[v7,10/16] reset: Add a reset controller driver for the Lantiq XWAY based SoCs

Message ID	20170702224051.15109-11-hauke@hauke-m.de (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-spi-owner@kernel.org> From: Hauke Mehrtens <hauke@hauke-m.de> To: ralf@linux-mips.org Cc: linux-mips@linux-mips.org, linux-mtd@lists.infradead.org, linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org, martin.blumenstingl@googlemail.com, john@phrozen.org, linux-spi@vger.kernel.org, hauke.mehrtens@intel.com, robh@kernel.org, andy.shevchenko@gmail.com, p.zabel@pengutronix.de, Hauke Mehrtens <hauke@hauke-m.de> Subject: [PATCH v7 10/16] reset: Add a reset controller driver for the Lantiq XWAY based SoCs Date: Mon, 3 Jul 2017 00:40:45 +0200 Message-Id: <20170702224051.15109-11-hauke@hauke-m.de> In-Reply-To: <20170702224051.15109-1-hauke@hauke-m.de> References: <20170702224051.15109-1-hauke@hauke-m.de> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk

diff --git a/Documentation/devicetree/bindings/reset/lantiq,reset.txt b/Documentation/devicetree/bindings/reset/lantiq,reset.txt new file mode 100644 index 000000000000..7737ed75f4c1 --- /dev/null +++ b/Documentation/devicetree/bindings/reset/lantiq,reset.txt @@ -0,0 +1,29 @@ +Lantiq XWAY SoC RCU reset controller binding +============================================ + +This binding describes a reset-controller found on the RCU module on Lantiq +XWAY SoCs. + +This driver has to be a sub node of the Lantiq RCU block. + +------------------------------------------------------------------------------- +Required properties: +- compatible : Should be one of + "lantiq,danube-reset" + "lantiq,xrx200-reset" +- offset-set : Offset of the reset set register +- offset-status : Offset of the reset status register +- #reset-cells : Specifies the number of cells needed to encode the + reset line, should be 2. + The first cell takes the reset set bit and the + second cell takes the status bit. + +------------------------------------------------------------------------------- +Example for the reset-controllers on the xRX200 SoCs: + reset0: reset-controller@0 { + compatible = "lantiq,xrx200-reset"; + + offset-set = <0x10>; + offset-status = <0x14>; + #reset-cells = <2>; + }; diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig index d21c07ccc94e..1742c2293bc3 100644 --- a/drivers/reset/Kconfig +++ b/drivers/reset/Kconfig @@ -41,6 +41,12 @@ config RESET_IMX7 help This enables the reset controller driver for i.MX7 SoCs. +config RESET_LANTIQ + bool "Lantiq XWAY Reset Driver" if COMPILE_TEST + default SOC_TYPE_XWAY + help + This enables the reset controller driver for Lantiq / Intel XWAY SoCs. + config RESET_LPC18XX bool "LPC18xx/43xx Reset Driver" if COMPILE_TEST default ARCH_LPC18XX diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile index 02a74db94339..112dba1db6b9 100644 --- a/drivers/reset/Makefile +++ b/drivers/reset/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o obj-$(CONFIG_RESET_ATH79) += reset-ath79.o obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o obj-$(CONFIG_RESET_IMX7) += reset-imx7.o +obj-$(CONFIG_RESET_LANTIQ) += reset-lantiq.o obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o obj-$(CONFIG_RESET_MESON) += reset-meson.o obj-$(CONFIG_RESET_OXNAS) += reset-oxnas.o diff --git a/drivers/reset/reset-lantiq.c b/drivers/reset/reset-lantiq.c new file mode 100644 index 000000000000..48b922798087 --- /dev/null +++ b/drivers/reset/reset-lantiq.c @@ -0,0 +1,210 @@ +/* + * 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_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_probe(struct platform_device *pdev, + struct lantiq_rcu_reset_priv *priv) +{ + struct device *dev = &pdev->dev; + int ret; + + 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); + } + + ret = device_property_read_u32(dev, "offset-set", &priv->reset_offset); + if (ret) { + dev_err(&pdev->dev, "Failed to get RCU reset offset\n"); + return -EINVAL; + } + + ret = device_property_read_u32(dev, "offset-status", + &priv->status_offset); + if (ret) { + dev_err(&pdev->dev, "Failed to get RCU status offset\n"); + return -EINVAL; + } + + 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_probe(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");

[v7,10/16] reset: Add a reset controller driver for the Lantiq XWAY based SoCs

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