do:

"Append the frame to existing data"

> + memcpy(mcu->reply->data+mcu->reply->size, raw_resp_data, size);
> + mcu->reply->size += size;
> + } else {
> + /* Start processing a new frame */
> + memcpy(mcu->reply->data, raw_resp_data, size);
> + mcu->reply->size = size;
> + mcu->reply->state = FRAME_PROCESSING;
> + }
> +
> + /* Create an xor checksum of the data */

Please remove. Code is clear enough.

> + xor_checksum = iei_wt61p803_puzzle_add_xor_checksum(mcu->reply->data,

Just 'checksum' will do.

> + ((int)mcu->reply->size)-1);

Why are you casting to a function you authored?

> +
> + /* Check whether the caluclated checksum matches the received one */

There's wayyyyy too much commenting happening here. You only need to
provide comments for points which would otherwise be unclear.

> + if (xor_checksum != mcu->reply->data[((int)mcu->reply->size)-1]) {

Remove all of these casts please - no need.

> + /* The checksum doesn't match, waiting for data */

No error messages to that effect?

> + mutex_unlock(&mcu->reply_lock);
> + return (int)size;
> + }
> +
> + /*
> + * Update internal driver state with the latest response code
> + */
> +
> + /* Received all the data */
> + mcu->reply->state = FRAME_OK;
> + complete(&mcu->reply->received);
> +
> + mutex_unlock(&mcu->reply_lock);
> +
> + return (int)size;
> +}
> +
> +static int iei_wt61p803_puzzle_recv_buf(struct serdev_device *serdev,
> + const unsigned char *data, size_t size)
> +{
> + struct iei_wt61p803_puzzle *mcu = serdev_device_get_drvdata(serdev);
> + int ret;
> +
> + ret = iei_wt61p803_puzzle_process_resp(mcu, (unsigned char *)data, size);
> +
> + /* Return the number of processed bytes if function returns error */
> + if (ret < 0)
> + return (int)size;
> +
> + return ret;
> +}
> +
> +static const struct serdev_device_ops iei_wt61p803_puzzle_serdev_device_ops = {
> + .receive_buf = iei_wt61p803_puzzle_recv_buf,
> + .write_wakeup = serdev_device_write_wakeup,
> +};
> +
> +/**
> + * iei_wt61p803_puzzle_write_command_watchdog() - Watchdog of the normal cmd
> + * @mcu: Pointer to the iei_wt61p803_puzzle core MFD struct
> + * @cmd: Pointer to the char array to send (size should be content + 1 (xor))
> + * @size: Size of the cmd char array
> + * @reply_data: Pointer to the reply/response data array (should be allocated)
> + * @reply_size: Pointer to size_t (size of reply_data)
> + * @retry_count: Number of times to retry sending the command to the MCU
> + */
> +int iei_wt61p803_puzzle_write_command_watchdog(struct iei_wt61p803_puzzle *mcu,
> + unsigned char *cmd, size_t size, unsigned char *reply_data,
> + size_t *reply_size, int retry_count)
> +{
> + struct device *dev = &mcu->serdev->dev;
> + int ret, i;
> +
> + for (i = 0; i < retry_count; i++) {
> + ret = iei_wt61p803_puzzle_write_command(mcu, cmd, size,
> + reply_data, reply_size);
> +
> + if (ret != -ETIMEDOUT)
> + return ret;
> + }
> +
> + dev_err(dev, "%s: Command response timed out. Retries: %d", __func__,
> + retry_count);
> +
> + return -ETIMEDOUT;
> +}
> +EXPORT_SYMBOL_GPL(iei_wt61p803_puzzle_write_command_watchdog);
> +
> +/**
> + * iei_wt61p803_puzzle_write_command() - Send a structured command to the MCU
> + * @mcu: Pointer to the iei_wt61p803_puzzle core MFD struct
> + * @cmd: Pointer to the char array to send (size should be content + 1 (xor))
> + * @size: Size of the cmd char array
> + * @reply_data: Pointer to the reply/response data array (should be allocated)
> + *
> + * Function iei_wt61p803_puzzle_write_command() sends a structured command to
> + * the MCU.
> + */
> +int iei_wt61p803_puzzle_write_command(struct iei_wt61p803_puzzle *mcu,
> + unsigned char *cmd, size_t size, unsigned char *reply_data,
> + size_t *reply_size)
> +{
> + struct device *dev = &mcu->serdev->dev;
> +
> + int ret;
> + int len = (int)size;
> +
> + if (size > IEI_WT61P803_PUZZLE_MAX_COMMAND_LENGTH)
> + return -EINVAL;
> +
> + /* Create an XOR checksum for the provided command */
> + cmd[len - 1] = iei_wt61p803_puzzle_add_xor_checksum(cmd, len);
> +
> + mutex_lock(&mcu->bus_lock);
> +
> + /* Initialize reply struct */
> + mutex_lock(&mcu->reply_lock);
> + if (mcu->reply) {
> + reinit_completion(&mcu->reply->received);
> +
> + mcu->reply->state = FRAME_STRUCT_EMPTY;
> +
> + mcu->reply->size = 0;
> + } else {
> + dev_err(dev, "Reply struct is NULL.\n");

This doesn't mean anything.

Please state what happened. 'Why' is the struct NULL?

> + mutex_unlock(&mcu->reply_lock);
> + mutex_unlock(&mcu->bus_lock);

Improve the error handling with 'goto's.

Move the unlocks to the bottom and 'goto' them instead of placing
unlocks in each error handler.

> + return -1;
> + }

Just check for '!mcu->reply'.

Break the 'reinit' code out of the 'if ()'

> + mutex_unlock(&mcu->reply_lock);
> +
> + /* Write to MCU UART */
> + ret = serdev_device_write(mcu->serdev, cmd, len,
> + IEI_WT61P803_PUZZLE_GENERAL_TIMEOUT);
> +

Remove this line.

> + if (ret < 0)
> + return ret;

Isn't the bus_lock still taken?

> + /* Wait for the MCU response */
> + if (!wait_for_completion_timeout(&mcu->reply->received,
> + IEI_WT61P803_PUZZLE_GENERAL_TIMEOUT)) {
> + dev_err(dev, "Command reply receive timeout\n");
> +
> + ret = -ETIMEDOUT;
> +
> + mutex_lock(&mcu->reply_lock);
> + reinit_completion(&mcu->reply->received);
> + mcu->reply->state = FRAME_TIMEOUT;
> + mutex_unlock(&mcu->reply_lock);
> + }
> +
> + if (ret < 0) {
> + mutex_unlock(&mcu->bus_lock);
> + return ret;
> + }

Why is this out here and not handled inside the 'if ()' above?

> + /* Verify MCU response status */
> + mutex_lock(&mcu->reply_lock);
> +
> + if (mcu->reply) {
> + /* Copy response */
> + *reply_size = mcu->reply->size;
> + memcpy(reply_data, mcu->reply->data, mcu->reply->size);
> + } else {
> + dev_err(dev, "Reply struct is NULL.\n");
> +
> + mutex_unlock(&mcu->reply_lock);
> + mutex_unlock(&mcu->bus_lock);
> +
> + return -1;
> + }

Same comments as above.

> + mutex_unlock(&mcu->reply_lock);
> + mutex_unlock(&mcu->bus_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(iei_wt61p803_puzzle_write_command);
> +
> +int iei_wt61p803_puzzle_buzzer(struct iei_wt61p803_puzzle *mcu, bool long_beep)
> +{
> + /* Buzzer 0.5 sec */

Place this at the end of the line.

> + unsigned char buzzer_short_cmd[4] = { '@', 'C', '2' };
> + /* Buzzer 1.5 sec */

As above.

> + unsigned char buzzer_long_cmd[4] = { '@', 'C', '3' };
> +

Remove this line.

> + int ret;
> +

Remove this line.

> + size_t reply_size = 0;
> + unsigned char *resp_buf;
> +
> + resp_buf = kmalloc(IEI_WT61P803_PUZZLE_BUF_SIZE, GFP_KERNEL);

What's the difference between this and 'mcu->reply->data'?

> + if (!resp_buf)
> + return -ENOMEM;
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu,
> + long_beep ? buzzer_long_cmd : buzzer_short_cmd, 4,

Define all magic numbers.

Do this throughout the code.

> + resp_buf, &reply_size);
> +
> + if (ret) {
> + kfree(resp_buf);

Use 'goto's so you don't have to free in each handler.

Do this throughout the code.

> + return ret;
> + }
> +
> + if (reply_size != 3) {
> + kfree(resp_buf);
> + return -EIO;
> + }
> +
> + if (!(resp_buf[0] == '@' && resp_buf[1] == '0' &&
> + resp_buf[2] == 0x70)) {
> + kfree(resp_buf);
> + return -EPROTO;
> + }
> +
> + kfree(resp_buf);
> + return 0;
> +}
> +
> +int iei_wt61p803_puzzle_get_version(struct iei_wt61p803_puzzle *mcu)
> +{
> + struct device *dev = &mcu->serdev->dev;
> +
> + /* Commands */

Not needed.

> + unsigned char version_cmd[3] = { '%', 'V' };
> + unsigned char build_info_cmd[3] = { '%', 'B' };
> + unsigned char bootloader_mode_cmd[3] = { '%', 'M' };
> + unsigned char protocol_version_cmd[3] = { '%', 'P' };
> +

Remove empty lines between declarations.

Do this throughout the code.

> + unsigned char *rd;
> + size_t reply_size = 0;
> +
> + int ret;
> +
> + /* Allocate memory for the buffer */
> + rd = kmalloc(IEI_WT61P803_PUZZLE_BUF_SIZE, GFP_KERNEL);
> + if (!rd)
> + return -ENOMEM;
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu, version_cmd,
> + sizeof(version_cmd), rd, &reply_size);
> + if (ret)
> + goto err;
> +
> + if (reply_size < 7) {
> + ret = -EIO;
> + goto err;
> + }
> +
> + mcu->version->version = devm_kasprintf(dev, GFP_KERNEL, "v%c.%c%c%c",
> + rd[2], rd[3], rd[4], rd[5]);

Please remove empty lines for each group. Like:

ret = iei_wt61p803_puzzle_write_command(mcu, version_cmd,
sizeof(version_cmd), rd, &reply_size);
if (ret)
goto err;
if (reply_size < 7) {
ret = -EIO;
goto err;
}
mcu->version->version = devm_kasprintf(dev, GFP_KERNEL, "v%c.%c%c%c",
rd[2], rd[3], rd[4], rd[5]);

> + ret = iei_wt61p803_puzzle_write_command(mcu, build_info_cmd,
> + sizeof(build_info_cmd), rd, &reply_size);
> + if (ret)
> + goto err;
> +
> + if (reply_size < 15) {
> + ret = -EIO;
> + goto err;
> + }
> +
> + mcu->version->build_info = devm_kasprintf(dev, GFP_KERNEL,
> + "%c%c/%c%c/%c%c%c%c %c%c:%c%c",
> + rd[8], rd[9], rd[6], rd[7], rd[2],
> + rd[3], rd[4], rd[5], rd[10], rd[11],
> + rd[12], rd[13]);
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu, bootloader_mode_cmd,
> + sizeof(bootloader_mode_cmd), rd, &reply_size);
> + if (ret)
> + goto err;
> +
> + if (reply_size < 4) {
> + ret = -EIO;
> + goto err;
> + }
> +
> + if (rd[2] == 0x31) {
> + /* The MCU is in normal mode */
> + mcu->version->bootloader_mode = false;
> + } else if (rd[2] == 0x30) {
> + /* The MCU is in bootloader mode */
> + mcu->version->bootloader_mode = true;
> + }
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu, protocol_version_cmd,
> + sizeof(protocol_version_cmd), rd, &reply_size);
> + if (ret)
> + goto err;
> +
> + if (reply_size < 9) {
> + ret = -EIO;
> + goto err;
> + }
> +
> + mcu->version->protocol_version = devm_kasprintf(dev, GFP_KERNEL,
> + "v%c.%c%c%c%c%c",
> + rd[7], rd[6], rd[5], rd[4], rd[3], rd[2]);
> +
> + /* Free the allocated memory resources */
> + kfree(rd);
> +
> + return 0;

No need to kfree/return twice.

Remove the 5 lines above.

> +err:
> + kfree(rd);
> + return ret;
> +}
> +
> +int iei_wt61p803_puzzle_get_mcu_status(struct iei_wt61p803_puzzle *mcu)
> +{
> + /* MCU Status Command */
> + unsigned char mcu_status_cmd[5] = { '@', 'O', 'S', 'S' };
> +
> + int ret;
> +
> + unsigned char *rd;
> + size_t reply_size = 0;
> +
> + /* Allocate memory for the buffer */
> + rd = kmalloc(IEI_WT61P803_PUZZLE_BUF_SIZE, GFP_KERNEL);
> + if (!rd)
> + return -ENOMEM;
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu, mcu_status_cmd,
> + sizeof(mcu_status_cmd), rd, &reply_size);
> + if (ret) {
> + kfree(rd);
> + return ret;
> + }
> +
> + if (reply_size < 20) {
> + kfree(rd);
> + return -EIO;
> + }
> +
> + /* Response format:
> + * (IDX RESPONSE)
> + * 0 @
> + * 1 O
> + * 2 S
> + * 3 S
> + * ...
> + * 5 AC Recovery Status Flag
> + * ...
> + * 10 Power Loss Recovery
> + * ...
> + * 19 Power Status (system power on method)
> + * 20 XOR checksum
> + */
> +
> + if (rd[0] == '@' && rd[1] == 'O' && rd[2] == 'S' && rd[3] == 'S') {
> + mutex_lock(&mcu->status_lock);
> + mcu->status->ac_recovery_status_flag = rd[5];
> + mcu->status->power_loss_recovery = rd[10];
> + mcu->status->power_status = rd[19];
> + mutex_unlock(&mcu->status_lock);
> + }
> +
> + /* Free the allocated memory resources */
> + kfree(rd);
> +
> + return 0;
> +}
> +
> +int iei_wt61p803_puzzle_get_serial_number(struct iei_wt61p803_puzzle *mcu)
> +{
> + struct device *dev = &mcu->serdev->dev;
> + unsigned char serial_number_cmd[5] = { 0xF7, 0xA1, 0x00, 0x24 };
> +
> + int ret;
> +
> + unsigned char *rd;
> + size_t reply_size = 0;
> +
> + /* Allocate memory for the buffer */
> + rd = kmalloc(IEI_WT61P803_PUZZLE_BUF_SIZE, GFP_KERNEL);
> + if (!rd)
> + return -ENOMEM;

Allocate this once in .probe().

No need to keep allocating and freeing each time.

> + ret = iei_wt61p803_puzzle_write_command(mcu, serial_number_cmd,
> + sizeof(serial_number_cmd), rd, &reply_size);
> + if (ret)
> + goto err;
> +
> + mutex_lock(&mcu->version_lock);
> + mcu->version->serial_number = devm_kasprintf(dev, GFP_KERNEL, "%.*s",
> + (int)reply_size - 5, rd + 4);
> + mutex_unlock(&mcu->version_lock);
> +
> + /* Free the allocated memory resources */
> + kfree(rd);
> +
> + return 0;
> +
> +err:
> + kfree(rd);
> + return ret;
> +

Remove all unnecessary blank lines.

> +}
> +
> +int iei_wt61p803_puzzle_write_serial_number(struct iei_wt61p803_puzzle *mcu,
> + unsigned char serial_number[36])
> +{
> + struct device *dev = &mcu->serdev->dev;
> + unsigned char serial_number_header[4] = { 0xF7, 0xA0, 0x00, 0xC };
> +
> + /* 4 byte header, 12 byte serial number chunk, 1 byte XOR checksum */
> + unsigned char serial_number_cmd[4+12+1];
> +
> + int ret, sn_counter;
> +
> + unsigned char *rd;
> + size_t reply_size = 0;
> +
> + /* Allocate memory for the buffer */
> + rd = kmalloc(IEI_WT61P803_PUZZLE_BUF_SIZE, GFP_KERNEL);
> + if (!rd)
> + return -ENOMEM;
> +
> + /* The MCU can only handle 22 byte messages, send the S/N in chunks */
> + for (sn_counter = 0; sn_counter < 3; sn_counter++) {
> + serial_number_header[2] = 0x0 + (0xC) * sn_counter;
> +
> + memcpy(serial_number_cmd, serial_number_header, 4);
> + memcpy(serial_number_cmd + 4, serial_number + (0xC) * sn_counter, 0xC);
> +
> + /* Initialize the last byte */
> + serial_number_cmd[sizeof(serial_number_cmd) - 1] = 0;
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu, serial_number_cmd,
> + sizeof(serial_number_cmd), rd, &reply_size);
> + if (ret)
> + goto err;
> +
> + if (reply_size != 3) {
> + ret = -EIO;
> + goto err;
> + }
> +
> + if (!(rd[0] == '@' && rd[1] == '0' && rd[2] == 0x70)) {
> + ret = -EPROTO;
> + goto err;
> + }
> + }
> +
> + mutex_lock(&mcu->version_lock);
> + mcu->version->serial_number = devm_kasprintf(dev, GFP_KERNEL, "%.*s",
> + 36, serial_number);
> + mutex_unlock(&mcu->version_lock);
> +
> + /* Free the allocated memory resources */
> + kfree(rd);
> +
> + return 0;
> +
> +err:
> + kfree(rd);
> + return ret;
> +}

Same comments as above.

> +int iei_wt61p803_puzzle_get_mac_addresses(struct iei_wt61p803_puzzle *mcu)
> +{
> + struct device *dev = &mcu->serdev->dev;
> + unsigned char mac_address_cmd[5] = { 0xF7, 0xA1, 0x00, 0x11 };
> +
> + int ret, mac_counter;
> +
> + unsigned char *rd;
> + size_t reply_size = 0;
> +
> + /* Allocate memory for the buffer */
> + rd = kmalloc(IEI_WT61P803_PUZZLE_BUF_SIZE, GFP_KERNEL);
> + if (!rd)
> + return -ENOMEM;
> +
> + for (mac_counter = 0; mac_counter < 8; mac_counter++) {
> + mac_address_cmd[2] = 0x24 + (0x11) * mac_counter;
> + mac_address_cmd[4] = 0x00;
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu, mac_address_cmd,
> + sizeof(mac_address_cmd), rd, &reply_size);
> + if (ret)
> + continue;
> +
> + if (reply_size < 22) {
> + ret = -EIO;
> + goto err;
> + }
> +
> + mutex_lock(&mcu->version_lock);
> + mcu->version->mac_address[mac_counter] = devm_kasprintf(dev,
> + GFP_KERNEL, "%.*s", (int)reply_size - 5,
> + rd + 4);
> + mutex_unlock(&mcu->version_lock);
> + }
> +
> + /* Free the allocated memory resources */
> + kfree(rd);
> +
> + return 0;
> +
> +err:
> + kfree(rd);
> + return ret;
> +}

Same comments as above.

> +int iei_wt61p803_puzzle_write_mac_address(struct iei_wt61p803_puzzle *mcu,
> + unsigned char mac_address[17], int mac_address_idx)
> +{
> + struct device *dev = &mcu->serdev->dev;
> + unsigned char mac_address_header[4] = { 0xF7, 0xA0, 0x00, 0x11 };
> +
> + /* 4 byte header, 17 byte MAC address, 1 byte XOR checksum */
> + unsigned char mac_address_cmd[4+17+1];
> +
> + int ret;
> +
> + unsigned char *rd;
> + size_t reply_size = 0;
> +
> + if (!(mac_address_idx < 8))
> + return -EINVAL;
> +
> + /* Allocate memory for the buffer */
> + rd = kmalloc(IEI_WT61P803_PUZZLE_BUF_SIZE, GFP_KERNEL);
> + if (!rd)
> + return -ENOMEM;
> +
> + mac_address_header[2] = 0x24 + (0x11) * mac_address_idx;
> +
> + /* Concat mac_address_header, mac_address to mac_address_cmd */
> + memcpy(mac_address_cmd, mac_address_header, 4);
> + memcpy(mac_address_cmd + 4, mac_address, 17);
> +
> + /* Initialize the last byte */
> + mac_address_cmd[sizeof(mac_address_cmd) - 1] = 0;
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu, mac_address_cmd,
> + sizeof(mac_address_cmd), rd, &reply_size);
> + if (ret)
> + goto err;
> +
> + if (reply_size != 3) {
> + ret = -EIO;
> + goto err;
> + }
> +
> + if (!(rd[0] == '@' && rd[1] == '0' && rd[2] == 0x70)) {
> + ret = -EPROTO;
> + goto err;
> + }
> +
> + mutex_lock(&mcu->version_lock);
> + mcu->version->mac_address[mac_address_idx] = devm_kasprintf(dev,
> + GFP_KERNEL, "%.*s", 17, mac_address);
> + mutex_unlock(&mcu->version_lock);
> +
> + /* Free the allocated memory resources */
> + kfree(rd);
> +
> + return 0;
> +
> +err:
> + kfree(rd);
> + return ret;
> +}

Same comments as above.

> +int iei_wt61p803_puzzle_write_power_loss_recovery(struct iei_wt61p803_puzzle *mcu,
> + int power_loss_recovery_action)
> +{
> + unsigned char power_loss_recovery_cmd[5] = { '@', 'O', 'A', '0' };
> +
> + unsigned char *resp_buf;
> + size_t reply_size = 0;
> +
> + /* Buffer for the power_loss_recovery_action to character */
> + unsigned char cmd_buf[2];
> +
> + int ret;
> +
> + /* Allocate memory for the buffer */
> + resp_buf = kmalloc(IEI_WT61P803_PUZZLE_BUF_SIZE, GFP_KERNEL);
> + if (!resp_buf)
> + return -ENOMEM;
> +
> + /* Check the acceptable range */
> + if (power_loss_recovery_action < 0 || power_loss_recovery_action > 4) {
> + kfree(resp_buf);
> + return -EINVAL;
> + }
> +
> + /* Convert int to char */
> + ret = snprintf(cmd_buf, sizeof(cmd_buf), "%d",
> + power_loss_recovery_action);
> + if (ret < 0) {
> + kfree(resp_buf);
> + return ret;
> + }
> +
> + /* Modify the command with the action index */
> + power_loss_recovery_cmd[3] = cmd_buf[0];
> +
> + ret = iei_wt61p803_puzzle_write_command(mcu, power_loss_recovery_cmd,
> + sizeof(power_loss_recovery_cmd), resp_buf, &reply_size);
> + if (ret) {
> + kfree(resp_buf);
> + return ret;
> + }
> +
> + /* Update the internal status (struct) */
> + mutex_lock(&mcu->status_lock);
> + mcu->status->power_loss_recovery = power_loss_recovery_action;
> + mutex_unlock(&mcu->status_lock);
> +
> + /* Free the allocated memory resources */
> + kfree(resp_buf);
> +
> + return 0;
> +}

Same comments as above.

> +
> +

Remove this line.

> +#define sysfs_container(dev) \
> + (container_of((dev)->kobj.parent, struct device, kobj))

What device is this fetching?

> +static ssize_t version_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + return sprintf(buf, "%s\n", mcu->version->version);
> +}
> +

Remove this line.

Same throughout.

> +static DEVICE_ATTR_RO(version);
> +
> +static ssize_t build_info_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + return sprintf(buf, "%s\n", mcu->version->build_info);
> +}
> +
> +static DEVICE_ATTR_RO(build_info);
> +
> +static ssize_t bootloader_mode_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + return sprintf(buf, "%d\n", mcu->version->bootloader_mode);
> +}
> +
> +static DEVICE_ATTR_RO(bootloader_mode);
> +
> +static ssize_t protocol_version_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + return sprintf(buf, "%s\n", mcu->version->protocol_version);
> +}
> +
> +static DEVICE_ATTR_RO(protocol_version);
> +
> +static ssize_t serial_number_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + int ret;
> +
> + mutex_lock(&mcu->version_lock);
> + ret = sprintf(buf, "%s\n", mcu->version->serial_number);
> + mutex_unlock(&mcu->version_lock);
> +
> + return ret;
> +}
> +
> +static ssize_t serial_number_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + unsigned char serial_number[36];
> + int ret;
> +
> + /* Check whether the serial number is 36 characters long + null */
> + if ((int)count != 36 + 1)
> + return -EINVAL;
> +
> + /* Copy 36 characters from the buffer to serial_number */
> + memcpy(serial_number, (unsigned char *)buf, 36);
> +
> + ret = iei_wt61p803_puzzle_write_serial_number(mcu, serial_number);
> + if (ret)
> + return ret;
> +
> + return count;
> +}
> +
> +static DEVICE_ATTR_RW(serial_number);
> +
> +static ssize_t mac_address_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + int ret;
> +
> + mutex_lock(&mcu->version_lock);
> +
> + if (!strcmp(attr->attr.name, "mac_address_0"))
> + ret = sprintf(buf, "%s\n", mcu->version->mac_address[0]);
> + else if (!strcmp(attr->attr.name, "mac_address_1"))
> + ret = sprintf(buf, "%s\n", mcu->version->mac_address[1]);
> + else if (!strcmp(attr->attr.name, "mac_address_2"))
> + ret = sprintf(buf, "%s\n", mcu->version->mac_address[2]);
> + else if (!strcmp(attr->attr.name, "mac_address_3"))
> + ret = sprintf(buf, "%s\n", mcu->version->mac_address[3]);
> + else if (!strcmp(attr->attr.name, "mac_address_4"))
> + ret = sprintf(buf, "%s\n", mcu->version->mac_address[4]);
> + else if (!strcmp(attr->attr.name, "mac_address_5"))
> + ret = sprintf(buf, "%s\n", mcu->version->mac_address[5]);
> + else if (!strcmp(attr->attr.name, "mac_address_6"))
> + ret = sprintf(buf, "%s\n", mcu->version->mac_address[6]);
> + else if (!strcmp(attr->attr.name, "mac_address_7"))
> + ret = sprintf(buf, "%s\n", mcu->version->mac_address[7]);
> + else
> + ret = sprintf(buf, "\n");
> +
> + mutex_unlock(&mcu->version_lock);
> +
> + return ret;
> +}
> +
> +static ssize_t mac_address_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + unsigned char mac_address[17];
> + int ret;
> +
> + /* Check whether the MAC address is 17 characters long + null */
> + if ((int)count != 17 + 1)
> + return -EINVAL;
> +
> + /* Copy 17 characters from the buffer to mac_address */
> + memcpy(mac_address, (unsigned char *)buf, 17);
> +
> + if (!strcmp(attr->attr.name, "mac_address_0"))
> + ret = iei_wt61p803_puzzle_write_mac_address(mcu, mac_address, 0);
> + else if (!strcmp(attr->attr.name, "mac_address_1"))
> + ret = iei_wt61p803_puzzle_write_mac_address(mcu, mac_address, 1);
> + else if (!strcmp(attr->attr.name, "mac_address_2"))
> + ret = iei_wt61p803_puzzle_write_mac_address(mcu, mac_address, 2);
> + else if (!strcmp(attr->attr.name, "mac_address_3"))
> + ret = iei_wt61p803_puzzle_write_mac_address(mcu, mac_address, 3);
> + else if (!strcmp(attr->attr.name, "mac_address_4"))
> + ret = iei_wt61p803_puzzle_write_mac_address(mcu, mac_address, 4);
> + else if (!strcmp(attr->attr.name, "mac_address_5"))
> + ret = iei_wt61p803_puzzle_write_mac_address(mcu, mac_address, 5);
> + else if (!strcmp(attr->attr.name, "mac_address_6"))
> + ret = iei_wt61p803_puzzle_write_mac_address(mcu, mac_address, 6);
> + else if (!strcmp(attr->attr.name, "mac_address_7"))
> + ret = iei_wt61p803_puzzle_write_mac_address(mcu, mac_address, 7);
> +
> + if (ret)
> + return ret;
> +
> + return count;
> +}
> +
> +static DEVICE_ATTR(mac_address_0, 0644, mac_address_show, mac_address_store);
> +static DEVICE_ATTR(mac_address_1, 0644, mac_address_show, mac_address_store);
> +static DEVICE_ATTR(mac_address_2, 0644, mac_address_show, mac_address_store);
> +static DEVICE_ATTR(mac_address_3, 0644, mac_address_show, mac_address_store);
> +static DEVICE_ATTR(mac_address_4, 0644, mac_address_show, mac_address_store);
> +static DEVICE_ATTR(mac_address_5, 0644, mac_address_show, mac_address_store);
> +static DEVICE_ATTR(mac_address_6, 0644, mac_address_show, mac_address_store);
> +static DEVICE_ATTR(mac_address_7, 0644, mac_address_show, mac_address_store);
> +
> +static ssize_t ac_recovery_status_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + int ret;
> +
> + ret = iei_wt61p803_puzzle_get_mcu_status(mcu);
> + if (ret)
> + return ret;
> +
> + mutex_lock(&mcu->status_lock);
> + ret = sprintf(buf, "%x\n", mcu->status->ac_recovery_status_flag);
> + mutex_unlock(&mcu->status_lock);
> +
> + return ret;
> +}
> +
> +static DEVICE_ATTR_RO(ac_recovery_status);
> +
> +static ssize_t power_loss_recovery_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + int ret;
> +
> + ret = iei_wt61p803_puzzle_get_mcu_status(mcu);
> + if (ret)
> + return ret;
> +
> + mutex_lock(&mcu->status_lock);
> + ret = sprintf(buf, "%x\n", mcu->status->power_loss_recovery);
> + mutex_unlock(&mcu->status_lock);
> +
> + return ret;
> +}
> +
> +static ssize_t power_loss_recovery_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + int ret;
> + long power_loss_recovery_action = 0;
> +
> + ret = kstrtol(buf, 10, &power_loss_recovery_action);
> + if (ret)
> + return ret;
> +
> + ret = iei_wt61p803_puzzle_write_power_loss_recovery(mcu,
> + (int)power_loss_recovery_action);
> + if (ret)
> + return ret;
> +
> + return count;
> +}
> +
> +static DEVICE_ATTR_RW(power_loss_recovery);
> +
> +static ssize_t power_status_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct device *dev_container = sysfs_container(dev);
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev_container);
> +
> + int ret;
> +
> + ret = iei_wt61p803_puzzle_get_mcu_status(mcu);
> + if (ret)
> + return ret;
> +
> + mutex_lock(&mcu->status_lock);
> + ret = sprintf(buf, "%x\n", mcu->status->power_status);
> + mutex_unlock(&mcu->status_lock);
> +
> + return ret;
> +}
> +
> +static DEVICE_ATTR_RO(power_status);
> +
> +static struct attribute *iei_wt61p803_puzzle_attrs[] = {
> + &dev_attr_version.attr,
> + &dev_attr_build_info.attr,
> + &dev_attr_bootloader_mode.attr,
> + &dev_attr_protocol_version.attr,
> + &dev_attr_serial_number.attr,
> + &dev_attr_mac_address_0.attr,
> + &dev_attr_mac_address_1.attr,
> + &dev_attr_mac_address_2.attr,
> + &dev_attr_mac_address_3.attr,
> + &dev_attr_mac_address_4.attr,
> + &dev_attr_mac_address_5.attr,
> + &dev_attr_mac_address_6.attr,
> + &dev_attr_mac_address_7.attr,
> + &dev_attr_ac_recovery_status.attr,
> + &dev_attr_power_loss_recovery.attr,
> + &dev_attr_power_status.attr,
> + NULL
> +};
> +
> +ATTRIBUTE_GROUPS(iei_wt61p803_puzzle);
> +
> +static int iei_wt61p803_puzzle_sysfs_create(struct device *dev,
> + struct iei_wt61p803_puzzle *mcu)
> +{
> + int ret;
> +
> + mcu->kobj =

This is an odd place for a line break.

> + kobject_create_and_add("iei_wt61p803_puzzle_core", &dev->kobj);
> + if (!mcu->kobj)
> + return -ENOMEM;
> +
> + ret = sysfs_create_groups(mcu->kobj, iei_wt61p803_puzzle_groups);
> + if (ret) {
> + dev_err(dev, "sysfs creation failed");
> +
> + /* Clean up */
> + kobject_del(mcu->kobj);
> + kobject_put(mcu->kobj);
> + mcu->kobj = NULL;
> +
> + return ret;

Drop this line.

> + }
> +
> + return 0;

Return ret.

> +}
> +
> +static int iei_wt61p803_puzzle_sysfs_remove(struct device *dev,
> + struct iei_wt61p803_puzzle *mcu)
> +{
> + /* Remove sysfs groups */
> + sysfs_remove_groups(mcu->kobj, iei_wt61p803_puzzle_groups);
> +
> + /* Remove the kobject */
> + kobject_del(mcu->kobj);
> + kobject_put(mcu->kobj);
> + mcu->kobj = NULL;
> +
> + return 0;
> +}
> +
> +static int iei_wt61p803_puzzle_probe(struct serdev_device *serdev)
> +{
> + struct device *dev = &serdev->dev;
> + struct iei_wt61p803_puzzle *mcu;
> + u32 baud;
> + int ret;
> +
> + /* Read the current-speed property from the device tree */
> + if (of_property_read_u32(dev->of_node, "current-speed", &baud)) {

Surely this is the baud you want to set, not what is already set?

> + dev_err(dev,
> + "'current-speed' is not specified in device node\n");
> + return -EINVAL;
> + }
> +
> + /* Log the specified BAUD RATE */
> + dev_info(dev, "Driver baud rate: %d", baud);
> +
> + /* Allocate the memory */
> + mcu = devm_kzalloc(dev, sizeof(*mcu), GFP_KERNEL);
> + if (!mcu)
> + return -ENOMEM;
> +
> + mcu->version = devm_kzalloc(dev, sizeof(*mcu->version), GFP_KERNEL);
> + if (!mcu->version)
> + return -ENOMEM;
> +
> + mcu->status = devm_kzalloc(dev, sizeof(*mcu->version), GFP_KERNEL);
> + if (!mcu->status)
> + return -ENOMEM;
> +
> + mcu->reply = devm_kzalloc(dev, sizeof(*mcu->reply), GFP_KERNEL);
> + if (!mcu->reply)
> + return -ENOMEM;
> +
> + mcu->reply->data = devm_kzalloc(dev, IEI_WT61P803_PUZZLE_RESP_BUF_SIZE,
> + GFP_KERNEL);
> + if (!mcu->reply->data)
> + return -ENOMEM;

Why not allocate all memory at once?

> + /* Initialize device struct data */
> + mcu->serdev = serdev;
> +
> + mcu->status->ac_recovery_status_flag = 0x00;
> + mcu->status->power_loss_recovery = 0x00;
> + mcu->status->power_status = 0x00;

These should already be 0.

> + init_completion(&mcu->reply->received);
> +
> + /* Mutexes */
> + mutex_init(&mcu->reply_lock);
> + mutex_init(&mcu->bus_lock);
> + mutex_init(&mcu->status_lock);
> + mutex_init(&mcu->version_lock);

Why so many?

> + /* Setup UART interface */
> + serdev_device_set_drvdata(serdev, mcu);
> + serdev_device_set_client_ops(serdev,
> + &iei_wt61p803_puzzle_serdev_device_ops);
> +
> + ret = devm_serdev_device_open(dev, serdev);
> + if (ret)
> + return ret;
> +
> + serdev_device_set_baudrate(serdev, baud);
> +
> + serdev_device_set_flow_control(serdev, false);
> +
> + ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
> + if (ret) {
> + dev_err(dev, "Failed to set parity\n");
> + return ret;
> + }
> +
> + ret = iei_wt61p803_puzzle_get_version(mcu);
> + if (ret)
> + return ret;
> +
> + ret = iei_wt61p803_puzzle_get_mac_addresses(mcu);
> + if (ret)
> + return ret;
> +
> + ret = iei_wt61p803_puzzle_get_serial_number(mcu);
> + if (ret)
> + return ret;
> +
> + dev_info(dev, "MCU version: %s", mcu->version->version);
> +
> + dev_info(dev, "MCU firmware build info: %s", mcu->version->build_info);
> + dev_info(dev, "MCU in bootloader mode: %s",
> + mcu->version->bootloader_mode ? "true" : "false");
> + dev_info(dev, "MCU protocol version: %s", mcu->version->protocol_version);
> +
> + if (of_property_read_bool(dev->of_node, "enable-probe-beep")) {

Probing is a Linuxisum. It has no place in DT.

> + ret = iei_wt61p803_puzzle_buzzer(mcu, false);
> + if (ret)
> + return ret;
> + }
> +
> + ret = iei_wt61p803_puzzle_sysfs_create(dev, mcu);
> + if (ret)
> + return ret;
> +
> + return devm_of_platform_populate(dev);
> +}
> +
> +static void iei_wt61p803_puzzle_remove(struct serdev_device *serdev)
> +{
> + struct device *dev = &serdev->dev;
> + struct iei_wt61p803_puzzle *mcu = dev_get_drvdata(dev);
> +
> + /* Remove sysfs kobjects and attributes */
> + iei_wt61p803_puzzle_sysfs_remove(dev, mcu);
> +
> + dev_info(dev, "Device unregistered");

No contentless/functionless prints please.

> +}
> +
> +

Place the table here.

> +MODULE_DEVICE_TABLE(of, iei_wt61p803_puzzle_dt_ids);
> +
> +static struct serdev_device_driver iei_wt61p803_puzzle_drv = {
> + .probe = iei_wt61p803_puzzle_probe,
> + .remove = iei_wt61p803_puzzle_remove,
> + .driver = {
> + .name = "iei-wt61p803-puzzle",
> + .of_match_table = iei_wt61p803_puzzle_dt_ids,
> + },
> +};
> +
> +module_serdev_device_driver(iei_wt61p803_puzzle_drv);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Luka Kovacic <luka.kovacic@sartura.hr>");
> +MODULE_DESCRIPTION("iEi WT61P803 PUZZLE MCU Driver");
> diff --git a/include/linux/mfd/iei-wt61p803-puzzle.h b/include/linux/mfd/iei-wt61p803-puzzle.h
> new file mode 100644
> index 000000000000..2bb6256574bc
> --- /dev/null
> +++ b/include/linux/mfd/iei-wt61p803-puzzle.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +
> +/* iEi WT61P803 PUZZLE MCU MFD Driver

No such thing as an MFD.

Please describe the device.

> + *
> + * Copyright (C) 2020 Sartura Ltd.
> + * Author: Luka Kovacic <luka.kovacic@sartura.hr>
> + */
> +
> +#ifndef _LINUX_IEI_WT61P803_PUZZLE_H_
> +#define _LINUX_IEI_WT61P803_PUZZLE_H_

s/LINUX/MFD/

> +#define IEI_WT61P803_PUZZLE_BUF_SIZE 512
> +
> +struct iei_wt61p803_puzzle_mcu_version;
> +struct iei_wt61p803_puzzle_reply;
> +struct iei_wt61p803_puzzle;
> +
> +int iei_wt61p803_puzzle_write_command_watchdog(struct iei_wt61p803_puzzle *mcu,
> + unsigned char *cmd, size_t size,
> + unsigned char *reply_data, size_t *reply_size,
> + int retry_count);
> +
> +int iei_wt61p803_puzzle_write_command(struct iei_wt61p803_puzzle *mcu,
> + unsigned char *cmd, size_t size,
> + unsigned char *reply_data, size_t *reply_size);
> +
> +#endif /* _LINUX_IEI_WT61P803_PUZZLE_H_ */

--
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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