Patchwork [2/2] mfd: intel-lpss: Add "linux,use-dynamic-adapter-nr" device-prop to i2c-devices

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Submitter Hans de Goede
Date March 11, 2019, 11:22 a.m.
Message ID <20190311112216.31391-3-hdegoede@redhat.com>
Download mbox | patch
Permalink /patch/745891/
State New
Headers show

Comments

Hans de Goede - March 11, 2019, 11:22 a.m.
The i2c-designware-platdrv assumes that if the pdev has an apci-companion
it should use a dynamic adapter-nr and otherwise it will use pdev->id as
adapter-nr.

On some devices e.g. the Apollo Lake using Acer TravelMate Spin B118,
some of the LPSS i2c-adapters are enumerated through PCI and do not have
an ACPI fwnode. These devices are handled as mfd devices so they end up
using the i2c-designware-platdrv driver.

This results in the i2c-adapter being registered with the mfd generated
pdev->id as adapter-nr, which conflicts with existing adapters, triggering
a WARN(id < 0, "couldn't get idr") in i2c-core-base.c and causing the
adapter registration to fail.

To fix this the i2c-designware-platdrv now also supports a
"linux,use-dynamic-adapter-nr" device-property, which tells it to use a
dynamic adapter nr even if there is no ACPI fwnode for the device.

This commit adds this device-property to the properties list for PCI
enumerated LPSS i2c-adapters.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1687065
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/mfd/intel-lpss-pci.c | 3 +++
 1 file changed, 3 insertions(+)
Wolfram Sang - March 11, 2019, 7:15 p.m.
On Mon, Mar 11, 2019 at 12:22:16PM +0100, Hans de Goede wrote:
> The i2c-designware-platdrv assumes that if the pdev has an apci-companion
> it should use a dynamic adapter-nr and otherwise it will use pdev->id as
> adapter-nr.
> 
> On some devices e.g. the Apollo Lake using Acer TravelMate Spin B118,
> some of the LPSS i2c-adapters are enumerated through PCI and do not have
> an ACPI fwnode. These devices are handled as mfd devices so they end up
> using the i2c-designware-platdrv driver.
> 
> This results in the i2c-adapter being registered with the mfd generated
> pdev->id as adapter-nr, which conflicts with existing adapters, triggering
> a WARN(id < 0, "couldn't get idr") in i2c-core-base.c and causing the
> adapter registration to fail.
> 
> To fix this the i2c-designware-platdrv now also supports a
> "linux,use-dynamic-adapter-nr" device-property, which tells it to use a
> dynamic adapter nr even if there is no ACPI fwnode for the device.
> 
> This commit adds this device-property to the properties list for PCI
> enumerated LPSS i2c-adapters.
> 
> BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1687065
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

You need to CC the devicetree ML on such patches. However, I am afraid I
can pretty much NACK this one already. This is a Linux configuration
item and DT is only for describing HW.

Maybe the designware maintainers have a better idea how to achieve what
you need.

Patch

diff --git a/drivers/mfd/intel-lpss-pci.c b/drivers/mfd/intel-lpss-pci.c
index 0e5282fc1467..c7b84a0f090e 100644
--- a/drivers/mfd/intel-lpss-pci.c
+++ b/drivers/mfd/intel-lpss-pci.c
@@ -69,6 +69,7 @@  static const struct intel_lpss_platform_info spt_info = {
 
 static struct property_entry spt_i2c_properties[] = {
 	PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 230),
+	PROPERTY_ENTRY_BOOL("linux,use-dynamic-adapter-nr"),
 	{ },
 };
 
@@ -104,6 +105,7 @@  static struct property_entry bxt_i2c_properties[] = {
 	PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 42),
 	PROPERTY_ENTRY_U32("i2c-sda-falling-time-ns", 171),
 	PROPERTY_ENTRY_U32("i2c-scl-falling-time-ns", 208),
+	PROPERTY_ENTRY_BOOL("linux,use-dynamic-adapter-nr"),
 	{ },
 };
 
@@ -116,6 +118,7 @@  static struct property_entry apl_i2c_properties[] = {
 	PROPERTY_ENTRY_U32("i2c-sda-hold-time-ns", 207),
 	PROPERTY_ENTRY_U32("i2c-sda-falling-time-ns", 171),
 	PROPERTY_ENTRY_U32("i2c-scl-falling-time-ns", 208),
+	PROPERTY_ENTRY_BOOL("linux,use-dynamic-adapter-nr"),
 	{ },
 };