i2c: emev2: add slave support

Add I2C slave provider using the generic slave interface.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-emev2.c b/drivers/i2c/busses/i2c-emev2.c
index 192ef6b50c794615b5c699a3e8eef3544f9359b2..96bb4e7490128c9e72e21df107cba70752e3f807 100644 (file)
--- a/drivers/i2c/busses/i2c-emev2.c
+++ b/drivers/i2c/busses/i2c-emev2.c
@@ -71,6 +71,7 @@ struct em_i2c_device {
        struct i2c_adapter adap;
        struct completion msg_done;
        struct clk *sclk;
+       struct i2c_client *slave;
 };
 
 static inline void em_clear_set_bit(struct em_i2c_device *priv, u8 clear, u8 set, u8 reg)
@@ -226,22 +227,131 @@ static int em_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
        return num;
 }
 
+static bool em_i2c_slave_irq(struct em_i2c_device *priv)
+{
+       u8 status, value;
+       enum i2c_slave_event event;
+       int ret;
+
+       if (!priv->slave)
+               return false;
+
+       status = readb(priv->base + I2C_OFS_IICSE0);
+
+       /* Extension code, do not participate */
+       if (status & I2C_BIT_EXC0) {
+               em_clear_set_bit(priv, 0, I2C_BIT_LREL0, I2C_OFS_IICC0);
+               return true;
+       }
+
+       /* Stop detected, we don't know if it's for slave or master */
+       if (status & I2C_BIT_SPD0) {
+               /* Notify slave device */
+               i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value);
+               /* Pretend we did not handle the interrupt */
+               return false;
+       }
+
+       /* Only handle interrupts addressed to us */
+       if (!(status & I2C_BIT_COI0))
+               return false;
+
+       /* Enable stop interrupts */
+       em_clear_set_bit(priv, 0, I2C_BIT_SPIE0, I2C_OFS_IICC0);
+
+       /* Transmission or Reception */
+       if (status & I2C_BIT_TRC0) {
+               if (status & I2C_BIT_ACKD0) {
+                       /* 9 bit interrupt mode */
+                       em_clear_set_bit(priv, 0, I2C_BIT_WTIM0, I2C_OFS_IICC0);
+
+                       /* Send data */
+                       event = status & I2C_BIT_STD0 ?
+                               I2C_SLAVE_READ_REQUESTED :
+                               I2C_SLAVE_READ_PROCESSED;
+                       i2c_slave_event(priv->slave, event, &value);
+                       writeb(value, priv->base + I2C_OFS_IIC0);
+               } else {
+                       /* NACK, stop transmitting */
+                       em_clear_set_bit(priv, 0, I2C_BIT_LREL0, I2C_OFS_IICC0);
+               }
+       } else {
+               /* 8 bit interrupt mode */
+               em_clear_set_bit(priv, I2C_BIT_WTIM0, I2C_BIT_ACKE0,
+                               I2C_OFS_IICC0);
+               em_clear_set_bit(priv, I2C_BIT_WTIM0, I2C_BIT_WREL0,
+                               I2C_OFS_IICC0);
+
+               if (status & I2C_BIT_STD0) {
+                       i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_REQUESTED,
+                                       &value);
+               } else {
+                       /* Recv data */
+                       value = readb(priv->base + I2C_OFS_IIC0);
+                       ret = i2c_slave_event(priv->slave,
+                                       I2C_SLAVE_WRITE_RECEIVED, &value);
+                       if (ret < 0)
+                               em_clear_set_bit(priv, I2C_BIT_ACKE0, 0,
+                                               I2C_OFS_IICC0);
+               }
+       }
+
+       return true;
+}
+
 static irqreturn_t em_i2c_irq_handler(int this_irq, void *dev_id)
 {
        struct em_i2c_device *priv = dev_id;
 
+       if (em_i2c_slave_irq(priv))
+               return IRQ_HANDLED;
+
        complete(&priv->msg_done);
+
        return IRQ_HANDLED;
 }
 
 static u32 em_i2c_func(struct i2c_adapter *adap)
 {
-       return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+       return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SLAVE;
+}
+
+static int em_i2c_reg_slave(struct i2c_client *slave)
+{
+       struct em_i2c_device *priv = i2c_get_adapdata(slave->adapter);
+
+       if (priv->slave)
+               return -EBUSY;
+
+       if (slave->flags & I2C_CLIENT_TEN)
+               return -EAFNOSUPPORT;
+
+       priv->slave = slave;
+
+       /* Set slave address */
+       writeb(slave->addr << 1, priv->base + I2C_OFS_SVA0);
+
+       return 0;
+}
+
+static int em_i2c_unreg_slave(struct i2c_client *slave)
+{
+       struct em_i2c_device *priv = i2c_get_adapdata(slave->adapter);
+
+       WARN_ON(!priv->slave);
+
+       writeb(0, priv->base + I2C_OFS_SVA0);
+
+       priv->slave = NULL;
+
+       return 0;
 }
 
 static struct i2c_algorithm em_i2c_algo = {
        .master_xfer = em_i2c_xfer,
        .functionality = em_i2c_func,
+       .reg_slave      = em_i2c_reg_slave,
+       .unreg_slave    = em_i2c_unreg_slave,
 };
 
 static int em_i2c_probe(struct platform_device *pdev)