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    Subject[PATCH v4 3/9] reset: add BCM6345 reset controller driver
    Date
    Add support for resetting blocks through the Linux reset controller
    subsystem for BCM63xx SoCs.

    Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
    ---
    v4: no changes.
    v3: using reset-simple isn't possible since sleeping after performing the
    reset is also needed.
    v2: add compatibility to reset-simple instead of adding a new driver.

    drivers/reset/Kconfig | 7 ++
    drivers/reset/Makefile | 1 +
    drivers/reset/reset-bcm6345.c | 135 ++++++++++++++++++++++++++++++++++
    3 files changed, 143 insertions(+)
    create mode 100644 drivers/reset/reset-bcm6345.c

    diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
    index d9efbfd29646..9f1da978cef6 100644
    --- a/drivers/reset/Kconfig
    +++ b/drivers/reset/Kconfig
    @@ -41,6 +41,13 @@ config RESET_BERLIN
    help
    This enables the reset controller driver for Marvell Berlin SoCs.

    +config RESET_BCM6345
    + bool "BCM6345 Reset Controller"
    + depends on BMIPS_GENERIC || COMPILE_TEST
    + default BMIPS_GENERIC
    + help
    + This enables the reset controller driver for BCM6345 SoCs.
    +
    config RESET_BRCMSTB
    tristate "Broadcom STB reset controller"
    depends on ARCH_BRCMSTB || COMPILE_TEST
    diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
    index 249ed357c997..e642aae42f0f 100644
    --- a/drivers/reset/Makefile
    +++ b/drivers/reset/Makefile
    @@ -6,6 +6,7 @@ obj-$(CONFIG_ARCH_TEGRA) += tegra/
    obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
    obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
    obj-$(CONFIG_RESET_AXS10X) += reset-axs10x.o
    +obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
    obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
    obj-$(CONFIG_RESET_BRCMSTB) += reset-brcmstb.o
    obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o
    diff --git a/drivers/reset/reset-bcm6345.c b/drivers/reset/reset-bcm6345.c
    new file mode 100644
    index 000000000000..6c9238762ee5
    --- /dev/null
    +++ b/drivers/reset/reset-bcm6345.c
    @@ -0,0 +1,135 @@
    +// SPDX-License-Identifier: GPL-2.0-or-later
    +/*
    + * BCM6345 Reset Controller Driver
    + *
    + * Copyright (C) 2020 Álvaro Fernández Rojas <noltari@gmail.com>
    + */
    +
    +#include <linux/delay.h>
    +#include <linux/init.h>
    +#include <linux/io.h>
    +#include <linux/mod_devicetable.h>
    +#include <linux/platform_device.h>
    +#include <linux/reset-controller.h>
    +
    +#define BCM6345_RESET_NUM 32
    +#define BCM6345_RESET_SLEEP_MIN_US 10000
    +#define BCM6345_RESET_SLEEP_MAX_US 20000
    +
    +struct bcm6345_reset {
    + struct reset_controller_dev rcdev;
    + void __iomem *base;
    + spinlock_t lock;
    +};
    +
    +static void bcm6345_reset_update(struct reset_controller_dev *rcdev,
    + unsigned long id, bool assert)
    +{
    + struct bcm6345_reset *bcm6345_reset =
    + container_of(rcdev, struct bcm6345_reset, rcdev);
    + unsigned long flags;
    + uint32_t val;
    +
    + spin_lock_irqsave(&bcm6345_reset->lock, flags);
    + val = __raw_readl(bcm6345_reset->base);
    + if (assert)
    + val &= ~BIT(id);
    + else
    + val |= BIT(id);
    + __raw_writel(val, bcm6345_reset->base);
    + spin_unlock_irqrestore(&bcm6345_reset->lock, flags);
    +}
    +
    +static int bcm6345_reset_assert(struct reset_controller_dev *rcdev,
    + unsigned long id)
    +{
    + bcm6345_reset_update(rcdev, id, true);
    +
    + return 0;
    +}
    +
    +static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev,
    + unsigned long id)
    +{
    + bcm6345_reset_update(rcdev, id, false);
    +
    + return 0;
    +}
    +
    +static int bcm6345_reset_reset(struct reset_controller_dev *rcdev,
    + unsigned long id)
    +{
    + bcm6345_reset_update(rcdev, id, true);
    + usleep_range(BCM6345_RESET_SLEEP_MIN_US,
    + BCM6345_RESET_SLEEP_MAX_US);
    +
    + bcm6345_reset_update(rcdev, id, false);
    + usleep_range(BCM6345_RESET_SLEEP_MIN_US,
    + BCM6345_RESET_SLEEP_MAX_US);
    +
    + return 0;
    +}
    +
    +static int bcm6345_reset_status(struct reset_controller_dev *rcdev,
    + unsigned long id)
    +{
    + struct bcm6345_reset *bcm6345_reset =
    + container_of(rcdev, struct bcm6345_reset, rcdev);
    +
    + return !(__raw_readl(bcm6345_reset->base) & BIT(id));
    +}
    +
    +static struct reset_control_ops bcm6345_reset_ops = {
    + .assert = bcm6345_reset_assert,
    + .deassert = bcm6345_reset_deassert,
    + .reset = bcm6345_reset_reset,
    + .status = bcm6345_reset_status,
    +};
    +
    +static int __init bcm6345_reset_probe(struct platform_device *pdev)
    +{
    + struct bcm6345_reset *bcm6345_reset;
    + struct resource *res;
    + int err;
    +
    + bcm6345_reset = devm_kzalloc(&pdev->dev,
    + sizeof(*bcm6345_reset), GFP_KERNEL);
    + if (!bcm6345_reset)
    + return -ENOMEM;
    +
    + platform_set_drvdata(pdev, bcm6345_reset);
    +
    + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    + bcm6345_reset->base = devm_ioremap_resource(&pdev->dev, res);
    + if (IS_ERR(bcm6345_reset->base))
    + return PTR_ERR(bcm6345_reset->base);
    +
    + spin_lock_init(&bcm6345_reset->lock);
    + bcm6345_reset->rcdev.ops = &bcm6345_reset_ops;
    + bcm6345_reset->rcdev.owner = THIS_MODULE;
    + bcm6345_reset->rcdev.of_node = pdev->dev.of_node;
    + bcm6345_reset->rcdev.of_reset_n_cells = 1;
    + bcm6345_reset->rcdev.nr_resets = BCM6345_RESET_NUM;
    +
    + err = devm_reset_controller_register(&pdev->dev,
    + &bcm6345_reset->rcdev);
    + if (err)
    + return err;
    +
    + return 0;
    +}
    +
    +static const struct of_device_id bcm6345_reset_of_match[] = {
    + { .compatible = "brcm,bcm6345-reset" },
    + { },
    +};
    +
    +static struct platform_driver bcm6345_reset_driver = {
    + .probe = bcm6345_reset_probe,
    + .driver = {
    + .name = "bcm6345-reset",
    + .of_match_table = bcm6345_reset_of_match,
    + .suppress_bind_attrs = true,
    + },
    +};
    +builtin_platform_driver(bcm6345_reset_driver);
    --
    2.27.0
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