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-rw-r--r--drivers/mux/mmio.c142
1 files changed, 142 insertions, 0 deletions
diff --git a/drivers/mux/mmio.c b/drivers/mux/mmio.c
new file mode 100644
index 000000000..44a7a0e88
--- /dev/null
+++ b/drivers/mux/mmio.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MMIO register bitfield-controlled multiplexer driver
+ *
+ * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
+ */
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/mux/driver.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+static int mux_mmio_set(struct mux_control *mux, int state)
+{
+ struct regmap_field **fields = mux_chip_priv(mux->chip);
+
+ return regmap_field_write(fields[mux_control_get_index(mux)], state);
+}
+
+static const struct mux_control_ops mux_mmio_ops = {
+ .set = mux_mmio_set,
+};
+
+static const struct of_device_id mux_mmio_dt_ids[] = {
+ { .compatible = "mmio-mux", },
+ { .compatible = "reg-mux", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mux_mmio_dt_ids);
+
+static int mux_mmio_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct regmap_field **fields;
+ struct mux_chip *mux_chip;
+ struct regmap *regmap;
+ int num_fields;
+ int ret;
+ int i;
+
+ if (of_device_is_compatible(np, "mmio-mux"))
+ regmap = syscon_node_to_regmap(np->parent);
+ else
+ regmap = dev_get_regmap(dev->parent, NULL) ?: ERR_PTR(-ENODEV);
+ if (IS_ERR(regmap)) {
+ ret = PTR_ERR(regmap);
+ dev_err(dev, "failed to get regmap: %d\n", ret);
+ return ret;
+ }
+
+ ret = of_property_count_u32_elems(np, "mux-reg-masks");
+ if (ret == 0 || ret % 2)
+ ret = -EINVAL;
+ if (ret < 0) {
+ dev_err(dev, "mux-reg-masks property missing or invalid: %d\n",
+ ret);
+ return ret;
+ }
+ num_fields = ret / 2;
+
+ mux_chip = devm_mux_chip_alloc(dev, num_fields, num_fields *
+ sizeof(*fields));
+ if (IS_ERR(mux_chip))
+ return PTR_ERR(mux_chip);
+
+ fields = mux_chip_priv(mux_chip);
+
+ for (i = 0; i < num_fields; i++) {
+ struct mux_control *mux = &mux_chip->mux[i];
+ struct reg_field field;
+ s32 idle_state = MUX_IDLE_AS_IS;
+ u32 reg, mask;
+ int bits;
+
+ ret = of_property_read_u32_index(np, "mux-reg-masks",
+ 2 * i, &reg);
+ if (!ret)
+ ret = of_property_read_u32_index(np, "mux-reg-masks",
+ 2 * i + 1, &mask);
+ if (ret < 0) {
+ dev_err(dev, "bitfield %d: failed to read mux-reg-masks property: %d\n",
+ i, ret);
+ return ret;
+ }
+
+ field.reg = reg;
+ field.msb = fls(mask) - 1;
+ field.lsb = ffs(mask) - 1;
+
+ if (mask != GENMASK(field.msb, field.lsb)) {
+ dev_err(dev, "bitfield %d: invalid mask 0x%x\n",
+ i, mask);
+ return -EINVAL;
+ }
+
+ fields[i] = devm_regmap_field_alloc(dev, regmap, field);
+ if (IS_ERR(fields[i])) {
+ ret = PTR_ERR(fields[i]);
+ dev_err(dev, "bitfield %d: failed allocate: %d\n",
+ i, ret);
+ return ret;
+ }
+
+ bits = 1 + field.msb - field.lsb;
+ mux->states = 1 << bits;
+
+ of_property_read_u32_index(np, "idle-states", i,
+ (u32 *)&idle_state);
+ if (idle_state != MUX_IDLE_AS_IS) {
+ if (idle_state < 0 || idle_state >= mux->states) {
+ dev_err(dev, "bitfield: %d: out of range idle state %d\n",
+ i, idle_state);
+ return -EINVAL;
+ }
+
+ mux->idle_state = idle_state;
+ }
+ }
+
+ mux_chip->ops = &mux_mmio_ops;
+
+ return devm_mux_chip_register(dev, mux_chip);
+}
+
+static struct platform_driver mux_mmio_driver = {
+ .driver = {
+ .name = "mmio-mux",
+ .of_match_table = of_match_ptr(mux_mmio_dt_ids),
+ },
+ .probe = mux_mmio_probe,
+};
+module_platform_driver(mux_mmio_driver);
+
+MODULE_DESCRIPTION("MMIO register bitfield-controlled multiplexer driver");
+MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
+MODULE_LICENSE("GPL v2");