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i2c: iproc: Extend I2C read up to 255 bytes

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Add support to allow I2C master read transfer up to 255 bytes.

Signed-off-by: Shreesha Rajashekar <shreesha@broadcom.com>
Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Signed-off-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Shreesha Rajashekar 2019-04-02 18:18:22 -07:00 committed by Wolfram Sang
parent f6ac28d616
commit c24b8d574b
1 changed files with 74 additions and 22 deletions
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96
drivers/i2c/busses/i2c-bcm-iproc.c
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@ -80,6 +80,10 @@
#define I2C_TIMEOUT_MSEC 50000
#define M_TX_RX_FIFO_SIZE 64
#define M_RX_FIFO_MAX_THLD_VALUE (M_TX_RX_FIFO_SIZE - 1)
#define M_RX_MAX_READ_LEN 255
#define M_RX_FIFO_THLD_VALUE 50
enum bus_speed_index {
I2C_SPD_100K = 0,
@ -102,17 +106,39 @@ struct bcm_iproc_i2c_dev {
/* bytes that have been transferred */
unsigned int tx_bytes;
/* bytes that have been read */
unsigned int rx_bytes;
unsigned int thld_bytes;
};
/*
* Can be expanded in the future if more interrupt status bits are utilized
*/
#define ISR_MASK (BIT(IS_M_START_BUSY_SHIFT) | BIT(IS_M_TX_UNDERRUN_SHIFT))
#define ISR_MASK (BIT(IS_M_START_BUSY_SHIFT) | BIT(IS_M_TX_UNDERRUN_SHIFT)\
| BIT(IS_M_RX_THLD_SHIFT))
static void bcm_iproc_i2c_read_valid_bytes(struct bcm_iproc_i2c_dev *iproc_i2c)
{
struct i2c_msg *msg = iproc_i2c->msg;
/* Read valid data from RX FIFO */
while (iproc_i2c->rx_bytes < msg->len) {
if (!((readl(iproc_i2c->base + M_FIFO_CTRL_OFFSET) >> M_FIFO_RX_CNT_SHIFT)
& M_FIFO_RX_CNT_MASK))
break;
msg->buf[iproc_i2c->rx_bytes] =
(readl(iproc_i2c->base + M_RX_OFFSET) >>
M_RX_DATA_SHIFT) & M_RX_DATA_MASK;
iproc_i2c->rx_bytes++;
}
}
static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data)
{
struct bcm_iproc_i2c_dev *iproc_i2c = data;
u32 status = readl(iproc_i2c->base + IS_OFFSET);
u32 tmp;
status &= ISR_MASK;
@ -136,8 +162,6 @@ static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data)
/* mark the last byte */
if (idx == msg->len - 1) {
u32 tmp;
val |= BIT(M_TX_WR_STATUS_SHIFT);
/*
@ -156,6 +180,32 @@ static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data)
iproc_i2c->tx_bytes += tx_bytes;
}
if (status & BIT(IS_M_RX_THLD_SHIFT)) {
struct i2c_msg *msg = iproc_i2c->msg;
u32 bytes_left;
bcm_iproc_i2c_read_valid_bytes(iproc_i2c);
bytes_left = msg->len - iproc_i2c->rx_bytes;
if (bytes_left == 0) {
/* finished reading all data, disable rx thld event */
tmp = readl(iproc_i2c->base + IE_OFFSET);
tmp &= ~BIT(IS_M_RX_THLD_SHIFT);
writel(tmp, iproc_i2c->base + IE_OFFSET);
} else if (bytes_left < iproc_i2c->thld_bytes) {
/* set bytes left as threshold */
tmp = readl(iproc_i2c->base + M_FIFO_CTRL_OFFSET);
tmp &= ~(M_FIFO_RX_THLD_MASK << M_FIFO_RX_THLD_SHIFT);
tmp |= (bytes_left << M_FIFO_RX_THLD_SHIFT);
writel(tmp, iproc_i2c->base + M_FIFO_CTRL_OFFSET);
iproc_i2c->thld_bytes = bytes_left;
}
/*
* bytes_left >= iproc_i2c->thld_bytes,
* hence no need to change the THRESHOLD SET.
* It will remain as iproc_i2c->thld_bytes itself
*/
}
if (status & BIT(IS_M_START_BUSY_SHIFT)) {
iproc_i2c->xfer_is_done = 1;
complete(&iproc_i2c->done);
@ -253,7 +303,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
{
int ret, i;
u8 addr;
u32 val;
u32 val, tmp, val_intr_en;
unsigned int tx_bytes;
unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MSEC);
@ -298,7 +348,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
* transaction is done, i.e., the internal start_busy bit, transitions
* from 1 to 0.
*/
val = BIT(IE_M_START_BUSY_SHIFT);
val_intr_en = BIT(IE_M_START_BUSY_SHIFT);
/*
* If TX data size is larger than the TX FIFO, need to enable TX
@ -307,9 +357,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
*/
if (!(msg->flags & I2C_M_RD) &&
msg->len > iproc_i2c->tx_bytes)
val |= BIT(IE_M_TX_UNDERRUN_SHIFT);
writel(val, iproc_i2c->base + IE_OFFSET);
val_intr_en |= BIT(IE_M_TX_UNDERRUN_SHIFT);
/*
* Now we can activate the transfer. For a read operation, specify the
@ -317,11 +365,27 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
*/
val = BIT(M_CMD_START_BUSY_SHIFT);
if (msg->flags & I2C_M_RD) {
iproc_i2c->rx_bytes = 0;
if (msg->len > M_RX_FIFO_MAX_THLD_VALUE)
iproc_i2c->thld_bytes = M_RX_FIFO_THLD_VALUE;
else
iproc_i2c->thld_bytes = msg->len;
/* set threshold value */
tmp = readl(iproc_i2c->base + M_FIFO_CTRL_OFFSET);
tmp &= ~(M_FIFO_RX_THLD_MASK << M_FIFO_RX_THLD_SHIFT);
tmp |= iproc_i2c->thld_bytes << M_FIFO_RX_THLD_SHIFT;
writel(tmp, iproc_i2c->base + M_FIFO_CTRL_OFFSET);
/* enable the RX threshold interrupt */
val_intr_en |= BIT(IE_M_RX_THLD_SHIFT);
val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) |
(msg->len << M_CMD_RD_CNT_SHIFT);
} else {
val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT);
}
writel(val_intr_en, iproc_i2c->base + IE_OFFSET);
writel(val, iproc_i2c->base + M_CMD_OFFSET);
time_left = wait_for_completion_timeout(&iproc_i2c->done, time_left);
@ -353,17 +417,6 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c,
return ret;
}
/*
* For a read operation, we now need to load the data from FIFO
* into the memory buffer
*/
if (msg->flags & I2C_M_RD) {
for (i = 0; i < msg->len; i++) {
msg->buf[i] = (readl(iproc_i2c->base + M_RX_OFFSET) >>
M_RX_DATA_SHIFT) & M_RX_DATA_MASK;
}
}
return 0;
}
@ -395,9 +448,8 @@ static const struct i2c_algorithm bcm_iproc_algo = {
.functionality = bcm_iproc_i2c_functionality,
};
static const struct i2c_adapter_quirks bcm_iproc_i2c_quirks = {
/* need to reserve one byte in the FIFO for the slave address */
.max_read_len = M_TX_RX_FIFO_SIZE - 1,
static struct i2c_adapter_quirks bcm_iproc_i2c_quirks = {
.max_read_len = M_RX_MAX_READ_LEN,
};
static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *iproc_i2c)