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SubjectRe: [RFC 10/11] reset: imx: Add audiomix reset controller support
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Hi Abel,

On Tue, 2020-03-03 at 11:03 +0200, Abel Vesa wrote:
> 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>
> Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com>
> ---
> drivers/reset/Kconfig | 7 ++
> drivers/reset/Makefile | 1 +
> drivers/reset/reset-imx-audiomix.c | 122 +++++++++++++++++++++++++
> include/dt-bindings/reset/imx-audiomix-reset.h | 15 +++
> 4 files changed, 145 insertions(+)
> create mode 100644 drivers/reset/reset-imx-audiomix.c
> create mode 100644 include/dt-bindings/reset/imx-audiomix-reset.h
>
> 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..d1c62ef
> --- /dev/null
> +++ b/drivers/reset/reset-imx-audiomix.c
> @@ -0,0 +1,122 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * 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/pm_runtime.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) {
> + pm_runtime_get_sync(rcdev->dev);

This seems wrong. Why is the runtime PM reference count incremented when
a reset is asserted ...

> + 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);
> + pm_runtime_put(rcdev->dev);

... and decremented when a reset is deasserted?

Apart from the runtime PM handling this looks like it could reuse reset-
simple.

> + }
> +
> + 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);
> +
> + pm_runtime_enable(dev);
> +
> + 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);
> diff --git a/include/dt-bindings/reset/imx-audiomix-reset.h b/include/dt-bindings/reset/imx-audiomix-reset.h
> new file mode 100644
> index 00000000..2e26878
> --- /dev/null
> +++ b/include/dt-bindings/reset/imx-audiomix-reset.h
> @@ -0,0 +1,15 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2019 NXP.
> + */
> +
> +#ifndef DT_BINDING_RESET_IMX_AUDIOMIX_H
> +#define DT_BINDING_RESET_IMX_AUDIOMIX_H
> +
> +#define IMX_AUDIOMIX_EARC_RESET 0x0
> +#define IMX_AUDIOMIX_EARC_PHY_RESET 0x1
> +
> +#define IMX_AUDIOMIX_RESET_NUM 2
> +
> +#endif
> +

The imx-audiomix-reset.h change should go into a separate patch,
together with the binding docs for fsl,imx8mp-audiomix-reset.

regards
Philipp

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