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-rw-r--r--drivers/i2c/busses/i2c-mpc.c426
1 files changed, 239 insertions, 187 deletions
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index 3c8bcdfff7e7..0a80fafbe6c6 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -58,11 +58,35 @@
#define CSR_MIF 0x02
#define CSR_RXAK 0x01
+enum mpc_i2c_action {
+ MPC_I2C_ACTION_START = 1,
+ MPC_I2C_ACTION_RESTART,
+ MPC_I2C_ACTION_READ_BEGIN,
+ MPC_I2C_ACTION_READ_BYTE,
+ MPC_I2C_ACTION_WRITE,
+ MPC_I2C_ACTION_STOP,
+
+ __MPC_I2C_ACTION_CNT
+};
+
+static const char * const action_str[] = {
+ "invalid",
+ "start",
+ "restart",
+ "read begin",
+ "read",
+ "write",
+ "stop",
+};
+
+static_assert(ARRAY_SIZE(action_str) == __MPC_I2C_ACTION_CNT);
+
struct mpc_i2c {
struct device *dev;
void __iomem *base;
u32 interrupt;
- wait_queue_head_t queue;
+ wait_queue_head_t waitq;
+ spinlock_t lock;
struct i2c_adapter adap;
int irq;
u32 real_clk;
@@ -70,6 +94,16 @@ struct mpc_i2c {
u8 fdr, dfsrr;
#endif
struct clk *clk_per;
+ u32 cntl_bits;
+ enum mpc_i2c_action action;
+ struct i2c_msg *msgs;
+ int num_msgs;
+ int curr_msg;
+ u32 byte_posn;
+ u32 block;
+ int rc;
+ int expect_rxack;
+
};
struct mpc_i2c_divider {
@@ -86,19 +120,6 @@ static inline void writeccr(struct mpc_i2c *i2c, u32 x)
writeb(x, i2c->base + MPC_I2C_CR);
}
-static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
-{
- struct mpc_i2c *i2c = dev_id;
- if (readb(i2c->base + MPC_I2C_SR) & CSR_MIF) {
- /* Read again to allow register to stabilise */
- i2c->interrupt = readb(i2c->base + MPC_I2C_SR);
- writeb(0, i2c->base + MPC_I2C_SR);
- wake_up(&i2c->queue);
- return IRQ_HANDLED;
- }
- return IRQ_NONE;
-}
-
/* Sometimes 9th clock pulse isn't generated, and slave doesn't release
* the bus, because it wants to send ACK.
* Following sequence of enabling/disabling and sending start/stop generates
@@ -121,45 +142,6 @@ static void mpc_i2c_fixup(struct mpc_i2c *i2c)
}
}
-static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
-{
- u32 cmd_err;
- int result;
-
- result = wait_event_timeout(i2c->queue,
- (i2c->interrupt & CSR_MIF), timeout);
-
- if (unlikely(!(i2c->interrupt & CSR_MIF))) {
- dev_dbg(i2c->dev, "wait timeout\n");
- writeccr(i2c, 0);
- result = -ETIMEDOUT;
- }
-
- cmd_err = i2c->interrupt;
- i2c->interrupt = 0;
-
- if (result < 0)
- return result;
-
- if (!(cmd_err & CSR_MCF)) {
- dev_dbg(i2c->dev, "unfinished\n");
- return -EIO;
- }
-
- if (cmd_err & CSR_MAL) {
- dev_dbg(i2c->dev, "MAL\n");
- return -EAGAIN;
- }
-
- if (writing && (cmd_err & CSR_RXAK)) {
- dev_dbg(i2c->dev, "No RXAK\n");
- /* generate stop */
- writeccr(i2c, CCR_MEN);
- return -ENXIO;
- }
- return 0;
-}
-
#if defined(CONFIG_PPC_MPC52xx) || defined(CONFIG_PPC_MPC512x)
static const struct mpc_i2c_divider mpc_i2c_dividers_52xx[] = {
{20, 0x20}, {22, 0x21}, {24, 0x22}, {26, 0x23},
@@ -434,168 +416,209 @@ static void mpc_i2c_setup_8xxx(struct device_node *node,
}
#endif /* CONFIG_FSL_SOC */
-static void mpc_i2c_start(struct mpc_i2c *i2c)
+static void mpc_i2c_finish(struct mpc_i2c *i2c, int rc)
{
- /* Clear arbitration */
- writeb(0, i2c->base + MPC_I2C_SR);
- /* Start with MEN */
- writeccr(i2c, CCR_MEN);
+ i2c->rc = rc;
+ i2c->block = 0;
+ i2c->cntl_bits = CCR_MEN;
+ writeccr(i2c, i2c->cntl_bits);
+ wake_up(&i2c->waitq);
}
-static void mpc_i2c_stop(struct mpc_i2c *i2c)
+static void mpc_i2c_do_action(struct mpc_i2c *i2c)
{
- writeccr(i2c, CCR_MEN);
-}
+ struct i2c_msg *msg = &i2c->msgs[i2c->curr_msg];
+ int dir = 0;
+ int recv_len = 0;
+ u8 byte;
+
+ dev_dbg(i2c->dev, "action = %s\n", action_str[i2c->action]);
+
+ i2c->cntl_bits &= ~(CCR_RSTA | CCR_MTX | CCR_TXAK);
+
+ if (msg->flags & I2C_M_RD)
+ dir = 1;
+ if (msg->flags & I2C_M_RECV_LEN)
+ recv_len = 1;
+
+ switch (i2c->action) {
+ case MPC_I2C_ACTION_RESTART:
+ i2c->cntl_bits |= CCR_RSTA;
+ fallthrough;
+
+ case MPC_I2C_ACTION_START:
+ i2c->cntl_bits |= CCR_MSTA | CCR_MTX;
+ writeccr(i2c, i2c->cntl_bits);
+ writeb((msg->addr << 1) | dir, i2c->base + MPC_I2C_DR);
+ i2c->expect_rxack = 1;
+ i2c->action = dir ? MPC_I2C_ACTION_READ_BEGIN : MPC_I2C_ACTION_WRITE;
+ break;
+
+ case MPC_I2C_ACTION_READ_BEGIN:
+ if (msg->len) {
+ if (msg->len == 1 && !(msg->flags & I2C_M_RECV_LEN))
+ i2c->cntl_bits |= CCR_TXAK;
+
+ writeccr(i2c, i2c->cntl_bits);
+ /* Dummy read */
+ readb(i2c->base + MPC_I2C_DR);
+ }
+ i2c->action = MPC_I2C_ACTION_READ_BYTE;
+ break;
+
+ case MPC_I2C_ACTION_READ_BYTE:
+ if (i2c->byte_posn || !recv_len) {
+ /* Generate Tx ACK on next to last byte */
+ if (i2c->byte_posn == msg->len - 2)
+ i2c->cntl_bits |= CCR_TXAK;
+ /* Do not generate stop on last byte */
+ if (i2c->byte_posn == msg->len - 1)
+ i2c->cntl_bits |= CCR_MTX;
-static int mpc_write(struct mpc_i2c *i2c, int target,
- const u8 *data, int length, int restart)
-{
- int i, result;
- unsigned timeout = i2c->adap.timeout;
- u32 flags = restart ? CCR_RSTA : 0;
+ writeccr(i2c, i2c->cntl_bits);
+ }
- /* Start as master */
- writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
- /* Write target byte */
- writeb((target << 1), i2c->base + MPC_I2C_DR);
+ byte = readb(i2c->base + MPC_I2C_DR);
- result = i2c_wait(i2c, timeout, 1);
- if (result < 0)
- return result;
+ if (i2c->byte_posn == 0 && recv_len) {
+ if (byte == 0 || byte > I2C_SMBUS_BLOCK_MAX) {
+ mpc_i2c_finish(i2c, -EPROTO);
+ return;
+ }
+ msg->len += byte;
+ /*
+ * For block reads, generate Tx ACK here if data length
+ * is 1 byte (total length is 2 bytes).
+ */
+ if (msg->len == 2) {
+ i2c->cntl_bits |= CCR_TXAK;
+ writeccr(i2c, i2c->cntl_bits);
+ }
+ }
+
+ dev_dbg(i2c->dev, "%s %02x\n", action_str[i2c->action], byte);
+ msg->buf[i2c->byte_posn++] = byte;
+ break;
- for (i = 0; i < length; i++) {
- /* Write data byte */
- writeb(data[i], i2c->base + MPC_I2C_DR);
+ case MPC_I2C_ACTION_WRITE:
+ dev_dbg(i2c->dev, "%s %02x\n", action_str[i2c->action],
+ msg->buf[i2c->byte_posn]);
+ writeb(msg->buf[i2c->byte_posn++], i2c->base + MPC_I2C_DR);
+ i2c->expect_rxack = 1;
+ break;
- result = i2c_wait(i2c, timeout, 1);
- if (result < 0)
- return result;
+ case MPC_I2C_ACTION_STOP:
+ mpc_i2c_finish(i2c, 0);
+ break;
+
+ default:
+ WARN(1, "Unexpected action %d\n", i2c->action);
+ break;
}
- return 0;
+ if (msg->len == i2c->byte_posn) {
+ i2c->curr_msg++;
+ i2c->byte_posn = 0;
+
+ if (i2c->curr_msg == i2c->num_msgs) {
+ i2c->action = MPC_I2C_ACTION_STOP;
+ /*
+ * We don't get another interrupt on read so
+ * finish the transfer now
+ */
+ if (dir)
+ mpc_i2c_finish(i2c, 0);
+ } else {
+ i2c->action = MPC_I2C_ACTION_RESTART;
+ }
+ }
}
-static int mpc_read(struct mpc_i2c *i2c, int target,
- u8 *data, int length, int restart, bool recv_len)
+static void mpc_i2c_do_intr(struct mpc_i2c *i2c, u8 status)
{
- unsigned timeout = i2c->adap.timeout;
- int i, result;
- u32 flags = restart ? CCR_RSTA : 0;
+ spin_lock(&i2c->lock);
- /* Switch to read - restart */
- writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
- /* Write target address byte - this time with the read flag set */
- writeb((target << 1) | 1, i2c->base + MPC_I2C_DR);
+ if (!(status & CSR_MCF)) {
+ dev_dbg(i2c->dev, "unfinished\n");
+ mpc_i2c_finish(i2c, -EIO);
+ goto out;
+ }
- result = i2c_wait(i2c, timeout, 1);
- if (result < 0)
- return result;
+ if (status & CSR_MAL) {
+ dev_dbg(i2c->dev, "arbitration lost\n");
+ mpc_i2c_finish(i2c, -EAGAIN);
+ goto out;
+ }
- if (length) {
- if (length == 1 && !recv_len)
- writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
- else
- writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA);
- /* Dummy read */
- readb(i2c->base + MPC_I2C_DR);
+ if (i2c->expect_rxack && (status & CSR_RXAK)) {
+ dev_dbg(i2c->dev, "no Rx ACK\n");
+ mpc_i2c_finish(i2c, -ENXIO);
+ goto out;
}
+ i2c->expect_rxack = 0;
- for (i = 0; i < length; i++) {
- u8 byte;
-
- result = i2c_wait(i2c, timeout, 0);
- if (result < 0)
- return result;
-
- /*
- * For block reads, we have to know the total length (1st byte)
- * before we can determine if we are done.
- */
- if (i || !recv_len) {
- /* Generate txack on next to last byte */
- if (i == length - 2)
- writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA
- | CCR_TXAK);
- /* Do not generate stop on last byte */
- if (i == length - 1)
- writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA
- | CCR_MTX);
- }
+ mpc_i2c_do_action(i2c);
- byte = readb(i2c->base + MPC_I2C_DR);
+out:
+ spin_unlock(&i2c->lock);
+}
- /*
- * Adjust length if first received byte is length.
- * The length is 1 length byte plus actually data length
- */
- if (i == 0 && recv_len) {
- if (byte == 0 || byte > I2C_SMBUS_BLOCK_MAX)
- return -EPROTO;
- length += byte;
- /*
- * For block reads, generate txack here if data length
- * is 1 byte (total length is 2 bytes).
- */
- if (length == 2)
- writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA
- | CCR_TXAK);
- }
- data[i] = byte;
+static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
+{
+ struct mpc_i2c *i2c = dev_id;
+ u8 status;
+
+ status = readb(i2c->base + MPC_I2C_SR);
+ if (status & CSR_MIF) {
+ writeb(0, i2c->base + MPC_I2C_SR);
+ mpc_i2c_do_intr(i2c, status);
+ return IRQ_HANDLED;
}
+ return IRQ_NONE;
+}
- return length;
+static int mpc_i2c_wait_for_completion(struct mpc_i2c *i2c)
+{
+ long time_left;
+
+ time_left = wait_event_timeout(i2c->waitq, !i2c->block, i2c->adap.timeout);
+ if (!time_left)
+ return -ETIMEDOUT;
+ if (time_left < 0)
+ return time_left;
+
+ return 0;
}
-static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+static int mpc_i2c_execute_msg(struct mpc_i2c *i2c)
{
- struct i2c_msg *pmsg;
- int i;
- int ret = 0;
- unsigned long orig_jiffies = jiffies;
- struct mpc_i2c *i2c = i2c_get_adapdata(adap);
+ unsigned long orig_jiffies;
+ unsigned long flags;
+ int ret;
- mpc_i2c_start(i2c);
+ spin_lock_irqsave(&i2c->lock, flags);
- /* Allow bus up to 1s to become not busy */
- while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
- if (signal_pending(current)) {
- dev_dbg(i2c->dev, "Interrupted\n");
- writeccr(i2c, 0);
- return -EINTR;
- }
- if (time_after(jiffies, orig_jiffies + HZ)) {
- u8 status = readb(i2c->base + MPC_I2C_SR);
+ i2c->curr_msg = 0;
+ i2c->rc = 0;
+ i2c->byte_posn = 0;
+ i2c->block = 1;
+ i2c->action = MPC_I2C_ACTION_START;
- dev_dbg(i2c->dev, "timeout\n");
- if ((status & (CSR_MCF | CSR_MBB | CSR_RXAK)) != 0) {
- writeb(status & ~CSR_MAL,
- i2c->base + MPC_I2C_SR);
- i2c_recover_bus(&i2c->adap);
- }
- return -EIO;
- }
- schedule();
- }
+ i2c->cntl_bits = CCR_MEN | CCR_MIEN;
+ writeb(0, i2c->base + MPC_I2C_SR);
+ writeccr(i2c, i2c->cntl_bits);
+
+ mpc_i2c_do_action(i2c);
+
+ spin_unlock_irqrestore(&i2c->lock, flags);
+
+ ret = mpc_i2c_wait_for_completion(i2c);
+ if (ret)
+ i2c->rc = ret;
+
+ if (i2c->rc == -EIO || i2c->rc == -EAGAIN || i2c->rc == -ETIMEDOUT)
+ i2c_recover_bus(&i2c->adap);
- for (i = 0; ret >= 0 && i < num; i++) {
- pmsg = &msgs[i];
- dev_dbg(i2c->dev,
- "Doing %s %d bytes to 0x%02x - %d of %d messages\n",
- pmsg->flags & I2C_M_RD ? "read" : "write",
- pmsg->len, pmsg->addr, i + 1, num);
- if (pmsg->flags & I2C_M_RD) {
- bool recv_len = pmsg->flags & I2C_M_RECV_LEN;
-
- ret = mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i,
- recv_len);
- if (recv_len && ret > 0)
- pmsg->len = ret;
- } else {
- ret =
- mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
- }
- }
- mpc_i2c_stop(i2c); /* Initiate STOP */
orig_jiffies = jiffies;
/* Wait until STOP is seen, allow up to 1 s */
while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
@@ -612,7 +635,35 @@ static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
}
cond_resched();
}
- return (ret < 0) ? ret : num;
+
+ return i2c->rc;
+}
+
+static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+ int rc, ret = num;
+ struct mpc_i2c *i2c = i2c_get_adapdata(adap);
+ int i;
+
+ dev_dbg(i2c->dev, "num = %d\n", num);
+ for (i = 0; i < num; i++)
+ dev_dbg(i2c->dev, " addr = %02x, flags = %02x, len = %d, %*ph\n",
+ msgs[i].addr, msgs[i].flags, msgs[i].len,
+ msgs[i].flags & I2C_M_RD ? 0 : msgs[i].len,
+ msgs[i].buf);
+
+ WARN_ON(i2c->msgs != NULL);
+ i2c->msgs = msgs;
+ i2c->num_msgs = num;
+
+ rc = mpc_i2c_execute_msg(i2c);
+ if (rc < 0)
+ ret = rc;
+
+ i2c->num_msgs = 0;
+ i2c->msgs = NULL;
+
+ return ret;
}
static u32 mpc_functionality(struct i2c_adapter *adap)
@@ -667,7 +718,8 @@ static int fsl_i2c_probe(struct platform_device *op)
i2c->dev = &op->dev; /* for debug and error output */
- init_waitqueue_head(&i2c->queue);
+ init_waitqueue_head(&i2c->waitq);
+ spin_lock_init(&i2c->lock);
i2c->base = devm_platform_ioremap_resource(op, 0);
if (IS_ERR(i2c->base)) {
generated by cgit (git 2.34.1) at 2024-07-02 13:05:44 +0000