diff options
author | Gabriel Fernandez <gabriel.fernandez@st.com> | 2018-03-19 08:25:51 +0100 |
---|---|---|
committer | Philipp Zabel <p.zabel@pengutronix.de> | 2018-03-27 10:44:04 +0200 |
commit | 197858b68532d415f21a5a92fb6661c67c6c9a97 (patch) | |
tree | 9124944c191c4072b49588713362340dc88094a8 /drivers/reset/reset-stm32mp1.c | |
parent | dt-bindings: reset: add STM32MP1 resets (diff) | |
download | linux-197858b68532d415f21a5a92fb6661c67c6c9a97.tar.xz linux-197858b68532d415f21a5a92fb6661c67c6c9a97.zip |
reset: stm32mp1: Enable stm32mp1 reset driver
stm32mp1 RCC IP 1 has a reset SET register and a reset CLEAR register.
Writing '0' on reset SET register has no effect
Writing '1' on reset SET register
activates the reset of the corresponding peripheral
Writing '0' on reset CLEAR register has no effect
Writing '1' on reset CLEAR register
releases the reset of the corresponding peripheral
See Documentation/devicetree/bindings/clock/st,stm32mp1-rcc.txt
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Diffstat (limited to 'drivers/reset/reset-stm32mp1.c')
-rw-r--r-- | drivers/reset/reset-stm32mp1.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/drivers/reset/reset-stm32mp1.c b/drivers/reset/reset-stm32mp1.c new file mode 100644 index 000000000000..b221a28041fa --- /dev/null +++ b/drivers/reset/reset-stm32mp1.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) STMicroelectronics 2018 - All Rights Reserved + * Author: Gabriel Fernandez <gabriel.fernandez@st.com> for STMicroelectronics. + */ + +#include <linux/device.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/reset-controller.h> + +#define CLR_OFFSET 0x4 + +struct stm32_reset_data { + struct reset_controller_dev rcdev; + void __iomem *membase; +}; + +static inline struct stm32_reset_data * +to_stm32_reset_data(struct reset_controller_dev *rcdev) +{ + return container_of(rcdev, struct stm32_reset_data, rcdev); +} + +static int stm32_reset_update(struct reset_controller_dev *rcdev, + unsigned long id, bool assert) +{ + struct stm32_reset_data *data = to_stm32_reset_data(rcdev); + int reg_width = sizeof(u32); + int bank = id / (reg_width * BITS_PER_BYTE); + int offset = id % (reg_width * BITS_PER_BYTE); + void __iomem *addr; + + addr = data->membase + (bank * reg_width); + if (!assert) + addr += CLR_OFFSET; + + writel(BIT(offset), addr); + + return 0; +} + +static int stm32_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return stm32_reset_update(rcdev, id, true); +} + +static int stm32_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return stm32_reset_update(rcdev, id, false); +} + +static int stm32_reset_status(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct stm32_reset_data *data = to_stm32_reset_data(rcdev); + int reg_width = sizeof(u32); + int bank = id / (reg_width * BITS_PER_BYTE); + int offset = id % (reg_width * BITS_PER_BYTE); + u32 reg; + + reg = readl(data->membase + (bank * reg_width)); + + return !!(reg & BIT(offset)); +} + +static const struct reset_control_ops stm32_reset_ops = { + .assert = stm32_reset_assert, + .deassert = stm32_reset_deassert, + .status = stm32_reset_status, +}; + +static const struct of_device_id stm32_reset_dt_ids[] = { + { .compatible = "st,stm32mp1-rcc"}, + { /* sentinel */ }, +}; + +static int stm32_reset_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct stm32_reset_data *data; + void __iomem *membase; + struct resource *res; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + membase = devm_ioremap_resource(dev, res); + if (IS_ERR(membase)) + return PTR_ERR(membase); + + data->membase = membase; + data->rcdev.owner = THIS_MODULE; + data->rcdev.nr_resets = resource_size(res) * BITS_PER_BYTE; + data->rcdev.ops = &stm32_reset_ops; + data->rcdev.of_node = dev->of_node; + + return devm_reset_controller_register(dev, &data->rcdev); +} + +static struct platform_driver stm32_reset_driver = { + .probe = stm32_reset_probe, + .driver = { + .name = "stm32mp1-reset", + .of_match_table = stm32_reset_dt_ids, + }, +}; + +builtin_platform_driver(stm32_reset_driver); |