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mmc: mmc_spi: Document the 3 local functions 

mmc_spi_sendcmd(), mmc_spi_readdata() and mmc_spi_writedata() are
currently undocumented. Add comment blocks to explain the arguments
and the return value.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
This commit is contained in:
Bin Meng 2021-02-02 10:48:48 +08:00 committed by Peng Fan
parent 2f22cb40e5
commit 46938abd2c
1 changed files with 35 additions and 1 deletions
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36
drivers/mmc/mmc_spi.c
View File

@ -37,7 +37,8 @@
#define SPI_RESPONSE_CRC_ERR ((5 << 1)|1)
#define SPI_RESPONSE_WRITE_ERR ((6 << 1)|1)
/* Read and write blocks start with these tokens and end with crc;
/*
* Read and write blocks start with these tokens and end with crc;
* on error, read tokens act like a subset of R2_SPI_* values.
*/
/* single block write multiblock read */
@ -70,6 +71,20 @@ struct mmc_spi_priv {
struct spi_slave *spi;
};
/**
* mmc_spi_sendcmd() - send a command to the SD card
*
* @dev: mmc_spi device
* @cmdidx: command index
* @cmdarg: command argument
* @resp_type: card response type
* @resp: buffer to store the card response
* @resp_size: size of the card response
* @resp_match: if true, compare each of received bytes with @resp_match_value
* @resp_match_value: a value to be compared with each of received bytes
* @r1b: if true, receive additional bytes for busy signal token
* @return 0 if OK, -ETIMEDOUT if no card response is received, -ve on error
*/
static int mmc_spi_sendcmd(struct udevice *dev,
ushort cmdidx, u32 cmdarg, u32 resp_type,
u8 *resp, u32 resp_size,
@ -159,6 +174,15 @@ static int mmc_spi_sendcmd(struct udevice *dev,
return 0;
}
/**
* mmc_spi_readdata() - read data block(s) from the SD card
*
* @dev: mmc_spi device
* @xbuf: buffer of the actual data (excluding token and crc) to read
* @bcnt: number of data blocks to transfer
* @bsize: size of the actual data (excluding token and crc) in bytes
* @return 0 if OK, -ECOMM if crc error, -ETIMEDOUT on other errors
*/
static int mmc_spi_readdata(struct udevice *dev,
void *xbuf, u32 bcnt, u32 bsize)
{
@ -207,6 +231,16 @@ static int mmc_spi_readdata(struct udevice *dev,
return ret;
}
/**
* mmc_spi_writedata() - write data block(s) to the SD card
*
* @dev: mmc_spi device
* @xbuf: buffer of the actual data (excluding token and crc) to write
* @bcnt: number of data blocks to transfer
* @bsize: size of actual data (excluding token and crc) in bytes
* @multi: indicate a transfer by multiple block write command (CMD25)
* @return 0 if OK, -ECOMM if crc error, -ETIMEDOUT on other errors
*/
static int mmc_spi_writedata(struct udevice *dev, const void *xbuf,
u32 bcnt, u32 bsize, int multi)
{