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i2c: add i2c_master_{send|recv}_dmasafe

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Use the new helper to create variants of i2c_master_{send|recv} which
mark their buffers as DMA safe.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Wolfram Sang 2017-11-04 21:20:05 +01:00 committed by Wolfram Sang
parent 8a91732b3b
commit ba98645c7d
1 changed files with 32 additions and 0 deletions
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32
include/linux/i2c.h
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@ -80,6 +80,22 @@ static inline int i2c_master_recv(const struct i2c_client *client,
return i2c_transfer_buffer_flags(client, buf, count, I2C_M_RD);
};
/**
* i2c_master_recv_dmasafe - issue a single I2C message in master receive mode
* using a DMA safe buffer
* @client: Handle to slave device
* @buf: Where to store data read from slave, must be safe to use with DMA
* @count: How many bytes to read, must be less than 64k since msg.len is u16
*
* Returns negative errno, or else the number of bytes read.
*/
static inline int i2c_master_recv_dmasafe(const struct i2c_client *client,
char *buf, int count)
{
return i2c_transfer_buffer_flags(client, buf, count,
I2C_M_RD | I2C_M_DMA_SAFE);
};
/**
* i2c_master_send - issue a single I2C message in master transmit mode
* @client: Handle to slave device
@ -94,6 +110,22 @@ static inline int i2c_master_send(const struct i2c_client *client,
return i2c_transfer_buffer_flags(client, (char *)buf, count, 0);
};
/**
* i2c_master_send_dmasafe - issue a single I2C message in master transmit mode
* using a DMA safe buffer
* @client: Handle to slave device
* @buf: Data that will be written to the slave, must be safe to use with DMA
* @count: How many bytes to write, must be less than 64k since msg.len is u16
*
* Returns negative errno, or else the number of bytes written.
*/
static inline int i2c_master_send_dmasafe(const struct i2c_client *client,
const char *buf, int count)
{
return i2c_transfer_buffer_flags(client, (char *)buf, count,
I2C_M_DMA_SAFE);
};
/* Transfer num messages.
*/
extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,