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-rw-r--r--drivers/i2c/muxes/i2c-mux-pca954x.c567
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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-15 01:41:44 +0000