From: Masahiro Yamada Date: Thu, 6 Dec 2018 03:55:26 +0000 (+0900) Subject: i2c: uniphier-f: fill TX-FIFO only in IRQ handler for repeated START X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=cd8843f541cc0ef057e27f1afba46374bbb84219;p=openwrt%2Fstaging%2Fblogic.git 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 Signed-off-by: Wolfram Sang --- 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"); /*