This applies a few fixes and improvements to the Nomadik I2C
controller:
- Add dynamic clocking so the bus is only clocked when it's
really necessary.
- Support SMBUS emulation, drop other flags that are already
implied from SMBUS emulation.
- Fixups for proper timeouts and delays on the controller.
- Minor coding style and kerneldoc updates.
Acked-by: Srinidhi Kasagar <srinidhi.kasagar@xxxxxxxxxxxxxx>
Signed-off-by: Sundar R Iyer <sundar.iyer@xxxxxxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-nomadik.c | 36 +++++++++++++++++++++---------------
1 files changed, 21 insertions(+), 15 deletions(-)
diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
index 73de8ad..1a3bd22 100644
--- a/drivers/i2c/busses/i2c-nomadik.c
+++ b/drivers/i2c/busses/i2c-nomadik.c
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2009 ST-Ericsson
+ * Copyright (C) 2009 ST-Ericsson SA
* Copyright (C) 2009 STMicroelectronics
*
* I2C master mode controller driver, used in Nomadik 8815
@@ -103,6 +103,9 @@
/* maximum threshold value */
#define MAX_I2C_FIFO_THRESHOLD 15
+/* delay for i2c transfers */
+#define I2C_DELAY 150
+
enum i2c_status {
I2C_NOP,
I2C_ON_GOING,
@@ -118,7 +121,7 @@ enum i2c_operation {
};
/* controller response timeout in ms */
-#define I2C_TIMEOUT_MS 500
+#define I2C_TIMEOUT_MS 2000
/**
* struct i2c_nmk_client - client specific data
@@ -250,6 +253,8 @@ static int init_hw(struct nmk_i2c_dev *dev)
{
int stat;
+ clk_enable(dev->clk);
+
stat = flush_i2c_fifo(dev);
if (stat)
return stat;
@@ -263,6 +268,9 @@ static int init_hw(struct nmk_i2c_dev *dev)
dev->cli.operation = I2C_NO_OPERATION;
+ clk_disable(dev->clk);
+
+ udelay(I2C_DELAY);
return 0;
}
@@ -431,7 +439,6 @@ static int read_i2c(struct nmk_i2c_dev *dev)
(void) init_hw(dev);
status = -ETIMEDOUT;
}
-
return status;
}
@@ -502,9 +509,9 @@ static int write_i2c(struct nmk_i2c_dev *dev)
/**
* nmk_i2c_xfer() - I2C transfer function used by kernel framework
- * @i2c_adap - Adapter pointer to the controller
- * @msgs[] - Pointer to data to be written.
- * @num_msgs - Number of messages to be executed
+ * @i2c_adap: Adapter pointer to the controller
+ * @msgs: Pointer to data to be written.
+ * @num_msgs: Number of messages to be executed
*
* This is the function called by the generic kernel i2c_transfer()
* or i2c_smbus...() API calls. Note that this code is protected by the
@@ -559,6 +566,8 @@ static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
if (status)
return status;
+ clk_enable(dev->clk);
+
/* setup the i2c controller */
setup_i2c_controller(dev);
@@ -591,10 +600,13 @@ static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
dev_err(&dev->pdev->dev, "%s\n",
cause >= ARRAY_SIZE(abort_causes)
? "unknown reason" : abort_causes[cause]);
+ clk_disable(dev->clk);
return status;
}
- mdelay(1);
+ udelay(I2C_DELAY);
}
+ clk_disable(dev->clk);
+
/* return the no. messages processed */
if (status)
return status;
@@ -605,6 +617,7 @@ static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
/**
* disable_interrupts() - disable the interrupts
* @dev: private data of controller
+ * @irq: interrupt number
*/
static int disable_interrupts(struct nmk_i2c_dev *dev, u32 irq)
{
@@ -794,10 +807,7 @@ static irqreturn_t i2c_irq_handler(int irq, void *arg)
static unsigned int nmk_i2c_functionality(struct i2c_adapter *adap)
{
- return I2C_FUNC_I2C
- | I2C_FUNC_SMBUS_BYTE_DATA
- | I2C_FUNC_SMBUS_WORD_DATA
- | I2C_FUNC_SMBUS_I2C_BLOCK;
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm nmk_i2c_algo = {
@@ -857,8 +867,6 @@ static int __devinit nmk_i2c_probe(struct platform_device *pdev)
goto err_no_clk;
}
- clk_enable(dev->clk);
-
adap = &dev->adap;
adap->dev.parent = &pdev->dev;
adap->owner = THIS_MODULE;
@@ -895,7 +903,6 @@ static int __devinit nmk_i2c_probe(struct platform_device *pdev)
return 0;
err_init_hw:
- clk_disable(dev->clk);
err_add_adap:
clk_put(dev->clk);
err_no_clk:
@@ -928,7 +935,6 @@ static int __devexit nmk_i2c_remove(struct platform_device *pdev)
iounmap(dev->virtbase);
if (res)
release_mem_region(res->start, resource_size(res));
- clk_disable(dev->clk);
clk_put(dev->clk);
platform_set_drvdata(pdev, NULL);
kfree(dev);
--
1.6.3.3
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