Patch for I2C transmit overflow error

[linux-2.6-omap-h63xx.git] / drivers / i2c / busses / i2c-omap.c

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 4777466437e15397a771fbe56dd9e3bf38abc379..3c4e5816156c6efd2f7b835421bb84ef1e00ea74 100644 (file)
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -160,7 +160,7 @@ static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
        return __raw_readw(i2c_dev->base + reg);
 }
 
-static int omap_i2c_get_clocks(struct omap_i2c_dev *dev)
+static int __init omap_i2c_get_clocks(struct omap_i2c_dev *dev)
 {
        if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
                dev->iclk = clk_get(dev->dev, "i2c_ick");
@@ -209,22 +209,28 @@ static void omap_i2c_unidle(struct omap_i2c_dev *dev)
        if (dev->iclk != NULL)
                clk_enable(dev->iclk);
        clk_enable(dev->fclk);
+       dev->idle = 0;
        if (dev->iestate)
                omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
-       dev->idle = 0;
 }
 
 static void omap_i2c_idle(struct omap_i2c_dev *dev)
 {
        u16 iv;
 
-       dev->idle = 1;
        dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
        omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0);
        if (dev->rev1)
                iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
        else
                omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate);
+       /*
+        * The wmb() is to ensure that the I2C interrupt mask write
+        * reaches the I2C controller before the dev->idle store
+        * occurs.
+        */
+       wmb();
+       dev->idle = 1;
        clk_disable(dev->fclk);
        if (dev->iclk != NULL)
                clk_disable(dev->iclk);
@@ -529,6 +535,9 @@ omap_i2c_ack_stat(struct omap_i2c_dev *dev, u16 stat)
        omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
 }
 
+/* rev1 devices are apparently only on some 15xx */
+#ifdef CONFIG_ARCH_OMAP15XX
+
 static irqreturn_t
 omap_i2c_rev1_isr(int this_irq, void *dev_id)
 {
@@ -583,6 +592,9 @@ omap_i2c_rev1_isr(int this_irq, void *dev_id)
 
        return IRQ_HANDLED;
 }
+#else
+#define omap_i2c_rev1_isr              0
+#endif
 
 static irqreturn_t
 omap_i2c_isr(int this_irq, void *dev_id)
@@ -590,7 +602,7 @@ omap_i2c_isr(int this_irq, void *dev_id)
        struct omap_i2c_dev *dev = dev_id;
        u16 bits;
        u16 stat, w;
-       int count = 0;
+       int err, count = 0;
 
        if (dev->idle)
                return IRQ_NONE;
@@ -605,10 +617,19 @@ omap_i2c_isr(int this_irq, void *dev_id)
 
                omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
 
-               if (stat & OMAP_I2C_STAT_ARDY) {
-                       omap_i2c_complete_cmd(dev, 0);
-                       continue;
+               err = 0;
+               if (stat & OMAP_I2C_STAT_NACK) {
+                       err |= OMAP_I2C_STAT_NACK;
+                       omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
+                                          OMAP_I2C_CON_STP);
                }
+               if (stat & OMAP_I2C_STAT_AL) {
+                       dev_err(dev->dev, "Arbitration lost\n");
+                       err |= OMAP_I2C_STAT_AL;
+               }
+               if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK |
+                                       OMAP_I2C_STAT_AL))
+                       omap_i2c_complete_cmd(dev, err);
                if (stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR)) {
                        u8 num_bytes = 1;
                        if (dev->fifo_size) {
@@ -681,18 +702,9 @@ omap_i2c_isr(int this_irq, void *dev_id)
                        dev->cmd_err |= OMAP_I2C_STAT_ROVR;
                }
                if (stat & OMAP_I2C_STAT_XUDF) {
-                       dev_err(dev->dev, "Transmit overflow\n");
+                       dev_err(dev->dev, "Transmit underflow\n");
                        dev->cmd_err |= OMAP_I2C_STAT_XUDF;
                }
-               if (stat & OMAP_I2C_STAT_NACK) {
-                       omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
-                       omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
-                                          OMAP_I2C_CON_STP);
-               }
-               if (stat & OMAP_I2C_STAT_AL) {
-                       dev_err(dev->dev, "Arbitration lost\n");
-                       omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
-               }
        }
 
        return count ? IRQ_HANDLED : IRQ_NONE;
@@ -703,7 +715,7 @@ static const struct i2c_algorithm omap_i2c_algo = {
        .functionality  = omap_i2c_func,
 };
 
-static int
+static int __init
 omap_i2c_probe(struct platform_device *pdev)
 {
        struct omap_i2c_dev     *dev;
@@ -846,14 +858,14 @@ static struct platform_driver omap_i2c_driver = {
 };
 
 /* I2C may be needed to bring up other drivers */
-static int __init
+static int __devinit
 omap_i2c_init_driver(void)
 {
        return platform_driver_register(&omap_i2c_driver);
 }
 subsys_initcall(omap_i2c_init_driver);
 
-static void __exit omap_i2c_exit_driver(void)
+static void __devexit omap_i2c_exit_driver(void)
 {
        platform_driver_unregister(&omap_i2c_driver);
 }
@@ -862,3 +874,4 @@ module_exit(omap_i2c_exit_driver);
 MODULE_AUTHOR("MontaVista Software, Inc. (and others)");
 MODULE_DESCRIPTION("TI OMAP I2C bus adapter");
 MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:i2c_omap");