Patch "[media] ir-spi: Fix issues with lirc API" has been added to the 4.12-stable tree

This is a note to let you know that I've just added the patch titled

[media] ir-spi: Fix issues with lirc API

to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
ir-spi-fix-issues-with-lirc-api.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Anton Blanchard <[email protected]>
Date: Sat, 6 May 2017 22:00:11 -0300
Subject: [media] ir-spi: Fix issues with lirc API

From: Anton Blanchard <[email protected]>

commit cc20ba4ed8576abfa10a17e81cb4521f474624f0 upstream.

The ir-spi driver has 2 issues which prevents it from working with lirc:

1. The ir-spi driver uses 16 bits of SPI data to create one cycle of the waveform. As such our SPI clock needs to be 16x faster than the carrier frequency.

The driver is inconsistent in how it currently handles this. It initializes it to the carrier frequency:

But the commit message has some example code which initialises it to 16x the carrier frequency:

	val = 608000;
	ret = ioctl(fd, LIRC_SET_SEND_CARRIER, &val);

To maintain compatibility with lirc, always do the frequency adjustment in the driver.

2. lirc presents pulses in microseconds, but the ir-spi driver treats them as cycles of the carrier. Similar to other lirc drivers, do the conversion with DIV_ROUND_CLOSEST().

---
 drivers/media/rc/ir-spi.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

@@ -57,10 +57,13 @@ static int ir_spi_tx(struct rc_dev *dev,
 
 	/* convert the pulse/space signal to raw binary signal */
 	for (i = 0; i < count; i++) {
+		unsigned int periods;
 		int j;
 		u16 val = ((i + 1) % 2) ? idata->pulse : idata->space;
 
-		if (len + buffer[i] >= IR_SPI_MAX_BUFSIZE)
+		periods = DIV_ROUND_CLOSEST(buffer[i] * idata->freq, 1000000);
+
+		if (len + periods >= IR_SPI_MAX_BUFSIZE)
 			return -EINVAL;
 
 		/*

@@ -69,13 +72,13 @@ static int ir_spi_tx(struct rc_dev *dev,
 		 * contain a space duration.
 		 */
 		val = (i % 2) ? idata->space : idata->pulse;
-		for (j = 0; j < buffer[i]; j++)
+		for (j = 0; j < periods; j++)
 			idata->tx_buf[len++] = val;
 	}
 
 	memset(&xfer, 0, sizeof(xfer));
 
-	xfer.speed_hz = idata->freq;
+	xfer.speed_hz = idata->freq * 16;
 	xfer.len = len * sizeof(*idata->tx_buf);
 	xfer.tx_buf = idata->tx_buf;
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.12/ir-spi-fix-issues-with-lirc-api.patch