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Subject[PATCH v2 2/2] reset: meson: add meson audio arb driver
Date
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>
---
drivers/reset/Kconfig | 7 ++
drivers/reset/Makefile | 1 +
drivers/reset/reset-meson-audio-arb.c | 168 ++++++++++++++++++++++++++++++++++
3 files changed, 176 insertions(+)
create mode 100644 drivers/reset/reset-meson-audio-arb.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index c0b292be1b72..782dc59b3855 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 c1261dcfe9ad..aca2240b48aa 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_SIMPLE) += reset-simple.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");
--
2.14.4
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