-/*
- * Do 0-length transaction using bit-banging through IIC_DIRECTCNTL register.
- */
-
-/* Wait for SCL and/or SDA to be high */
-static int iic_dc_wait(volatile struct iic_regs *iic, u8 mask)
-{
- unsigned long x = jiffies + HZ / 28 + 2;
- while ((in_8(&iic->directcntl) & mask) != mask){
- if (unlikely(time_after(jiffies, x)))
- return -1;
- cond_resched();
- }
- return 0;
-}
-
-static int iic_smbus_quick(struct ibm_iic_private* dev, const struct i2c_msg* p)
-{
- volatile struct iic_regs* iic = dev->vaddr;
- const struct i2c_timings* t = &timings[dev->fast_mode ? 1 : 0];
- u8 mask, v, sda;
- int i, res;
-
- /* Only 7-bit addresses are supported */
- if (unlikely(p->flags & I2C_M_TEN)){
- DBG("%d: smbus_quick - 10 bit addresses are not supported\n",
- dev->idx);
- return -EINVAL;
- }
-
- DBG("%d: smbus_quick(0x%02x)\n", dev->idx, p->addr);
-
- /* Reset IIC interface */
- out_8(&iic->xtcntlss, XTCNTLSS_SRST);
-
- /* Wait for bus to become free */
- out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
- if (unlikely(iic_dc_wait(iic, DIRCNTL_MSDA | DIRCNTL_MSC)))
- goto err;
- ndelay(t->buf);
-
- /* START */
- out_8(&iic->directcntl, DIRCNTL_SCC);
- sda = 0;
- ndelay(t->hd_sta);
-
- /* Send address */
- v = (u8)((p->addr << 1) | ((p->flags & I2C_M_RD) ? 1 : 0));
- for (i = 0, mask = 0x80; i < 8; ++i, mask >>= 1){
- out_8(&iic->directcntl, sda);
- ndelay(t->low / 2);
- sda = (v & mask) ? DIRCNTL_SDAC : 0;
- out_8(&iic->directcntl, sda);
- ndelay(t->low / 2);
-
- out_8(&iic->directcntl, DIRCNTL_SCC | sda);
- if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
- goto err;
- ndelay(t->high);
- }
-
- /* ACK */
- out_8(&iic->directcntl, sda);
- ndelay(t->low / 2);
- out_8(&iic->directcntl, DIRCNTL_SDAC);
- ndelay(t->low / 2);
- out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
- if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
- goto err;
- res = (in_8(&iic->directcntl) & DIRCNTL_MSDA) ? -EREMOTEIO : 1;
- ndelay(t->high);
-
- /* STOP */
- out_8(&iic->directcntl, 0);
- ndelay(t->low);
- out_8(&iic->directcntl, DIRCNTL_SCC);
- if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
- goto err;
- ndelay(t->su_sto);
- out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
-
- ndelay(t->buf);
-
- DBG("%d: smbus_quick -> %s\n", dev->idx, res ? "NACK" : "ACK");
-out:
- /* Remove reset */
- out_8(&iic->xtcntlss, 0);
-
- /* Reinitialize interface */
- iic_dev_init(dev);
-
- return res;
-err:
- DBG("%d: smbus_quick - bus is stuck\n", dev->idx);
- res = -EREMOTEIO;
- goto out;
-}
-