mux: mmio-based syscon mux controller (73726380) · Commits · e / devices / android_kernel_fairphone_FP5

drivers/mux/Kconfig

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		@@ -43,4 +43,17 @@ config MUX_GPIO
		To compile the driver as a module, choose M here: the module will
		be called mux-gpio.

		config MUX_MMIO
		tristate "MMIO register bitfield-controlled Multiplexer"
		depends on (OF && MFD_SYSCON) \|\| COMPILE_TEST
		help
		MMIO register bitfield-controlled Multiplexer controller.

		The driver builds multiplexer controllers for bitfields in a syscon
		register. For N bit wide bitfields, there will be 2^N possible
		multiplexer states.

		To compile the driver as a module, choose M here: the module will
		be called mux-mmio.

		endif

drivers/mux/Makefile

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		@@ -5,3 +5,4 @@
		obj-$(CONFIG_MULTIPLEXER) += mux-core.o
		obj-$(CONFIG_MUX_ADG792A) += mux-adg792a.o
		obj-$(CONFIG_MUX_GPIO) += mux-gpio.o
		obj-$(CONFIG_MUX_MMIO) += mux-mmio.o

drivers/mux/mux-mmio.c

0 → 100644

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		/*
		* MMIO register bitfield-controlled multiplexer driver
		*
		* Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
		*
		* 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.
		*/

		#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", },
		{ /* 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;

		regmap = syscon_node_to_regmap(np->parent);
		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");