1 files changed, 567 insertions, 0 deletions
diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
new file mode 100644
index 000000000..4ad665757
--- /dev/null
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -0,0 +1,567 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * I2C multiplexer
+ *
+ * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
+ * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
+ *
+ * This module supports the PCA954x and PCA984x series of I2C multiplexer/switch
+ * chips made by NXP Semiconductors.
+ * This includes the:
+ *	 PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547,
+ *	 PCA9548, PCA9846, PCA9847, PCA9848 and PCA9849.
+ *
+ * These chips are all controlled via the I2C bus itself, and all have a
+ * single 8-bit register. The upstream "parent" bus fans out to two,
+ * four, or eight downstream busses or channels; which of these
+ * are selected is determined by the chip type and register contents. A
+ * mux can select only one sub-bus at a time; a switch can select any
+ * combination simultaneously.
+ *
+ * Based on:
+ *	pca954x.c from Kumar Gala <galak@kernel.crashing.org>
+ * Copyright (C) 2006
+ *
+ * Based on:
+ *	pca954x.c from Ken Harrenstien
+ * Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
+ *
+ * Based on:
+ *	i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
+ * and
+ *	pca9540.c from Jean Delvare <jdelvare@suse.de>.
+ */
+
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <dt-bindings/mux/mux.h>
+
+#define PCA954X_MAX_NCHANS 8
+
+#define PCA954X_IRQ_OFFSET 4
+
+enum pca_type {
+	pca_9540,
+	pca_9542,
+	pca_9543,
+	pca_9544,
+	pca_9545,
+	pca_9546,
+	pca_9547,
+	pca_9548,
+	pca_9846,
+	pca_9847,
+	pca_9848,
+	pca_9849,
+};
+
+struct chip_desc {
+	u8 nchans;
+	u8 enable;	/* used for muxes only */
+	u8 has_irq;
+	enum muxtype {
+		pca954x_ismux = 0,
+		pca954x_isswi
+	} muxtype;
+	struct i2c_device_identity id;
+};
+
+struct pca954x {
+	const struct chip_desc *chip;
+
+	u8 last_chan;		/* last register value */
+	/* MUX_IDLE_AS_IS, MUX_IDLE_DISCONNECT or >= 0 for channel */
+	s32 idle_state;
+
+	struct i2c_client *client;
+
+	struct irq_domain *irq;
+	unsigned int irq_mask;
+	raw_spinlock_t lock;
+};
+
+/* Provide specs for the PCA954x types we know about */
+static const struct chip_desc chips[] = {
+	[pca_9540] = {
+		.nchans = 2,
+		.enable = 0x4,
+		.muxtype = pca954x_ismux,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[pca_9542] = {
+		.nchans = 2,
+		.enable = 0x4,
+		.has_irq = 1,
+		.muxtype = pca954x_ismux,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[pca_9543] = {
+		.nchans = 2,
+		.has_irq = 1,
+		.muxtype = pca954x_isswi,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[pca_9544] = {
+		.nchans = 4,
+		.enable = 0x4,
+		.has_irq = 1,
+		.muxtype = pca954x_ismux,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[pca_9545] = {
+		.nchans = 4,
+		.has_irq = 1,
+		.muxtype = pca954x_isswi,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[pca_9546] = {
+		.nchans = 4,
+		.muxtype = pca954x_isswi,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[pca_9547] = {
+		.nchans = 8,
+		.enable = 0x8,
+		.muxtype = pca954x_ismux,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[pca_9548] = {
+		.nchans = 8,
+		.muxtype = pca954x_isswi,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+	},
+	[pca_9846] = {
+		.nchans = 4,
+		.muxtype = pca954x_isswi,
+		.id = {
+			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
+			.part_id = 0x10b,
+		},
+	},
+	[pca_9847] = {
+		.nchans = 8,
+		.enable = 0x8,
+		.muxtype = pca954x_ismux,
+		.id = {
+			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
+			.part_id = 0x108,
+		},
+	},
+	[pca_9848] = {
+		.nchans = 8,
+		.muxtype = pca954x_isswi,
+		.id = {
+			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
+			.part_id = 0x10a,
+		},
+	},
+	[pca_9849] = {
+		.nchans = 4,
+		.enable = 0x4,
+		.muxtype = pca954x_ismux,
+		.id = {
+			.manufacturer_id = I2C_DEVICE_ID_NXP_SEMICONDUCTORS,
+			.part_id = 0x109,
+		},
+	},
+};
+
+static const struct i2c_device_id pca954x_id[] = {
+	{ "pca9540", pca_9540 },
+	{ "pca9542", pca_9542 },
+	{ "pca9543", pca_9543 },
+	{ "pca9544", pca_9544 },
+	{ "pca9545", pca_9545 },
+	{ "pca9546", pca_9546 },
+	{ "pca9547", pca_9547 },
+	{ "pca9548", pca_9548 },
+	{ "pca9846", pca_9846 },
+	{ "pca9847", pca_9847 },
+	{ "pca9848", pca_9848 },
+	{ "pca9849", pca_9849 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, pca954x_id);
+
+static const struct of_device_id pca954x_of_match[] = {
+	{ .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
+	{ .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
+	{ .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
+	{ .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
+	{ .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
+	{ .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
+	{ .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
+	{ .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
+	{ .compatible = "nxp,pca9846", .data = &chips[pca_9846] },
+	{ .compatible = "nxp,pca9847", .data = &chips[pca_9847] },
+	{ .compatible = "nxp,pca9848", .data = &chips[pca_9848] },
+	{ .compatible = "nxp,pca9849", .data = &chips[pca_9849] },
+	{}
+};
+MODULE_DEVICE_TABLE(of, pca954x_of_match);
+
+/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
+   for this as they will try to lock adapter a second time */
+static int pca954x_reg_write(struct i2c_adapter *adap,
+			     struct i2c_client *client, u8 val)
+{
+	union i2c_smbus_data dummy;
+
+	return __i2c_smbus_xfer(adap, client->addr, client->flags,
+				I2C_SMBUS_WRITE, val,
+				I2C_SMBUS_BYTE, &dummy);
+}
+
+static u8 pca954x_regval(struct pca954x *data, u8 chan)
+{
+	/* We make switches look like muxes, not sure how to be smarter. */
+	if (data->chip->muxtype == pca954x_ismux)
+		return chan | data->chip->enable;
+	else
+		return 1 << chan;
+}
+
+static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
+{
+	struct pca954x *data = i2c_mux_priv(muxc);
+	struct i2c_client *client = data->client;
+	u8 regval;
+	int ret = 0;
+
+	regval = pca954x_regval(data, chan);
+	/* Only select the channel if its different from the last channel */
+	if (data->last_chan != regval) {
+		ret = pca954x_reg_write(muxc->parent, client, regval);
+		data->last_chan = ret < 0 ? 0 : regval;
+	}
+
+	return ret;
+}
+
+static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
+{
+	struct pca954x *data = i2c_mux_priv(muxc);
+	struct i2c_client *client = data->client;
+	s32 idle_state;
+
+	idle_state = READ_ONCE(data->idle_state);
+	if (idle_state >= 0)
+		/* Set the mux back to a predetermined channel */
+		return pca954x_select_chan(muxc, idle_state);
+
+	if (idle_state == MUX_IDLE_DISCONNECT) {
+		/* Deselect active channel */
+		data->last_chan = 0;
+		return pca954x_reg_write(muxc->parent, client,
+					 data->last_chan);
+	}
+
+	/* otherwise leave as-is */
+
+	return 0;
+}
+
+static ssize_t idle_state_show(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
+	struct pca954x *data = i2c_mux_priv(muxc);
+
+	return sprintf(buf, "%d\n", READ_ONCE(data->idle_state));
+}
+
+static ssize_t idle_state_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
+	struct pca954x *data = i2c_mux_priv(muxc);
+	int val;
+	int ret;
+
+	ret = kstrtoint(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+
+	if (val != MUX_IDLE_AS_IS && val != MUX_IDLE_DISCONNECT &&
+	    (val < 0 || val >= data->chip->nchans))
+		return -EINVAL;
+
+	i2c_lock_bus(muxc->parent, I2C_LOCK_SEGMENT);
+
+	WRITE_ONCE(data->idle_state, val);
+	/*
+	 * Set the mux into a state consistent with the new
+	 * idle_state.
+	 */
+	if (data->last_chan || val != MUX_IDLE_DISCONNECT)
+		ret = pca954x_deselect_mux(muxc, 0);
+
+	i2c_unlock_bus(muxc->parent, I2C_LOCK_SEGMENT);
+
+	return ret < 0 ? ret : count;
+}
+
+static DEVICE_ATTR_RW(idle_state);
+
+static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
+{
+	struct pca954x *data = dev_id;
+	unsigned long pending;
+	int ret, i;
+
+	ret = i2c_smbus_read_byte(data->client);
+	if (ret < 0)
+		return IRQ_NONE;
+
+	pending = (ret >> PCA954X_IRQ_OFFSET) & (BIT(data->chip->nchans) - 1);
+	for_each_set_bit(i, &pending, data->chip->nchans)
+		handle_nested_irq(irq_linear_revmap(data->irq, i));
+
+	return IRQ_RETVAL(pending);
+}
+
+static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
+{
+	if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
+		return -EINVAL;
+	return 0;
+}
+
+static struct irq_chip pca954x_irq_chip = {
+	.name = "i2c-mux-pca954x",
+	.irq_set_type = pca954x_irq_set_type,
+};
+
+static int pca954x_irq_setup(struct i2c_mux_core *muxc)
+{
+	struct pca954x *data = i2c_mux_priv(muxc);
+	struct i2c_client *client = data->client;
+	int c, irq;
+
+	if (!data->chip->has_irq || client->irq <= 0)
+		return 0;
+
+	raw_spin_lock_init(&data->lock);
+
+	data->irq = irq_domain_add_linear(client->dev.of_node,
+					  data->chip->nchans,
+					  &irq_domain_simple_ops, data);
+	if (!data->irq)
+		return -ENODEV;
+
+	for (c = 0; c < data->chip->nchans; c++) {
+		irq = irq_create_mapping(data->irq, c);
+		if (!irq) {
+			dev_err(&client->dev, "failed irq create map\n");
+			return -EINVAL;
+		}
+		irq_set_chip_data(irq, data);
+		irq_set_chip_and_handler(irq, &pca954x_irq_chip,
+			handle_simple_irq);
+	}
+
+	return 0;
+}
+
+static void pca954x_cleanup(struct i2c_mux_core *muxc)
+{
+	struct pca954x *data = i2c_mux_priv(muxc);
+	int c, irq;
+
+	if (data->irq) {
+		for (c = 0; c < data->chip->nchans; c++) {
+			irq = irq_find_mapping(data->irq, c);
+			irq_dispose_mapping(irq);
+		}
+		irq_domain_remove(data->irq);
+	}
+	i2c_mux_del_adapters(muxc);
+}
+
+static int pca954x_init(struct i2c_client *client, struct pca954x *data)
+{
+	int ret;
+
+	if (data->idle_state >= 0)
+		data->last_chan = pca954x_regval(data, data->idle_state);
+	else
+		data->last_chan = 0; /* Disconnect multiplexer */
+
+	ret = i2c_smbus_write_byte(client, data->last_chan);
+	if (ret < 0)
+		data->last_chan = 0;
+
+	return ret;
+}
+
+/*
+ * I2C init/probing/exit functions
+ */
+static int pca954x_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct i2c_adapter *adap = client->adapter;
+	struct device *dev = &client->dev;
+	struct gpio_desc *gpio;
+	struct i2c_mux_core *muxc;
+	struct pca954x *data;
+	int num;
+	int ret;
+
+	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
+		return -ENODEV;
+
+	muxc = i2c_mux_alloc(adap, dev, PCA954X_MAX_NCHANS, sizeof(*data), 0,
+			     pca954x_select_chan, pca954x_deselect_mux);
+	if (!muxc)
+		return -ENOMEM;
+	data = i2c_mux_priv(muxc);
+
+	i2c_set_clientdata(client, muxc);
+	data->client = client;
+
+	/* Reset the mux if a reset GPIO is specified. */
+	gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(gpio))
+		return PTR_ERR(gpio);
+	if (gpio) {
+		udelay(1);
+		gpiod_set_value_cansleep(gpio, 0);
+		/* Give the chip some time to recover. */
+		udelay(1);
+	}
+
+	data->chip = device_get_match_data(dev);
+	if (!data->chip)
+		data->chip = &chips[id->driver_data];
+
+	if (data->chip->id.manufacturer_id != I2C_DEVICE_ID_NONE) {
+		struct i2c_device_identity id;
+
+		ret = i2c_get_device_id(client, &id);
+		if (ret && ret != -EOPNOTSUPP)
+			return ret;
+
+		if (!ret &&
+		    (id.manufacturer_id != data->chip->id.manufacturer_id ||
+		     id.part_id != data->chip->id.part_id)) {
+			dev_warn(dev, "unexpected device id %03x-%03x-%x\n",
+				 id.manufacturer_id, id.part_id,
+				 id.die_revision);
+			return -ENODEV;
+		}
+	}
+
+	data->idle_state = MUX_IDLE_AS_IS;
+	if (device_property_read_u32(dev, "idle-state", &data->idle_state)) {
+		if (device_property_read_bool(dev, "i2c-mux-idle-disconnect"))
+			data->idle_state = MUX_IDLE_DISCONNECT;
+	}
+
+	/*
+	 * Write the mux register at addr to verify
+	 * that the mux is in fact present. This also
+	 * initializes the mux to a channel
+	 * or disconnected state.
+	 */
+	ret = pca954x_init(client, data);
+	if (ret < 0) {
+		dev_warn(dev, "probe failed\n");
+		return -ENODEV;
+	}
+
+	ret = pca954x_irq_setup(muxc);
+	if (ret)
+		goto fail_cleanup;
+
+	/* Now create an adapter for each channel */
+	for (num = 0; num < data->chip->nchans; num++) {
+		ret = i2c_mux_add_adapter(muxc, 0, num, 0);
+		if (ret)
+			goto fail_cleanup;
+	}
+
+	if (data->irq) {
+		ret = devm_request_threaded_irq(dev, data->client->irq,
+						NULL, pca954x_irq_handler,
+						IRQF_ONESHOT | IRQF_SHARED,
+						"pca954x", data);
+		if (ret)
+			goto fail_cleanup;
+	}
+
+	/*
+	 * The attr probably isn't going to be needed in most cases,
+	 * so don't fail completely on error.
+	 */
+	device_create_file(dev, &dev_attr_idle_state);
+
+	dev_info(dev, "registered %d multiplexed busses for I2C %s %s\n",
+		 num, data->chip->muxtype == pca954x_ismux
+				? "mux" : "switch", client->name);
+
+	return 0;
+
+fail_cleanup:
+	pca954x_cleanup(muxc);
+	return ret;
+}
+
+static int pca954x_remove(struct i2c_client *client)
+{
+	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
+
+	device_remove_file(&client->dev, &dev_attr_idle_state);
+
+	pca954x_cleanup(muxc);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int pca954x_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
+	struct pca954x *data = i2c_mux_priv(muxc);
+	int ret;
+
+	ret = pca954x_init(client, data);
+	if (ret < 0)
+		dev_err(&client->dev, "failed to verify mux presence\n");
+
+	return ret;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
+
+static struct i2c_driver pca954x_driver = {
+	.driver		= {
+		.name	= "pca954x",
+		.pm	= &pca954x_pm,
+		.of_match_table = pca954x_of_match,
+	},
+	.probe		= pca954x_probe,
+	.remove		= pca954x_remove,
+	.id_table	= pca954x_id,
+};
+
+module_i2c_driver(pca954x_driver);
+
+MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
+MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
+MODULE_LICENSE("GPL v2");