From 82531dfdf163319cbeaa969c734ebf8d84456810 Mon Sep 17 00:00:00 2001 From: Ulrich Hecht Date: Fri, 12 Feb 2021 17:45:41 +0100 Subject: [PATCH] i2c: rcar: implement atomic transfers Implements atomic transfers. Tested by rebooting an r8a7790 Lager board after connecting the i2c-rcar controller to the PMIC in arch/arm/boot/dts/r8a7790-lager.dts like so: compatible = "i2c-demux-pinctrl"; pinctrl-names = "default"; pinctrl-0 = <&pmic_irq_pins>; - i2c-parent = <&iic3>, <&i2c3>; + i2c-parent = <&i2c3>, <&iic3>; i2c-bus-name = "i2c-pwr"; #address-cells = <1>; #size-cells = <0>; Signed-off-by: Ulrich Hecht Reviewed-by: Geert Uytterhoeven Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-rcar.c | 84 ++++++++++++++++++++++++++++++++--- 1 file changed, 78 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 12f6d452c0f7..1f0c164f671a 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -141,6 +141,7 @@ struct rcar_i2c_priv { enum dma_data_direction dma_direction; struct reset_control *rstc; + bool atomic_xfer; int irq; struct i2c_client *host_notify_client; @@ -353,7 +354,9 @@ static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv) rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START); rcar_i2c_write(priv, ICMSR, 0); } - rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND); + + if (!priv->atomic_xfer) + rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND); } static void rcar_i2c_next_msg(struct rcar_i2c_priv *priv) @@ -418,7 +421,7 @@ static bool rcar_i2c_dma(struct rcar_i2c_priv *priv) int len; /* Do various checks to see if DMA is feasible at all */ - if (IS_ERR(chan) || msg->len < RCAR_MIN_DMA_LEN || + if (priv->atomic_xfer || IS_ERR(chan) || msg->len < RCAR_MIN_DMA_LEN || !(msg->flags & I2C_M_DMA_SAFE) || (read && priv->flags & ID_P_NO_RXDMA)) return false; @@ -646,7 +649,8 @@ static irqreturn_t rcar_i2c_irq(int irq, struct rcar_i2c_priv *priv, u32 msr) /* Nack */ if (msr & MNR) { /* HW automatically sends STOP after received NACK */ - rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP); + if (!priv->atomic_xfer) + rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP); priv->flags |= ID_NACK; goto out; } @@ -667,7 +671,8 @@ out: if (priv->flags & ID_DONE) { rcar_i2c_write(priv, ICMIER, 0); rcar_i2c_write(priv, ICMSR, 0); - wake_up(&priv->wait); + if (!priv->atomic_xfer) + wake_up(&priv->wait); } return IRQ_HANDLED; @@ -684,7 +689,8 @@ static irqreturn_t rcar_i2c_gen2_irq(int irq, void *ptr) /* Only handle interrupts that are currently enabled */ msr = rcar_i2c_read(priv, ICMSR); - msr &= rcar_i2c_read(priv, ICMIER); + if (!priv->atomic_xfer) + msr &= rcar_i2c_read(priv, ICMIER); return rcar_i2c_irq(irq, priv, msr); } @@ -696,7 +702,8 @@ static irqreturn_t rcar_i2c_gen3_irq(int irq, void *ptr) /* Only handle interrupts that are currently enabled */ msr = rcar_i2c_read(priv, ICMSR); - msr &= rcar_i2c_read(priv, ICMIER); + if (!priv->atomic_xfer) + msr &= rcar_i2c_read(priv, ICMIER); /* * Clear START or STOP immediately, except for REPSTART after read or @@ -804,6 +811,8 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap, int i, ret; long time_left; + priv->atomic_xfer = false; + pm_runtime_get_sync(dev); /* Check bus state before init otherwise bus busy info will be lost */ @@ -858,6 +867,68 @@ out: return ret; } +static int rcar_i2c_master_xfer_atomic(struct i2c_adapter *adap, + struct i2c_msg *msgs, + int num) +{ + struct rcar_i2c_priv *priv = i2c_get_adapdata(adap); + struct device *dev = rcar_i2c_priv_to_dev(priv); + unsigned long j; + bool time_left; + int ret; + + priv->atomic_xfer = true; + + pm_runtime_get_sync(dev); + + /* Check bus state before init otherwise bus busy info will be lost */ + ret = rcar_i2c_bus_barrier(priv); + if (ret < 0) + goto out; + + rcar_i2c_init(priv); + + /* init first message */ + priv->msg = msgs; + priv->msgs_left = num; + priv->flags = (priv->flags & ID_P_MASK) | ID_FIRST_MSG; + rcar_i2c_prepare_msg(priv); + + j = jiffies + num * adap->timeout; + do { + u32 msr = rcar_i2c_read(priv, ICMSR); + + msr &= (rcar_i2c_is_recv(priv) ? RCAR_IRQ_RECV : RCAR_IRQ_SEND) | RCAR_IRQ_STOP; + + if (msr) { + if (priv->devtype < I2C_RCAR_GEN3) + rcar_i2c_gen2_irq(0, priv); + else + rcar_i2c_gen3_irq(0, priv); + } + + time_left = time_before_eq(jiffies, j); + } while (!(priv->flags & ID_DONE) && time_left); + + if (!time_left) { + rcar_i2c_init(priv); + ret = -ETIMEDOUT; + } else if (priv->flags & ID_NACK) { + ret = -ENXIO; + } else if (priv->flags & ID_ARBLOST) { + ret = -EAGAIN; + } else { + ret = num - priv->msgs_left; /* The number of transfer */ + } +out: + pm_runtime_put(dev); + + if (ret < 0 && ret != -ENXIO) + dev_err(dev, "error %d : %x\n", ret, priv->flags); + + return ret; +} + static int rcar_reg_slave(struct i2c_client *slave) { struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter); @@ -922,6 +993,7 @@ static u32 rcar_i2c_func(struct i2c_adapter *adap) static const struct i2c_algorithm rcar_i2c_algo = { .master_xfer = rcar_i2c_master_xfer, + .master_xfer_atomic = rcar_i2c_master_xfer_atomic, .functionality = rcar_i2c_func, .reg_slave = rcar_reg_slave, .unreg_slave = rcar_unreg_slave,