From: Moritz Fischer <m...@kernel.org> Add cros_ec_readmem() based helpers for I2C/SPI based ECs. Unlike the LPC based ECs the I2C/SPI based ones cannot just directly read the mapped region.
This is useful for things like accessing fan speeds or temperatures. Signed-off-by: Moritz Fischer <m...@kernel.org> --- Hi all, I had submitted this back in May 2017 [1] and then somewhat forgot about it. So here's a new version :) As to why is this required? we're using this in some of our devices [2] that run a modified firmware based on Chromium-EC. I've been carrying the patch downstream in our tree for a while and it would be nice if we can merge this upstream so I can stop rebasing this :) Thanks, Moritz [1] https://lore.kernel.org/patchwork/patch/786065/ [2] https://www.ettus.com/product/details/USRP-E320 --- drivers/platform/chrome/cros_ec_i2c.c | 1 + drivers/platform/chrome/cros_ec_proto.c | 38 +++++++++++++++++++++++++ drivers/platform/chrome/cros_ec_spi.c | 1 + include/linux/mfd/cros_ec.h | 12 ++++++++ 4 files changed, 52 insertions(+) diff --git a/drivers/platform/chrome/cros_ec_i2c.c b/drivers/platform/chrome/cros_ec_i2c.c index ef9b4763356f..c3a9bee37b1d 100644 --- a/drivers/platform/chrome/cros_ec_i2c.c +++ b/drivers/platform/chrome/cros_ec_i2c.c @@ -303,6 +303,7 @@ static int cros_ec_i2c_probe(struct i2c_client *client, ec_dev->irq = client->irq; ec_dev->cmd_xfer = cros_ec_cmd_xfer_i2c; ec_dev->pkt_xfer = cros_ec_pkt_xfer_i2c; + ec_dev->cmd_readmem = cros_ec_readmem; ec_dev->phys_name = client->adapter->name; ec_dev->din_size = sizeof(struct ec_host_response_i2c) + sizeof(struct ec_response_get_protocol_info); diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c index cc7baf0ecb3c..2f1d45a7a934 100644 --- a/drivers/platform/chrome/cros_ec_proto.c +++ b/drivers/platform/chrome/cros_ec_proto.c @@ -636,3 +636,41 @@ u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev) return host_event; } EXPORT_SYMBOL(cros_ec_get_host_event); + +int cros_ec_readmem(struct cros_ec_device *ec, unsigned int offset, + unsigned int bytes, void *dest) +{ + int ret; + struct ec_params_read_memmap *params; + struct cros_ec_command *msg; + + if (offset >= EC_MEMMAP_SIZE - bytes) + return -EINVAL; + + msg = kzalloc(sizeof(*msg) + max(sizeof(*params), bytes), GFP_KERNEL); + if (!msg) + return -ENOMEM; + + msg->version = 0; + msg->command = EC_CMD_READ_MEMMAP; + msg->insize = bytes; + msg->outsize = sizeof(*params); + + params = (struct ec_params_read_memmap *)msg->data; + params->offset = offset; + params->size = bytes; + + ret = cros_ec_cmd_xfer_status(ec, msg); + if (ret < 0) { + dev_warn(ec->dev, "cannot read mapped reg: %d/%d\n", + ret, msg->result); + goto out_free; + } + + memcpy(dest, msg->data, bytes); + +out_free: + kfree(msg); + return ret; +} +EXPORT_SYMBOL_GPL(cros_ec_readmem); diff --git a/drivers/platform/chrome/cros_ec_spi.c b/drivers/platform/chrome/cros_ec_spi.c index 2060d1483043..b95c1a25adfc 100644 --- a/drivers/platform/chrome/cros_ec_spi.c +++ b/drivers/platform/chrome/cros_ec_spi.c @@ -666,6 +666,7 @@ static int cros_ec_spi_probe(struct spi_device *spi) ec_dev->irq = spi->irq; ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi; ec_dev->pkt_xfer = cros_ec_pkt_xfer_spi; + ec_dev->cmd_readmem = cros_ec_readmem; ec_dev->phys_name = dev_name(&ec_spi->spi->dev); ec_dev->din_size = EC_MSG_PREAMBLE_COUNT + sizeof(struct ec_host_response) + diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h index de8b588c8776..0228fb42dcda 100644 --- a/include/linux/mfd/cros_ec.h +++ b/include/linux/mfd/cros_ec.h @@ -335,6 +335,18 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event); */ u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev); +/** + * cros_ec_readmem - Read mapped memory in the ChromeOS EC + * + * @ec: Device to read from + * @offset: Offset to read within the mapped region + * @bytes: number of bytes to read + * @data: Return data + * @return: 0 if Ok, -ve on error + */ +int cros_ec_readmem(struct cros_ec_device *ec, unsigned int offset, + unsigned int bytes, void *dest); + /* sysfs stuff */ extern struct attribute_group cros_ec_attr_group; extern struct attribute_group cros_ec_lightbar_attr_group; -- 2.20.1
