[PATCH v3 12/13] reset: imx: Add audiomix reset controller support

[Abel Vesa <abel.vesa@nxp.com>]

The imx-mix MFD driver registers some devices, one of which, in case of
audiomix, maps correctly to a reset controller type. This driver registers
a reset controller for that. For now, only the EARC specific resets are added.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
---
 drivers/reset/Kconfig              |   7 +++
 drivers/reset/Makefile             |   1 +
 drivers/reset/reset-imx-audiomix.c | 117 +++++++++++++++++++++++++++++++++++++
 3 files changed, 125 insertions(+)
 create mode 100644 drivers/reset/reset-imx-audiomix.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index d9efbfd..2f8d9b3 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -81,6 +81,13 @@ config RESET_INTEL_GW
 	  Say Y to control the reset signals provided by reset controller.
 	  Otherwise, say N.
 
+config RESET_IMX_AUDIOMIX
+	bool "i.MX Audiomix Reset Driver" if COMPILE_TEST
+	depends on HAS_IOMEM
+	default ARCH_MXC
+	help
+	  This enables the audiomix reset controller driver for i.MX SoCs.
+
 config RESET_LANTIQ
 	bool "Lantiq XWAY Reset Driver" if COMPILE_TEST
 	default SOC_TYPE_XWAY
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 249ed35..cf23d38 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o
 obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
 obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
 obj-$(CONFIG_RESET_INTEL_GW) += reset-intel-gw.o
+obj-$(CONFIG_RESET_IMX_AUDIOMIX) += reset-imx-audiomix.o
 obj-$(CONFIG_RESET_LANTIQ) += reset-lantiq.o
 obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o
 obj-$(CONFIG_RESET_MESON) += reset-meson.o
diff --git a/drivers/reset/reset-imx-audiomix.c b/drivers/reset/reset-imx-audiomix.c
new file mode 100644
index 00000000..9533e41
--- /dev/null
+++ b/drivers/reset/reset-imx-audiomix.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2019 NXP.
+ */
+
+#include <dt-bindings/reset/imx-audiomix-reset.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+
+#define IMX_AUDIOMIX_EARC_CTRL_REG	0x200
+
+#define IMX_AUDIOMIX_EARC_RESET_BIT	0x0
+#define IMX_AUDIOMIX_EARC_PHY_RESET_BIT	0x1
+
+struct imx_audiomix_reset_data {
+	void __iomem *base;
+	struct reset_controller_dev rcdev;
+	spinlock_t lock;
+};
+
+static int imx_audiomix_reset_set(struct reset_controller_dev *rcdev,
+			  unsigned long id, bool assert)
+{
+	struct imx_audiomix_reset_data *drvdata = container_of(rcdev,
+			struct imx_audiomix_reset_data, rcdev);
+	void __iomem *reg_addr = drvdata->base;
+	unsigned long flags;
+	unsigned int offset;
+	u32 reg;
+
+	switch (id) {
+	case IMX_AUDIOMIX_EARC_PHY_RESET:
+		reg_addr += IMX_AUDIOMIX_EARC_CTRL_REG;
+		offset = IMX_AUDIOMIX_EARC_PHY_RESET_BIT;
+		break;
+	case IMX_AUDIOMIX_EARC_RESET:
+		reg_addr += IMX_AUDIOMIX_EARC_CTRL_REG;
+		offset = IMX_AUDIOMIX_EARC_RESET_BIT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (assert) {
+		spin_lock_irqsave(&drvdata->lock, flags);
+		reg = readl(reg_addr);
+		writel(reg & ~BIT(offset), reg_addr);
+		spin_unlock_irqrestore(&drvdata->lock, flags);
+	} else {
+		spin_lock_irqsave(&drvdata->lock, flags);
+		reg = readl(reg_addr);
+		writel(reg | BIT(offset), reg_addr);
+		spin_unlock_irqrestore(&drvdata->lock, flags);
+	}
+
+	return 0;
+}
+
+static int imx_audiomix_reset_assert(struct reset_controller_dev *rcdev,
+			     unsigned long id)
+{
+	return imx_audiomix_reset_set(rcdev, id, true);
+}
+
+static int imx_audiomix_reset_deassert(struct reset_controller_dev *rcdev,
+			       unsigned long id)
+{
+	return imx_audiomix_reset_set(rcdev, id, false);
+}
+
+static const struct reset_control_ops imx_audiomix_reset_ops = {
+	.assert		= imx_audiomix_reset_assert,
+	.deassert	= imx_audiomix_reset_deassert,
+};
+
+static int imx_audiomix_reset_probe(struct platform_device *pdev)
+{
+	struct imx_audiomix_reset_data *drvdata;
+	struct device *dev = &pdev->dev;
+
+	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
+	if (drvdata == NULL)
+		return -ENOMEM;
+
+	drvdata->base = dev_get_drvdata(dev->parent);
+
+	platform_set_drvdata(pdev, drvdata);
+
+	spin_lock_init(&drvdata->lock);
+
+	drvdata->rcdev.owner     = THIS_MODULE;
+	drvdata->rcdev.nr_resets = IMX_AUDIOMIX_RESET_NUM;
+	drvdata->rcdev.ops       = &imx_audiomix_reset_ops;
+	drvdata->rcdev.of_node   = dev->of_node;
+	drvdata->rcdev.dev	 = dev;
+
+	return devm_reset_controller_register(dev, &drvdata->rcdev);
+}
+
+static const struct of_device_id imx_audiomix_reset_dt_ids[] = {
+	{ .compatible = "fsl,imx8mp-audiomix-reset", },
+	{ /* sentinel */ },
+};
+
+static struct platform_driver imx_audiomix_reset_driver = {
+	.probe	= imx_audiomix_reset_probe,
+	.driver = {
+		.name		= KBUILD_MODNAME,
+		.of_match_table	= imx_audiomix_reset_dt_ids,
+	},
+};
+module_platform_driver(imx_audiomix_reset_driver);
-- 
2.7.4