/* * I2C multiplexer * * Copyright (c) 2008-2009 Rodolfo Giometti * Copyright (c) 2008-2009 Eurotech S.p.A. * * This module supports the PCA954x and PCA954x 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 . * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #include #include #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 */ u8 deselect; 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); #ifdef CONFIG_OF 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); #endif /* 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 int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan) { struct pca954x *data = i2c_mux_priv(muxc); struct i2c_client *client = data->client; const struct chip_desc *chip = data->chip; u8 regval; int ret = 0; /* we make switches look like muxes, not sure how to be smarter */ if (chip->muxtype == pca954x_ismux) regval = chan | chip->enable; else regval = 1 << 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; if (!(data->deselect & (1 << chan))) return 0; /* Deselect active channel */ data->last_chan = 0; return pca954x_reg_write(muxc->parent, client, data->last_chan); } static irqreturn_t pca954x_irq_handler(int irq, void *dev_id) { struct pca954x *data = dev_id; unsigned int child_irq; int ret, i, handled = 0; ret = i2c_smbus_read_byte(data->client); if (ret < 0) return IRQ_NONE; for (i = 0; i < data->chip->nchans; i++) { if (ret & BIT(PCA954X_IRQ_OFFSET + i)) { child_irq = irq_linear_revmap(data->irq, i); handle_nested_irq(child_irq); handled++; } } return handled ? IRQ_HANDLED : IRQ_NONE; } 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); } /* * 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 pca954x_platform_data *pdata = dev_get_platdata(&client->dev); struct device *dev = &client->dev; struct device_node *np = dev->of_node; bool idle_disconnect_dt; struct gpio_desc *gpio; int num, force, class; struct i2c_mux_core *muxc; struct pca954x *data; 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 = of_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; } } /* Write the mux register at addr to verify * that the mux is in fact present. This also * initializes the mux to disconnected state. */ if (i2c_smbus_write_byte(client, 0) < 0) { dev_warn(dev, "probe failed\n"); return -ENODEV; } data->last_chan = 0; /* force the first selection */ idle_disconnect_dt = np && of_property_read_bool(np, "i2c-mux-idle-disconnect"); 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++) { bool idle_disconnect_pd = false; force = 0; /* dynamic adap number */ class = 0; /* no class by default */ if (pdata) { if (num < pdata->num_modes) { /* force static number */ force = pdata->modes[num].adap_id; class = pdata->modes[num].class; } else /* discard unconfigured channels */ break; idle_disconnect_pd = pdata->modes[num].deselect_on_exit; } data->deselect |= (idle_disconnect_pd || idle_disconnect_dt) << num; ret = i2c_mux_add_adapter(muxc, force, num, class); 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; } 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); 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); data->last_chan = 0; return i2c_smbus_write_byte(client, 0); } #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 = of_match_ptr(pca954x_of_match), }, .probe = 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");