diff options
Diffstat (limited to 'drivers/reset/reset-meson-audio-arb.c')
| -rw-r--r-- | drivers/reset/reset-meson-audio-arb.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/drivers/reset/reset-meson-audio-arb.c b/drivers/reset/reset-meson-audio-arb.c new file mode 100644 index 000000000..c53a2185a --- /dev/null +++ b/drivers/reset/reset-meson-audio-arb.c @@ -0,0 +1,169 @@ +// 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; + arb->rstc.owner = THIS_MODULE; + + /* + * 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"); |