From 8661ab5b23d6d30d8687fc05bc1dba8f9a64b444 Mon Sep 17 00:00:00 2001
From: Shengjiu Wang <shengjiu.wang@nxp.com>
Date: Fri, 16 Aug 2019 01:03:14 -0400
Subject: [PATCH] ASoC: imx-audmux: Add driver suspend and resume to support MEGA Fast
Git-commit: 8661ab5b23d6d30d8687fc05bc1dba8f9a64b444
Patch-mainline: v5.4-rc1
References: jsc#SLE-16518

For i.MX6 SoloX, there is a mode of the SoC to shutdown all power
source of modules during system suspend and resume procedure.
Thus, AUDMUX needs to save all the values of registers before the
system suspend and restore them after the system resume.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://lore.kernel.org/r/1565931794-7218-1-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 sound/soc/fsl/imx-audmux.c | 54 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 53 insertions(+), 1 deletion(-)

diff --git a/sound/soc/fsl/imx-audmux.c b/sound/soc/fsl/imx-audmux.c
index b2351cd33b0f..16ede3b5cb32 100644
--- a/sound/soc/fsl/imx-audmux.c
+++ b/sound/soc/fsl/imx-audmux.c
@@ -23,6 +23,8 @@
 
 static struct clk *audmux_clk;
 static void __iomem *audmux_base;
+static u32 *regcache;
+static u32 reg_max;
 
 #define IMX_AUDMUX_V2_PTCR(x)		((x) * 8)
 #define IMX_AUDMUX_V2_PDCR(x)		((x) * 8 + 4)
@@ -317,8 +319,23 @@ static int imx_audmux_probe(struct platform_device *pdev)
 	if (of_id)
 		pdev->id_entry = of_id->data;
 	audmux_type = pdev->id_entry->driver_data;
-	if (audmux_type == IMX31_AUDMUX)
+
+	switch (audmux_type) {
+	case IMX31_AUDMUX:
 		audmux_debugfs_init();
+		reg_max = 14;
+		break;
+	case IMX21_AUDMUX:
+		reg_max = 6;
+		break;
+	default:
+		dev_err(&pdev->dev, "unsupported version!\n");
+		return -EINVAL;
+	}
+
+	regcache = devm_kzalloc(&pdev->dev, sizeof(u32) * reg_max, GFP_KERNEL);
+	if (!regcache)
+		return -ENOMEM;
 
 	if (of_id)
 		imx_audmux_parse_dt_defaults(pdev, pdev->dev.of_node);
@@ -334,12 +351,47 @@ static int imx_audmux_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int imx_audmux_suspend(struct device *dev)
+{
+	int i;
+
+	clk_prepare_enable(audmux_clk);
+
+	for (i = 0; i < reg_max; i++)
+		regcache[i] = readl(audmux_base + i * 4);
+
+	clk_disable_unprepare(audmux_clk);
+
+	return 0;
+}
+
+static int imx_audmux_resume(struct device *dev)
+{
+	int i;
+
+	clk_prepare_enable(audmux_clk);
+
+	for (i = 0; i < reg_max; i++)
+		writel(regcache[i], audmux_base + i * 4);
+
+	clk_disable_unprepare(audmux_clk);
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops imx_audmux_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(imx_audmux_suspend, imx_audmux_resume)
+};
+
 static struct platform_driver imx_audmux_driver = {
 	.probe		= imx_audmux_probe,
 	.remove		= imx_audmux_remove,
 	.id_table	= imx_audmux_ids,
 	.driver	= {
 		.name	= DRIVER_NAME,
+		.pm = &imx_audmux_pm,
 		.of_match_table = imx_audmux_dt_ids,
 	}
 };
-- 
2.16.4