reset: meson: add meson audio arb driver

The Amlogic Audio ARB is a simple device which enables or
disables the access of Audio FIFOs to DDR on AXG based SoC.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index a70262c..13d28fd 100644 (file)
--- 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 0676b6b..4243c38 100644 (file)
--- 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 (file)
index 0000000..9175161
--- /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");