Hi Hauke, thank you for the patch. I have a few questions and comments below: On Sun, 2017-05-21 at 15:09 +0200, Hauke Mehrtens wrote: > From: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> > > The reset controllers (on xRX200 and newer SoCs have two of them) are > provided by the RCU module. This was initially implemented as a simple > reset controller. However, the RCU module provides more functionality > (ethernet GPHYs, USB PHY, etc.), which makes it a MFD device. > The old reset controller driver implementation from > arch/mips/lantiq/xway/reset.c did not honor this fact. Does this driver replace arch/mips/lantiq/xway/reset.c? > For some devices the request and the status bits are different. > > Signed-off-by: Hauke Mehrtens <hauke@xxxxxxxxxx> > Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > --- > .../devicetree/bindings/reset/lantiq,rcu-reset.txt | 30 +++ > drivers/reset/Kconfig | 6 + > drivers/reset/Makefile | 1 + > drivers/reset/reset-lantiq-rcu.c | 201 +++++++++++++++++++++ > 4 files changed, 238 insertions(+) > create mode 100644 Documentation/devicetree/bindings/reset/lantiq,rcu-reset.txt > create mode 100644 drivers/reset/reset-lantiq-rcu.c > > diff --git a/Documentation/devicetree/bindings/reset/lantiq,rcu-reset.txt b/Documentation/devicetree/bindings/reset/lantiq,rcu-reset.txt > new file mode 100644 > index 000000000000..ac57c4a1b191 > --- /dev/null > +++ b/Documentation/devicetree/bindings/reset/lantiq,rcu-reset.txt > @@ -0,0 +1,30 @@ > +Lantiq XWAY SoC RCU reset controller binding > +============================================ > + > +This binding describes a reset-controller found on the RCU module on Lantiq > +XWAY SoCs. > + > + > +------------------------------------------------------------------------------- > +Required properties (controller (parent) node): > +- compatible : Should be "lantiq,rcu-reset" > +- lantiq,rcu-syscon : A phandle to the RCU syscon, the reset register > + offset and the status register offset. > +- #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: > + rcu_reset0: rcu_reset { I'd prefer rcu_reset0: reset-controller { > + compatible = "lantiq,rcu-reset"; > + lantiq,rcu-syscon = <&rcu0 0x10 0x14>; > + #reset-cells = <2>; > + }; > + > + rcu_reset1: rcu_reset { > + compatible = "lantiq,rcu-reset"; > + lantiq,rcu-syscon = <&rcu0 0x48 0x24>; > + #reset-cells = <2>; > + }; I think these should be children of the &rcu0 node. Then you could use the reg property to specify the registers. Also, have you considered using a binding like the ti-syscon-reset? That could remove the need for a rcu_reset node per register pair altogether, but might not make sense if the reset registers are densely populated. > diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig > index d21c07ccc94e..632e82155590 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_RCU > + 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..b19e77847b98 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-$(CONFIG_RESET_LANTIQ_RCU) += reset-lantiq-rcu.o > obj-$(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-rcu.c b/drivers/reset/reset-lantiq-rcu.c > new file mode 100644 > index 000000000000..f24191beed56 > --- /dev/null > +++ b/drivers/reset/reset-lantiq-rcu.c > @@ -0,0 +1,201 @@ > +/* > + * 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@xxxxxxxxxxx> > + * Copyright (C) 2013-2015 Lantiq Beteiligungs-GmbH & Co.KG > + * Copyright (C) 2016 Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> > + * Copyright (C) 2017 Hauke Mehrtens <hauke@xxxxxxxxxx> > + */ > + > +#include <linux/mfd/syscon.h> > +#include <linux/module.h> > +#include <linux/regmap.h> > +#include <linux/reset-controller.h> > +#include <linux/of_platform.h> > + > +#define LANTIQ_RCU_RESET_TIMEOUT 1000000 > + > +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) Please align with the opening parenthesis above, or use consistent indentation for broken lines, also in the other cases below. > +{ > + struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev); > + unsigned int status = (id >> 8) & 0x1f; > + u32 val; > + int ret; > + > + if (status >= rcdev->nr_resets) > + return -EINVAL; This should be checked in lantiq_rcu_reset_xlate instead. > + ret = regmap_read(priv->regmap, priv->status_offset, &val); > + if (ret) > + return ret; > + > + return !!(val & BIT(status)); > +} > + > +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); > + int ret, retry = LANTIQ_RCU_RESET_TIMEOUT; > + unsigned int set = id & 0x1f; > + u32 val; > + > + if (set >= rcdev->nr_resets) > + return -EINVAL; This should be checked in lantiq_rcu_reset_xlate instead. > + if (assert) > + val = BIT(set); > + else > + val = 0; > + > + 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; > + } > + > + do {} while (--retry && lantiq_rcu_reset_status(rcdev, id) != assert); This ignores errors returned by lantiq_rcu_reset_status. Consider using regmap_read_poll_timeout() instead of open-coding the timeout. > + if (!retry) { > + dev_err(priv->dev, "Failed to %s bit %u\n", > + assert ? "assert" : "deassert", set); > + return -EIO; > + } > + > + return 0; > +} > + > +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 struct reset_control_ops lantiq_rcu_reset_ops = { reset_control_ops should be const. > + .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_node *np = pdev->dev.of_node; > + > + priv->regmap = syscon_regmap_lookup_by_phandle(np, > + "lantiq,rcu-syscon"); This could be priv->regmap = syscon_node_to_regmap(np->parent); if the reset controller device node is a child of the MFD device node. > + if (IS_ERR(priv->regmap)) { > + dev_err(&pdev->dev, "Failed to lookup RCU regmap\n"); > + return PTR_ERR(priv->regmap); > + } > + > + if (of_property_read_u32_index(np, "lantiq,rcu-syscon", 1, > + &priv->reset_offset)) { > + dev_err(&pdev->dev, "Failed to get RCU reset offset\n"); > + return -EINVAL; > + } > + > + if (of_property_read_u32_index(np, "lantiq,rcu-syscon", 2, > + &priv->status_offset)) { > + 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]; Check that set and status are valid here. > + 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; > + > + err = reset_controller_register(&priv->rcdev); > + if (err) > + return err; > + > + return 0; You can just return reset_controller_register(&priv->rcdev); here. > +} > + > +static const struct of_device_id lantiq_rcu_reset_dt_ids[] = { > + { .compatible = "lantiq,rcu-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-rcu-reset", > + .of_match_table = lantiq_rcu_reset_dt_ids, > + }, > +}; > +module_platform_driver(lantiq_rcu_reset_driver); > + > +MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("Lantiq XWAY RCU Reset Controller Driver"); > +MODULE_LICENSE("GPL"); regards Philipp -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html