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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.c49
1 files changed, 41 insertions, 8 deletions
diff --git a/drivers/i2c/busses/i2c-uniphier-f.c b/drivers/i2c/busses/i2c-uniphier-f.c
index dd384743dbbd..03da4a539a2f 100644
--- a/drivers/i2c/busses/i2c-uniphier-f.c
+++ b/drivers/i2c/busses/i2c-uniphier-f.c
@@ -173,8 +173,6 @@ static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id)
"interrupt: enabled_irqs=%04x, irq_status=%04x\n",
priv->enabled_irqs, irq_status);
- uniphier_fi2c_clear_irqs(priv, irq_status);
-
if (irq_status & UNIPHIER_FI2C_INT_STOP)
goto complete;
@@ -214,7 +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)) {
@@ -253,12 +257,20 @@ complete:
}
handled:
+ /*
+ * 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;
}
-static void uniphier_fi2c_tx_init(struct uniphier_fi2c_priv *priv, u16 addr)
+static void uniphier_fi2c_tx_init(struct uniphier_fi2c_priv *priv, u16 addr,
+ bool repeat)
{
priv->enabled_irqs |= UNIPHIER_FI2C_INT_TE;
uniphier_fi2c_set_irqs(priv);
@@ -268,8 +280,12 @@ static void uniphier_fi2c_tx_init(struct uniphier_fi2c_priv *priv, u16 addr)
/* set slave address */
writel(UNIPHIER_FI2C_DTTX_CMD | addr << 1,
priv->membase + UNIPHIER_FI2C_DTTX);
- /* first chunk of data */
- uniphier_fi2c_fill_txfifo(priv, true);
+ /*
+ * First chunk of data. For a repeated START condition, do not write
+ * data to the TX fifo here to avoid the timing issue.
+ */
+ if (!repeat)
+ uniphier_fi2c_fill_txfifo(priv, true);
}
static void uniphier_fi2c_rx_init(struct uniphier_fi2c_priv *priv, u16 addr)
@@ -350,7 +366,7 @@ static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
if (is_read)
uniphier_fi2c_rx_init(priv, msg->addr);
else
- uniphier_fi2c_tx_init(priv, msg->addr);
+ uniphier_fi2c_tx_init(priv, msg->addr, repeat);
dev_dbg(&adap->dev, "start condition\n");
/*
@@ -502,9 +518,26 @@ static void uniphier_fi2c_hw_init(struct uniphier_fi2c_priv *priv)
uniphier_fi2c_reset(priv);
+ /*
+ * Standard-mode: tLOW + tHIGH = 10 us
+ * Fast-mode: tLOW + tHIGH = 2.5 us
+ */
writel(cyc, priv->membase + UNIPHIER_FI2C_CYC);
- writel(cyc / 2, priv->membase + UNIPHIER_FI2C_LCTL);
+ /*
+ * Standard-mode: tLOW = 4.7 us, tHIGH = 4.0 us, tBUF = 4.7 us
+ * Fast-mode: tLOW = 1.3 us, tHIGH = 0.6 us, tBUF = 1.3 us
+ * "tLow/tHIGH = 5/4" meets both.
+ */
+ writel(cyc * 5 / 9, priv->membase + UNIPHIER_FI2C_LCTL);
+ /*
+ * Standard-mode: tHD;STA = 4.0 us, tSU;STA = 4.7 us, tSU;STO = 4.0 us
+ * Fast-mode: tHD;STA = 0.6 us, tSU;STA = 0.6 us, tSU;STO = 0.6 us
+ */
writel(cyc / 2, priv->membase + UNIPHIER_FI2C_SSUT);
+ /*
+ * Standard-mode: tSU;DAT = 250 ns
+ * Fast-mode: tSU;DAT = 100 ns
+ */
writel(cyc / 16, priv->membase + UNIPHIER_FI2C_DSUT);
uniphier_fi2c_prepare_operation(priv);