diff options
Diffstat (limited to 'drivers/reset/reset-zynq.c')
| -rw-r--r-- | drivers/reset/reset-zynq.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/drivers/reset/reset-zynq.c b/drivers/reset/reset-zynq.c new file mode 100644 index 000000000..87a4e3555 --- /dev/null +++ b/drivers/reset/reset-zynq.c @@ -0,0 +1,142 @@ +/* + * Copyright (c) 2015, National Instruments Corp. + * + * Xilinx Zynq Reset controller driver + * + * Author: Moritz Fischer <moritz.fischer@ettus.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/err.h> +#include <linux/io.h> +#include <linux/init.h> +#include <linux/mfd/syscon.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/reset-controller.h> +#include <linux/regmap.h> +#include <linux/types.h> + +struct zynq_reset_data { + struct regmap *slcr; + struct reset_controller_dev rcdev; + u32 offset; +}; + +#define to_zynq_reset_data(p) \ + container_of((p), struct zynq_reset_data, rcdev) + +static int zynq_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct zynq_reset_data *priv = to_zynq_reset_data(rcdev); + + int bank = id / BITS_PER_LONG; + int offset = id % BITS_PER_LONG; + + pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__, + bank, offset); + + return regmap_update_bits(priv->slcr, + priv->offset + (bank * 4), + BIT(offset), + BIT(offset)); +} + +static int zynq_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct zynq_reset_data *priv = to_zynq_reset_data(rcdev); + + int bank = id / BITS_PER_LONG; + int offset = id % BITS_PER_LONG; + + pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__, + bank, offset); + + return regmap_update_bits(priv->slcr, + priv->offset + (bank * 4), + BIT(offset), + ~BIT(offset)); +} + +static int zynq_reset_status(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct zynq_reset_data *priv = to_zynq_reset_data(rcdev); + + int bank = id / BITS_PER_LONG; + int offset = id % BITS_PER_LONG; + int ret; + u32 reg; + + pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__, + bank, offset); + + ret = regmap_read(priv->slcr, priv->offset + (bank * 4), ®); + if (ret) + return ret; + + return !!(reg & BIT(offset)); +} + +static const struct reset_control_ops zynq_reset_ops = { + .assert = zynq_reset_assert, + .deassert = zynq_reset_deassert, + .status = zynq_reset_status, +}; + +static int zynq_reset_probe(struct platform_device *pdev) +{ + struct resource *res; + struct zynq_reset_data *priv; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + platform_set_drvdata(pdev, priv); + + priv->slcr = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, + "syscon"); + if (IS_ERR(priv->slcr)) { + dev_err(&pdev->dev, "unable to get zynq-slcr regmap"); + return PTR_ERR(priv->slcr); + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "missing IO resource\n"); + return -ENODEV; + } + + priv->offset = res->start; + + priv->rcdev.owner = THIS_MODULE; + priv->rcdev.nr_resets = resource_size(res) / 4 * BITS_PER_LONG; + priv->rcdev.ops = &zynq_reset_ops; + priv->rcdev.of_node = pdev->dev.of_node; + + return devm_reset_controller_register(&pdev->dev, &priv->rcdev); +} + +static const struct of_device_id zynq_reset_dt_ids[] = { + { .compatible = "xlnx,zynq-reset", }, + { /* sentinel */ }, +}; + +static struct platform_driver zynq_reset_driver = { + .probe = zynq_reset_probe, + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = zynq_reset_dt_ids, + }, +}; +builtin_platform_driver(zynq_reset_driver); |