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On systems with ACPI instantiated i2c-clients, normally there is 1 fw_node per i2c-device and that fw-node contains 1 I2cSerialBus resource for that 1 i2c-device. But in some rare cases the manufacturer has decided to describe multiple i2c-devices in a single ACPI fwnode with multiple I2cSerialBus resources. An earlier attempt to fix this in the i2c-core resulted in a lot of extra code to support this corner-case. This commit introduces a new i2c-multi-instantiate driver which fixes this in a different way. This new driver can be built as a module which will only loaded on affected systems. This driver will instantiate a new i2c-client per I2cSerialBus resource, using the driver_data from the acpi_device_id it is binding to to tell it which chip-type (and optional irq-resource) to use when instantiating. Note this driver depends on a platform device being instantiated for the ACPI fwnode, see the i2c_multi_instantiate_ids list of ACPI device-ids in drivers/acpi/scan.c: acpi_device_enumeration_by_parent(). Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
132 lines
3.3 KiB
C
132 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* I2C multi-instantiate driver, pseudo driver to instantiate multiple
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* i2c-clients from a single fwnode.
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*
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* Copyright 2018 Hans de Goede <hdegoede@redhat.com>
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*/
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#include <linux/acpi.h>
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#include <linux/i2c.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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struct i2c_inst_data {
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const char *type;
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int gpio_irq_idx;
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};
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struct i2c_multi_inst_data {
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int num_clients;
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struct i2c_client *clients[0];
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};
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static int i2c_multi_inst_probe(struct platform_device *pdev)
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{
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struct i2c_multi_inst_data *multi;
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const struct acpi_device_id *match;
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const struct i2c_inst_data *inst_data;
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struct i2c_board_info board_info = {};
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struct device *dev = &pdev->dev;
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struct acpi_device *adev;
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char name[32];
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int i, ret;
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match = acpi_match_device(dev->driver->acpi_match_table, dev);
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if (!match) {
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dev_err(dev, "Error ACPI match data is missing\n");
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return -ENODEV;
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}
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inst_data = (const struct i2c_inst_data *)match->driver_data;
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adev = ACPI_COMPANION(dev);
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/* Count number of clients to instantiate */
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for (i = 0; inst_data[i].type; i++) {}
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multi = devm_kmalloc(dev,
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offsetof(struct i2c_multi_inst_data, clients[i]),
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GFP_KERNEL);
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if (!multi)
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return -ENOMEM;
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multi->num_clients = i;
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for (i = 0; i < multi->num_clients; i++) {
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memset(&board_info, 0, sizeof(board_info));
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strlcpy(board_info.type, inst_data[i].type, I2C_NAME_SIZE);
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snprintf(name, sizeof(name), "%s-%s", match->id,
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inst_data[i].type);
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board_info.dev_name = name;
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board_info.irq = 0;
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if (inst_data[i].gpio_irq_idx != -1) {
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ret = acpi_dev_gpio_irq_get(adev,
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inst_data[i].gpio_irq_idx);
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if (ret < 0) {
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dev_err(dev, "Error requesting irq at index %d: %d\n",
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inst_data[i].gpio_irq_idx, ret);
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goto error;
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}
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board_info.irq = ret;
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}
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multi->clients[i] = i2c_acpi_new_device(dev, i, &board_info);
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if (!multi->clients[i]) {
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dev_err(dev, "Error creating i2c-client, idx %d\n", i);
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ret = -ENODEV;
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goto error;
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}
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}
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platform_set_drvdata(pdev, multi);
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return 0;
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error:
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while (--i >= 0)
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i2c_unregister_device(multi->clients[i]);
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return ret;
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}
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static int i2c_multi_inst_remove(struct platform_device *pdev)
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{
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struct i2c_multi_inst_data *multi = platform_get_drvdata(pdev);
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int i;
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for (i = 0; i < multi->num_clients; i++)
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i2c_unregister_device(multi->clients[i]);
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return 0;
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}
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static const struct i2c_inst_data bsg1160_data[] = {
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{ "bmc150_accel", 0 },
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{ "bmc150_magn", -1 },
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{ "bmg160", -1 },
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{}
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};
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/*
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* Note new device-ids must also be added to i2c_multi_instantiate_ids in
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* drivers/acpi/scan.c: acpi_device_enumeration_by_parent().
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*/
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static const struct acpi_device_id i2c_multi_inst_acpi_ids[] = {
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{ "BSG1160", (unsigned long)bsg1160_data },
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{ }
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};
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MODULE_DEVICE_TABLE(acpi, i2c_multi_inst_acpi_ids);
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static struct platform_driver i2c_multi_inst_driver = {
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.driver = {
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.name = "I2C multi instantiate pseudo device driver",
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.acpi_match_table = ACPI_PTR(i2c_multi_inst_acpi_ids),
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},
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.probe = i2c_multi_inst_probe,
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.remove = i2c_multi_inst_remove,
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};
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module_platform_driver(i2c_multi_inst_driver);
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MODULE_DESCRIPTION("I2C multi instantiate pseudo device driver");
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MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
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MODULE_LICENSE("GPL");
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