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authorDamien Le Moal <damien.lemoal@wdc.com>2020-12-13 16:50:47 +0300
committerPalmer Dabbelt <palmerdabbelt@google.com>2021-01-15 02:08:53 +0300
commit5a2308da9f60312addfb5f7bdd15d96ba1299480 (patch)
treef3bb65ddfd5343d854e5997421cbe80559eb1985 /drivers/reset/reset-k210.c
parented3137edb31b86702511e7ad12b4abe8686b6805 (diff)
downloadlinux-5a2308da9f60312addfb5f7bdd15d96ba1299480.tar.xz
riscv: Add Canaan Kendryte K210 reset controller
Add a reset controller driver for the Canaan Kendryte K210 SoC. This driver relies on its syscon compatible parent node (sysctl) for its register mapping. Default this driver compilation to y when the SOC_CANAAN option is selected. The MAINTAINERS file is updated, adding the entry "CANAAN/KENDRYTE K210 SOC RESET CONTROLLER DRIVER" with myself listed as maintainer for this driver. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'drivers/reset/reset-k210.c')
-rw-r--r--drivers/reset/reset-k210.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/drivers/reset/reset-k210.c b/drivers/reset/reset-k210.c
new file mode 100644
index 000000000000..1b6e03522b40
--- /dev/null
+++ b/drivers/reset/reset-k210.c
@@ -0,0 +1,131 @@
+// 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 <soc/canaan/k210-sysctl.h>
+
+#include <dt-bindings/reset/k210-rst.h>
+
+#define K210_RST_MASK 0x27FFFFFF
+
+struct k210_rst {
+ struct regmap *map;
+ 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);
+
+ return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 1);
+}
+
+static inline int k210_rst_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct k210_rst *ksr = to_k210_rst(rcdev);
+
+ return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 0);
+}
+
+static int k210_rst_reset(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ int ret;
+
+ 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;
+
+ ret = regmap_read(ksr->map, K210_SYSCTL_PERI_RESET, &reg);
+ if (ret)
+ return ret;
+
+ return reg & bit;
+}
+
+static int k210_rst_xlate(struct reset_controller_dev *rcdev,
+ const struct of_phandle_args *reset_spec)
+{
+ unsigned long id = reset_spec->args[0];
+
+ if (!(BIT(id) & K210_RST_MASK))
+ return -EINVAL;
+
+ return id;
+}
+
+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 k210_rst_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *parent_np = of_get_parent(dev->of_node);
+ struct k210_rst *ksr;
+
+ dev_info(dev, "K210 reset controller\n");
+
+ ksr = devm_kzalloc(dev, sizeof(*ksr), GFP_KERNEL);
+ if (!ksr)
+ return -ENOMEM;
+
+ ksr->map = syscon_node_to_regmap(parent_np);
+ of_node_put(parent_np);
+ if (IS_ERR(ksr->map))
+ return PTR_ERR(ksr->map);
+
+ ksr->rcdev.owner = THIS_MODULE;
+ ksr->rcdev.dev = dev;
+ ksr->rcdev.of_node = dev->of_node;
+ ksr->rcdev.ops = &k210_rst_ops;
+ ksr->rcdev.nr_resets = fls(K210_RST_MASK);
+ ksr->rcdev.of_reset_n_cells = 1;
+ ksr->rcdev.of_xlate = k210_rst_xlate;
+
+ return devm_reset_controller_register(dev, &ksr->rcdev);
+}
+
+static const struct of_device_id k210_rst_dt_ids[] = {
+ { .compatible = "canaan,k210-rst" },
+ { /* sentinel */ },
+};
+
+static struct platform_driver k210_rst_driver = {
+ .probe = k210_rst_probe,
+ .driver = {
+ .name = "k210-rst",
+ .of_match_table = k210_rst_dt_ids,
+ },
+};
+builtin_platform_driver(k210_rst_driver);