diff options
| -rw-r--r-- | drivers/media/usb/stk1160/stk1160-ac97.c | 39 | ||||
| -rw-r--r-- | drivers/media/usb/stk1160/stk1160-reg.h | 2 | ||||
| -rw-r--r-- | drivers/media/usb/stk1160/stk1160.h | 2 |
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 |