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Diffstat (limited to 'drivers/i2c/busses/i2c-at91.c')
-rw-r--r--drivers/i2c/busses/i2c-at91.c24
1 files changed, 14 insertions, 10 deletions
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
index f23372669f77..1bb97f658b47 100644
--- a/drivers/i2c/busses/i2c-at91.c
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -38,6 +38,7 @@
#define AT91_I2C_TIMEOUT msecs_to_jiffies(100) /* transfer timeout */
#define AT91_I2C_DMA_THRESHOLD 8 /* enable DMA if transfer size is bigger than this threshold */
#define AUTOSUSPEND_TIMEOUT 2000
+#define AT91_I2C_MAX_ALT_CMD_DATA_SIZE 256
/* AT91 TWI register definitions */
#define AT91_TWI_CR 0x0000 /* Control Register */
@@ -141,6 +142,7 @@ struct at91_twi_dev {
unsigned twi_cwgr_reg;
struct at91_twi_pdata *pdata;
bool use_dma;
+ bool use_alt_cmd;
bool recv_len_abort;
u32 fifo_size;
struct at91_twi_dma dma;
@@ -269,7 +271,7 @@ static void at91_twi_write_next_byte(struct at91_twi_dev *dev)
/* send stop when last byte has been written */
if (--dev->buf_len == 0)
- if (!dev->pdata->has_alt_cmd)
+ if (!dev->use_alt_cmd)
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
dev_dbg(dev->dev, "wrote 0x%x, to go %d\n", *dev->buf, dev->buf_len);
@@ -292,7 +294,7 @@ static void at91_twi_write_data_dma_callback(void *data)
* we just have to enable TXCOMP one.
*/
at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
- if (!dev->pdata->has_alt_cmd)
+ if (!dev->use_alt_cmd)
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
}
@@ -410,7 +412,7 @@ static void at91_twi_read_next_byte(struct at91_twi_dev *dev)
}
/* send stop if second but last byte has been read */
- if (!dev->pdata->has_alt_cmd && dev->buf_len == 1)
+ if (!dev->use_alt_cmd && dev->buf_len == 1)
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
dev_dbg(dev->dev, "read 0x%x, to go %d\n", *dev->buf, dev->buf_len);
@@ -426,7 +428,7 @@ static void at91_twi_read_data_dma_callback(void *data)
dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg[0]),
dev->buf_len, DMA_FROM_DEVICE);
- if (!dev->pdata->has_alt_cmd) {
+ if (!dev->use_alt_cmd) {
/* The last two bytes have to be read without using dma */
dev->buf += dev->buf_len - 2;
dev->buf_len = 2;
@@ -443,7 +445,7 @@ static void at91_twi_read_data_dma(struct at91_twi_dev *dev)
struct dma_chan *chan_rx = dma->chan_rx;
size_t buf_len;
- buf_len = (dev->pdata->has_alt_cmd) ? dev->buf_len : dev->buf_len - 2;
+ buf_len = (dev->use_alt_cmd) ? dev->buf_len : dev->buf_len - 2;
dma->direction = DMA_FROM_DEVICE;
/* Keep in mind that we won't use dma to read the last two bytes */
@@ -651,7 +653,7 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
unsigned start_flags = AT91_TWI_START;
/* if only one byte is to be read, immediately stop transfer */
- if (!has_alt_cmd && dev->buf_len <= 1 &&
+ if (!dev->use_alt_cmd && dev->buf_len <= 1 &&
!(dev->msg->flags & I2C_M_RECV_LEN))
start_flags |= AT91_TWI_STOP;
at91_twi_write(dev, AT91_TWI_CR, start_flags);
@@ -745,7 +747,7 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
int ret;
unsigned int_addr_flag = 0;
struct i2c_msg *m_start = msg;
- bool is_read, use_alt_cmd = false;
+ bool is_read;
dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
@@ -768,14 +770,16 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
at91_twi_write(dev, AT91_TWI_IADR, internal_address);
}
+ dev->use_alt_cmd = false;
is_read = (m_start->flags & I2C_M_RD);
if (dev->pdata->has_alt_cmd) {
- if (m_start->len > 0) {
+ if (m_start->len > 0 &&
+ m_start->len < AT91_I2C_MAX_ALT_CMD_DATA_SIZE) {
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_ACMEN);
at91_twi_write(dev, AT91_TWI_ACR,
AT91_TWI_ACR_DATAL(m_start->len) |
((is_read) ? AT91_TWI_ACR_DIR : 0));
- use_alt_cmd = true;
+ dev->use_alt_cmd = true;
} else {
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_ACMDIS);
}
@@ -784,7 +788,7 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
at91_twi_write(dev, AT91_TWI_MMR,
(m_start->addr << 16) |
int_addr_flag |
- ((!use_alt_cmd && is_read) ? AT91_TWI_MREAD : 0));
+ ((!dev->use_alt_cmd && is_read) ? AT91_TWI_MREAD : 0));
dev->buf_len = m_start->len;
dev->buf = m_start->buf;