diff options
| -rw-r--r-- | drivers/reset/Makefile | 1 | ||||
| -rw-r--r-- | drivers/reset/reset-stm32.c | 108 |
2 files changed, 109 insertions, 0 deletions
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile index 5d65a93d3c43..64ebb0c4615c 100644 --- a/drivers/reset/Makefile +++ b/drivers/reset/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o obj-$(CONFIG_ARCH_BERLIN) += reset-berlin.o obj-$(CONFIG_MACH_PISTACHIO) += reset-pistachio.o obj-$(CONFIG_ARCH_MESON) += reset-meson.o +obj-$(CONFIG_ARCH_STM32) += reset-stm32.o obj-$(CONFIG_ARCH_SUNXI) += reset-sunxi.o obj-$(CONFIG_ARCH_STI) += sti/ obj-$(CONFIG_ARCH_HISI) += hisilicon/ diff --git a/drivers/reset/reset-stm32.c b/drivers/reset/reset-stm32.c new file mode 100644 index 000000000000..3a7c8527e66a --- /dev/null +++ b/drivers/reset/reset-stm32.c @@ -0,0 +1,108 @@ +/* + * Copyright (C) Maxime Coquelin 2015 + * Author: Maxime Coquelin <mcoquelin.stm32@gmail.com> + * License terms: GNU General Public License (GPL), version 2 + * + * Heavily based on sunxi driver from Maxime Ripard. + */ + +#include <linux/err.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> +#include <linux/reset-controller.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/types.h> + +struct stm32_reset_data { + spinlock_t lock; + void __iomem *membase; + struct reset_controller_dev rcdev; +}; + +static int stm32_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct stm32_reset_data *data = container_of(rcdev, + struct stm32_reset_data, + rcdev); + int bank = id / BITS_PER_LONG; + int offset = id % BITS_PER_LONG; + unsigned long flags; + u32 reg; + + spin_lock_irqsave(&data->lock, flags); + + reg = readl(data->membase + (bank * 4)); + writel(reg | BIT(offset), data->membase + (bank * 4)); + + spin_unlock_irqrestore(&data->lock, flags); + + return 0; +} + +static int stm32_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct stm32_reset_data *data = container_of(rcdev, + struct stm32_reset_data, + rcdev); + int bank = id / BITS_PER_LONG; + int offset = id % BITS_PER_LONG; + unsigned long flags; + u32 reg; + + spin_lock_irqsave(&data->lock, flags); + + reg = readl(data->membase + (bank * 4)); + writel(reg & ~BIT(offset), data->membase + (bank * 4)); + + spin_unlock_irqrestore(&data->lock, flags); + + return 0; +} + +static const struct reset_control_ops stm32_reset_ops = { + .assert = stm32_reset_assert, + .deassert = stm32_reset_deassert, +}; + +static const struct of_device_id stm32_reset_dt_ids[] = { + { .compatible = "st,stm32-rcc", }, + { /* sentinel */ }, +}; + +static int stm32_reset_probe(struct platform_device *pdev) +{ + struct stm32_reset_data *data; + struct resource *res; + + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + data->membase = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(data->membase)) + return PTR_ERR(data->membase); + + spin_lock_init(&data->lock); + + data->rcdev.owner = THIS_MODULE; + data->rcdev.nr_resets = resource_size(res) * 8; + data->rcdev.ops = &stm32_reset_ops; + data->rcdev.of_node = pdev->dev.of_node; + + return devm_reset_controller_register(&pdev->dev, &data->rcdev); +} + +static struct platform_driver stm32_reset_driver = { + .probe = stm32_reset_probe, + .driver = { + .name = "stm32-rcc-reset", + .of_match_table = stm32_reset_dt_ids, + }, +}; +builtin_platform_driver(stm32_reset_driver); |