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path: root/drivers/i2c/busses/i2c-uniphier-f.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-uniphier-f.c')
-rw-r--r--drivers/i2c/busses/i2c-uniphier-f.c72
1 files changed, 58 insertions, 14 deletions
diff --git a/drivers/i2c/busses/i2c-uniphier-f.c b/drivers/i2c/busses/i2c-uniphier-f.c
index bc26ec822e26..dd0687e36a47 100644
--- a/drivers/i2c/busses/i2c-uniphier-f.c
+++ b/drivers/i2c/busses/i2c-uniphier-f.c
@@ -98,6 +98,7 @@ struct uniphier_fi2c_priv {
unsigned int flags;
unsigned int busy_cnt;
unsigned int clk_cycle;
+ spinlock_t lock; /* IRQ synchronization */
};
static void uniphier_fi2c_fill_txfifo(struct uniphier_fi2c_priv *priv,
@@ -142,9 +143,10 @@ static void uniphier_fi2c_set_irqs(struct uniphier_fi2c_priv *priv)
writel(priv->enabled_irqs, priv->membase + UNIPHIER_FI2C_IE);
}
-static void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv)
+static void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv,
+ u32 mask)
{
- writel(-1, priv->membase + UNIPHIER_FI2C_IC);
+ writel(mask, priv->membase + UNIPHIER_FI2C_IC);
}
static void uniphier_fi2c_stop(struct uniphier_fi2c_priv *priv)
@@ -162,7 +164,10 @@ static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id)
struct uniphier_fi2c_priv *priv = dev_id;
u32 irq_status;
+ spin_lock(&priv->lock);
+
irq_status = readl(priv->membase + UNIPHIER_FI2C_INT);
+ irq_status &= priv->enabled_irqs;
dev_dbg(&priv->adap.dev,
"interrupt: enabled_irqs=%04x, irq_status=%04x\n",
@@ -207,7 +212,13 @@ static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id)
if (irq_status & (UNIPHIER_FI2C_INT_RF | UNIPHIER_FI2C_INT_RB)) {
uniphier_fi2c_drain_rxfifo(priv);
- if (!priv->len)
+ /*
+ * If the number of bytes to read is multiple of the FIFO size
+ * (msg->len == 8, 16, 24, ...), the INT_RF bit is set a little
+ * earlier than INT_RB. We wait for INT_RB to confirm the
+ * completion of the current message.
+ */
+ if (!priv->len && (irq_status & UNIPHIER_FI2C_INT_RB))
goto data_done;
if (unlikely(priv->flags & UNIPHIER_FI2C_MANUAL_NACK)) {
@@ -230,6 +241,8 @@ static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id)
goto handled;
}
+ spin_unlock(&priv->lock);
+
return IRQ_NONE;
data_done:
@@ -244,7 +257,14 @@ complete:
}
handled:
- uniphier_fi2c_clear_irqs(priv);
+ /*
+ * This controller makes a pause while any bit of the IRQ status is
+ * asserted. Clear the asserted bit to kick the controller just before
+ * exiting the handler.
+ */
+ uniphier_fi2c_clear_irqs(priv, irq_status);
+
+ spin_unlock(&priv->lock);
return IRQ_HANDLED;
}
@@ -252,6 +272,8 @@ handled:
static void uniphier_fi2c_tx_init(struct uniphier_fi2c_priv *priv, u16 addr)
{
priv->enabled_irqs |= UNIPHIER_FI2C_INT_TE;
+ uniphier_fi2c_set_irqs(priv);
+
/* do not use TX byte counter */
writel(0, priv->membase + UNIPHIER_FI2C_TBC);
/* set slave address */
@@ -284,6 +306,8 @@ static void uniphier_fi2c_rx_init(struct uniphier_fi2c_priv *priv, u16 addr)
priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF;
}
+ uniphier_fi2c_set_irqs(priv);
+
/* set slave address with RD bit */
writel(UNIPHIER_FI2C_DTTX_CMD | UNIPHIER_FI2C_DTTX_RD | addr << 1,
priv->membase + UNIPHIER_FI2C_DTTX);
@@ -307,14 +331,16 @@ static void uniphier_fi2c_recover(struct uniphier_fi2c_priv *priv)
}
static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
- struct i2c_msg *msg, bool stop)
+ struct i2c_msg *msg, bool repeat,
+ bool stop)
{
struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
bool is_read = msg->flags & I2C_M_RD;
- unsigned long time_left;
+ unsigned long time_left, flags;
- dev_dbg(&adap->dev, "%s: addr=0x%02x, len=%d, stop=%d\n",
- is_read ? "receive" : "transmit", msg->addr, msg->len, stop);
+ dev_dbg(&adap->dev, "%s: addr=0x%02x, len=%d, repeat=%d, stop=%d\n",
+ is_read ? "receive" : "transmit", msg->addr, msg->len,
+ repeat, stop);
priv->len = msg->len;
priv->buf = msg->buf;
@@ -326,22 +352,36 @@ static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
priv->flags |= UNIPHIER_FI2C_STOP;
reinit_completion(&priv->comp);
- uniphier_fi2c_clear_irqs(priv);
+ uniphier_fi2c_clear_irqs(priv, U32_MAX);
writel(UNIPHIER_FI2C_RST_TBRST | UNIPHIER_FI2C_RST_RBRST,
priv->membase + UNIPHIER_FI2C_RST); /* reset TX/RX FIFO */
+ spin_lock_irqsave(&priv->lock, flags);
+
if (is_read)
uniphier_fi2c_rx_init(priv, msg->addr);
else
uniphier_fi2c_tx_init(priv, msg->addr);
- uniphier_fi2c_set_irqs(priv);
-
dev_dbg(&adap->dev, "start condition\n");
- writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STA,
- priv->membase + UNIPHIER_FI2C_CR);
+ /*
+ * For a repeated START condition, writing a slave address to the FIFO
+ * kicks the controller. So, the UNIPHIER_FI2C_CR register should be
+ * written only for a non-repeated START condition.
+ */
+ if (!repeat)
+ writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STA,
+ priv->membase + UNIPHIER_FI2C_CR);
+
+ spin_unlock_irqrestore(&priv->lock, flags);
time_left = wait_for_completion_timeout(&priv->comp, adap->timeout);
+
+ spin_lock_irqsave(&priv->lock, flags);
+ priv->enabled_irqs = 0;
+ uniphier_fi2c_set_irqs(priv);
+ spin_unlock_irqrestore(&priv->lock, flags);
+
if (!time_left) {
dev_err(&adap->dev, "transaction timeout.\n");
uniphier_fi2c_recover(priv);
@@ -394,6 +434,7 @@ static int uniphier_fi2c_master_xfer(struct i2c_adapter *adap,
struct i2c_msg *msgs, int num)
{
struct i2c_msg *msg, *emsg = msgs + num;
+ bool repeat = false;
int ret;
ret = uniphier_fi2c_check_bus_busy(adap);
@@ -404,9 +445,11 @@ static int uniphier_fi2c_master_xfer(struct i2c_adapter *adap,
/* Emit STOP if it is the last message or I2C_M_STOP is set. */
bool stop = (msg + 1 == emsg) || (msg->flags & I2C_M_STOP);
- ret = uniphier_fi2c_master_xfer_one(adap, msg, stop);
+ ret = uniphier_fi2c_master_xfer_one(adap, msg, repeat, stop);
if (ret)
return ret;
+
+ repeat = !stop;
}
return num;
@@ -546,6 +589,7 @@ static int uniphier_fi2c_probe(struct platform_device *pdev)
priv->clk_cycle = clk_rate / bus_speed;
init_completion(&priv->comp);
+ spin_lock_init(&priv->lock);
priv->adap.owner = THIS_MODULE;
priv->adap.algo = &uniphier_fi2c_algo;
priv->adap.dev.parent = dev;