From ba98645c7d54640f163096cda3609d4d55c6ae54 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Sat, 4 Nov 2017 21:20:05 +0100 Subject: [PATCH] i2c: add i2c_master_{send|recv}_dmasafe Use the new helper to create variants of i2c_master_{send|recv} which mark their buffers as DMA safe. Signed-off-by: Wolfram Sang Acked-by: Jonathan Cameron Signed-off-by: Wolfram Sang --- include/linux/i2c.h | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 5ac0f9055715..5d7f3c1853ae 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -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,