platform/x86: Add ACPI i2c-multi-instantiate pseudo driver

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>

diff --git a/MAINTAINERS b/MAINTAINERS
index 7cebd5bba8a8eb15305966228440f77174744a97..a7cf519991ec6094b1d9ccf44235fa949f0a1a8a 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -367,6 +367,12 @@ L: linux-acpi@vger.kernel.org
 S:     Maintained
 F:     drivers/acpi/arm64
 
+ACPI I2C MULTI INSTANTIATE DRIVER
+M:     Hans de Goede <hdegoede@redhat.com>
+L:     platform-driver-x86@vger.kernel.org
+S:     Maintained
+F:     drivers/platform/x86/i2c-multi-instantiate.c
+
 ACPI PMIC DRIVERS
 M:     "Rafael J. Wysocki" <rjw@rjwysocki.net>
 M:     Len Brown <lenb@kernel.org>

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index ac4d4883041537c3f4c6124acd6b52f141b6c89a..107d336453b2c3d15d804ba75ad843dc765a2e93 100644 (file)
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1218,6 +1218,17 @@ config INTEL_CHTDC_TI_PWRBTN
          To compile this driver as a module, choose M here: the module
          will be called intel_chtdc_ti_pwrbtn.
 
+config I2C_MULTI_INSTANTIATE
+       tristate "I2C multi instantiate pseudo device driver"
+       depends on I2C && ACPI
+       help
+         Some ACPI-based 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.
+
+         To compile this driver as a module, choose M here: the module
+         will be called i2c-multi-instantiate.
+
 endif # X86_PLATFORM_DEVICES
 
 config PMC_ATOM

diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 2ba6cb7953384e8af9b150adca7775c3bea6ec29..50dc8f2809144cf23491b1ee473e874b7decc00f 100644 (file)
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -91,3 +91,4 @@ obj-$(CONFIG_PMC_ATOM)                += pmc_atom.o
 obj-$(CONFIG_MLX_PLATFORM)     += mlx-platform.o
 obj-$(CONFIG_INTEL_TURBO_MAX_3) += intel_turbo_max_3.o
 obj-$(CONFIG_INTEL_CHTDC_TI_PWRBTN)    += intel_chtdc_ti_pwrbtn.o
+obj-$(CONFIG_I2C_MULTI_INSTANTIATE)    += i2c-multi-instantiate.o

diff --git a/drivers/platform/x86/i2c-multi-instantiate.c b/drivers/platform/x86/i2c-multi-instantiate.c
new file mode 100644 (file)
index 0000000..5456581
--- /dev/null
+++ b/drivers/platform/x86/i2c-multi-instantiate.c
@@ -0,0 +1,132 @@
+// 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@redhat.com>
+ */
+
+#include <linux/acpi.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+struct i2c_inst_data {
+       const char *type;
+       int gpio_irq_idx;
+};
+
+struct i2c_multi_inst_data {
+       int num_clients;
+       struct i2c_client *clients[0];
+};
+
+static int i2c_multi_inst_probe(struct platform_device *pdev)
+{
+       struct i2c_multi_inst_data *multi;
+       const struct acpi_device_id *match;
+       const struct i2c_inst_data *inst_data;
+       struct i2c_board_info board_info = {};
+       struct device *dev = &pdev->dev;
+       struct acpi_device *adev;
+       char name[32];
+       int i, ret;
+
+       match = acpi_match_device(dev->driver->acpi_match_table, dev);
+       if (!match) {
+               dev_err(dev, "Error ACPI match data is missing\n");
+               return -ENODEV;
+       }
+       inst_data = (const struct i2c_inst_data *)match->driver_data;
+
+       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->num_clients = i;
+
+       for (i = 0; i < multi->num_clients; i++) {
+               memset(&board_info, 0, sizeof(board_info));
+               strlcpy(board_info.type, inst_data[i].type, I2C_NAME_SIZE);
+               snprintf(name, sizeof(name), "%s-%s", match->id,
+                        inst_data[i].type);
+               board_info.dev_name = name;
+               board_info.irq = 0;
+               if (inst_data[i].gpio_irq_idx != -1) {
+                       ret = acpi_dev_gpio_irq_get(adev,
+                                                   inst_data[i].gpio_irq_idx);
+                       if (ret < 0) {
+                               dev_err(dev, "Error requesting irq at index %d: %d\n",
+                                       inst_data[i].gpio_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;
+               }
+       }
+
+       platform_set_drvdata(pdev, multi);
+       return 0;
+
+error:
+       while (--i >= 0)
+               i2c_unregister_device(multi->clients[i]);
+
+       return ret;
+}
+
+static int i2c_multi_inst_remove(struct platform_device *pdev)
+{
+       struct i2c_multi_inst_data *multi = platform_get_drvdata(pdev);
+       int i;
+
+       for (i = 0; i < multi->num_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 },
+       {}
+};
+
+/*
+ * Note new device-ids must also be added to i2c_multi_instantiate_ids in
+ * drivers/acpi/scan.c: acpi_device_enumeration_by_parent().
+ */
+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 platform_driver i2c_multi_inst_driver = {
+       .driver = {
+               .name = "I2C multi instantiate pseudo device driver",
+               .acpi_match_table = ACPI_PTR(i2c_multi_inst_acpi_ids),
+       },
+       .probe = i2c_multi_inst_probe,
+       .remove = i2c_multi_inst_remove,
+};
+module_platform_driver(i2c_multi_inst_driver);
+
+MODULE_DESCRIPTION("I2C multi instantiate pseudo device driver");
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_LICENSE("GPL");