Commit 82531dfd authored by Ulrich Hecht's avatar Ulrich Hecht Committed by Wolfram Sang
Browse files

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: default avatarUlrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent b8775252

drivers/i2c/busses/i2c-rcar.c

+78 −6
Original line number Diff line number Diff line
@@ -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;
@@ -353,6 +354,8 @@ 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);

	}



	if (!priv->atomic_xfer)

		rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND);

}
@@ -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;
@@ -646,6 +649,7 @@ 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 */

		if (!priv->atomic_xfer)

			rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP);

		priv->flags |= ID_NACK;

		goto out;
@@ -667,6 +671,7 @@ static irqreturn_t rcar_i2c_irq(int irq, struct rcar_i2c_priv *priv, u32 msr) 
	if (priv->flags & ID_DONE) {

		rcar_i2c_write(priv, ICMIER, 0);

		rcar_i2c_write(priv, ICMSR, 0);

		if (!priv->atomic_xfer)

			wake_up(&priv->wait);

	}
@@ -684,6 +689,7 @@ static irqreturn_t rcar_i2c_gen2_irq(int irq, void *ptr) 


	/* Only handle interrupts that are currently enabled */

	msr = rcar_i2c_read(priv, ICMSR);

	if (!priv->atomic_xfer)

		msr &= rcar_i2c_read(priv, ICMIER);



	return rcar_i2c_irq(irq, priv, msr);
@@ -696,6 +702,7 @@ static irqreturn_t rcar_i2c_gen3_irq(int irq, void *ptr) 


	/* Only handle interrupts that are currently enabled */

	msr = rcar_i2c_read(priv, ICMSR);

	if (!priv->atomic_xfer)

		msr &= rcar_i2c_read(priv, ICMIER);



	/*
@@ -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 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap, 
	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,