Am 04.01.2014 11:55, schrieb Mauro Carvalho Chehab:
> The I2C wait completion/timeout logic currently assumes that
> msleep(5) will wait exaclty 5 ms. This is not true at all,
> as it depends on CONFIG_HZ.
>
> Convert it to use jiffies, in order to not wait for more time
> than needed.
>
> Signed-off-by: Mauro Carvalho Chehab <m.chehab@xxxxxxxxxxx>
> ---
> drivers/media/usb/em28xx/em28xx-i2c.c | 65 ++++++++++++++++++-----------------
> 1 file changed, 34 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/media/usb/em28xx/em28xx-i2c.c b/drivers/media/usb/em28xx/em28xx-i2c.c
> index 9e6a11d01858..9fa7ed51e5b1 100644
> --- a/drivers/media/usb/em28xx/em28xx-i2c.c
> +++ b/drivers/media/usb/em28xx/em28xx-i2c.c
> @@ -26,6 +26,7 @@
> #include <linux/kernel.h>
> #include <linux/usb.h>
> #include <linux/i2c.h>
> +#include <linux/jiffies.h>
>
> #include "em28xx.h"
> #include "tuner-xc2028.h"
> @@ -48,8 +49,8 @@ MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
> */
> static int em2800_i2c_send_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
> {
> + unsigned long timeout = jiffies + msecs_to_jiffies(EM2800_I2C_XFER_TIMEOUT);
> int ret;
> - int write_timeout;
> u8 b2[6];
>
> if (len < 1 || len > 4)
> @@ -74,15 +75,15 @@ static int em2800_i2c_send_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
> return (ret < 0) ? ret : -EIO;
> }
> /* wait for completion */
> - for (write_timeout = EM2800_I2C_XFER_TIMEOUT; write_timeout > 0;
> - write_timeout -= 5) {
> + while (time_is_after_jiffies(timeout)) {
AFAIU, it must be time_is_before_jiffies(timeout).
> ret = dev->em28xx_read_reg(dev, 0x05);
> - if (ret == 0x80 + len - 1) {
> + if (ret == 0x80 + len - 1)
> return len;
> - } else if (ret == 0x94 + len - 1) {
> + if (ret == 0x94 + len - 1) {
> em28xx_warn("R05 returned 0x%02x: I2C timeout", ret);
> return -ENODEV;
> - } else if (ret < 0) {
> + }
> + if (ret < 0) {
> em28xx_warn("failed to get i2c transfer status from bridge register (error=%i)\n",
> ret);
> return ret;
> @@ -99,9 +100,9 @@ static int em2800_i2c_send_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
> */
> static int em2800_i2c_recv_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
> {
> + unsigned long timeout = jiffies + msecs_to_jiffies(EM2800_I2C_XFER_TIMEOUT);
> u8 buf2[4];
> int ret;
> - int read_timeout;
> int i;
>
> if (len < 1 || len > 4)
> @@ -118,15 +119,15 @@ static int em2800_i2c_recv_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
> }
>
> /* wait for completion */
> - for (read_timeout = EM2800_I2C_XFER_TIMEOUT; read_timeout > 0;
> - read_timeout -= 5) {
> + while (time_is_after_jiffies(timeout)) {
The same here...
> ret = dev->em28xx_read_reg(dev, 0x05);
> - if (ret == 0x84 + len - 1) {
> + if (ret == 0x84 + len - 1)
> break;
> - } else if (ret == 0x94 + len - 1) {
> + if (ret == 0x94 + len - 1) {
> em28xx_warn("R05 returned 0x%02x: I2C timeout", ret);
> return -ENODEV;
> - } else if (ret < 0) {
> + }
> + if (ret < 0) {
> em28xx_warn("failed to get i2c transfer status from bridge register (error=%i)\n",
> ret);
> return ret;
> @@ -170,7 +171,8 @@ static int em2800_i2c_check_for_device(struct em28xx *dev, u8 addr)
> static int em28xx_i2c_send_bytes(struct em28xx *dev, u16 addr, u8 *buf,
> u16 len, int stop)
> {
> - int write_timeout, ret;
> + unsigned long timeout = jiffies + msecs_to_jiffies(EM2800_I2C_XFER_TIMEOUT);
> + int ret;
>
> if (len < 1 || len > 64)
> return -EOPNOTSUPP;
> @@ -193,17 +195,18 @@ static int em28xx_i2c_send_bytes(struct em28xx *dev, u16 addr, u8 *buf,
> }
> }
>
> - /* Check success of the i2c operation */
> - for (write_timeout = EM2800_I2C_XFER_TIMEOUT; write_timeout > 0;
> - write_timeout -= 5) {
> + /* wait for completion */
> + while (time_is_after_jiffies(timeout)) {
... and here.
> ret = dev->em28xx_read_reg(dev, 0x05);
> - if (ret == 0) { /* success */
> + if (ret == 0) /* success */
> return len;
> - } else if (ret == 0x10) {
> - em28xx_warn("I2C transfer timeout on writing to addr 0x%02x", addr);
> + if (ret == 0x10) {
> + em28xx_warn("I2C transfer timeout on writing to addr 0x%02x",
> + addr);
> return -ENODEV;
> - } else if (ret < 0) {
> - em28xx_warn("failed to read i2c transfer status from bridge (error=%i)\n",
> + }
> + if (ret < 0) {
> + em28xx_warn("failed to get i2c transfer status from bridge register (error=%i)\n",
> ret);
> return ret;
> }
> @@ -214,6 +217,7 @@ static int em28xx_i2c_send_bytes(struct em28xx *dev, u16 addr, u8 *buf,
> * (even with high payload) ...
> */
> }
> +
> em28xx_warn("write to i2c device at 0x%x timed out\n", addr);
> return -EIO;
> }
> @@ -251,21 +255,20 @@ static int em28xx_i2c_recv_bytes(struct em28xx *dev, u16 addr, u8 *buf, u16 len)
>
> /* Check success of the i2c operation */
> ret = dev->em28xx_read_reg(dev, 0x05);
> + if (ret == 0) /* success */
> + return len;
> if (ret < 0) {
> - em28xx_warn("failed to read i2c transfer status from bridge (error=%i)\n",
> + em28xx_warn("failed to get i2c transfer status from bridge register (error=%i)\n",
> ret);
> return ret;
> }
> - if (ret > 0) {
> - if (ret == 0x10) {
> - em28xx_warn("I2C transfer timeout on read from addr 0x%02x", addr);
> - return -ENODEV;
> - } else {
> - em28xx_warn("unknown i2c error (status=%i)\n", ret);
> - return -EIO;
> - }
> + if (ret == 0x10) {
> + em28xx_warn("I2C transfer timeout on read from addr 0x%02x", addr);
> + return -ENODEV;
> }
> - return len;
> +
> + em28xx_warn("unknown i2c error (status=%i)\n", ret);
> + return -EIO;
> }
>
> /*
--
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