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Diffstat (limited to 'drivers/i2c/busses/i2c-axxia.c')
-rw-r--r--drivers/i2c/busses/i2c-axxia.c109
1 files changed, 102 insertions, 7 deletions
diff --git a/drivers/i2c/busses/i2c-axxia.c b/drivers/i2c/busses/i2c-axxia.c
index 35258321e81b..bf564391091f 100644
--- a/drivers/i2c/busses/i2c-axxia.c
+++ b/drivers/i2c/busses/i2c-axxia.c
@@ -12,6 +12,7 @@
*/
#include <linux/clk.h>
#include <linux/clkdev.h>
+#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
@@ -25,6 +26,7 @@
#define I2C_XFER_TIMEOUT (msecs_to_jiffies(250))
#define I2C_STOP_TIMEOUT (msecs_to_jiffies(100))
#define FIFO_SIZE 8
+#define SEQ_LEN 2
#define GLOBAL_CONTROL 0x00
#define GLOBAL_MST_EN BIT(0)
@@ -51,6 +53,7 @@
#define CMD_BUSY (1<<3)
#define CMD_MANUAL (0x00 | CMD_BUSY)
#define CMD_AUTO (0x01 | CMD_BUSY)
+#define CMD_SEQUENCE (0x02 | CMD_BUSY)
#define MST_RX_XFER 0x2c
#define MST_TX_XFER 0x30
#define MST_ADDR_1 0x34
@@ -87,7 +90,9 @@
* axxia_i2c_dev - I2C device context
* @base: pointer to register struct
* @msg: pointer to current message
- * @msg_xfrd: number of bytes transferred in msg
+ * @msg_r: pointer to current read message (sequence transfer)
+ * @msg_xfrd: number of bytes transferred in tx_fifo
+ * @msg_xfrd_r: number of bytes transferred in rx_fifo
* @msg_err: error code for completed message
* @msg_complete: xfer completion object
* @dev: device reference
@@ -98,7 +103,9 @@
struct axxia_i2c_dev {
void __iomem *base;
struct i2c_msg *msg;
+ struct i2c_msg *msg_r;
size_t msg_xfrd;
+ size_t msg_xfrd_r;
int msg_err;
struct completion msg_complete;
struct device *dev;
@@ -227,14 +234,14 @@ static int i2c_m_recv_len(const struct i2c_msg *msg)
*/
static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev)
{
- struct i2c_msg *msg = idev->msg;
+ struct i2c_msg *msg = idev->msg_r;
size_t rx_fifo_avail = readl(idev->base + MST_RX_FIFO);
- int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd);
+ int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd_r);
while (bytes_to_transfer-- > 0) {
int c = readl(idev->base + MST_DATA);
- if (idev->msg_xfrd == 0 && i2c_m_recv_len(msg)) {
+ if (idev->msg_xfrd_r == 0 && i2c_m_recv_len(msg)) {
/*
* Check length byte for SMBus block read
*/
@@ -247,7 +254,7 @@ static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev)
msg->len = 1 + c;
writel(msg->len, idev->base + MST_RX_XFER);
}
- msg->buf[idev->msg_xfrd++] = c;
+ msg->buf[idev->msg_xfrd_r++] = c;
}
return 0;
@@ -287,7 +294,7 @@ static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
}
/* RX FIFO needs service? */
- if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL))
+ if (i2c_m_rd(idev->msg_r) && (status & MST_STATUS_RFL))
axxia_i2c_empty_rx_fifo(idev);
/* TX FIFO needs service? */
@@ -320,9 +327,12 @@ static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
} else if (status & MST_STATUS_SNS) {
/* Transfer done */
i2c_int_disable(idev, ~MST_STATUS_TSS);
- if (i2c_m_rd(idev->msg) && idev->msg_xfrd < idev->msg->len)
+ if (i2c_m_rd(idev->msg_r) && idev->msg_xfrd_r < idev->msg_r->len)
axxia_i2c_empty_rx_fifo(idev);
complete(&idev->msg_complete);
+ } else if (status & MST_STATUS_SS) {
+ /* Auto/Sequence transfer done */
+ complete(&idev->msg_complete);
} else if (status & MST_STATUS_TSS) {
/* Transfer timeout */
idev->msg_err = -ETIMEDOUT;
@@ -363,6 +373,71 @@ static void axxia_i2c_set_addr(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
writel(addr_2, idev->base + MST_ADDR_2);
}
+/* The NAK interrupt will be sent _before_ issuing STOP command
+ * so the controller might still be busy processing it. No
+ * interrupt will be sent at the end so we have to poll for it
+ */
+static int axxia_i2c_handle_seq_nak(struct axxia_i2c_dev *idev)
+{
+ unsigned long timeout = jiffies + I2C_XFER_TIMEOUT;
+
+ do {
+ if ((readl(idev->base + MST_COMMAND) & CMD_BUSY) == 0)
+ return 0;
+ usleep_range(1, 100);
+ } while (time_before(jiffies, timeout));
+
+ return -ETIMEDOUT;
+}
+
+static int axxia_i2c_xfer_seq(struct axxia_i2c_dev *idev, struct i2c_msg msgs[])
+{
+ u32 int_mask = MST_STATUS_ERR | MST_STATUS_SS | MST_STATUS_RFL;
+ u32 rlen = i2c_m_recv_len(&msgs[1]) ? I2C_SMBUS_BLOCK_MAX : msgs[1].len;
+ unsigned long time_left;
+
+ axxia_i2c_set_addr(idev, &msgs[0]);
+
+ writel(msgs[0].len, idev->base + MST_TX_XFER);
+ writel(rlen, idev->base + MST_RX_XFER);
+
+ idev->msg = &msgs[0];
+ idev->msg_r = &msgs[1];
+ idev->msg_xfrd = 0;
+ idev->msg_xfrd_r = 0;
+ axxia_i2c_fill_tx_fifo(idev);
+
+ writel(CMD_SEQUENCE, idev->base + MST_COMMAND);
+
+ reinit_completion(&idev->msg_complete);
+ i2c_int_enable(idev, int_mask);
+
+ time_left = wait_for_completion_timeout(&idev->msg_complete,
+ I2C_XFER_TIMEOUT);
+
+ i2c_int_disable(idev, int_mask);
+
+ axxia_i2c_empty_rx_fifo(idev);
+
+ if (idev->msg_err == -ENXIO) {
+ if (axxia_i2c_handle_seq_nak(idev))
+ axxia_i2c_init(idev);
+ } else if (readl(idev->base + MST_COMMAND) & CMD_BUSY) {
+ dev_warn(idev->dev, "busy after xfer\n");
+ }
+
+ if (time_left == 0) {
+ idev->msg_err = -ETIMEDOUT;
+ i2c_recover_bus(&idev->adapter);
+ axxia_i2c_init(idev);
+ }
+
+ if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO)
+ axxia_i2c_init(idev);
+
+ return idev->msg_err;
+}
+
static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
{
u32 int_mask = MST_STATUS_ERR | MST_STATUS_SNS;
@@ -371,7 +446,9 @@ static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
unsigned int wt_value;
idev->msg = msg;
+ idev->msg_r = msg;
idev->msg_xfrd = 0;
+ idev->msg_xfrd_r = 0;
reinit_completion(&idev->msg_complete);
axxia_i2c_set_addr(idev, msg);
@@ -452,6 +529,18 @@ static int axxia_i2c_stop(struct axxia_i2c_dev *idev)
return 0;
}
+/* This function checks if the msgs[] array contains messages compatible with
+ * Sequence mode of operation. This mode assumes there will be exactly one
+ * write of non-zero length followed by exactly one read of non-zero length,
+ * both targeted at the same client device.
+ */
+static bool axxia_i2c_sequence_ok(struct i2c_msg msgs[], int num)
+{
+ return num == SEQ_LEN && !i2c_m_rd(&msgs[0]) && i2c_m_rd(&msgs[1]) &&
+ msgs[0].len > 0 && msgs[0].len <= FIFO_SIZE &&
+ msgs[1].len > 0 && msgs[0].addr == msgs[1].addr;
+}
+
static int
axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
@@ -460,6 +549,12 @@ axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
int ret = 0;
idev->msg_err = 0;
+
+ if (axxia_i2c_sequence_ok(msgs, num)) {
+ ret = axxia_i2c_xfer_seq(idev, msgs);
+ return ret ? : SEQ_LEN;
+ }
+
i2c_int_enable(idev, MST_STATUS_TSS);
for (i = 0; ret == 0 && i < num; ++i)
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-09 14:03:22 +0000