Re: [PATCH v6 5/9] i2c: add i2c_master_{send|recv}_dmasafe

Jonathan Cameron
2017-11-11T00:08:50Z

On Sat, 4 Nov 2017 21:20:05 +0100
Wolfram Sang <wsa+renesas@sang-engineering.com> wrote:

> 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>
Can't really argue with such a simple patch ;)
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
> include/linux/i2c.h | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index ef1a8791c1ae24..8c144e3cbfb261 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -81,6 +81,22 @@ static inline int i2c_master_recv(const struct i2c_client *client,
> };
>
> /**
> + * 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
> * @buf: Data that will be written to the slave
> @@ -93,6 +109,21 @@ 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.
> */