Re: [PATCH] ARC: reset: introduce AXS10x reset driver

From: Philipp Zabel
Date: Fri Aug 11 2017 - 09:46:25 EST


Hi Eugeniy,

On Thu, 2017-08-10 at 19:41 +0300, Eugeniy Paltsev wrote:
> ARC AXS10x boards support custom IP-block which allows to control
> reset signals of selected peripherals. For example DW GMAC, etc...
> This block is controlled via memory-mapped register (AKA CREG) which
> represents up-to 32 reset lines.
>
> As of today only the following lines are used:
> Â- DW GMAC - line 5
>
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>

Could you check if the reset-simple driver that I posted today would
work for you?

> ---
> Â.../bindings/reset/snps,axs10x-reset.txtÂÂÂÂÂÂÂÂÂÂÂ|ÂÂ34 +++++++
> ÂMAINTAINERSÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ|ÂÂÂ6 ++
> Âdrivers/reset/KconfigÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ|ÂÂÂ6 ++
> Âdrivers/reset/MakefileÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ|ÂÂÂ1 +
> Âdrivers/reset/reset-axs10x.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ| 109 +++++++++++++++++++++
> Â5 files changed, 156 insertions(+)
> Âcreate mode 100644 Documentation/devicetree/bindings/reset/snps,axs10x-reset.txt
> Âcreate mode 100644 drivers/reset/reset-axs10x.c
>
> diff --git a/Documentation/devicetree/bindings/reset/snps,axs10x-reset.txt b/Documentation/devicetree/bindings/reset/snps,axs10x-reset.txt
> new file mode 100644
> index 0000000..32eed7a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/reset/snps,axs10x-reset.txt
> @@ -0,0 +1,34 @@
> +Binding for the AXS10x reset controller
> +
> +This binding describes the ARC AXS10x boards custom IP-block which allows
> +to control reset signals of selected peripherals. For example DW GMAC, etc...
> +This block is controlled via memory-mapped register (AKA CREG) which
> +represents up-to 32 reset lines.
> +
> +As of today only the following lines are used:
> + - DW GMAC - line 5
> +
> +This binding uses the common reset binding[1].
> +
> +[1] Documentation/devicetree/bindings/reset/reset.txt
> +
> +Required properties:
> +- compatible: should be "snps,axs10x-reset".
> +- reg: should always contain pair address - length: for creg reset
> +ÂÂbits register.
> +- #reset-cells: from common reset binding; Should always be set to 1.
> +
> +Example:
> > > + reset: reset@11220 {

The node name should be reset-controller for consistency with the other
bindings. Other than that, the binding description looks good to me.

> + compatible = "snps,axs10x-reset";
> + #reset-cells = <1>;
> + reg = <0x11220 0x4>;
+ };
> +
> +Specifying reset lines connected to IP modules:
> + ethernet@.... {
> + ....
> + resets = <&reset 5>;
> + ....
> + };
> +
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 93dfb9d..f14e804 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12711,6 +12711,12 @@ F: arch/arc/plat-axs10x
> ÂF: arch/arc/boot/dts/ax*
> ÂF: Documentation/devicetree/bindings/arc/axs10*
> Â
> +SYNOPSYS AXS10x RESET CONTROLLER DRIVER
> +M: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
> +S: Supported
> +F: drivers/reset/reset-axs10x.c
> +F: Documentation/devicetree/bindings/reset/snps,axs10x-
> reset.txt
> +
> ÂSYNOPSYS DESIGNWARE DMAC DRIVER
> ÂM: Viresh Kumar <vireshk@xxxxxxxxxx>
> ÂM: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> index 52d5251..65d13f4 100644
> --- a/drivers/reset/Kconfig
> +++ b/drivers/reset/Kconfig
> @@ -28,6 +28,12 @@ config RESET_ATH79
> Â ÂÂThis enables the ATH79 reset controller driver that
> supports the
> Â ÂÂAR71xx SoC reset controller.
> Â
> +config RESET_AXS10X
> + bool "AXS10x Reset Driver" if COMPILE_TEST
> + default ARC_PLAT_AXS10X
> + help
> + ÂÂThis enables the reset controller driver for AXS10x.
> +
> Âconfig RESET_BERLIN
> Â bool "Berlin Reset Driver" if COMPILE_TEST
> Â default ARCH_BERLIN
> diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> index b62783f..45000a5 100644
> --- a/drivers/reset/Makefile
> +++ b/drivers/reset/Makefile
> @@ -4,6 +4,7 @@ obj-$(CONFIG_ARCH_STI) += sti/
> Âobj-$(CONFIG_ARCH_TEGRA) += tegra/
> Âobj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
> Âobj-$(CONFIG_RESET_ATH79) += reset-ath79.o
> +obj-$(CONFIG_RESET_AXS10X) += reset-axs10x.o
> Âobj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
> Âobj-$(CONFIG_RESET_HSDK_V1) += reset-hsdk-v1.o
> Âobj-$(CONFIG_RESET_IMX7) += reset-imx7.o
> diff --git a/drivers/reset/reset-axs10x.c b/drivers/reset/reset-
> axs10x.c
> new file mode 100644
> index 0000000..17a4cb4
> --- /dev/null
> +++ b/drivers/reset/reset-axs10x.c
> @@ -0,0 +1,109 @@
> +/*
> + * Copyright (C) 2017 Synopsys.
> + *
> + * Synopsys AXS10x reset driver.
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset-controller.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +
> +#define to_axs10x_rst(p) container_of((p), struct axs10x_rst,
> rcdev)
> +
> +#define AXS10X_MAX_RESETS 32
> +
> +struct axs10x_rst {
> + void __iomem *regs_rst;
> + spinlock_t lock;
> + struct reset_controller_dev rcdev;
> +};
> +
> +static int axs10x_reset_assert(struct reset_controller_dev *rcdev,
> + ÂÂÂÂÂÂunsigned long id)
> +{
> + struct axs10x_rst *rst = to_axs10x_rst(rcdev);
> + unsigned long flags;
> + u32 reg;
> +
> + spin_lock_irqsave(&rst->lock, flags);
> + reg = readl(rst->regs_rst);
> + reg |= BIT(id);
> + writel(reg, rst->regs_rst);
> + spin_unlock_irqrestore(&rst->lock, flags);
> +
> + return 0;
> +}
> +
> +static int axs10x_reset_deassert(struct reset_controller_dev *rcdev,
> + ÂÂÂÂÂÂunsigned long id)
> +{
> + struct axs10x_rst *rst = to_axs10x_rst(rcdev);
> + unsigned long flags;
> + u32 reg;
> +
> + spin_lock_irqsave(&rst->lock, flags);
> + reg = readl(rst->regs_rst);
> + reg &= ~BIT(id);
> + writel(reg, rst->regs_rst);
> + spin_unlock_irqrestore(&rst->lock, flags);
> +
> + return 0;
> +}
> +
> +static const struct reset_control_ops axs10x_reset_ops = {
> + .assert = axs10x_reset_assert,
> + .deassert = axs10x_reset_deassert,
> +};
> +
> +static int axs10x_reset_probe(struct platform_device *pdev)
> +{
> + struct axs10x_rst *rst;
> + struct resource *mem;
> +
> + rst = devm_kzalloc(&pdev->dev, sizeof(*rst), GFP_KERNEL);
> + if (!rst)
> + return -ENOMEM;
> +
> + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + rst->regs_rst = devm_ioremap_resource(&pdev->dev, mem);
> + if (IS_ERR(rst->regs_rst))
> + return PTR_ERR(rst->regs_rst);
> +
> + spin_lock_init(&rst->lock);
> +
> + rst->rcdev.owner = THIS_MODULE;
> + rst->rcdev.ops = &axs10x_reset_ops;
> + rst->rcdev.of_node = pdev->dev.of_node;
> + rst->rcdev.nr_resets = AXS10X_MAX_RESETS;
> + rst->rcdev.of_reset_n_cells = 1;

If of_xlate is not set, of_reset_n_cells will be set to 1 by the core
anyway. No need to do it here.

> +
> + return reset_controller_register(&rst->rcdev);

This should be devm_reset_controller_register.

> +}
> +
> +static const struct of_device_id axs10x_reset_dt_match[] = {
> + { .compatible = "snps,axs10x-reset" },
> + { },
> +};
> +
> +static struct platform_driver axs10x_reset_driver = {
> + .probe = axs10x_reset_probe,
> + .driver = {
> + .name = "axs10x-reset",
> + .of_match_table = axs10x_reset_dt_match,
> + },
> +};
> +builtin_platform_driver(axs10x_reset_driver);
> +
> +MODULE_AUTHOR("Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Synopsys AXS10x reset driver");
> +MODULE_LICENSE("GPL v2");

regards
Philipp