Re: [PATCH 19/32] riscv: Add Kendryte K210 SoC reset controller

Sean Anderson
2020-11-07T13:58:39Z

On 11/7/20 3:14 AM, Damien Le Moal wrote:
> Add a reset controller driver for the Kendryte K210 SoC. This driver
> relies on its syscon compatible parent node for its register mapping.
> Automatically select this driver for compilation when the SOC_KENDRYTE
> option is selected.
>
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> ---
> arch/riscv/Kconfig.socs | 3 +
> drivers/reset/Kconfig | 9 ++
> drivers/reset/Makefile | 1 +
> drivers/reset/reset-k210.c | 186 +++++++++++++++++++++++++++++++++++++
> 4 files changed, 199 insertions(+)
> create mode 100644 drivers/reset/reset-k210.c
>
> diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
> index a4c851ffc6b0..4d8e66d0556a 100644
> --- a/arch/riscv/Kconfig.socs
> +++ b/arch/riscv/Kconfig.socs
> @@ -31,6 +31,9 @@ config SOC_KENDRYTE
> select SIFIVE_PLIC
> select SOC_K210
> select CLK_K210
> + select ARCH_HAS_RESET_CONTROLLER
> + select RESET_CONTROLLER
> + select RESET_K210
> help
> This enables support for Kendryte K210 SoC platform hardware.
>
> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> index 07d162b179fc..c943051b5fc8 100644
> --- a/drivers/reset/Kconfig
> +++ b/drivers/reset/Kconfig
> @@ -245,6 +245,15 @@ config RESET_ZYNQ
> help
> This enables the reset controller driver for Xilinx Zynq SoCs.
>
> +config RESET_K210
> + bool "Reset controller driver for Kendryte K210 SoC"
> + depends on RISCV && SOC_KENDRYTE
> + depends on OF && MFD_SYSCON
> + help
> + Support for the Kendryte K210 RISC-V SoC reset controller. If
> + Say Y if you want to control reset signals provided by this
> + controller.
> +
> source "drivers/reset/sti/Kconfig"
> source "drivers/reset/hisilicon/Kconfig"
> source "drivers/reset/tegra/Kconfig"
> diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> index 16947610cc3b..1730a31e6871 100644
> --- a/drivers/reset/Makefile
> +++ b/drivers/reset/Makefile
> @@ -33,4 +33,5 @@ obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o
> obj-$(CONFIG_RESET_UNIPHIER_GLUE) += reset-uniphier-glue.o
> obj-$(CONFIG_RESET_ZYNQ) += reset-zynq.o
> obj-$(CONFIG_ARCH_ZYNQMP) += reset-zynqmp.o
> +obj-$(CONFIG_RESET_K210) += reset-k210.o
>
> diff --git a/drivers/reset/reset-k210.c b/drivers/reset/reset-k210.c
> new file mode 100644
> index 000000000000..b6401aef2923
> --- /dev/null
> +++ b/drivers/reset/reset-k210.c
> @@ -0,0 +1,186 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2020 Western Digital Corporation or its affiliates.
> + */
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset-controller.h>
> +#include <linux/delay.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +
> +#include <dt-bindings/mfd/k210-sysctl.h>
> +#include <dt-bindings/reset/k210-rst.h>
> +
> +struct k210_rst {
> + struct regmap *map;
> + u32 offset;
> + u32 mask;
> + u32 assert_high;
> + struct reset_controller_dev rcdev;
> +};
> +
> +static inline struct k210_rst *
> +to_k210_rst(struct reset_controller_dev *rcdev)
> +{
> + return container_of(rcdev, struct k210_rst, rcdev);
> +}
> +
> +static inline int k210_rst_assert(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct k210_rst *ksr = to_k210_rst(rcdev);
> + u32 bit = BIT(id);
> +
> + if (!(bit & ksr->mask)) {
> + dev_err(rcdev->dev, "Invalid assert id %lu\n", id);
> + return -EINVAL;
> + }
> +
> + dev_dbg(rcdev->dev, "assert %s %lu\n",
> + ksr->assert_high ? "high" : "low", id);
> +
> + regmap_update_bits(ksr->map, ksr->offset, bit,
> + ksr->assert_high ? bit : 0);
> +
> + return 0;
> +}
> +
> +static inline int k210_rst_deassert(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct k210_rst *ksr = to_k210_rst(rcdev);
> + u32 bit = BIT(id);
> +
> + if (!(bit & ksr->mask)) {
> + dev_err(rcdev->dev, "Invalid deassert id %lu\n", id);
> + return -EINVAL;
> + }
> +
> + dev_dbg(rcdev->dev, "deassert %s %lu\n",
> + ksr->assert_high ? "high" : "low", id);
> +
> + regmap_update_bits(ksr->map, ksr->offset, bit,
> + ksr->assert_high ? 0 : bit);
> +
> + return 0;
> +}
> +
> +static int k210_rst_reset(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct k210_rst *ksr = to_k210_rst(rcdev);
> + int ret;
> +
> + dev_dbg(rcdev->dev, "reset %s %lu\n",
> + ksr->assert_high ? "high" : "low", id);
> +
> + ret = k210_rst_assert(rcdev, id);
> + if (ret == 0) {
> + udelay(10);
> + ret = k210_rst_deassert(rcdev, id);
> + }
> +
> + return ret;
> +}
> +
> +static int k210_rst_status(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct k210_rst *ksr = to_k210_rst(rcdev);
> + u32 reg, bit = BIT(id);
> + int ret;
> +
> + if (!(bit & ksr->mask)) {
> + dev_err(rcdev->dev, "Invalid reset %lx\n", id);
> + return -EINVAL;
> + }
> +
> + ret = regmap_read(ksr->map, ksr->offset, &reg);
> + if (ret)
> + return ret;
> +
> + if (ksr->assert_high)
> + return ret & bit;
> +
> + return !(ret & bit);
> +}
> +
> +static const struct reset_control_ops k210_rst_ops = {
> + .assert = k210_rst_assert,
> + .deassert = k210_rst_deassert,
> + .reset = k210_rst_reset,
> + .status = k210_rst_status,
> +};
> +
> +static int __init k210_rst_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct k210_rst *ksr;
> + int ret, nr_resets;
> +
> + dev_info(dev, "K210 reset controller\n");
> +
> + ksr = devm_kzalloc(dev, sizeof(*ksr), GFP_KERNEL);
> + if (!ksr)
> + return -ENOMEM;
> +
> + ksr->map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
> + if (IS_ERR(ksr->map)) {
> + ksr->map = syscon_node_to_regmap(dev->parent->of_node);
> + if (IS_ERR(ksr->map)) {
> + dev_err(dev, "get register map failed\n");
> + return PTR_ERR(ksr->map);
> + }
> + }
> +
> + ret = of_property_read_u32(dev->of_node, "offset", &ksr->offset);
> + ret = of_property_read_u32(dev->of_node, "assert-high",
> + &ksr->assert_high);
> + if (ret) {
> + dev_err(dev, "unable to read 'offset' and 'assert-high'\n");
> + return -EINVAL;
> + }
> +
> + ret = of_property_read_u32(dev->of_node, "mask", &ksr->mask);
> + if (ret) {
> + /* Use default mask */
> + ksr->mask = 0x27FFFFFF;
> + }
> + nr_resets = fls(ksr->mask);
> + if (!nr_resets) {
> + dev_err(dev, "Invalid mask 0x%08x\n", ksr->mask);
> + return -EINVAL;
> + }
> +
> + ksr->rcdev.owner = THIS_MODULE;
> + ksr->rcdev.dev = dev;
> + ksr->rcdev.of_node = dev->of_node;
> + ksr->rcdev.nr_resets = nr_resets;
> + ksr->rcdev.ops = &k210_rst_ops;
> +
> + return devm_reset_controller_register(dev, &ksr->rcdev);
> +}
> +
> +static const struct of_device_id k210_rst_dt_ids[] = {
> + { .compatible = "kendryte,k210-rst" },
> +};
> +
> +static struct platform_driver k210_rst_driver = {
> + .probe = k210_rst_probe,
> + .driver = {
> + .name = "k210-rst",
> + .of_match_table = k210_rst_dt_ids,
> + },
> +};
> +
> +/*
> + * Most devices on the K210 SoC need reset as part of their initialization.
> + * So initialize this driver early as part of the post core initialization.
> + */
> +static int __init k210_rst_init(void)
> +{
> + return platform_driver_register(&k210_rst_driver);
> +}
> +postcore_initcall(k210_rst_init);
>

Reviewed-by: Sean Anderson <seanga2@gmail.com>