Merge tag 'reset-for-4.19-2' of git://git.pengutronix.de/git/pza/linux into next/late

Reset controller changes for v4.19, part 2

This adds a single new driver for the Amlogic Meson Audio Memory Arbiter
resets.

* tag 'reset-for-4.19-2' of git://git.pengutronix.de/git/pza/linux:
  reset: meson: add meson audio arb driver
  reset: meson: add dt-bindings for meson-axg audio arb

Signed-off-by: Olof Johansson <olof@lixom.net>

5 files changed, 214 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/reset/amlogic,meson-axg-audio-arb.txt b/Documentation/devicetree/bindings/reset/amlogic,meson-axg-audio-arb.txt
new file mode 100644
index 000000000000..26e542eb96df
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/amlogic,meson-axg-audio-arb.txt
@@ -0,0 +1,21 @@
+* Amlogic audio memory arbiter controller
+
+The Amlogic Audio ARB is a simple device which enables or
+disables the access of Audio FIFOs to DDR on AXG based SoC.
+
+Required properties:
+- compatible: 'amlogic,meson-axg-audio-arb'
+- reg: physical base address of the controller and length of memory
+       mapped region.
+- clocks: phandle to the fifo peripheral clock provided by the audio
+          clock controller.
+- #reset-cells: must be 1.
+
+Example on the A113 SoC:
+
+arb: reset-controller@280 {
+        compatible = "amlogic,meson-axg-audio-arb";
+        reg = <0x0 0x280 0x0 0x4>;
+        #reset-cells = <1>;
+        clocks = <&clkc_audio AUD_CLKID_DDR_ARB>;
+};
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index a70262cb7e56..13d28fdbdbb5 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -73,6 +73,13 @@ config RESET_MESON
         help
           This enables the reset driver for Amlogic Meson SoCs.
 
+config RESET_MESON_AUDIO_ARB
+        tristate "Meson Audio Memory Arbiter Reset Driver"
+        depends on ARCH_MESON || COMPILE_TEST
+        help
+          This enables the reset driver for Audio Memory Arbiter of
+          Amlogic's A113 based SoCs
+
 config RESET_OXNAS
         bool
 
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 0676b6b1976f..4243c38228e2 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
 obj-$(CONFIG_RESET_LANTIQ) += reset-lantiq.o
 obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o
 obj-$(CONFIG_RESET_MESON) += reset-meson.o
+obj-$(CONFIG_RESET_MESON_AUDIO_ARB) += reset-meson-audio-arb.o
 obj-$(CONFIG_RESET_OXNAS) += reset-oxnas.o
 obj-$(CONFIG_RESET_PISTACHIO) += reset-pistachio.o
 obj-$(CONFIG_RESET_QCOM_AOSS) += reset-qcom-aoss.o
diff --git a/drivers/reset/reset-meson-audio-arb.c b/drivers/reset/reset-meson-audio-arb.c
new file mode 100644
index 000000000000..91751617b37a
--- /dev/null
+++ b/drivers/reset/reset-meson-audio-arb.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+// Copyright (c) 2018 BayLibre, SAS.
+// Author: Jerome Brunet <jbrunet@baylibre.com>
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/reset-controller.h>
+#include <linux/spinlock.h>
+
+#include <dt-bindings/reset/amlogic,meson-axg-audio-arb.h>
+
+struct meson_audio_arb_data {
+        struct reset_controller_dev rstc;
+        void __iomem *regs;
+        struct clk *clk;
+        const unsigned int *reset_bits;
+        spinlock_t lock;
+};
+
+#define ARB_GENERAL_BIT 31
+
+static const unsigned int axg_audio_arb_reset_bits[] = {
+        [AXG_ARB_TODDR_A]       = 0,
+        [AXG_ARB_TODDR_B]       = 1,
+        [AXG_ARB_TODDR_C]       = 2,
+        [AXG_ARB_FRDDR_A]       = 4,
+        [AXG_ARB_FRDDR_B]       = 5,
+        [AXG_ARB_FRDDR_C]       = 6,
+};
+
+static int meson_audio_arb_update(struct reset_controller_dev *rcdev,
+                                  unsigned long id, bool assert)
+{
+        u32 val;
+        struct meson_audio_arb_data *arb =
+                container_of(rcdev, struct meson_audio_arb_data, rstc);
+
+        spin_lock(&arb->lock);
+        val = readl(arb->regs);
+
+        if (assert)
+                val &= ~BIT(arb->reset_bits[id]);
+        else
+                val |= BIT(arb->reset_bits[id]);
+
+        writel(val, arb->regs);
+        spin_unlock(&arb->lock);
+
+        return 0;
+}
+
+static int meson_audio_arb_status(struct reset_controller_dev *rcdev,
+                                  unsigned long id)
+{
+        u32 val;
+        struct meson_audio_arb_data *arb =
+                container_of(rcdev, struct meson_audio_arb_data, rstc);
+
+        val = readl(arb->regs);
+
+        return !(val & BIT(arb->reset_bits[id]));
+}
+
+static int meson_audio_arb_assert(struct reset_controller_dev *rcdev,
+                                  unsigned long id)
+{
+        return meson_audio_arb_update(rcdev, id, true);
+}
+
+static int meson_audio_arb_deassert(struct reset_controller_dev *rcdev,
+                                    unsigned long id)
+{
+        return meson_audio_arb_update(rcdev, id, false);
+}
+
+static const struct reset_control_ops meson_audio_arb_rstc_ops = {
+        .assert = meson_audio_arb_assert,
+        .deassert = meson_audio_arb_deassert,
+        .status = meson_audio_arb_status,
+};
+
+static const struct of_device_id meson_audio_arb_of_match[] = {
+        { .compatible = "amlogic,meson-axg-audio-arb", },
+        {}
+};
+MODULE_DEVICE_TABLE(of, meson_audio_arb_of_match);
+
+static int meson_audio_arb_remove(struct platform_device *pdev)
+{
+        struct meson_audio_arb_data *arb = platform_get_drvdata(pdev);
+
+        /* Disable all access */
+        spin_lock(&arb->lock);
+        writel(0, arb->regs);
+        spin_unlock(&arb->lock);
+
+        clk_disable_unprepare(arb->clk);
+
+        return 0;
+}
+
+static int meson_audio_arb_probe(struct platform_device *pdev)
+{
+        struct device *dev = &pdev->dev;
+        struct meson_audio_arb_data *arb;
+        struct resource *res;
+        int ret;
+
+        arb = devm_kzalloc(dev, sizeof(*arb), GFP_KERNEL);
+        if (!arb)
+                return -ENOMEM;
+        platform_set_drvdata(pdev, arb);
+
+        arb->clk = devm_clk_get(dev, NULL);
+        if (IS_ERR(arb->clk)) {
+                if (PTR_ERR(arb->clk) != -EPROBE_DEFER)
+                        dev_err(dev, "failed to get clock\n");
+                return PTR_ERR(arb->clk);
+        }
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        arb->regs = devm_ioremap_resource(dev, res);
+        if (IS_ERR(arb->regs))
+                return PTR_ERR(arb->regs);
+
+        spin_lock_init(&arb->lock);
+        arb->reset_bits = axg_audio_arb_reset_bits;
+        arb->rstc.nr_resets = ARRAY_SIZE(axg_audio_arb_reset_bits);
+        arb->rstc.ops = &meson_audio_arb_rstc_ops;
+        arb->rstc.of_node = dev->of_node;
+
+        /*
+         * Enable general :
+         * In the initial state, all memory interfaces are disabled
+         * and the general bit is on
+         */
+        ret = clk_prepare_enable(arb->clk);
+        if (ret) {
+                dev_err(dev, "failed to enable arb clock\n");
+                return ret;
+        }
+        writel(BIT(ARB_GENERAL_BIT), arb->regs);
+
+        /* Register reset controller */
+        ret = devm_reset_controller_register(dev, &arb->rstc);
+        if (ret) {
+                dev_err(dev, "failed to register arb reset controller\n");
+                meson_audio_arb_remove(pdev);
+        }
+
+        return ret;
+}
+
+static struct platform_driver meson_audio_arb_pdrv = {
+        .probe = meson_audio_arb_probe,
+        .remove = meson_audio_arb_remove,
+        .driver = {
+                .name = "meson-audio-arb-reset",
+                .of_match_table = meson_audio_arb_of_match,
+        },
+};
+module_platform_driver(meson_audio_arb_pdrv);
+
+MODULE_DESCRIPTION("Amlogic A113 Audio Memory Arbiter");
+MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/dt-bindings/reset/amlogic,meson-axg-audio-arb.h b/include/dt-bindings/reset/amlogic,meson-axg-audio-arb.h
new file mode 100644
index 000000000000..05c36367875c
--- /dev/null
+++ b/include/dt-bindings/reset/amlogic,meson-axg-audio-arb.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR MIT)
+ *
+ * Copyright (c) 2018 Baylibre SAS.
+ * Author: Jerome Brunet <jbrunet@baylibre.com>
+ */
+
+#ifndef _DT_BINDINGS_AMLOGIC_MESON_AXG_AUDIO_ARB_H
+#define _DT_BINDINGS_AMLOGIC_MESON_AXG_AUDIO_ARB_H
+
+#define AXG_ARB_TODDR_A 0
+#define AXG_ARB_TODDR_B 1
+#define AXG_ARB_TODDR_C 2
+#define AXG_ARB_FRDDR_A 3
+#define AXG_ARB_FRDDR_B 4
+#define AXG_ARB_FRDDR_C 5
+
+#endif /* _DT_BINDINGS_AMLOGIC_MESON_AXG_AUDIO_ARB_H */