[PATCH v6 0/6] i2c-i801 / dell-lis3lv02d: Move instantiation of lis3lv02d i2c_client from i2c-i801 to dell-lis3lv02d

[PATCH v6 0/6] i2c-i801 / dell-lis3lv02d: Move instantiation of lis3lv02d i2c_client from i2c-i801 to dell-lis3lv02d

[Hans de Goede]

Hi All,

Here is v6 of my patch series to move the manual instantation of lis3lv02d
i2c_client-s for SMO88xx ACPI device from the generic i2c-i801.c code to
a SMO88xx specific dell-lis3lv02d driver.

Moving the i2c_client instantiation there has the following advantages:

1. This moves the SMO88xx ACPI device quirk handling away from the generic
i2c-i801 module which is loaded on all Intel x86 machines to a module
which will only be loaded when there is an ACPI SMO88xx device.

2. This removes the duplication of the SMO88xx ACPI Hardware ID (HID) table
between the i2c-i801 and dell-smo8800 drivers.

3. This allows extending the quirk handling by adding new code and related
module parameters to the dell-lis3lv02d driver, without needing to modify
the i2c-i801 code.

This series also extends the i2c_client instantiation with support for
probing for the i2c-address of the lis3lv02d chip on devices which
are not yet listed in the DMI table with i2c-addresses for known models.
This probing is only done when requested through a module parameter.

Changes in v6:
- Use i2c_new_scanned_device() instead of re-inventing it

Changes in v5:
- Make match_acpi_device_ids() and match_acpi_device_ids[] __init[const]
- Add "Depends on I2C" to Kconfig (to fix kernel-test-robot reported issues)
- Add "this may be dangerous warning" to MODULE_PARM_DESC(probe_i2c_addr)

Changes in v4:
- Move the i2c_client instantiation to a new dell-lis3lv02d driver instead
  of adding it to the dell-smo8800 driver
- Address a couple of other minor review comments

Changes in v3:
- Use an i2c bus notifier so that the i2c_client will still be instantiated if
  the i801 i2c_adapter shows up later or is re-probed (removed + added again).
  This addresses the main concern / review-comments made during review of v2.
- Add 2 prep patches to the i2c-core / the i2c-i801 driver to allow bus-notifier
  use / to avoid the need to duplicate the PCI-ids of IDF i2c-i801 adapters.
- Switch to standard dmi_system_id matching to check both sys-vendor +
  product-name DMI fields
- Drop the patch to alternatively use the st_accel IIO driver instead of
  drivers/misc/lis3lv02d/lis3lv02d.c

Changes in v2:
- Drop "[PATCH 1/6] platform/x86: dell-smo8800: Only load on Dell laptops"
- Use a pci_device_id table to check for IDF (non main) i2c-i801 SMBusses
- Add a comment documenting the IDF PCI device ids
- Keep using drivers/misc/lis3lv02d/lis3lv02d.c by default
- Rename the module-parameter to use_iio_driver which can be set to
  use the IIO st_accel driver instead
- Add a new patch adding the accelerometer address for the 2 models
  I have tested this on to dell_lis3lv02d_devices[]

Since this touches files under both drivers/i2c and drivers/platform/x86
some subsystem coordination is necessary. I think it would be best to just
merge the entire series through the i2c subsystem since this touches some
core i2c files. As pdx86 subsys co-maintainer I'm fine with doing so.

Regards,

Hans


Hans de Goede (6):
  i2c: core: Setup i2c_adapter runtime-pm before calling device_add()
  i2c: i801: Use a different adapter-name for IDF adapters
  platform/x86: dell-smo8800: Move SMO88xx acpi_device_ids to
    dell-smo8800-ids.h
  platform/x86: dell-smo8800: Move instantiation of lis3lv02d i2c_client
    from i2c-i801 to dell-lis3lv02d
  platform/x86: dell-smo8800: Add a couple more models to
    lis3lv02d_devices[]
  platform/x86: dell-smo8800: Add support for probing for the
    accelerometer i2c address

 drivers/i2c/busses/i2c-i801.c                | 133 +---------
 drivers/i2c/i2c-core-base.c                  |  18 +-
 drivers/platform/x86/dell/Kconfig            |   1 +
 drivers/platform/x86/dell/Makefile           |   1 +
 drivers/platform/x86/dell/dell-lis3lv02d.c   | 249 +++++++++++++++++++
 drivers/platform/x86/dell/dell-smo8800-ids.h |  26 ++
 drivers/platform/x86/dell/dell-smo8800.c     |  16 +-
 7 files changed, 298 insertions(+), 146 deletions(-)
 create mode 100644 drivers/platform/x86/dell/dell-lis3lv02d.c
 create mode 100644 drivers/platform/x86/dell/dell-smo8800-ids.h

-- 
2.45.1

[PATCH v6 1/6] i2c: core: Setup i2c_adapter runtime-pm before calling device_add()

[Hans de Goede]

Platform glue code, which is not build into the kernel and thus cannot
use i2c_register_board_info() may want to use bus_register_notifier()
to listen for i2c-adapters to show up on which the platform code needs
to manually instantiate platform specific i2c_clients.

This results in calling i2c_new_client_device() from the bus notifier
which happens near the device_add() call.

If the i2c-core has not yet setup runtime-pm (specifically the
no-callbacks and ignore-children flags) for the device embedded
inside struct i2c_adapter and the driver for the i2c_client
calls pm_runtime_set_active() this will trigger the following
error inside __pm_runtime_set_status():

"runtime PM trying to activate child device %s but parent (%s) is not active\n"

and the i2c_client's runtime-status will not be updated.

Split the device_register() call for the adapter into device_initialize()
and device_add() and move the pm-runtime init calls inbetween these 2 calls
so that the runtime-status can be correctly set when a driver binds from
the bus-notifier.

Note the moved pm-runtime init calls just override the initial value of
some flags in struct device set by device_initialize() and calling these
before device_add() is safe.

Reviewed-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v4:
- Add a comment explaining why runtime-pm needs to be setup before
  the device_add()

Changes in v3:
- This is a new patch in v3 of this patch-set
---
 drivers/i2c/i2c-core-base.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index db0d1ac82910..c4517d97a49f 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -1521,7 +1521,18 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
 	adap->dev.bus = &i2c_bus_type;
 	adap->dev.type = &i2c_adapter_type;
-	res = device_register(&adap->dev);
+	device_initialize(&adap->dev);
+
+	/*
+	 * This adapter can be used as a parent immediately after device_add(),
+	 * setup runtime-pm (especially ignore-children) before hand.
+	 */
+	device_enable_async_suspend(&adap->dev);
+	pm_runtime_no_callbacks(&adap->dev);
+	pm_suspend_ignore_children(&adap->dev, true);
+	pm_runtime_enable(&adap->dev);
+
+	res = device_add(&adap->dev);
 	if (res) {
 		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
 		goto out_list;
@@ -1533,11 +1544,6 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	if (res)
 		goto out_reg;
 
-	device_enable_async_suspend(&adap->dev);
-	pm_runtime_no_callbacks(&adap->dev);
-	pm_suspend_ignore_children(&adap->dev, true);
-	pm_runtime_enable(&adap->dev);
-
 	res = i2c_init_recovery(adap);
 	if (res == -EPROBE_DEFER)
 		goto out_reg;
-- 
2.45.1

[PATCH v6 2/6] i2c: i801: Use a different adapter-name for IDF adapters

[Hans de Goede]

On chipsets with a second 'Integrated Device Function' SMBus controller use
a different adapter-name for the second IDF adapter.

This allows platform glue code which is looking for the primary i801
adapter to manually instantiate i2c_clients on to differentiate
between the 2.

This allows such code to find the primary i801 adapter by name, without
needing to duplicate the PCI-ids to feature-flags mapping from i2c-i801.c.

Reviewed-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v4:
- Use a single snprintf() with a conditional argument for the 2 names
- Add a comment that the adapter-name is used by platform code

Changes in v3:
- This is a new patch in v3 of this patch-set
---
 drivers/i2c/busses/i2c-i801.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index d2d2a6dbe29f..94265ee300c0 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -1760,8 +1760,15 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 
 	i801_add_tco(priv);
 
+	/*
+	 * adapter.name is used by platform code to find the main I801 adapter
+	 * to instantiante i2c_clients, do not change.
+	 */
 	snprintf(priv->adapter.name, sizeof(priv->adapter.name),
-		"SMBus I801 adapter at %04lx", priv->smba);
+		 "SMBus %s adapter at %04lx",
+		 (priv->features & FEATURE_IDF) ? "I801 IDF" : "I801",
+		 priv->smba);
+
 	err = i2c_add_adapter(&priv->adapter);
 	if (err) {
 		platform_device_unregister(priv->tco_pdev);
-- 
2.45.1

[PATCH v6 3/6] platform/x86: dell-smo8800: Move SMO88xx acpi_device_ids to dell-smo8800-ids.h

[Hans de Goede]

Move the SMO88xx acpi_device_ids to a new dell-smo8800-ids.h header,
so that these can be shared with the new dell-lis3lv02d code.

Reviewed-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v4:
- This is a new patch in v3 of this patch-set
---
 drivers/platform/x86/dell/dell-smo8800-ids.h | 26 ++++++++++++++++++++
 drivers/platform/x86/dell/dell-smo8800.c     | 16 +-----------
 2 files changed, 27 insertions(+), 15 deletions(-)
 create mode 100644 drivers/platform/x86/dell/dell-smo8800-ids.h

diff --git a/drivers/platform/x86/dell/dell-smo8800-ids.h b/drivers/platform/x86/dell/dell-smo8800-ids.h
new file mode 100644
index 000000000000..f85d8b707d85
--- /dev/null
+++ b/drivers/platform/x86/dell/dell-smo8800-ids.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *  ACPI SMO88XX lis3lv02d freefall / accelerometer device-ids.
+ *
+ *  Copyright (C) 2012 Sonal Santan <sonal.santan@gmail.com>
+ *  Copyright (C) 2014 Pali Rohár <pali@kernel.org>
+ */
+#ifndef _DELL_SMO8800_IDS_H_
+#define _DELL_SMO8800_IDS_H_
+
+#include <linux/mod_devicetable.h>
+
+static const struct acpi_device_id smo8800_ids[] = {
+	{ "SMO8800" },
+	{ "SMO8801" },
+	{ "SMO8810" },
+	{ "SMO8811" },
+	{ "SMO8820" },
+	{ "SMO8821" },
+	{ "SMO8830" },
+	{ "SMO8831" },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, smo8800_ids);
+
+#endif
diff --git a/drivers/platform/x86/dell/dell-smo8800.c b/drivers/platform/x86/dell/dell-smo8800.c
index f7ec17c56833..f9119ed2bd92 100644
--- a/drivers/platform/x86/dell/dell-smo8800.c
+++ b/drivers/platform/x86/dell/dell-smo8800.c
@@ -14,10 +14,10 @@
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/miscdevice.h>
-#include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/uaccess.h>
+#include "dell-smo8800-ids.h"
 
 struct smo8800_device {
 	u32 irq;                     /* acpi device irq */
@@ -163,20 +163,6 @@ static void smo8800_remove(struct platform_device *device)
 	dev_dbg(&device->dev, "device /dev/freefall unregistered\n");
 }
 
-/* NOTE: Keep this list in sync with drivers/i2c/busses/i2c-i801.c */
-static const struct acpi_device_id smo8800_ids[] = {
-	{ "SMO8800", 0 },
-	{ "SMO8801", 0 },
-	{ "SMO8810", 0 },
-	{ "SMO8811", 0 },
-	{ "SMO8820", 0 },
-	{ "SMO8821", 0 },
-	{ "SMO8830", 0 },
-	{ "SMO8831", 0 },
-	{ "", 0 },
-};
-MODULE_DEVICE_TABLE(acpi, smo8800_ids);
-
 static struct platform_driver smo8800_driver = {
 	.probe = smo8800_probe,
 	.remove_new = smo8800_remove,
-- 
2.45.1

[PATCH v6 4/6] platform/x86: dell-smo8800: Move instantiation of lis3lv02d i2c_client from i2c-i801 to dell-lis3lv02d

[Hans de Goede]

Various Dell laptops have an lis3lv02d freefall/accelerometer sensor.
The lis3lv02d chip has an interrupt line as well as an I2C connection to
the system's main SMBus.

The lis3lv02d is described in the ACPI tables by an SMO88xx ACPI device,
but the SMO88xx ACPI fwnodes are incomplete and only list an IRQ resource.

So far this has been worked around with some SMO88xx specific quirk code
in the generic i2c-i801 driver, but it is not necessary to handle the Dell
specific instantiation of i2c_client-s for SMO88xx ACPI devices there.

The kernel already instantiates platform_device-s for these with an
acpi:SMO88xx modalias. The drivers/platform/x86/dell/dell-smo8800.c
driver binds to this platform device but this only deals with
the interrupt resource. Add a drivers/platform/x86/dell/dell-lis3lv02d.c
which will matches on the same acpi:SMO88xx modaliases and move
the i2c_client instantiation from the generic i2c-i801 driver there.

Moving the i2c_client instantiation has the following advantages:

1. This moves the SMO88xx ACPI device quirk handling away from the generic
i2c-i801 module which is loaded on all Intel x86 machines to a module
which will only be loaded when there is an ACPI SMO88xx device.

2. This removes the duplication of the SMO88xx ACPI Hardware ID (HID) table
between the i2c-i801 and dell-smo8800 drivers.

3. This allows extending the quirk handling by adding new code and related
module parameters to the dell-lis3lv02d driver, without needing to modify
the i2c-i801 code.

Reviewed-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v5:
- Make match_acpi_device_ids() and match_acpi_device_ids[] __init[const]
- Add "Depends on I2C" to Kconfig

Changes in v4:
- Move the i2c_client instantiation to a new dell-lis3lv02d driver instead
  of adding it to the dell-smo8800 driver

Changes in v3:
- Use an i2c bus notifier so that the i2c_client will still be instantiated if
  the i801 i2c_adapter shows up later or is re-probed (removed + added again)
- Switch to standard dmi_system_id matching to check both sys-vendor +
  product-name DMI fields
- Use unique i2c_adapter->name prefix for primary i2c_801 controller
  to avoid needing to duplicate PCI ids for extra IDF i2c_801 i2c_adapter-s
- Drop MODULE_SOFTDEP("pre: i2c-i801"), this is now no longer necessary
- Rebase on Torvalds master for recent additions of extra models in
  the dell_lis3lv02d_devices[] list

Changes in v2:
- Use a pci_device_id table to check for IDF (non main) i2c-i801 SMBusses
- Add a comment documenting the IDF PCI device ids
---
 drivers/i2c/busses/i2c-i801.c              | 124 -------------
 drivers/platform/x86/dell/Kconfig          |   1 +
 drivers/platform/x86/dell/Makefile         |   1 +
 drivers/platform/x86/dell/dell-lis3lv02d.c | 202 +++++++++++++++++++++
 4 files changed, 204 insertions(+), 124 deletions(-)
 create mode 100644 drivers/platform/x86/dell/dell-lis3lv02d.c

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 94265ee300c0..375781079e0d 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -1153,127 +1153,6 @@ static void dmi_check_onboard_devices(const struct dmi_header *dm, void *adap)
 	}
 }
 
-/* NOTE: Keep this list in sync with drivers/platform/x86/dell-smo8800.c */
-static const char *const acpi_smo8800_ids[] = {
-	"SMO8800",
-	"SMO8801",
-	"SMO8810",
-	"SMO8811",
-	"SMO8820",
-	"SMO8821",
-	"SMO8830",
-	"SMO8831",
-};
-
-static acpi_status check_acpi_smo88xx_device(acpi_handle obj_handle,
-					     u32 nesting_level,
-					     void *context,
-					     void **return_value)
-{
-	struct acpi_device_info *info;
-	acpi_status status;
-	char *hid;
-	int i;
-
-	status = acpi_get_object_info(obj_handle, &info);
-	if (ACPI_FAILURE(status))
-		return AE_OK;
-
-	if (!(info->valid & ACPI_VALID_HID))
-		goto smo88xx_not_found;
-
-	hid = info->hardware_id.string;
-	if (!hid)
-		goto smo88xx_not_found;
-
-	i = match_string(acpi_smo8800_ids, ARRAY_SIZE(acpi_smo8800_ids), hid);
-	if (i < 0)
-		goto smo88xx_not_found;
-
-	kfree(info);
-
-	*return_value = NULL;
-	return AE_CTRL_TERMINATE;
-
-smo88xx_not_found:
-	kfree(info);
-	return AE_OK;
-}
-
-static bool is_dell_system_with_lis3lv02d(void)
-{
-	void *err = ERR_PTR(-ENOENT);
-
-	if (!dmi_match(DMI_SYS_VENDOR, "Dell Inc."))
-		return false;
-
-	/*
-	 * Check that ACPI device SMO88xx is present and is functioning.
-	 * Function acpi_get_devices() already filters all ACPI devices
-	 * which are not present or are not functioning.
-	 * ACPI device SMO88xx represents our ST microelectronics lis3lv02d
-	 * accelerometer but unfortunately ACPI does not provide any other
-	 * information (like I2C address).
-	 */
-	acpi_get_devices(NULL, check_acpi_smo88xx_device, NULL, &err);
-
-	return !IS_ERR(err);
-}
-
-/*
- * Accelerometer's I2C address is not specified in DMI nor ACPI,
- * so it is needed to define mapping table based on DMI product names.
- */
-static const struct {
-	const char *dmi_product_name;
-	unsigned short i2c_addr;
-} dell_lis3lv02d_devices[] = {
-	/*
-	 * Dell platform team told us that these Latitude devices have
-	 * ST microelectronics accelerometer at I2C address 0x29.
-	 */
-	{ "Latitude E5250",     0x29 },
-	{ "Latitude E5450",     0x29 },
-	{ "Latitude E5550",     0x29 },
-	{ "Latitude E6440",     0x29 },
-	{ "Latitude E6440 ATG", 0x29 },
-	{ "Latitude E6540",     0x29 },
-	/*
-	 * Additional individual entries were added after verification.
-	 */
-	{ "Latitude 5480",      0x29 },
-	{ "Precision 3540",     0x29 },
-	{ "Vostro V131",        0x1d },
-	{ "Vostro 5568",        0x29 },
-	{ "XPS 15 7590",        0x29 },
-};
-
-static void register_dell_lis3lv02d_i2c_device(struct i801_priv *priv)
-{
-	struct i2c_board_info info;
-	const char *dmi_product_name;
-	int i;
-
-	dmi_product_name = dmi_get_system_info(DMI_PRODUCT_NAME);
-	for (i = 0; i < ARRAY_SIZE(dell_lis3lv02d_devices); ++i) {
-		if (strcmp(dmi_product_name,
-			   dell_lis3lv02d_devices[i].dmi_product_name) == 0)
-			break;
-	}
-
-	if (i == ARRAY_SIZE(dell_lis3lv02d_devices)) {
-		dev_warn(&priv->pci_dev->dev,
-			 "Accelerometer lis3lv02d is present on SMBus but its"
-			 " address is unknown, skipping registration\n");
-		return;
-	}
-
-	memset(&info, 0, sizeof(struct i2c_board_info));
-	info.addr = dell_lis3lv02d_devices[i].i2c_addr;
-	strscpy(info.type, "lis3lv02d", I2C_NAME_SIZE);
-	i2c_new_client_device(&priv->adapter, &info);
-}
-
 /* Register optional slaves */
 static void i801_probe_optional_slaves(struct i801_priv *priv)
 {
@@ -1293,9 +1172,6 @@ static void i801_probe_optional_slaves(struct i801_priv *priv)
 	if (dmi_name_in_vendors("FUJITSU"))
 		dmi_walk(dmi_check_onboard_devices, &priv->adapter);
 
-	if (is_dell_system_with_lis3lv02d())
-		register_dell_lis3lv02d_i2c_device(priv);
-
 	/* Instantiate SPD EEPROMs unless the SMBus is multiplexed */
 #ifdef CONFIG_I2C_I801_MUX
 	if (!priv->mux_pdev)
diff --git a/drivers/platform/x86/dell/Kconfig b/drivers/platform/x86/dell/Kconfig
index 195a8bf532cc..2fbaf08a2e79 100644
--- a/drivers/platform/x86/dell/Kconfig
+++ b/drivers/platform/x86/dell/Kconfig
@@ -137,6 +137,7 @@ config DELL_SMBIOS_SMM
 config DELL_SMO8800
 	tristate "Dell Latitude freefall driver (ACPI SMO88XX)"
 	default m
+	depends on I2C
 	depends on ACPI || COMPILE_TEST
 	help
 	  Say Y here if you want to support SMO88XX freefall devices
diff --git a/drivers/platform/x86/dell/Makefile b/drivers/platform/x86/dell/Makefile
index 8176a257d9c3..970409c107b0 100644
--- a/drivers/platform/x86/dell/Makefile
+++ b/drivers/platform/x86/dell/Makefile
@@ -14,6 +14,7 @@ dell-smbios-objs			:= dell-smbios-base.o
 dell-smbios-$(CONFIG_DELL_SMBIOS_WMI)	+= dell-smbios-wmi.o
 dell-smbios-$(CONFIG_DELL_SMBIOS_SMM)	+= dell-smbios-smm.o
 obj-$(CONFIG_DELL_SMO8800)		+= dell-smo8800.o
+obj-$(CONFIG_DELL_SMO8800)		+= dell-lis3lv02d.o
 obj-$(CONFIG_DELL_UART_BACKLIGHT)	+= dell-uart-backlight.o
 obj-$(CONFIG_DELL_WMI)			+= dell-wmi.o
 dell-wmi-objs				:= dell-wmi-base.o
diff --git a/drivers/platform/x86/dell/dell-lis3lv02d.c b/drivers/platform/x86/dell/dell-lis3lv02d.c
new file mode 100644
index 000000000000..c74f0825d252
--- /dev/null
+++ b/drivers/platform/x86/dell/dell-lis3lv02d.c
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * lis3lv02d i2c-client instantiation for ACPI SMO88xx devices without I2C resources.
+ *
+ *  Copyright (C) 2024 Hans de Goede <hansg@kernel.org>
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/device/bus.h>
+#include <linux/dmi.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/platform_device.h>
+#include <linux/workqueue.h>
+#include "dell-smo8800-ids.h"
+
+#define DELL_LIS3LV02D_DMI_ENTRY(product_name, i2c_addr)                 \
+	{                                                                \
+		.matches = {                                             \
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),    \
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, product_name), \
+		},                                                       \
+		.driver_data = (void *)(uintptr_t)(i2c_addr),            \
+	}
+
+/*
+ * Accelerometer's I2C address is not specified in DMI nor ACPI,
+ * so it is needed to define mapping table based on DMI product names.
+ */
+static const struct dmi_system_id lis3lv02d_devices[] __initconst = {
+	/*
+	 * Dell platform team told us that these Latitude devices have
+	 * ST microelectronics accelerometer at I2C address 0x29.
+	 */
+	DELL_LIS3LV02D_DMI_ENTRY("Latitude E5250",     0x29),
+	DELL_LIS3LV02D_DMI_ENTRY("Latitude E5450",     0x29),
+	DELL_LIS3LV02D_DMI_ENTRY("Latitude E5550",     0x29),
+	DELL_LIS3LV02D_DMI_ENTRY("Latitude E6440",     0x29),
+	DELL_LIS3LV02D_DMI_ENTRY("Latitude E6440 ATG", 0x29),
+	DELL_LIS3LV02D_DMI_ENTRY("Latitude E6540",     0x29),
+	/*
+	 * Additional individual entries were added after verification.
+	 */
+	DELL_LIS3LV02D_DMI_ENTRY("Latitude 5480",      0x29),
+	DELL_LIS3LV02D_DMI_ENTRY("Precision 3540",     0x29),
+	DELL_LIS3LV02D_DMI_ENTRY("Vostro V131",        0x1d),
+	DELL_LIS3LV02D_DMI_ENTRY("Vostro 5568",        0x29),
+	DELL_LIS3LV02D_DMI_ENTRY("XPS 15 7590",        0x29),
+	{ }
+};
+
+static u8 i2c_addr;
+static struct i2c_client *i2c_dev;
+static bool notifier_registered;
+
+static bool i2c_adapter_is_main_i801(struct i2c_adapter *adap)
+{
+	/*
+	 * Only match the main I801 adapter and reject secondary adapters
+	 * which names start with "SMBus I801 IDF adapter".
+	 */
+	return strstarts(adap->name, "SMBus I801 adapter");
+}
+
+static int find_i801(struct device *dev, void *data)
+{
+	struct i2c_adapter *adap, **adap_ret = data;
+
+	adap = i2c_verify_adapter(dev);
+	if (!adap)
+		return 0;
+
+	if (!i2c_adapter_is_main_i801(adap))
+		return 0;
+
+	*adap_ret = i2c_get_adapter(adap->nr);
+	return 1;
+}
+
+static void instantiate_i2c_client(struct work_struct *work)
+{
+	struct i2c_board_info info = { };
+	struct i2c_adapter *adap = NULL;
+
+	if (i2c_dev)
+		return;
+
+	bus_for_each_dev(&i2c_bus_type, NULL, &adap, find_i801);
+	if (!adap)
+		return;
+
+	info.addr = i2c_addr;
+	strscpy(info.type, "lis3lv02d", I2C_NAME_SIZE);
+
+	i2c_dev = i2c_new_client_device(adap, &info);
+	if (IS_ERR(i2c_dev)) {
+		pr_err("error %ld registering i2c_client\n", PTR_ERR(i2c_dev));
+		i2c_dev = NULL;
+	} else {
+		pr_debug("registered lis3lv02d on address 0x%02x\n", info.addr);
+	}
+
+	i2c_put_adapter(adap);
+}
+static DECLARE_WORK(i2c_work, instantiate_i2c_client);
+
+static int i2c_bus_notify(struct notifier_block *nb, unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct i2c_client *client;
+	struct i2c_adapter *adap;
+
+	switch (action) {
+	case BUS_NOTIFY_ADD_DEVICE:
+		adap = i2c_verify_adapter(dev);
+		if (!adap)
+			break;
+
+		if (i2c_adapter_is_main_i801(adap))
+			queue_work(system_long_wq, &i2c_work);
+		break;
+	case BUS_NOTIFY_REMOVED_DEVICE:
+		client = i2c_verify_client(dev);
+		if (!client)
+			break;
+
+		if (i2c_dev == client) {
+			pr_debug("lis3lv02d i2c_client removed\n");
+			i2c_dev = NULL;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+static struct notifier_block i2c_nb = { .notifier_call = i2c_bus_notify };
+
+static int __init match_acpi_device_ids(struct device *dev, const void *data)
+{
+	const struct acpi_device_id *ids = data;
+
+	return acpi_match_device(ids, dev) ? 1 : 0;
+}
+
+static int __init dell_lis3lv02d_init(void)
+{
+	const struct dmi_system_id *lis3lv02d_dmi_id;
+	struct device *dev;
+	int err;
+
+	/*
+	 * First check for a matching platform_device. This protects against
+	 * SMO88xx ACPI fwnodes which actually do have an I2C resource, which
+	 * will already have an i2c_client instantiated (not a platform_device).
+	 */
+	dev = bus_find_device(&platform_bus_type, NULL, smo8800_ids, match_acpi_device_ids);
+	if (!dev) {
+		pr_debug("No SMO88xx platform-device found\n");
+		return 0;
+	}
+	put_device(dev);
+
+	lis3lv02d_dmi_id = dmi_first_match(lis3lv02d_devices);
+	if (!lis3lv02d_dmi_id) {
+		pr_warn("accelerometer is present on SMBus but its address is unknown, skipping registration\n");
+		return 0;
+	}
+
+	i2c_addr = (long)lis3lv02d_dmi_id->driver_data;
+
+	/*
+	 * Register i2c-bus notifier + queue initial scan for lis3lv02d
+	 * i2c_client instantiation.
+	 */
+	err = bus_register_notifier(&i2c_bus_type, &i2c_nb);
+	if (err)
+		return err;
+
+	notifier_registered = true;
+
+	queue_work(system_long_wq, &i2c_work);
+	return 0;
+}
+module_init(dell_lis3lv02d_init);
+
+static void __exit dell_lis3lv02d_module_exit(void)
+{
+	if (!notifier_registered)
+		return;
+
+	bus_unregister_notifier(&i2c_bus_type, &i2c_nb);
+	cancel_work_sync(&i2c_work);
+	i2c_unregister_device(i2c_dev);
+}
+module_exit(dell_lis3lv02d_module_exit);
+
+MODULE_DESCRIPTION("lis3lv02d i2c-client instantiation for ACPI SMO88xx devices");
+MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>");
+MODULE_LICENSE("GPL");
-- 
2.45.1

[PATCH v6 5/6] platform/x86: dell-smo8800: Add a couple more models to lis3lv02d_devices[]

[Hans de Goede]

Add the accelerometer address for the following laptop models
to lis3lv02d_devices[]:

Dell Latitude E6330
Dell Latitude E6430
Dell XPS 15 9550

Tested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/platform/x86/dell/dell-lis3lv02d.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/platform/x86/dell/dell-lis3lv02d.c b/drivers/platform/x86/dell/dell-lis3lv02d.c
index c74f0825d252..ab02ad93758a 100644
--- a/drivers/platform/x86/dell/dell-lis3lv02d.c
+++ b/drivers/platform/x86/dell/dell-lis3lv02d.c
@@ -43,10 +43,13 @@ static const struct dmi_system_id lis3lv02d_devices[] __initconst = {
 	 * Additional individual entries were added after verification.
 	 */
 	DELL_LIS3LV02D_DMI_ENTRY("Latitude 5480",      0x29),
+	DELL_LIS3LV02D_DMI_ENTRY("Latitude E6330",     0x29),
+	DELL_LIS3LV02D_DMI_ENTRY("Latitude E6430",     0x29),
 	DELL_LIS3LV02D_DMI_ENTRY("Precision 3540",     0x29),
 	DELL_LIS3LV02D_DMI_ENTRY("Vostro V131",        0x1d),
 	DELL_LIS3LV02D_DMI_ENTRY("Vostro 5568",        0x29),
 	DELL_LIS3LV02D_DMI_ENTRY("XPS 15 7590",        0x29),
+	DELL_LIS3LV02D_DMI_ENTRY("XPS 15 9550",        0x29),
 	{ }
 };
 
-- 
2.45.1

[PATCH v6 6/6] platform/x86: dell-smo8800: Add support for probing for the accelerometer i2c address

[Hans de Goede]

Unfortunately the SMOxxxx ACPI device does not contain the i2c-address
of the accelerometer. So a DMI product-name to address mapping table
is used.

At support to have the kernel probe for the i2c-address for modesl
which are not on the list.

The new probing code sits behind a new probe_i2c_addr module parameter,
which is disabled by default because probing might be dangerous.

Link: https://lore.kernel.org/linux-i2c/4820e280-9ca4-4d97-9d21-059626161bfc@molgen.mpg.de/
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v6:
- Use i2c_new_scanned_device() instead of re-inventing it

Changes in v5:
- Add "this may be dangerous warning" to MODULE_PARM_DESC(probe_i2c_addr)
---
 drivers/platform/x86/dell/dell-lis3lv02d.c | 52 ++++++++++++++++++++--
 1 file changed, 48 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/dell/dell-lis3lv02d.c b/drivers/platform/x86/dell/dell-lis3lv02d.c
index ab02ad93758a..21390e6302a0 100644
--- a/drivers/platform/x86/dell/dell-lis3lv02d.c
+++ b/drivers/platform/x86/dell/dell-lis3lv02d.c
@@ -15,6 +15,8 @@
 #include <linux/workqueue.h>
 #include "dell-smo8800-ids.h"
 
+#define LIS3_WHO_AM_I 0x0f
+
 #define DELL_LIS3LV02D_DMI_ENTRY(product_name, i2c_addr)                 \
 	{                                                                \
 		.matches = {                                             \
@@ -57,6 +59,38 @@ static u8 i2c_addr;
 static struct i2c_client *i2c_dev;
 static bool notifier_registered;
 
+static bool probe_i2c_addr;
+module_param(probe_i2c_addr, bool, 0444);
+MODULE_PARM_DESC(probe_i2c_addr, "Probe the i801 I2C bus for the accelerometer on models where the address is unknown, this may be dangerous.");
+
+static int detect_lis3lv02d(struct i2c_adapter *adap, unsigned short addr)
+{
+	union i2c_smbus_data smbus_data;
+	int err;
+
+	pr_info("Probing for lis3lv02d on address 0x%02x\n", addr);
+
+	err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, LIS3_WHO_AM_I,
+			     I2C_SMBUS_BYTE_DATA, &smbus_data);
+	if (err < 0)
+		return 0; /* Not found */
+
+	/* valid who-am-i values are from drivers/misc/lis3lv02d/lis3lv02d.c */
+	switch (smbus_data.byte) {
+	case 0x32:
+	case 0x33:
+	case 0x3a:
+	case 0x3b:
+		break;
+	default:
+		pr_warn("Unknown who-am-i register value 0x%02x\n", smbus_data.byte);
+		return 0; /* Not found */
+	}
+
+	pr_debug("Detected lis3lv02d on address 0x%02x\n", addr);
+	return 1; /* Found */
+}
+
 static bool i2c_adapter_is_main_i801(struct i2c_adapter *adap)
 {
 	/*
@@ -93,10 +127,18 @@ static void instantiate_i2c_client(struct work_struct *work)
 	if (!adap)
 		return;
 
-	info.addr = i2c_addr;
 	strscpy(info.type, "lis3lv02d", I2C_NAME_SIZE);
 
-	i2c_dev = i2c_new_client_device(adap, &info);
+	if (i2c_addr) {
+		info.addr = i2c_addr;
+		i2c_dev = i2c_new_client_device(adap, &info);
+	} else {
+		/* First try address 0x29 (most used) and then try 0x1d */
+		static const unsigned short addr_list[] = { 0x29, 0x1d, I2C_CLIENT_END };
+
+		i2c_dev = i2c_new_scanned_device(adap, &info, addr_list, detect_lis3lv02d);
+	}
+
 	if (IS_ERR(i2c_dev)) {
 		pr_err("error %ld registering i2c_client\n", PTR_ERR(i2c_dev));
 		i2c_dev = NULL;
@@ -167,12 +209,14 @@ static int __init dell_lis3lv02d_init(void)
 	put_device(dev);
 
 	lis3lv02d_dmi_id = dmi_first_match(lis3lv02d_devices);
-	if (!lis3lv02d_dmi_id) {
+	if (!lis3lv02d_dmi_id && !probe_i2c_addr) {
 		pr_warn("accelerometer is present on SMBus but its address is unknown, skipping registration\n");
+		pr_info("Pass dell_lis3lv02d.probe_i2c_addr=1 on the kernel commandline to probe, this may be dangerous!\n");
 		return 0;
 	}
 
-	i2c_addr = (long)lis3lv02d_dmi_id->driver_data;
+	if (lis3lv02d_dmi_id)
+		i2c_addr = (long)lis3lv02d_dmi_id->driver_data;
 
 	/*
 	 * Register i2c-bus notifier + queue initial scan for lis3lv02d
-- 
2.45.1

Re: [PATCH v6 1/6] i2c: core: Setup i2c_adapter runtime-pm before calling device_add()

[Andi Shyti]

Hi Hans,

...

> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -1521,7 +1521,18 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
>  	dev_set_name(&adap->dev, "i2c-%d", adap->nr);
>  	adap->dev.bus = &i2c_bus_type;
>  	adap->dev.type = &i2c_adapter_type;
> -	res = device_register(&adap->dev);
> +	device_initialize(&adap->dev);
> +
> +	/*
> +	 * This adapter can be used as a parent immediately after device_add(),
> +	 * setup runtime-pm (especially ignore-children) before hand.
> +	 */
> +	device_enable_async_suspend(&adap->dev);
> +	pm_runtime_no_callbacks(&adap->dev);
> +	pm_suspend_ignore_children(&adap->dev, true);
> +	pm_runtime_enable(&adap->dev);
> +
> +	res = device_add(&adap->dev);

I see a pattern here around in the kernel:

	device_initialize(...)
	...
	device_add(...)

which makes the device_register() helper not that useful. Perhaps
for the future we could add a device_register_fn() where we pass
the reference of a function that does whatever lies in between
the initialize and the add... food for thoughts.

As of now, looks good to me:

Reviewed-by: Andi Shyti <andi.shyti@kernel.org>

Thanks,
Andi

>  	if (res) {
>  		pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
>  		goto out_list;
> @@ -1533,11 +1544,6 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
>  	if (res)
>  		goto out_reg;
>  
> -	device_enable_async_suspend(&adap->dev);
> -	pm_runtime_no_callbacks(&adap->dev);
> -	pm_suspend_ignore_children(&adap->dev, true);
> -	pm_runtime_enable(&adap->dev);
> -
>  	res = i2c_init_recovery(adap);
>  	if (res == -EPROBE_DEFER)
>  		goto out_reg;
> -- 
> 2.45.1
> 

Re: [PATCH v6 2/6] i2c: i801: Use a different adapter-name for IDF adapters

[Andi Shyti]

Hi Hans,

On Thu, Jul 04, 2024 at 02:56:39PM GMT, Hans de Goede wrote:
> On chipsets with a second 'Integrated Device Function' SMBus controller use
> a different adapter-name for the second IDF adapter.
> 
> This allows platform glue code which is looking for the primary i801
> adapter to manually instantiate i2c_clients on to differentiate
> between the 2.
> 
> This allows such code to find the primary i801 adapter by name, without
> needing to duplicate the PCI-ids to feature-flags mapping from i2c-i801.c.
> 
> Reviewed-by: Pali Rohár <pali@kernel.org>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

I believe Wolfram will take patch 1. Once he takes it, I will
pick this up.

Thanks,
Andi

Re: [PATCH v6 6/6] platform/x86: dell-smo8800: Add support for probing for the accelerometer i2c address

[Pali Rohár]

On Thursday 04 July 2024 14:56:43 Hans de Goede wrote:
> Unfortunately the SMOxxxx ACPI device does not contain the i2c-address
> of the accelerometer. So a DMI product-name to address mapping table
> is used.
> 
> At support to have the kernel probe for the i2c-address for modesl
> which are not on the list.
> 
> The new probing code sits behind a new probe_i2c_addr module parameter,
> which is disabled by default because probing might be dangerous.
> 
> Link: https://lore.kernel.org/linux-i2c/4820e280-9ca4-4d97-9d21-059626161bfc@molgen.mpg.de/
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

NAK.

This is a hack, which should be avoided as specified in previous
discussions (e.g. it can cause regression for future or also existing
products).

Author refused to improve the code, also refused to ask vendor about the
details and proper implementation and author also refused to do any
future discussion about it.

Based on this state, this patch 6/6 should not be merged at all.

> ---
> Changes in v6:
> - Use i2c_new_scanned_device() instead of re-inventing it
> 
> Changes in v5:
> - Add "this may be dangerous warning" to MODULE_PARM_DESC(probe_i2c_addr)
> ---
>  drivers/platform/x86/dell/dell-lis3lv02d.c | 52 ++++++++++++++++++++--
>  1 file changed, 48 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/platform/x86/dell/dell-lis3lv02d.c b/drivers/platform/x86/dell/dell-lis3lv02d.c
> index ab02ad93758a..21390e6302a0 100644
> --- a/drivers/platform/x86/dell/dell-lis3lv02d.c
> +++ b/drivers/platform/x86/dell/dell-lis3lv02d.c
> @@ -15,6 +15,8 @@
>  #include <linux/workqueue.h>
>  #include "dell-smo8800-ids.h"
>  
> +#define LIS3_WHO_AM_I 0x0f
> +
>  #define DELL_LIS3LV02D_DMI_ENTRY(product_name, i2c_addr)                 \
>  	{                                                                \
>  		.matches = {                                             \
> @@ -57,6 +59,38 @@ static u8 i2c_addr;
>  static struct i2c_client *i2c_dev;
>  static bool notifier_registered;
>  
> +static bool probe_i2c_addr;
> +module_param(probe_i2c_addr, bool, 0444);
> +MODULE_PARM_DESC(probe_i2c_addr, "Probe the i801 I2C bus for the accelerometer on models where the address is unknown, this may be dangerous.");
> +
> +static int detect_lis3lv02d(struct i2c_adapter *adap, unsigned short addr)
> +{
> +	union i2c_smbus_data smbus_data;
> +	int err;
> +
> +	pr_info("Probing for lis3lv02d on address 0x%02x\n", addr);
> +
> +	err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, LIS3_WHO_AM_I,
> +			     I2C_SMBUS_BYTE_DATA, &smbus_data);
> +	if (err < 0)
> +		return 0; /* Not found */
> +
> +	/* valid who-am-i values are from drivers/misc/lis3lv02d/lis3lv02d.c */
> +	switch (smbus_data.byte) {
> +	case 0x32:
> +	case 0x33:
> +	case 0x3a:
> +	case 0x3b:
> +		break;
> +	default:
> +		pr_warn("Unknown who-am-i register value 0x%02x\n", smbus_data.byte);
> +		return 0; /* Not found */
> +	}
> +
> +	pr_debug("Detected lis3lv02d on address 0x%02x\n", addr);
> +	return 1; /* Found */
> +}
> +
>  static bool i2c_adapter_is_main_i801(struct i2c_adapter *adap)
>  {
>  	/*
> @@ -93,10 +127,18 @@ static void instantiate_i2c_client(struct work_struct *work)
>  	if (!adap)
>  		return;
>  
> -	info.addr = i2c_addr;
>  	strscpy(info.type, "lis3lv02d", I2C_NAME_SIZE);
>  
> -	i2c_dev = i2c_new_client_device(adap, &info);
> +	if (i2c_addr) {
> +		info.addr = i2c_addr;
> +		i2c_dev = i2c_new_client_device(adap, &info);
> +	} else {
> +		/* First try address 0x29 (most used) and then try 0x1d */
> +		static const unsigned short addr_list[] = { 0x29, 0x1d, I2C_CLIENT_END };
> +
> +		i2c_dev = i2c_new_scanned_device(adap, &info, addr_list, detect_lis3lv02d);
> +	}
> +
>  	if (IS_ERR(i2c_dev)) {
>  		pr_err("error %ld registering i2c_client\n", PTR_ERR(i2c_dev));
>  		i2c_dev = NULL;
> @@ -167,12 +209,14 @@ static int __init dell_lis3lv02d_init(void)
>  	put_device(dev);
>  
>  	lis3lv02d_dmi_id = dmi_first_match(lis3lv02d_devices);
> -	if (!lis3lv02d_dmi_id) {
> +	if (!lis3lv02d_dmi_id && !probe_i2c_addr) {
>  		pr_warn("accelerometer is present on SMBus but its address is unknown, skipping registration\n");
> +		pr_info("Pass dell_lis3lv02d.probe_i2c_addr=1 on the kernel commandline to probe, this may be dangerous!\n");
>  		return 0;
>  	}
>  
> -	i2c_addr = (long)lis3lv02d_dmi_id->driver_data;
> +	if (lis3lv02d_dmi_id)
> +		i2c_addr = (long)lis3lv02d_dmi_id->driver_data;
>  
>  	/*
>  	 * Register i2c-bus notifier + queue initial scan for lis3lv02d
> -- 
> 2.45.1
> 

Re: [PATCH v6 6/6] platform/x86: dell-smo8800: Add support for probing for the accelerometer i2c address

[Hans de Goede]

Hi,

On 7/4/24 11:37 PM, Pali Rohár wrote:
> On Thursday 04 July 2024 14:56:43 Hans de Goede wrote:
>> Unfortunately the SMOxxxx ACPI device does not contain the i2c-address
>> of the accelerometer. So a DMI product-name to address mapping table
>> is used.
>>
>> At support to have the kernel probe for the i2c-address for modesl
>> which are not on the list.
>>
>> The new probing code sits behind a new probe_i2c_addr module parameter,
>> which is disabled by default because probing might be dangerous.
>>
>> Link: https://lore.kernel.org/linux-i2c/4820e280-9ca4-4d97-9d21-059626161bfc@molgen.mpg.de/
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> 
> NAK.
> 
> This is a hack

This is not a hack, notice the existing i2c_new_scanned_device() i2c-core
function exists for a reason. As I have tried to explain before scanning
for i2c-devices if we don't know the address is something which the kernel
has been doing for a long time already.

Current kernels scan for i2c devices on pretty much any Intel PC in the form
of i2c_register_spd() running.

>, which should be avoided as specified in previous
> discussions (e.g. it can cause regression for future or also existing
> products).

You have provided 0 proof or even any hypothesis / speculations how this can
cause regressions. Al you have done is said this may cause regressions
without providing any details as to how you believe this would cause
regressions please provide details.

Also the new code is only activated if a new module option is st. By default
this options is not set, so this cannot cause any regressions since it
does not change anything for end users unless they explicitly enable it.

You have made it plenty clear that you don't like this approach, but
claiming it can cause regressions when by default it does not do anything
is just dishonest.

> Author refused to improve the code,

Really? I have gone out of my way to please you, I've moved all of the i2c
handling to a separate file because you asked for this, adding a text to
both the kernel message informing users about the module-parameter to
probe and the module-param help text that this may be dangerous.

Also after I last discussion I moved to i2c_new_scanned_device() instead
of DIY code. There is a reason why this patch-set is at v6 and it is not
because I'm refusing to improve it.

> also refused to ask vendor about the
> details and proper implementation and author also refused to do any
> future discussion about it.

As I have explained countless times I have no contacts inside Dell
to ask about this. If e.g. Mario was still at Dell I would have asked
Mario about this immediately back when the discussion started.

Besides the Dell.Client.Kernel@dell.com which no-one seems to be
reading, there is only one other @dell.com address in all of MAINTAINERS:
Prasanth Ksr <prasanth.ksr@dell.com>

To put an end to this whole discussion about contacting Dell I'll email
them with you (Pali) in the Cc. I don't expect much to come from this
but we will see.

> Based on this state, this patch 6/6 should not be merged at all.

Lets move forward with merging patches 1-5 and wait to see if we get
any response from Dell. But I do very much want to move forward
with this if contacting Dell does not result in another solution
to allow users to easily find out what the i2c-address is.

Regards,

Hans


> 
>> ---
>> Changes in v6:
>> - Use i2c_new_scanned_device() instead of re-inventing it
>>
>> Changes in v5:
>> - Add "this may be dangerous warning" to MODULE_PARM_DESC(probe_i2c_addr)
>> ---
>>  drivers/platform/x86/dell/dell-lis3lv02d.c | 52 ++++++++++++++++++++--
>>  1 file changed, 48 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/platform/x86/dell/dell-lis3lv02d.c b/drivers/platform/x86/dell/dell-lis3lv02d.c
>> index ab02ad93758a..21390e6302a0 100644
>> --- a/drivers/platform/x86/dell/dell-lis3lv02d.c
>> +++ b/drivers/platform/x86/dell/dell-lis3lv02d.c
>> @@ -15,6 +15,8 @@
>>  #include <linux/workqueue.h>
>>  #include "dell-smo8800-ids.h"
>>  
>> +#define LIS3_WHO_AM_I 0x0f
>> +
>>  #define DELL_LIS3LV02D_DMI_ENTRY(product_name, i2c_addr)                 \
>>  	{                                                                \
>>  		.matches = {                                             \
>> @@ -57,6 +59,38 @@ static u8 i2c_addr;
>>  static struct i2c_client *i2c_dev;
>>  static bool notifier_registered;
>>  
>> +static bool probe_i2c_addr;
>> +module_param(probe_i2c_addr, bool, 0444);
>> +MODULE_PARM_DESC(probe_i2c_addr, "Probe the i801 I2C bus for the accelerometer on models where the address is unknown, this may be dangerous.");
>> +
>> +static int detect_lis3lv02d(struct i2c_adapter *adap, unsigned short addr)
>> +{
>> +	union i2c_smbus_data smbus_data;
>> +	int err;
>> +
>> +	pr_info("Probing for lis3lv02d on address 0x%02x\n", addr);
>> +
>> +	err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, LIS3_WHO_AM_I,
>> +			     I2C_SMBUS_BYTE_DATA, &smbus_data);
>> +	if (err < 0)
>> +		return 0; /* Not found */
>> +
>> +	/* valid who-am-i values are from drivers/misc/lis3lv02d/lis3lv02d.c */
>> +	switch (smbus_data.byte) {
>> +	case 0x32:
>> +	case 0x33:
>> +	case 0x3a:
>> +	case 0x3b:
>> +		break;
>> +	default:
>> +		pr_warn("Unknown who-am-i register value 0x%02x\n", smbus_data.byte);
>> +		return 0; /* Not found */
>> +	}
>> +
>> +	pr_debug("Detected lis3lv02d on address 0x%02x\n", addr);
>> +	return 1; /* Found */
>> +}
>> +
>>  static bool i2c_adapter_is_main_i801(struct i2c_adapter *adap)
>>  {
>>  	/*
>> @@ -93,10 +127,18 @@ static void instantiate_i2c_client(struct work_struct *work)
>>  	if (!adap)
>>  		return;
>>  
>> -	info.addr = i2c_addr;
>>  	strscpy(info.type, "lis3lv02d", I2C_NAME_SIZE);
>>  
>> -	i2c_dev = i2c_new_client_device(adap, &info);
>> +	if (i2c_addr) {
>> +		info.addr = i2c_addr;
>> +		i2c_dev = i2c_new_client_device(adap, &info);
>> +	} else {
>> +		/* First try address 0x29 (most used) and then try 0x1d */
>> +		static const unsigned short addr_list[] = { 0x29, 0x1d, I2C_CLIENT_END };
>> +
>> +		i2c_dev = i2c_new_scanned_device(adap, &info, addr_list, detect_lis3lv02d);
>> +	}
>> +
>>  	if (IS_ERR(i2c_dev)) {
>>  		pr_err("error %ld registering i2c_client\n", PTR_ERR(i2c_dev));
>>  		i2c_dev = NULL;
>> @@ -167,12 +209,14 @@ static int __init dell_lis3lv02d_init(void)
>>  	put_device(dev);
>>  
>>  	lis3lv02d_dmi_id = dmi_first_match(lis3lv02d_devices);
>> -	if (!lis3lv02d_dmi_id) {
>> +	if (!lis3lv02d_dmi_id && !probe_i2c_addr) {
>>  		pr_warn("accelerometer is present on SMBus but its address is unknown, skipping registration\n");
>> +		pr_info("Pass dell_lis3lv02d.probe_i2c_addr=1 on the kernel commandline to probe, this may be dangerous!\n");
>>  		return 0;
>>  	}
>>  
>> -	i2c_addr = (long)lis3lv02d_dmi_id->driver_data;
>> +	if (lis3lv02d_dmi_id)
>> +		i2c_addr = (long)lis3lv02d_dmi_id->driver_data;
>>  
>>  	/*
>>  	 * Register i2c-bus notifier + queue initial scan for lis3lv02d
>> -- 
>> 2.45.1
>>
>