i2c-pxa: Add polling transfer
Add polling I2C transfer implementation for PXA I2C. This is needed
for cases where I2C transactions have to occur at times interrups are
disabled.
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Acked-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index da3ecf5..2598d29 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -65,6 +65,7 @@
unsigned long iosize;
int irq;
+ int use_pio;
};
#define _IBMR(i2c) ((i2c)->reg_base + 0)
@@ -163,6 +164,7 @@
#define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0)
static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);
+static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id);
static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)
{
@@ -554,6 +556,71 @@
writel(icr, _ICR(i2c));
}
+static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c)
+{
+ /* make timeout the same as for interrupt based functions */
+ long timeout = 2 * DEF_TIMEOUT;
+
+ /*
+ * Wait for the bus to become free.
+ */
+ while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
+ udelay(1000);
+ show_state(i2c);
+ }
+
+ if (timeout <= 0) {
+ show_state(i2c);
+ dev_err(&i2c->adap.dev,
+ "i2c_pxa: timeout waiting for bus free\n");
+ return I2C_RETRY;
+ }
+
+ /*
+ * Set master mode.
+ */
+ writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c));
+
+ return 0;
+}
+
+static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c,
+ struct i2c_msg *msg, int num)
+{
+ unsigned long timeout = 500000; /* 5 seconds */
+ int ret = 0;
+
+ ret = i2c_pxa_pio_set_master(i2c);
+ if (ret)
+ goto out;
+
+ i2c->msg = msg;
+ i2c->msg_num = num;
+ i2c->msg_idx = 0;
+ i2c->msg_ptr = 0;
+ i2c->irqlogidx = 0;
+
+ i2c_pxa_start_message(i2c);
+
+ while (timeout-- && i2c->msg_num > 0) {
+ i2c_pxa_handler(0, i2c);
+ udelay(10);
+ }
+
+ i2c_pxa_stop_message(i2c);
+
+ /*
+ * We place the return code in i2c->msg_idx.
+ */
+ ret = i2c->msg_idx;
+
+out:
+ if (timeout == 0)
+ i2c_pxa_scream_blue_murder(i2c, "timeout");
+
+ return ret;
+}
+
/*
* We are protected by the adapter bus mutex.
*/
@@ -610,6 +677,35 @@
return ret;
}
+static int i2c_pxa_pio_xfer(struct i2c_adapter *adap,
+ struct i2c_msg msgs[], int num)
+{
+ struct pxa_i2c *i2c = adap->algo_data;
+ int ret, i;
+
+ /* If the I2C controller is disabled we need to reset it
+ (probably due to a suspend/resume destroying state). We do
+ this here as we can then avoid worrying about resuming the
+ controller before its users. */
+ if (!(readl(_ICR(i2c)) & ICR_IUE))
+ i2c_pxa_reset(i2c);
+
+ for (i = adap->retries; i >= 0; i--) {
+ ret = i2c_pxa_do_pio_xfer(i2c, msgs, num);
+ if (ret != I2C_RETRY)
+ goto out;
+
+ if (i2c_debug)
+ dev_dbg(&adap->dev, "Retrying transmission\n");
+ udelay(100);
+ }
+ i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
+ ret = -EREMOTEIO;
+ out:
+ i2c_pxa_set_slave(i2c, ret);
+ return ret;
+}
+
/*
* i2c_pxa_master_complete - complete the message and wake up.
*/
@@ -621,7 +717,8 @@
i2c->msg_num = 0;
if (ret)
i2c->msg_idx = ret;
- wake_up(&i2c->wait);
+ if (!i2c->use_pio)
+ wake_up(&i2c->wait);
}
static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr)
@@ -840,6 +937,11 @@
.functionality = i2c_pxa_functionality,
};
+static const struct i2c_algorithm i2c_pxa_pio_algorithm = {
+ .master_xfer = i2c_pxa_pio_xfer,
+ .functionality = i2c_pxa_functionality,
+};
+
static void i2c_pxa_enable(struct platform_device *dev)
{
if (cpu_is_pxa27x()) {
@@ -890,7 +992,6 @@
}
i2c->adap.owner = THIS_MODULE;
- i2c->adap.algo = &i2c_pxa_algorithm;
i2c->adap.retries = 5;
spin_lock_init(&i2c->lock);
@@ -927,20 +1028,26 @@
clk_enable(i2c->clk);
i2c_pxa_enable(dev);
- ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED,
- i2c->adap.name, i2c);
- if (ret)
- goto ereqirq;
+ if (plat) {
+ i2c->adap.class = plat->class;
+ i2c->use_pio = plat->use_pio;
+ }
+
+ if (i2c->use_pio) {
+ i2c->adap.algo = &i2c_pxa_pio_algorithm;
+ } else {
+ i2c->adap.algo = &i2c_pxa_algorithm;
+ ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED,
+ i2c->adap.name, i2c);
+ if (ret)
+ goto ereqirq;
+ }
i2c_pxa_reset(i2c);
i2c->adap.algo_data = i2c;
i2c->adap.dev.parent = &dev->dev;
- if (plat) {
- i2c->adap.class = plat->class;
- }
-
/*
* If "dev->id" is negative we consider it as zero.
* The reason to do so is to avoid sysfs names that only make
@@ -966,7 +1073,8 @@
return 0;
eadapt:
- free_irq(irq, i2c);
+ if (!i2c->use_pio)
+ free_irq(irq, i2c);
ereqirq:
clk_disable(i2c->clk);
i2c_pxa_disable(dev);
@@ -986,7 +1094,8 @@
platform_set_drvdata(dev, NULL);
i2c_del_adapter(&i2c->adap);
- free_irq(i2c->irq, i2c);
+ if (!i2c->use_pio)
+ free_irq(i2c->irq, i2c);
clk_disable(i2c->clk);
clk_put(i2c->clk);