Re: [PATCH v12 1/3] platform/chrome: cros_ec_uart: Add cros-ec-uart transport layer

Tzung-Bi Shih
2022-12-26T08:12:50Z

On Fri, Dec 09, 2022 at 09:26:22AM -0700, Mark Hasemeyer wrote:
> diff --git a/drivers/platform/chrome/cros_ec_uart.c b/drivers/platform/chrome/cros_ec_uart.c
[...]
> +static int cros_ec_uart_rx_bytes(struct serdev_device *serdev,
> + const u8 *data,
> + size_t count)
> +{
> + struct ec_host_response *response;

There are 2 "response" in the context: struct response_info vs.
struct ec_host_response. The pointer `response` here is only used for
setting `exp_len`.

I would suggest to introduce another pointer:
struct response_info *resp = &ec_uart->response;
So that most of the following "ec_uart->response." could simplify to
"resp->".

[...]
> + /* Read data_len if we received response header and if exp_len was not read before. */
> + if (ec_uart->response.size >= sizeof(*response) &&
> + ec_uart->response.exp_len == 0) {
> + response = (struct ec_host_response *) ec_uart->response.data;

Please drop the extra space.

> +static int cros_ec_uart_pkt_xfer(struct cros_ec_device *ec_dev,
> + struct cros_ec_command *ec_msg)
> +{
> + struct cros_ec_uart *ec_uart = ec_dev->priv;
> + struct serdev_device *serdev = ec_uart->serdev;
> + struct ec_host_response *response;

Ditto, if using another pointer to struct response_info could simplify the
function a bit.

> + unsigned int len;
> + int ret, i;
> + u8 sum = 0;

To make it clear, please drop the initialization and set it to 0 just right
before it is used.

[...]
> + /* Validate checksum */
> + for (i = 0; i < sizeof(*response) + response->data_len; i++)
> + sum += ec_dev->din[i];

The function is long. Setting sum to 0 before the loop improves the
readability.

> +static int cros_ec_uart_probe(struct serdev_device *serdev)
> +{
> + struct device *dev = &serdev->dev;
> + struct cros_ec_device *ec_dev;
> + struct cros_ec_uart *ec_uart;
> + int ret;
> +
> + ec_uart = devm_kzalloc(dev, sizeof(*ec_uart), GFP_KERNEL);
> + if (!ec_uart)
> + return -ENOMEM;
> +
> + ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> + if (!ec_dev)
> + return -ENOMEM;
> +
> + ec_uart->serdev = serdev;

The assignment can move somewhere before calling cros_ec_uart_acpi_probe().

> +
> + ret = devm_serdev_device_open(dev, ec_uart->serdev);

Using `ec_uart->serdev` here makes less sense. Please use `serdev` directly.