[PATCH] ARM: OMAP: i2c-omap: Fix support for OMAP15xx

Current implementation of omap_i2c_isr doesn't work on OMAP5910 (Too
much work in one IRQ). Interrupt service routine is broken in these
aspects:
* it tries to ack interrupt by writing to read-only status register.
* it doesn't ackowledge interrupt properly by reading interrupt vector
  register.
I'm assuming that driver works correctly on other OMAPs (right? ;-)), so
proposed patch adds interrupt service routine for 15xx cpus and deletes
rev1 stuff from omap_i2c_isr. Tested on OMAP5910 with DS1339 clock on
I2C bus.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 5572e5d467b5474a3903ae5202d2a57991133c71..b0210730c02e482356e66131646f8642a92b0300 100644 (file)
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -429,6 +429,60 @@ omap_i2c_ack_stat(struct omap_i2c_dev *dev, u16 stat)
        omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
 }
 
+#ifdef CONFIG_ARCH_OMAP15XX
+static irqreturn_t
+omap_i2c_rev1_isr(int this_irq, void *dev_id, struct pt_regs *regs)
+{
+       struct omap_i2c_dev *dev = dev_id;
+       u16 iv, w;
+
+       iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
+       switch (iv) {
+       case 0x00:      /* None */
+               break;
+       case 0x01:      /* Arbitration lost */
+               dev_err(dev->dev, "Arbitration lost\n");
+               omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
+               break;
+       case 0x02:      /* No acknowledgement */
+               omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
+               omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_STP);
+               break;
+       case 0x03:      /* Register access ready */
+               omap_i2c_complete_cmd(dev, 0);
+               break;
+       case 0x04:      /* Receive data ready */
+               if (dev->buf_len) {
+                       w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
+                       *dev->buf++ = w;
+                       dev->buf_len--;
+                       if (dev->buf_len) {
+                               *dev->buf++ = w >> 8;
+                               dev->buf_len--;
+                       }
+               } else
+                       dev_err(dev->dev, "RRDY IRQ while no data requested\n");
+               break;
+       case 0x05:      /* Transmit data ready */
+               if (dev->buf_len) {
+                       w = *dev->buf++;
+                       dev->buf_len--;
+                       if (dev->buf_len) {
+                               w |= *dev->buf++ << 8;
+                               dev->buf_len--;
+                       }
+                       omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
+               } else
+                       dev_err(dev->dev, "XRDY IRQ while no data to send\n");
+               break;
+       default:
+               return IRQ_NONE;
+       }
+
+       return IRQ_HANDLED;
+}
+#endif
+
 static irqreturn_t
 omap_i2c_isr(int this_irq, void *dev_id, struct pt_regs *regs)
 {
@@ -436,7 +490,6 @@ omap_i2c_isr(int this_irq, void *dev_id, struct pt_regs *regs)
        u16 bits;
        u16 stat, w;
        int count = 0;
-       u16 iv_read;
 
        bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
        while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) {
@@ -450,8 +503,6 @@ omap_i2c_isr(int this_irq, void *dev_id, struct pt_regs *regs)
 
                if (stat & OMAP_I2C_STAT_ARDY) {
                        omap_i2c_complete_cmd(dev, 0);
-                       if (dev->rev1)
-                               iv_read = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
                        continue;
                }
                if (stat & OMAP_I2C_STAT_RRDY) {
@@ -463,13 +514,9 @@ omap_i2c_isr(int this_irq, void *dev_id, struct pt_regs *regs)
                                        *dev->buf++ = w >> 8;
                                        dev->buf_len--;
                                }
-                               if (dev->rev1 && !dev->buf_len)
-                                       omap_i2c_complete_cmd(dev, 0);
                        } else
                                dev_err(dev->dev, "RRDY IRQ while no data requested\n");
                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RRDY);
-                       if (dev->rev1)
-                               iv_read = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
                        continue;
                }
                if (stat & OMAP_I2C_STAT_XRDY) {
@@ -493,11 +540,6 @@ omap_i2c_isr(int this_irq, void *dev_id, struct pt_regs *regs)
 #endif
                        omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_XRDY);
-                       if (dev->rev1) {
-                               iv_read = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
-                               if (!dev->buf_len)
-                                       omap_i2c_complete_cmd(dev, 0);
-                       }
                        if (bail_out)
                                omap_i2c_complete_cmd(dev, 1 << 15);
                        continue;
@@ -518,8 +560,6 @@ omap_i2c_isr(int this_irq, void *dev_id, struct pt_regs *regs)
                        dev_err(dev->dev, "Arbitration lost\n");
                        omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
                }
-               if (dev->rev1)
-                       iv_read = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
        }
 
        return count ? IRQ_HANDLED : IRQ_NONE;
@@ -591,8 +631,12 @@ omap_i2c_probe(struct platform_device *pdev)
        /* reset ASAP, clearing any IRQs */
        omap_i2c_reset(dev);
 
-       r = request_irq(dev->irq, omap_i2c_isr, 0,
-                       driver_name, dev);
+#ifdef CONFIG_ARCH_OMAP15XX
+       r = request_irq(dev->irq, dev->rev1 ? omap_i2c_rev1_isr : omap_i2c_isr,
+                       0, driver_name, dev);
+#else
+       r = request_irq(dev->irq, omap_i2c_isr, 0, driver_name, dev);
+#endif
        if (r) {
                dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
                goto do_unuse_clocks;