[PATCH RFC v2 net-next 2/2] net: phy: sfp: enable i2c-bus detection on ACPI based systems

Ruslan Babayev
2019-05-07T00:37:50Z

Lookup I2C adapter using the "i2c-bus" device property on ACPI based
systems similar to how it's done with DT.

An example DSD describing an SFP on an ACPI based system:

Device (SFP0)
{
Name (_HID, "PRP0001")
Name (_CRS, ResourceTemplate()
{
GpioIo(Exclusive, PullDefault, 0, 0, IoRestrictionNone,
"\\_SB.PCI0.RP01.GPIO", 0, ResourceConsumer)
{ 0, 1, 2, 3, 4 }
})
Name (_DSD, Package ()
{
ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package () {
Package () { "compatible", "sff,sfp" },
Package () { "i2c-bus", \_SB.PCI0.RP01.I2C.MUX.CH0 },
Package () { "maximum-power-milliwatt", 1000 },
Package () { "tx-disable-gpios", Package () { ^SFP0, 0, 0, 1} },
Package () { "reset-gpio", Package () { ^SFP0, 0, 1, 1} },
Package () { "mod-def0-gpios", Package () { ^SFP0, 0, 2, 1} },
Package () { "tx-fault-gpios", Package () { ^SFP0, 0, 3, 0} },
Package () { "los-gpios", Package () { ^SFP0, 0, 4, 1} },
},
})
}

Device (PHY0)
{
Name (_HID, "PRP0001")
Name (_DSD, Package ()
{
ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package () {
Package () { "compatible", "ethernet-phy-ieee802.3-c45" },
Package () { "sfp", \_SB.PCI0.RP01.SFP0 },
Package () { "managed", "in-band-status" },
Package () { "phy-mode", "sgmii" },
},
})
}

Signed-off-by: Ruslan Babayev <ruslan@babayev.com>
Cc: xe-linux-external@cisco.com
---
drivers/net/phy/sfp.c | 33 +++++++++++++++++++++++++--------
1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index d4635c2178d1..7a6c8df8899b 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -9,6 +9,7 @@
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
+#include <linux/acpi.h>
#include <linux/phy.h>
#include <linux/platform_device.h>
#include <linux/rtnetlink.h>
@@ -1783,6 +1784,7 @@ static int sfp_probe(struct platform_device *pdev)
{
const struct sff_data *sff;
struct sfp *sfp;
+ struct i2c_adapter *i2c = NULL;
bool poll = false;
int irq, err, i;

@@ -1801,7 +1803,6 @@ static int sfp_probe(struct platform_device *pdev)
if (pdev->dev.of_node) {
struct device_node *node = pdev->dev.of_node;
const struct of_device_id *id;
- struct i2c_adapter *i2c;
struct device_node *np;

id = of_match_node(sfp_of_match, node);
@@ -1818,14 +1819,30 @@ static int sfp_probe(struct platform_device *pdev)

i2c = of_find_i2c_adapter_by_node(np);
of_node_put(np);
- if (!i2c)
- return -EPROBE_DEFER;
-
- err = sfp_i2c_configure(sfp, i2c);
- if (err < 0) {
- i2c_put_adapter(i2c);
- return err;
+ } else if (ACPI_COMPANION(&pdev->dev)) {
+ struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+ struct fwnode_handle *fw = acpi_fwnode_handle(adev);
+ struct fwnode_reference_args args;
+ struct acpi_handle *acpi_handle;
+ int ret;
+
+ ret = acpi_node_get_property_reference(fw, "i2c-bus", 0, &args);
+ if (ACPI_FAILURE(ret) || !is_acpi_device_node(args.fwnode)) {
+ dev_err(&pdev->dev, "missing 'i2c-bus' property\n");
+ return -ENODEV;
}
+
+ acpi_handle = ACPI_HANDLE_FWNODE(args.fwnode);
+ i2c = i2c_acpi_find_adapter_by_handle(acpi_handle);
+ }
+
+ if (!i2c)
+ return -EPROBE_DEFER;
+
+ err = sfp_i2c_configure(sfp, i2c);
+ if (err < 0) {
+ i2c_put_adapter(i2c);
+ return err;
}

for (i = 0; i < GPIO_MAX; i++)
--
2.17.1