On Fri, 2018-06-08 at 23:11 +0200, Hans de Goede wrote:
> 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.
>
You forgot to Cc Heikki.
> 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");
--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy
