diff options
| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2018-12-06 12:55:26 +0900 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2018-12-06 23:14:59 +0100 |
| commit | cd8843f541cc0ef057e27f1afba46374bbb84219 (patch) | |
| tree | a110d8df03db4882e4caaeb21460e2407736d786 /drivers/i2c | |
| parent | c2a653deaa81f5a750c0dfcbaf9f8e5195cbe4a5 (diff) | |
| download | linux-cd8843f541cc0ef057e27f1afba46374bbb84219.tar.bz2 | |
i2c: uniphier-f: fill TX-FIFO only in IRQ handler for repeated START
- For a repeated START condition, this controller starts data transfer
immediately after the slave address is written to the TX-FIFO.
- Once the TX-FIFO empty interrupt is asserted, the controller makes
a pause even if additional data are written to the TX-FIFO.
Given those circumstances, the data after a repeated START may not be
transferred if the interrupt is asserted while the TX-FIFO is being
filled up. A more reliable way is to append TX data only in the
interrupt handler.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-uniphier-f.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/i2c/busses/i2c-uniphier-f.c b/drivers/i2c/busses/i2c-uniphier-f.c index fad2b00a8c8c..d8a5db14da79 100644 --- a/drivers/i2c/busses/i2c-uniphier-f.c +++ b/drivers/i2c/busses/i2c-uniphier-f.c @@ -269,7 +269,8 @@ handled: 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); @@ -279,8 +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) @@ -361,7 +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"); /* |