diff options
Diffstat (limited to 'drivers/reset/reset-lantiq.c')
| -rw-r--r-- | drivers/reset/reset-lantiq.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/drivers/reset/reset-lantiq.c b/drivers/reset/reset-lantiq.c new file mode 100644 index 000000000000..11a582e50d30 --- /dev/null +++ b/drivers/reset/reset-lantiq.c @@ -0,0 +1,212 @@ +/* + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + * + * Copyright (C) 2010 John Crispin <blogic@phrozen.org> + * Copyright (C) 2013-2015 Lantiq Beteiligungs-GmbH & Co.KG + * Copyright (C) 2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com> + * Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de> + */ + +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/regmap.h> +#include <linux/reset-controller.h> +#include <linux/of_address.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/property.h> + +#define LANTIQ_RCU_RESET_TIMEOUT 10000 + +struct lantiq_rcu_reset_priv { + struct reset_controller_dev rcdev; + struct device *dev; + struct regmap *regmap; + u32 reset_offset; + u32 status_offset; +}; + +static struct lantiq_rcu_reset_priv *to_lantiq_rcu_reset_priv( + struct reset_controller_dev *rcdev) +{ + return container_of(rcdev, struct lantiq_rcu_reset_priv, rcdev); +} + +static int lantiq_rcu_reset_status(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev); + unsigned int status = (id >> 8) & 0x1f; + u32 val; + int ret; + + ret = regmap_read(priv->regmap, priv->status_offset, &val); + if (ret) + return ret; + + return !!(val & BIT(status)); +} + +static int lantiq_rcu_reset_status_timeout(struct reset_controller_dev *rcdev, + unsigned long id, bool assert) +{ + int ret; + int retry = LANTIQ_RCU_RESET_TIMEOUT; + + do { + ret = lantiq_rcu_reset_status(rcdev, id); + if (ret < 0) + return ret; + if (ret == assert) + return 0; + usleep_range(20, 40); + } while (--retry); + + return -ETIMEDOUT; +} + +static int lantiq_rcu_reset_update(struct reset_controller_dev *rcdev, + unsigned long id, bool assert) +{ + struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev); + unsigned int set = id & 0x1f; + u32 val = assert ? BIT(set) : 0; + int ret; + + ret = regmap_update_bits(priv->regmap, priv->reset_offset, BIT(set), + val); + if (ret) { + dev_err(priv->dev, "Failed to set reset bit %u\n", set); + return ret; + } + + + ret = lantiq_rcu_reset_status_timeout(rcdev, id, assert); + if (ret) + dev_err(priv->dev, "Failed to %s bit %u\n", + assert ? "assert" : "deassert", set); + + return ret; +} + +static int lantiq_rcu_reset_assert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return lantiq_rcu_reset_update(rcdev, id, true); +} + +static int lantiq_rcu_reset_deassert(struct reset_controller_dev *rcdev, + unsigned long id) +{ + return lantiq_rcu_reset_update(rcdev, id, false); +} + +static int lantiq_rcu_reset_reset(struct reset_controller_dev *rcdev, + unsigned long id) +{ + int ret; + + ret = lantiq_rcu_reset_assert(rcdev, id); + if (ret) + return ret; + + return lantiq_rcu_reset_deassert(rcdev, id); +} + +static const struct reset_control_ops lantiq_rcu_reset_ops = { + .assert = lantiq_rcu_reset_assert, + .deassert = lantiq_rcu_reset_deassert, + .status = lantiq_rcu_reset_status, + .reset = lantiq_rcu_reset_reset, +}; + +static int lantiq_rcu_reset_of_parse(struct platform_device *pdev, + struct lantiq_rcu_reset_priv *priv) +{ + struct device *dev = &pdev->dev; + const __be32 *offset; + + priv->regmap = syscon_node_to_regmap(dev->of_node->parent); + if (IS_ERR(priv->regmap)) { + dev_err(&pdev->dev, "Failed to lookup RCU regmap\n"); + return PTR_ERR(priv->regmap); + } + + offset = of_get_address(dev->of_node, 0, NULL, NULL); + if (!offset) { + dev_err(&pdev->dev, "Failed to get RCU reset offset\n"); + return -ENOENT; + } + priv->reset_offset = __be32_to_cpu(*offset); + + offset = of_get_address(dev->of_node, 1, NULL, NULL); + if (!offset) { + dev_err(&pdev->dev, "Failed to get RCU status offset\n"); + return -ENOENT; + } + priv->status_offset = __be32_to_cpu(*offset); + + return 0; +} + +static int lantiq_rcu_reset_xlate(struct reset_controller_dev *rcdev, + const struct of_phandle_args *reset_spec) +{ + unsigned int status, set; + + set = reset_spec->args[0]; + status = reset_spec->args[1]; + + if (set >= rcdev->nr_resets || status >= rcdev->nr_resets) + return -EINVAL; + + return (status << 8) | set; +} + +static int lantiq_rcu_reset_probe(struct platform_device *pdev) +{ + struct lantiq_rcu_reset_priv *priv; + int err; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->dev = &pdev->dev; + platform_set_drvdata(pdev, priv); + + err = lantiq_rcu_reset_of_parse(pdev, priv); + if (err) + return err; + + priv->rcdev.ops = &lantiq_rcu_reset_ops; + priv->rcdev.owner = THIS_MODULE; + priv->rcdev.of_node = pdev->dev.of_node; + priv->rcdev.nr_resets = 32; + priv->rcdev.of_xlate = lantiq_rcu_reset_xlate; + priv->rcdev.of_reset_n_cells = 2; + + return reset_controller_register(&priv->rcdev); +} + +static const struct of_device_id lantiq_rcu_reset_dt_ids[] = { + { .compatible = "lantiq,danube-reset", }, + { .compatible = "lantiq,xrx200-reset", }, + { }, +}; +MODULE_DEVICE_TABLE(of, lantiq_rcu_reset_dt_ids); + +static struct platform_driver lantiq_rcu_reset_driver = { + .probe = lantiq_rcu_reset_probe, + .driver = { + .name = "lantiq-reset", + .of_match_table = lantiq_rcu_reset_dt_ids, + }, +}; +module_platform_driver(lantiq_rcu_reset_driver); + +MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>"); +MODULE_DESCRIPTION("Lantiq XWAY RCU Reset Controller Driver"); +MODULE_LICENSE("GPL"); |