From 9b27a62d11be1afbccbefddaad39761c8212fd92 Mon Sep 17 00:00:00 2001
From: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Date: Mon, 27 Sep 2021 18:58:05 +0300
Subject: [PATCH] staging: most: dim2: force fcnt=3 on Renesas GEN3
Git-commit: 9b27a62d11be1afbccbefddaad39761c8212fd92
References: git-fixes
Patch-mainline: v5.16-rc1

Per Renesas datasheet, MLBC0 register's fcnt field in the embedded
dim2 module must be never set to value different from 3.

Enforce that, via an optional field in struct dim2_platform_data.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Link: https://lore.kernel.org/r/20210927155804.27877-1-nikita.yoush@cogentembedded.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/staging/most/dim2/dim2.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/most/dim2/dim2.c b/drivers/staging/most/dim2/dim2.c
index 093ef9a2b291..9300040ec84c 100644
--- a/drivers/staging/most/dim2/dim2.c
+++ b/drivers/staging/most/dim2/dim2.c
@@ -108,6 +108,7 @@ struct dim2_hdm {
 struct dim2_platform_data {
 	int (*enable)(struct platform_device *pdev);
 	void (*disable)(struct platform_device *pdev);
+	u8 fcnt;
 };
 
 #define iface_to_hdm(iface) container_of(iface, struct dim2_hdm, most_iface)
@@ -731,7 +732,7 @@ static int dim2_probe(struct platform_device *pdev)
 	struct dim2_hdm *dev;
 	struct resource *res;
 	int ret, i;
-	u8 hal_ret;
+	u8 dev_fcnt, hal_ret;
 	int irq;
 
 	enum { MLB_INT_IDX, AHB0_INT_IDX };
@@ -770,8 +771,14 @@ static int dim2_probe(struct platform_device *pdev)
 
 	dev->disable_platform = pdata ? pdata->disable : NULL;
 
-	dev_info(&pdev->dev, "sync: num of frames per sub-buffer: %u\n", fcnt);
-	hal_ret = dim_startup(dev->io_base, dev->clk_speed, fcnt);
+	if (pdata && pdata->fcnt)
+		dev_fcnt = pdata->fcnt;
+	else
+		dev_fcnt = fcnt;
+
+	dev_info(&pdev->dev, "sync: num of frames per sub-buffer: %u\n",
+		 dev_fcnt);
+	hal_ret = dim_startup(dev->io_base, dev->clk_speed, dev_fcnt);
 	if (hal_ret != DIM_NO_ERROR) {
 		dev_err(&pdev->dev, "dim_startup failed: %d\n", hal_ret);
 		ret = -ENODEV;
@@ -1047,9 +1054,19 @@ static void rcar_m3_disable(struct platform_device *pdev)
 enum dim2_platforms { FSL_MX6, RCAR_H2, RCAR_M3 };
 
 static struct dim2_platform_data plat_data[] = {
-	[FSL_MX6] = { .enable = fsl_mx6_enable, .disable = fsl_mx6_disable },
-	[RCAR_H2] = { .enable = rcar_h2_enable, .disable = rcar_h2_disable },
-	[RCAR_M3] = { .enable = rcar_m3_enable, .disable = rcar_m3_disable },
+	[FSL_MX6] = {
+		.enable = fsl_mx6_enable,
+		.disable = fsl_mx6_disable,
+	},
+	[RCAR_H2] = {
+		.enable = rcar_h2_enable,
+		.disable = rcar_h2_disable,
+	},
+	[RCAR_M3] = {
+		.enable = rcar_m3_enable,
+		.disable = rcar_m3_disable,
+		.fcnt = 3,
+	},
 };
 
 static const struct of_device_id dim2_of_match[] = {
-- 
2.35.3