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Date: Tue, 4 Jun 2024 11:57:07 +0800
From: Shengjiu Wang <shengjiu.wang@...il.com>
To: Marco Felsch <m.felsch@...gutronix.de>
Cc: Shengjiu Wang <shengjiu.wang@....com>, p.zabel@...gutronix.de, abelvesa@...nel.org,
peng.fan@....com, mturquette@...libre.com, sboyd@...nel.org, robh@...nel.org,
krzk+dt@...nel.org, conor+dt@...nel.org, shawnguo@...nel.org,
s.hauer@...gutronix.de, kernel@...gutronix.de, festevam@...il.com,
marex@...x.de, linux-clk@...r.kernel.org, imx@...ts.linux.dev,
devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 3/5] reset: imx-aux: Add i.MX auxiliary reset driver
On Thu, May 30, 2024 at 5:06 PM Marco Felsch <m.felsch@...gutronix.de> wrote:
>
> Hi,
>
> On 24-05-30, Shengjiu Wang wrote:
> > Add support for the resets on i.MX8MP Audio Block Control module,
> > which includes the EARC PHY software reset and EARC controller
> > software reset. The reset controller is created using the auxiliary
> > device framework and set up in the clock driver.
> >
> > Signed-off-by: Shengjiu Wang <shengjiu.wang@....com>
> > ---
> > drivers/reset/Kconfig | 8 ++
> > drivers/reset/Makefile | 1 +
> > drivers/reset/reset-imx-aux.c | 217 ++++++++++++++++++++++++++++++++++
> ^
> You make use of the auxiliary bus but this isn't a aux driver, it's the
> i.MX8MP EARC reset driver. According the TRM only the EARC reset bits
> are covered by the AUDIOMIX blk-ctrl.
I am confused. According to below discussion:
https://lore.kernel.org/lkml/b86c83a520f0c45a60249468fa92b1de.sboyd@kernel.org/
Stephen and Conor suggested using auxdev.
Best regards
Shengjiu Wang
>
> > 3 files changed, 226 insertions(+)
> > create mode 100644 drivers/reset/reset-imx-aux.c
> >
> > diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> > index 7112f5932609..38fdf05b326b 100644
> > --- a/drivers/reset/Kconfig
> > +++ b/drivers/reset/Kconfig
> > @@ -91,6 +91,14 @@ config RESET_IMX7
> > help
> > This enables the reset controller driver for i.MX7 SoCs.
> >
> > +config RESET_IMX_AUX
> > + tristate "i.MX Auxiliary Reset Driver"
> ^
> Same applies here
>
> > + depends on CLK_IMX8MP
> > + select AUXILIARY_BUS
> > + default CLK_IMX8MP
> > + help
> > + This enables the auxiliary reset controller driver for i.MX.
> > +
> > config RESET_INTEL_GW
> > bool "Intel Reset Controller Driver"
> > depends on X86 || COMPILE_TEST
> > diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> > index fd8b49fa46fc..f078da14c327 100644
> > --- a/drivers/reset/Makefile
> > +++ b/drivers/reset/Makefile
> > @@ -14,6 +14,7 @@ obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o
> > obj-$(CONFIG_RESET_GPIO) += reset-gpio.o
> > obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
> > obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
> > +obj-$(CONFIG_RESET_IMX_AUX) += reset-imx-aux.o
> > obj-$(CONFIG_RESET_INTEL_GW) += reset-intel-gw.o
> > obj-$(CONFIG_RESET_K210) += reset-k210.o
> > obj-$(CONFIG_RESET_LANTIQ) += reset-lantiq.o
> > diff --git a/drivers/reset/reset-imx-aux.c b/drivers/reset/reset-imx-aux.c
> > new file mode 100644
> > index 000000000000..61c353abc84e
> > --- /dev/null
> > +++ b/drivers/reset/reset-imx-aux.c
> > @@ -0,0 +1,217 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * Copyright 2024 NXP
> > + */
> > +
> > +#include <linux/auxiliary_bus.h>
> > +#include <linux/device.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/reset-controller.h>
> > +
> > +/*
> > + * The reset does not support the feature and corresponding
> > + * values are not valid
> > + */
> > +#define ASSERT_NONE BIT(0)
> > +#define DEASSERT_NONE BIT(1)
> > +#define STATUS_NONE BIT(2)
> > +
> > +/* When set this function is activated by setting(vs clearing) this bit */
> > +#define ASSERT_SET BIT(3)
> > +#define DEASSERT_SET BIT(4)
> > +#define STATUS_SET BIT(5)
> > +
> > +/* The following are the inverse of the above and are added for consistency */
> > +#define ASSERT_CLEAR (0 << 3)
> > +#define DEASSERT_CLEAR (0 << 4)
> > +#define STATUS_CLEAR (0 << 5)
> > +
> > +/**
> > + * struct imx_reset_ctrl - reset control structure
> > + * @assert_offset: reset assert control register offset
> > + * @assert_bit: reset assert bit in the reset assert control register
> > + * @deassert_offset: reset deassert control register offset
> > + * @deassert_bit: reset deassert bit in the reset deassert control register
> > + * @status_offset: reset status register offset
> > + * @status_bit: reset status bit in the reset status register
> > + * @flags: reset flag indicating how the (de)assert and status are handled
> > + */
> > +struct imx_reset_ctrl {
> > + u32 assert_offset;
> > + u32 assert_bit;
> > + u32 deassert_offset;
> > + u32 deassert_bit;
> > + u32 status_offset;
> > + u32 status_bit;
> > + u32 flags;
> > +};
>
> Why do we make it this compicated for an simple EARC module reset? I
> understand that you want to provide a generic driver which can be
> re-used but there is actual no other user and may will get no other user
> in the future too. Therefore I would like to keep it simple at the
> begin and adapt the code on-demand.
>
> Regards,
> Marco
>
> > +struct imx_reset_data {
> > + const struct imx_reset_ctrl *rst_ctrl;
> > + size_t rst_ctrl_num;
> > +};
> > +
> > +struct imx_aux_reset_priv {
> > + struct reset_controller_dev rcdev;
> > + void __iomem *base;
> > + const struct imx_reset_data *data;
> > +};
> > +
> > +static int imx_aux_reset_assert(struct reset_controller_dev *rcdev,
> > + unsigned long id)
> > +{
> > + struct imx_aux_reset_priv *priv = container_of(rcdev,
> > + struct imx_aux_reset_priv, rcdev);
> > + const struct imx_reset_data *data = priv->data;
> > + void __iomem *reg_addr = priv->base;
> > + const struct imx_reset_ctrl *ctrl;
> > + unsigned int mask, value, reg;
> > +
> > + if (id >= data->rst_ctrl_num)
> > + return -EINVAL;
> > +
> > + ctrl = &data->rst_ctrl[id];
> > +
> > + /* assert not supported for this reset */
> > + if (ctrl->flags & ASSERT_NONE)
> > + return -EOPNOTSUPP;
> > +
> > + mask = BIT(ctrl->assert_bit);
> > + value = (ctrl->flags & ASSERT_SET) ? mask : 0x0;
> > +
> > + reg = readl(reg_addr + ctrl->assert_offset);
> > + writel(reg | value, reg_addr + ctrl->assert_offset);
> > +
> > + return 0;
> > +}
> > +
> > +static int imx_aux_reset_deassert(struct reset_controller_dev *rcdev,
> > + unsigned long id)
> > +{
> > + struct imx_aux_reset_priv *priv = container_of(rcdev,
> > + struct imx_aux_reset_priv, rcdev);
> > + const struct imx_reset_data *data = priv->data;
> > + void __iomem *reg_addr = priv->base;
> > + const struct imx_reset_ctrl *ctrl;
> > + unsigned int mask, value, reg;
> > +
> > + if (id >= data->rst_ctrl_num)
> > + return -EINVAL;
> > +
> > + ctrl = &data->rst_ctrl[id];
> > +
> > + /* deassert not supported for this reset */
> > + if (ctrl->flags & DEASSERT_NONE)
> > + return -EOPNOTSUPP;
> > +
> > + mask = BIT(ctrl->deassert_bit);
> > + value = (ctrl->flags & DEASSERT_SET) ? mask : 0x0;
> > +
> > + reg = readl(reg_addr + ctrl->deassert_offset);
> > + writel(reg | value, reg_addr + ctrl->deassert_offset);
> > +
> > + return 0;
> > +}
> > +
> > +static int imx_aux_reset_status(struct reset_controller_dev *rcdev,
> > + unsigned long id)
> > +{
> > + struct imx_aux_reset_priv *priv = container_of(rcdev,
> > + struct imx_aux_reset_priv, rcdev);
> > + const struct imx_reset_data *data = priv->data;
> > + void __iomem *reg_addr = priv->base;
> > + const struct imx_reset_ctrl *ctrl;
> > + unsigned int reset_state;
> > +
> > + if (id >= data->rst_ctrl_num)
> > + return -EINVAL;
> > +
> > + ctrl = &data->rst_ctrl[id];
> > +
> > + /* status not supported for this reset */
> > + if (ctrl->flags & STATUS_NONE)
> > + return -EOPNOTSUPP;
> > +
> > + reset_state = readl(reg_addr + ctrl->status_offset);
> > +
> > + return !(reset_state & BIT(ctrl->status_bit)) ==
> > + !(ctrl->flags & STATUS_SET);
> > +}
> > +
> > +static const struct reset_control_ops imx_aux_reset_ops = {
> > + .assert = imx_aux_reset_assert,
> > + .deassert = imx_aux_reset_deassert,
> > + .status = imx_aux_reset_status,
> > +};
> > +
> > +static int imx_aux_reset_probe(struct auxiliary_device *adev,
> > + const struct auxiliary_device_id *id)
> > +{
> > + struct imx_reset_data *data = (struct imx_reset_data *)(id->driver_data);
> > + struct imx_aux_reset_priv *priv;
> > + struct device *dev = &adev->dev;
> > +
> > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return -ENOMEM;
> > +
> > + priv->rcdev.owner = THIS_MODULE;
> > + priv->rcdev.nr_resets = data->rst_ctrl_num;
> > + priv->rcdev.ops = &imx_aux_reset_ops;
> > + priv->rcdev.of_node = dev->parent->of_node;
> > + priv->rcdev.dev = dev;
> > + priv->rcdev.of_reset_n_cells = 1;
> > + priv->base = of_iomap(dev->parent->of_node, 0);
> > + priv->data = data;
> > +
> > + return devm_reset_controller_register(dev, &priv->rcdev);
> > +}
> > +
> > +#define EARC 0x200
> > +
> > +static const struct imx_reset_ctrl imx8mp_audiomix_rst_ctrl[] = {
> > + {
> > + .assert_offset = EARC,
> > + .assert_bit = 0,
> > + .deassert_offset = EARC,
> > + .deassert_bit = 0,
> > + .flags = ASSERT_CLEAR | DEASSERT_SET | STATUS_NONE,
> > + },
> > + {
> > + .assert_offset = EARC,
> > + .assert_bit = 1,
> > + .deassert_offset = EARC,
> > + .deassert_bit = 1,
> > + .flags = ASSERT_CLEAR | DEASSERT_SET | STATUS_NONE,
> > + },
> > +};
> > +
> > +static const struct imx_reset_data imx8mp_audiomix_rst_data = {
> > + .rst_ctrl = imx8mp_audiomix_rst_ctrl,
> > + .rst_ctrl_num = ARRAY_SIZE(imx8mp_audiomix_rst_ctrl),
> > +};
> > +
> > +static const struct auxiliary_device_id imx_aux_reset_ids[] = {
> > + {
> > + .name = "clk_imx8mp_audiomix.reset",
> > + .driver_data = (kernel_ulong_t)&imx8mp_audiomix_rst_data,
> > + },
> > + { }
> > +};
> > +MODULE_DEVICE_TABLE(auxiliary, imx_aux_reset_ids);
> > +
> > +static struct auxiliary_driver imx_aux_reset_driver = {
> > + .probe = imx_aux_reset_probe,
> > + .id_table = imx_aux_reset_ids,
> > +};
> > +
> > +module_auxiliary_driver(imx_aux_reset_driver);
> > +
> > +MODULE_AUTHOR("Shengjiu Wang <shengjiu.wang@....com>");
> > +MODULE_DESCRIPTION("Freescale i.MX auxiliary reset driver");
> > +MODULE_LICENSE("GPL");
> > --
> > 2.34.1
> >
> >
> >
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