Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 362196e5 authored by Doug Anderson's avatar Doug Anderson Committed by Lee Jones
Browse files

mfd: cros_ec: spi: Add mutex to cros_ec_spi 



The main transfer function for cros_ec_spi can be called by more than
one client at a time.  Make sure that those clients don't stomp on
each other by locking the bus for the duration of the transfer
function.

Signed-off-by: default avatarDoug Anderson <dianders@chromium.org>
Reviewed-by: default avatarSimon Glass <sjg@chromium.org>
Tested-by: default avatarAndrew Bresticker <abrestic@chromium.org>
Tested-by: default avatarStephen Warren <swarren@nvidia.com>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 1fe36866

drivers/mfd/cros_ec_spi.c

+21 −5
Original line number Diff line number Diff line
@@ -65,11 +65,13 @@ 
 *	if no record

 * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that

 *      is sent when we want to turn off CS at the end of a transaction.

 * @lock: mutex to ensure only one user of cros_ec_command_spi_xfer at a time

 */

struct cros_ec_spi {

	struct spi_device *spi;

	s64 last_transfer_ns;

	unsigned int end_of_msg_delay;

	struct mutex lock;

};



static void debug_packet(struct device *dev, const char *name, u8 *ptr,
@@ -208,6 +210,13 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, 
	int ret = 0, final_ret;

	struct timespec ts;



	/*

	 * We have the shared ec_dev buffer plus we do lots of separate spi_sync

	 * calls, so we need to make sure only one person is using this at a

	 * time.

	 */

	mutex_lock(&ec_spi->lock);



	len = cros_ec_prepare_tx(ec_dev, ec_msg);

	dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
@@ -260,7 +269,7 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, 
		ret = final_ret;

	if (ret < 0) {

		dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);

		return ret;

		goto exit;

	}



	/* check response error code */
@@ -269,14 +278,16 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, 
		dev_warn(ec_dev->dev, "command 0x%02x returned an error %d\n",

			 ec_msg->cmd, ptr[0]);

		debug_packet(ec_dev->dev, "in_err", ptr, len);

		return -EINVAL;

		ret = -EINVAL;

		goto exit;

	}

	len = ptr[1];

	sum = ptr[0] + ptr[1];

	if (len > ec_msg->in_len) {

		dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",

			len, ec_msg->in_len);

		return -ENOSPC;

		ret = -ENOSPC;

		goto exit;

	}



	/* copy response packet payload and compute checksum */
@@ -293,10 +304,14 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, 
		dev_err(ec_dev->dev,

			"bad packet checksum, expected %02x, got %02x\n",

			sum, ptr[len + 2]);

		return -EBADMSG;

		ret = -EBADMSG;

		goto exit;

	}



	return 0;

	ret = 0;

exit:

	mutex_unlock(&ec_spi->lock);

	return ret;

}



static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
@@ -327,6 +342,7 @@ static int cros_ec_spi_probe(struct spi_device *spi) 
	if (ec_spi == NULL)

		return -ENOMEM;

	ec_spi->spi = spi;

	mutex_init(&ec_spi->lock);

	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);

	if (!ec_dev)

		return -ENOMEM;