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-rw-r--r--drivers/media/usb/stk1160/stk1160-ac97.c39
-rw-r--r--drivers/media/usb/stk1160/stk1160-reg.h2
-rw-r--r--drivers/media/usb/stk1160/stk1160.h2
3 files changed, 35 insertions, 8 deletions
diff --git a/drivers/media/usb/stk1160/stk1160-ac97.c b/drivers/media/usb/stk1160/stk1160-ac97.c
index 5e9b76edd81c..85f0b84a33b8 100644
--- a/drivers/media/usb/stk1160/stk1160-ac97.c
+++ b/drivers/media/usb/stk1160/stk1160-ac97.c
@@ -23,9 +23,30 @@
*
*/
+#include <linux/delay.h>
+
#include "stk1160.h"
#include "stk1160-reg.h"
+static int stk1160_ac97_wait_transfer_complete(struct stk1160 *dev)
+{
+ unsigned long timeout = jiffies + msecs_to_jiffies(STK1160_AC97_TIMEOUT);
+ u8 value;
+
+ /* Wait for AC97 transfer to complete */
+ while (time_is_after_jiffies(timeout)) {
+ stk1160_read_reg(dev, STK1160_AC97CTL_0, &value);
+
+ if (!(value & (STK1160_AC97CTL_0_CR | STK1160_AC97CTL_0_CW)))
+ return 0;
+
+ usleep_range(50, 100);
+ }
+
+ stk1160_err("AC97 transfer took too long, this should never happen!");
+ return -EBUSY;
+}
+
static void stk1160_write_ac97(struct stk1160 *dev, u16 reg, u16 value)
{
/* Set codec register address */
@@ -35,11 +56,11 @@ static void stk1160_write_ac97(struct stk1160 *dev, u16 reg, u16 value)
stk1160_write_reg(dev, STK1160_AC97_CMD, value & 0xff);
stk1160_write_reg(dev, STK1160_AC97_CMD + 1, (value & 0xff00) >> 8);
- /*
- * Set command write bit to initiate write operation.
- * The bit will be cleared when transfer is done.
- */
+ /* Set command write bit to initiate write operation */
stk1160_write_reg(dev, STK1160_AC97CTL_0, 0x8c);
+
+ /* Wait for command write bit to be cleared */
+ stk1160_ac97_wait_transfer_complete(dev);
}
#ifdef DEBUG
@@ -51,12 +72,14 @@ static u16 stk1160_read_ac97(struct stk1160 *dev, u16 reg)
/* Set codec register address */
stk1160_write_reg(dev, STK1160_AC97_ADDR, reg);
- /*
- * Set command read bit to initiate read operation.
- * The bit will be cleared when transfer is done.
- */
+ /* Set command read bit to initiate read operation */
stk1160_write_reg(dev, STK1160_AC97CTL_0, 0x8b);
+ /* Wait for command read bit to be cleared */
+ if (stk1160_ac97_wait_transfer_complete(dev) < 0)
+ return 0;
+
+
/* Retrieve register value */
stk1160_read_reg(dev, STK1160_AC97_CMD, &vall);
stk1160_read_reg(dev, STK1160_AC97_CMD + 1, &valh);
diff --git a/drivers/media/usb/stk1160/stk1160-reg.h b/drivers/media/usb/stk1160/stk1160-reg.h
index 296a9e712c81..7b08a3cc4504 100644
--- a/drivers/media/usb/stk1160/stk1160-reg.h
+++ b/drivers/media/usb/stk1160/stk1160-reg.h
@@ -122,6 +122,8 @@
/* AC97 Audio Control */
#define STK1160_AC97CTL_0 0x500
#define STK1160_AC97CTL_1 0x504
+#define STK1160_AC97CTL_0_CR BIT(1)
+#define STK1160_AC97CTL_0_CW BIT(2)
/* Use [0:6] bits of register 0x504 to set codec command address */
#define STK1160_AC97_ADDR 0x504
diff --git a/drivers/media/usb/stk1160/stk1160.h b/drivers/media/usb/stk1160/stk1160.h
index e85e12eedcd2..acd1c811db08 100644
--- a/drivers/media/usb/stk1160/stk1160.h
+++ b/drivers/media/usb/stk1160/stk1160.h
@@ -50,6 +50,8 @@
#define STK1160_MAX_INPUT 4
#define STK1160_SVIDEO_INPUT 4
+#define STK1160_AC97_TIMEOUT 50
+
#define STK1160_I2C_TIMEOUT 100
/* TODO: Print helpers

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