diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index 140e50b7f9f7..a5548ea69ba7 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -265,86 +265,6 @@ static u32 uvc_colorspace(const u8 primaries) return 0; } -/* Simplify a fraction using a simple continued fraction decomposition. The - * idea here is to convert fractions such as 333333/10000000 to 1/30 using - * 32 bit arithmetic only. The algorithm is not perfect and relies upon two - * arbitrary parameters to remove non-significative terms from the simple - * continued fraction decomposition. Using 8 and 333 for n_terms and threshold - * respectively seems to give nice results. - */ -void uvc_simplify_fraction(u32 *numerator, u32 *denominator, - unsigned int n_terms, unsigned int threshold) -{ - u32 *an; - u32 x, y, r; - unsigned int i, n; - - an = kmalloc_array(n_terms, sizeof(*an), GFP_KERNEL); - if (an == NULL) - return; - - /* Convert the fraction to a simple continued fraction. See - * https://mathforum.org/dr.math/faq/faq.fractions.html - * Stop if the current term is bigger than or equal to the given - * threshold. - */ - x = *numerator; - y = *denominator; - - for (n = 0; n < n_terms && y != 0; ++n) { - an[n] = x / y; - if (an[n] >= threshold) { - if (n < 2) - n++; - break; - } - - r = x - an[n] * y; - x = y; - y = r; - } - - /* Expand the simple continued fraction back to an integer fraction. */ - x = 0; - y = 1; - - for (i = n; i > 0; --i) { - r = y; - y = an[i-1] * y + x; - x = r; - } - - *numerator = y; - *denominator = x; - kfree(an); -} - -/* Convert a fraction to a frame interval in 100ns multiples. The idea here is - * to compute numerator / denominator * 10000000 using 32 bit fixed point - * arithmetic only. - */ -u32 uvc_fraction_to_interval(u32 numerator, u32 denominator) -{ - u32 multiplier; - - /* Saturate the result if the operation would overflow. */ - if (denominator == 0 || - numerator/denominator >= ((u32)-1)/10000000) - return (u32)-1; - - /* Divide both the denominator and the multiplier by two until - * numerator * multiplier doesn't overflow. If anyone knows a better - * algorithm please let me know. - */ - multiplier = 10000000; - while (numerator > ((u32)-1)/multiplier) { - multiplier /= 2; - denominator /= 2; - } - - return denominator ? numerator * multiplier / denominator : 0; -} - /* ------------------------------------------------------------------------ * Terminal and unit management */ diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c index 8abd3f554912..0dc2d399a5f2 100644 --- a/drivers/media/usb/uvc/uvc_v4l2.c +++ b/drivers/media/usb/uvc/uvc_v4l2.c @@ -376,7 +376,7 @@ static int uvc_v4l2_get_streamparm(struct uvc_streaming *stream, mutex_unlock(&stream->mutex); denominator = 10000000; - uvc_simplify_fraction(&numerator, &denominator, 8, 333); + v4l2_simplify_fraction(&numerator, &denominator, 8, 333); memset(parm, 0, sizeof(*parm)); parm->type = stream->type; @@ -417,7 +417,7 @@ static int uvc_v4l2_set_streamparm(struct uvc_streaming *stream, else timeperframe = parm->parm.output.timeperframe; - interval = uvc_fraction_to_interval(timeperframe.numerator, + interval = v4l2_fraction_to_interval(timeperframe.numerator, timeperframe.denominator); uvc_trace(UVC_TRACE_FORMAT, "Setting frame interval to %u/%u (%u).\n", timeperframe.numerator, timeperframe.denominator, interval); @@ -471,7 +471,7 @@ static int uvc_v4l2_set_streamparm(struct uvc_streaming *stream, /* Return the actual frame period. */ timeperframe.numerator = probe.dwFrameInterval; timeperframe.denominator = 10000000; - uvc_simplify_fraction(&timeperframe.numerator, + v4l2_simplify_fraction(&timeperframe.numerator, &timeperframe.denominator, 8, 333); if (parm->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) { @@ -1295,7 +1295,7 @@ static int uvc_ioctl_enum_frameintervals(struct file *file, void *fh, fival->discrete.numerator = frame->dwFrameInterval[index]; fival->discrete.denominator = 10000000; - uvc_simplify_fraction(&fival->discrete.numerator, + v4l2_simplify_fraction(&fival->discrete.numerator, &fival->discrete.denominator, 8, 333); } else { fival->type = V4L2_FRMIVAL_TYPE_STEPWISE; @@ -1305,11 +1305,11 @@ static int uvc_ioctl_enum_frameintervals(struct file *file, void *fh, fival->stepwise.max.denominator = 10000000; fival->stepwise.step.numerator = frame->dwFrameInterval[2]; fival->stepwise.step.denominator = 10000000; - uvc_simplify_fraction(&fival->stepwise.min.numerator, + v4l2_simplify_fraction(&fival->stepwise.min.numerator, &fival->stepwise.min.denominator, 8, 333); - uvc_simplify_fraction(&fival->stepwise.max.numerator, + v4l2_simplify_fraction(&fival->stepwise.max.numerator, &fival->stepwise.max.denominator, 8, 333); - uvc_simplify_fraction(&fival->stepwise.step.numerator, + v4l2_simplify_fraction(&fival->stepwise.step.numerator, &fival->stepwise.step.denominator, 8, 333); } diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h index df0584b31c18..ef934b66f2b1 100644 --- a/drivers/media/usb/uvc/uvcvideo.h +++ b/drivers/media/usb/uvc/uvcvideo.h @@ -802,9 +802,6 @@ int uvc_xu_ctrl_query(struct uvc_video_chain *chain, struct uvc_xu_control_query *xqry); /* Utility functions */ -void uvc_simplify_fraction(u32 *numerator, u32 *denominator, - unsigned int n_terms, unsigned int threshold); -u32 uvc_fraction_to_interval(u32 numerator, u32 denominator); struct usb_host_endpoint *uvc_find_endpoint(struct usb_host_interface *alts, u8 epaddr); diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c index b518b92d6d96..94ad051b7628 100644 --- a/drivers/media/v4l2-core/v4l2-common.c +++ b/drivers/media/v4l2-core/v4l2-common.c @@ -444,3 +444,127 @@ int v4l2_s_parm_cap(struct video_device *vdev, return ret; } EXPORT_SYMBOL_GPL(v4l2_s_parm_cap); + +s64 v4l2_get_link_freq(struct v4l2_ctrl_handler *handler, unsigned int mul, + unsigned int div) +{ + struct v4l2_ctrl *ctrl; + s64 freq; + + ctrl = v4l2_ctrl_find(handler, V4L2_CID_LINK_FREQ); + if (ctrl) { + struct v4l2_querymenu qm = { .id = V4L2_CID_LINK_FREQ }; + int ret; + + qm.index = v4l2_ctrl_g_ctrl(ctrl); + + ret = v4l2_querymenu(handler, &qm); + if (ret) + return -ENOENT; + + freq = qm.value; + } else { + if (!mul || !div) + return -ENOENT; + + ctrl = v4l2_ctrl_find(handler, V4L2_CID_PIXEL_RATE); + if (!ctrl) + return -ENOENT; + + freq = div_u64(v4l2_ctrl_g_ctrl_int64(ctrl) * mul, div); + + pr_warn("%s: Link frequency estimated using pixel rate: result might be inaccurate\n", + __func__); + pr_warn("%s: Consider implementing support for V4L2_CID_LINK_FREQ in the transmitter driver\n", + __func__); + } + + return freq > 0 ? freq : -EINVAL; +} +EXPORT_SYMBOL_GPL(v4l2_get_link_freq); + +/* + * Simplify a fraction using a simple continued fraction decomposition. The + * idea here is to convert fractions such as 333333/10000000 to 1/30 using + * 32 bit arithmetic only. The algorithm is not perfect and relies upon two + * arbitrary parameters to remove non-significative terms from the simple + * continued fraction decomposition. Using 8 and 333 for n_terms and threshold + * respectively seems to give nice results. + */ +void v4l2_simplify_fraction(u32 *numerator, u32 *denominator, + unsigned int n_terms, unsigned int threshold) +{ + u32 *an; + u32 x, y, r; + unsigned int i, n; + + an = kmalloc_array(n_terms, sizeof(*an), GFP_KERNEL); + if (an == NULL) + return; + + /* + * Convert the fraction to a simple continued fraction. See + * https://en.wikipedia.org/wiki/Continued_fraction + * Stop if the current term is bigger than or equal to the given + * threshold. + */ + x = *numerator; + y = *denominator; + + for (n = 0; n < n_terms && y != 0; ++n) { + an[n] = x / y; + if (an[n] >= threshold) { + if (n < 2) + n++; + break; + } + + r = x - an[n] * y; + x = y; + y = r; + } + + /* Expand the simple continued fraction back to an integer fraction. */ + x = 0; + y = 1; + + for (i = n; i > 0; --i) { + r = y; + y = an[i-1] * y + x; + x = r; + } + + *numerator = y; + *denominator = x; + kfree(an); +} +EXPORT_SYMBOL_GPL(v4l2_simplify_fraction); + +/* + * Convert a fraction to a frame interval in 100ns multiples. The idea here is + * to compute numerator / denominator * 10000000 using 32 bit fixed point + * arithmetic only. + */ +u32 v4l2_fraction_to_interval(u32 numerator, u32 denominator) +{ + u32 multiplier; + + /* Saturate the result if the operation would overflow. */ + if (denominator == 0 || + numerator/denominator >= ((u32)-1)/10000000) + return (u32)-1; + + /* + * Divide both the denominator and the multiplier by two until + * numerator * multiplier doesn't overflow. If anyone knows a better + * algorithm please let me know. + */ + multiplier = 10000000; + while (numerator > ((u32)-1)/multiplier) { + multiplier /= 2; + denominator /= 2; + } + + return denominator ? numerator * multiplier / denominator : 0; +} +EXPORT_SYMBOL_GPL(v4l2_fraction_to_interval); diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h index cdc87ec61e54..5816b5442a80 100644 --- a/include/media/v4l2-common.h +++ b/include/media/v4l2-common.h @@ -384,4 +384,29 @@ int v4l2_g_parm_cap(struct video_device *vdev, int v4l2_s_parm_cap(struct video_device *vdev, struct v4l2_subdev *sd, struct v4l2_streamparm *a); +/** + * v4l2_get_link_freq - Get link rate from transmitter + * + * @handler: The transmitter's control handler + * @mul: The multiplier between pixel rate and link frequency. Bits per pixel on + * D-PHY, samples per clock on parallel. 0 otherwise. + * @div: The divisor between pixel rate and link frequency. Number of data lanes + * times two on D-PHY, 1 on parallel. 0 otherwise. + * + * This function is intended for obtaining the link frequency from the + * transmitter sub-devices. It returns the link rate, either from the + * V4L2_CID_LINK_FREQ control implemented by the transmitter, or value + * calculated based on the V4L2_CID_PIXEL_RATE implemented by the transmitter. + * + * Returns link frequency on success, otherwise a negative error code: + * -ENOENT: Link frequency or pixel rate control not found + * -EINVAL: Invalid link frequency value + */ +s64 v4l2_get_link_freq(struct v4l2_ctrl_handler *handler, unsigned int mul, + unsigned int div); + +void v4l2_simplify_fraction(u32 *numerator, u32 *denominator, + unsigned int n_terms, unsigned int threshold); +u32 v4l2_fraction_to_interval(u32 numerator, u32 denominator); + #endif /* V4L2_COMMON_H_ */