// SPDX-License-Identifier: GPL-2.0 /* * I2C multiplexer * * Copyright (c) 2008-2009 Rodolfo Giometti * Copyright (c) 2008-2009 Eurotech S.p.A. * * 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 * 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 * and * pca9540.c from Jean Delvare . */ #include #include #include #include #include #include #include #include #include #include #include #include #include #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 = i2c_client_get_device_id(client); 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 void 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); } #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_new = pca954x_probe, .remove = pca954x_remove, .id_table = pca954x_id, }; module_i2c_driver(pca954x_driver); MODULE_AUTHOR("Rodolfo Giometti "); MODULE_DESCRIPTION("PCA954x I2C mux/switch driver"); MODULE_LICENSE("GPL v2");