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 commitintroduces 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 means that we will be instantiating 2 i2c_client-s for the first
I2cSerialBus resource, this is not pretty, but since the multi-instantiate
driver does exactly 0 i2c-transfers this is not a problem.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/i2c/Kconfig | 8 ++
drivers/i2c/Makefile | 1 +
drivers/i2c/i2c-multi-instantiate.c | 125 ++++++++++++++++++++++++++++
3 files changed, 134 insertions(+)
create mode 100644 drivers/i2c/i2c-multi-instantiate.c
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index efc3354d60ae..12ca950e7549 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -120,6 +120,14 @@ config I2C_SLAVE_EEPROM
endif
+config I2C_MULTI_INSTANTIATE
+ tristate "I2C multi instantiate pseudo device driver"
+ depends on ACPI
+ help
+ Some ACPI bases systems list multiple i2c-devices in a single ACPI
+ firmware-node. This driver will instantiate separate i2c-clients
+ for each device in the firmware-node.
+
config I2C_DEBUG_CORE
bool "I2C Core debugging messages"
help
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index 72c94c60fdd1..d9c5bae1d64f 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_I2C_MUX) += i2c-mux.o
obj-y += algos/ busses/ muxes/
obj-$(CONFIG_I2C_STUB) += i2c-stub.o
obj-$(CONFIG_I2C_SLAVE_EEPROM) += i2c-slave-eeprom.o
+obj-$(CONFIG_I2C_MULTI_INSTANTIATE) += i2c-multi-instantiate.o
ccflags-$(CONFIG_I2C_DEBUG_CORE) := -DDEBUG
CFLAGS_i2c-core-base.o := -Wno-deprecated-declarations
diff --git a/drivers/i2c/i2c-multi-instantiate.c b/drivers/i2c/i2c-multi-instantiate.c
new file mode 100644
index 000000000000..480b7a694eae
--- /dev/null
+++ b/drivers/i2c/i2c-multi-instantiate.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * I2C multi-instantiate driver, pseudo driver to instantiate multiple
+ * i2c-clients from a single fwnode.
+ *
+ * Copyright 2018 Hans de Goede <hdegoede@xxxxxxxxxx>
+ */
+
+#include <linux/acpi.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+struct i2c_inst_data {
+ const char *type;
+ int irq_idx;
+};
+
+struct i2c_multi_inst_data {
+ int no_clients;
+ struct i2c_client *clients[0];
+};
+
+static int i2c_multi_inst_probe(struct i2c_client *client)
+{
+ struct i2c_multi_inst_data *multi;
+ const struct i2c_inst_data *inst_data;
+ struct i2c_board_info board_info = {};
+ struct device *dev = &client->dev;
+ struct acpi_device *adev;
+ char name[32];
+ int i, ret;
+
+ inst_data = acpi_device_get_match_data(dev);
+ if (!inst_data) {
+ dev_err(dev, "Error ACPI match data is missing\n");
+ return -ENODEV;
+ }
+
+ adev = ACPI_COMPANION(dev);
+
+ /* Count number of clients to instantiate */
+ for (i = 0; inst_data[i].type; i++) {}
+
+ multi = devm_kmalloc(dev,
+ offsetof(struct i2c_multi_inst_data, clients[i]),
+ GFP_KERNEL);
+ if (!multi)
+ return -ENOMEM;
+
+ multi->no_clients = i;
+
+ for (i = 0; i < multi->no_clients; i++) {
+ memset(&board_info, 0, sizeof(board_info));
+ strlcpy(board_info.type, inst_data[i].type, I2C_NAME_SIZE);
+ board_info.flags = (i == 0) ? I2C_CLIENT_IGNORE_BUSY : 0;
+ snprintf(name, sizeof(name), "%s-%s", client->name,
+ inst_data[i].type);
+ board_info.dev_name = name;
+ board_info.irq = 0;
+ if (inst_data[i].irq_idx != -1) {
+ ret = acpi_dev_gpio_irq_get(adev, inst_data[i].irq_idx);
+ if (ret < 0) {
+ dev_err(dev, "Error requesting irq at index %d: %d\n",
+ inst_data[i].irq_idx, ret);
+ goto error;
+ }
+ board_info.irq = ret;
+ }
+ multi->clients[i] = i2c_acpi_new_device(dev, i, &board_info);
+ if (!multi->clients[i]) {
+ dev_err(dev, "Error creating i2c-client, idx %d\n", i);
+ ret = -ENODEV;
+ goto error;
+ }
+ }
+
+ return 0;
+
+error:
+ while (--i >= 0)
+ i2c_unregister_device(multi->clients[i]);
+
+ return ret;
+}
+
+static int i2c_multi_inst_remove(struct i2c_client *i2c)
+{
+ struct i2c_multi_inst_data *multi = i2c_get_clientdata(i2c);
+ int i;
+
+ for (i = 0; i < multi->no_clients; i++)
+ i2c_unregister_device(multi->clients[i]);
+
+ return 0;
+}
+
+static const struct i2c_inst_data bsg1160_data[] = {
+ { "bmc150_accel", 0 },
+ { "bmc150_magn", -1 },
+ { "bmg160", -1 },
+ {}
+};
+
+static const struct acpi_device_id i2c_multi_inst_acpi_ids[] = {
+ { "BSG1160", (unsigned long)bsg1160_data },
+ { }
+};
+MODULE_DEVICE_TABLE(acpi, i2c_multi_inst_acpi_ids);
+
+static struct i2c_driver i2c_multi_inst_driver = {
+ .driver = {
+ .name = "I2C multi instantiate pseudo device driver",
+ .acpi_match_table = ACPI_PTR(i2c_multi_inst_acpi_ids),
+ },
+ .probe_new = i2c_multi_inst_probe,
+ .remove = i2c_multi_inst_remove,
+};
+
+module_i2c_driver(i2c_multi_inst_driver);
+
+MODULE_DESCRIPTION("I2C multi instantiate pseudo device driver");
+MODULE_AUTHOR("Hans de Goede <hdegoede@xxxxxxxxxx>");
+MODULE_LICENSE("GPL");
--
2.17.0
--
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