From e8e6b5aae45b269c2fcc14159894901514961161 Mon Sep 17 00:00:00 2001
From: Matthias Reichl <hias@horus.com>
Date: Sun, 11 Oct 2015 15:55:21 +0200
Subject: [PATCH] bcm2835-i2s: Enable MMAP support via a DT property

Code ported from bcm2708-i2s driver in Raspberry Pi tree.

RPi commit 7ee829fd77a30127db5d0b3c7d79b8718166e568 ("bcm2708-i2s:
Enable MMAP support via a DT property and overlay")

The i2s driver used to claim to support MMAP, but that feature was disabled
when some problems were found. Add the ability to enable this feature
through Device Tree, using the i2s-mmap overlay.

See: #1004

Signed-off-by: Matthias Reichl <hias@horus.com>
---
 sound/soc/bcm/bcm2835-i2s.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/sound/soc/bcm/bcm2835-i2s.c
+++ b/sound/soc/bcm/bcm2835-i2s.c
@@ -799,7 +799,7 @@ static const struct snd_soc_component_dr
 	.name		= "bcm2835-i2s-comp",
 };
 
-static const struct snd_pcm_hardware bcm2835_pcm_hardware = {
+static struct snd_pcm_hardware bcm2835_pcm_hardware = {
 	.info			= SNDRV_PCM_INFO_INTERLEAVED |
 				  SNDRV_PCM_INFO_JOINT_DUPLEX,
 	.formats		= SNDRV_PCM_FMTBIT_S16_LE |
@@ -835,6 +835,11 @@ static int bcm2835_i2s_probe(struct plat
 	}
 	dma_reg_base = be32_to_cpup(addr);
 
+	if (of_property_read_bool(pdev->dev.of_node, "brcm,enable-mmap"))
+		bcm2835_pcm_hardware.info |=
+			SNDRV_PCM_INFO_MMAP |
+			SNDRV_PCM_INFO_MMAP_VALID;
+
 	/* Request both ioareas */
 	for (i = 0; i <= 1; i++) {
 		void __iomem *base;
