From aac025437f14c1647dc6054b95daeebed34f6971 Mon Sep 17 00:00:00 2001 From: Álvaro Fernández Rojas Date: Wed, 17 Jun 2020 12:50:35 +0200 Subject: reset: add BCM6345 reset controller driver MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add support for resetting blocks through the Linux reset controller subsystem for BCM63xx SoCs. Signed-off-by: Álvaro Fernández Rojas Reviewed-by: Florian Fainelli Reviewed-by: Philipp Zabel Signed-off-by: Thomas Bogendoerfer --- drivers/reset/reset-bcm6345.c | 135 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 135 insertions(+) create mode 100644 drivers/reset/reset-bcm6345.c (limited to 'drivers/reset/reset-bcm6345.c') diff --git a/drivers/reset/reset-bcm6345.c b/drivers/reset/reset-bcm6345.c new file mode 100644 index 000000000000..737e4e81f6b7 --- /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 + */ + +#include +#include +#include +#include +#include +#include + +#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 inline struct bcm6345_reset * +to_bcm6345_reset(struct reset_controller_dev *rcdev) +{ + return container_of(rcdev, struct bcm6345_reset, rcdev); +} + +static int bcm6345_reset_update(struct reset_controller_dev *rcdev, + unsigned long id, bool assert) +{ + struct bcm6345_reset *bcm6345_reset = to_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); + + return 0; +} + +static int bcm6345_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return bcm6345_reset_update(rcdev, id, true); +} + +static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return bcm6345_reset_update(rcdev, id, false); +} + +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); + /* + * Ensure component is taken out reset state by sleeping also after + * deasserting the reset. Otherwise, the component may not be ready + * for operation. + */ + 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 = to_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 bcm6345_reset_probe(struct platform_device *pdev) +{ + struct bcm6345_reset *bcm6345_reset; + + bcm6345_reset = devm_kzalloc(&pdev->dev, + sizeof(*bcm6345_reset), GFP_KERNEL); + if (!bcm6345_reset) + return -ENOMEM; + + platform_set_drvdata(pdev, bcm6345_reset); + + bcm6345_reset->base = devm_platform_ioremap_resource(pdev, 0); + 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; + + return devm_reset_controller_register(&pdev->dev, + &bcm6345_reset->rcdev); +} + +static const struct of_device_id bcm6345_reset_of_match[] = { + { .compatible = "brcm,bcm6345-reset" }, + { /* sentinel */ }, +}; + +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); -- cgit v1.2.3