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author | Florian Fainelli <f.fainelli@gmail.com> | 2019-01-23 23:54:36 +0100 |
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committer | Philipp Zabel <p.zabel@pengutronix.de> | 2019-01-28 11:16:04 +0100 |
commit | 77750bc089e4508ff62f036e6e6626cf8d7384cb (patch) | |
tree | 90572bc9cbb4eeaf3f2eb5e987fab194f8d8c186 /drivers/reset/reset-brcmstb.c | |
parent | dt-bindings: reset: Add document for Broadcom STB reset controller (diff) | |
download | linux-77750bc089e4508ff62f036e6e6626cf8d7384cb.tar.xz linux-77750bc089e4508ff62f036e6e6626cf8d7384cb.zip |
reset: Add Broadcom STB SW_INIT reset controller driver
Add support for resetting blocks through the Linux reset controller
subsystem when reset lines are provided through a SW_INIT-style reset
controller on Broadcom STB SoCs.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Diffstat (limited to 'drivers/reset/reset-brcmstb.c')
-rw-r--r-- | drivers/reset/reset-brcmstb.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/drivers/reset/reset-brcmstb.c b/drivers/reset/reset-brcmstb.c new file mode 100644 index 000000000000..a608f445dad6 --- /dev/null +++ b/drivers/reset/reset-brcmstb.c @@ -0,0 +1,132 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Broadcom STB generic reset controller for SW_INIT style reset controller + * + * Author: Florian Fainelli <f.fainelli@gmail.com> + * Copyright (C) 2018 Broadcom + */ +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/reset-controller.h> +#include <linux/types.h> + +struct brcmstb_reset { + void __iomem *base; + struct reset_controller_dev rcdev; +}; + +#define SW_INIT_SET 0x00 +#define SW_INIT_CLEAR 0x04 +#define SW_INIT_STATUS 0x08 + +#define SW_INIT_BIT(id) BIT((id) & 0x1f) +#define SW_INIT_BANK(id) ((id) >> 5) + +/* A full bank contains extra registers that we are not utilizing but still + * qualify as a single bank. + */ +#define SW_INIT_BANK_SIZE 0x18 + +static inline +struct brcmstb_reset *to_brcmstb(struct reset_controller_dev *rcdev) +{ + return container_of(rcdev, struct brcmstb_reset, rcdev); +} + +static int brcmstb_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; + struct brcmstb_reset *priv = to_brcmstb(rcdev); + + writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_SET); + + return 0; +} + +static int brcmstb_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; + struct brcmstb_reset *priv = to_brcmstb(rcdev); + + writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_CLEAR); + /* Maximum reset delay after de-asserting a line and seeing block + * operation is typically 14us for the worst case, build some slack + * here. + */ + usleep_range(100, 200); + + return 0; +} + +static int brcmstb_reset_status(struct reset_controller_dev *rcdev, + unsigned long id) +{ + unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; + struct brcmstb_reset *priv = to_brcmstb(rcdev); + + return readl_relaxed(priv->base + off + SW_INIT_STATUS) & + SW_INIT_BIT(id); +} + +static const struct reset_control_ops brcmstb_reset_ops = { + .assert = brcmstb_reset_assert, + .deassert = brcmstb_reset_deassert, + .status = brcmstb_reset_status, +}; + +static int brcmstb_reset_probe(struct platform_device *pdev) +{ + struct device *kdev = &pdev->dev; + struct brcmstb_reset *priv; + struct resource *res; + + priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!IS_ALIGNED(res->start, SW_INIT_BANK_SIZE) || + !IS_ALIGNED(resource_size(res), SW_INIT_BANK_SIZE)) { + dev_err(kdev, "incorrect register range\n"); + return -EINVAL; + } + + priv->base = devm_ioremap_resource(kdev, res); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + dev_set_drvdata(kdev, priv); + + priv->rcdev.owner = THIS_MODULE; + priv->rcdev.nr_resets = DIV_ROUND_DOWN_ULL(resource_size(res), + SW_INIT_BANK_SIZE) * 32; + priv->rcdev.ops = &brcmstb_reset_ops; + priv->rcdev.of_node = kdev->of_node; + /* Use defaults: 1 cell and simple xlate function */ + + return devm_reset_controller_register(kdev, &priv->rcdev); +} + +static const struct of_device_id brcmstb_reset_of_match[] = { + { .compatible = "brcm,brcmstb-reset" }, + { /* sentinel */ } +}; + +static struct platform_driver brcmstb_reset_driver = { + .probe = brcmstb_reset_probe, + .driver = { + .name = "brcmstb-reset", + .of_match_table = brcmstb_reset_of_match, + }, +}; +module_platform_driver(brcmstb_reset_driver); + +MODULE_AUTHOR("Broadcom"); +MODULE_DESCRIPTION("Broadcom STB reset controller"); +MODULE_LICENSE("GPL"); |