[PATCH 4/4] platform/chrome: i2c: i2c-cros-ec-tunnel: Convert i2c tunnel to MFD Cell

Raul E Rangel
2019-11-21T21:11:15Z

If the i2c-cros-ec-tunnel driver is compiled into the kernel, it is
possible that i2c-cros-ec-tunnel could be probed before cros_ec_XXX
has finished initializing and setting the drvdata. This would cause a
NULL pointer panic.

Converting this driver over to an MFD solves the problem and aligns with
where the cros_ec is going.

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
---
You can now see the device node lives under the mfd device.

$ find /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/ -iname firmware_node -exec ls -l '{}' \;
/sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/firmware_node -> ../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
/sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/firmware_node -> ../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
/sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/i2c-10EC5682:00/firmware_node -> ../../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00/10EC5682:00

drivers/i2c/busses/i2c-cros-ec-tunnel.c | 36 +++++++++----------------
drivers/mfd/cros_ec_dev.c | 19 +++++++++++++
2 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/drivers/i2c/busses/i2c-cros-ec-tunnel.c b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
index 5d91e33eb600..2e3217678fa3 100644
--- a/drivers/i2c/busses/i2c-cros-ec-tunnel.c
+++ b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
@@ -6,6 +6,7 @@
#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/i2c.h>
+#include <linux/mfd/cros_ec.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/platform_device.h>
@@ -27,7 +28,6 @@
struct ec_i2c_device {
struct device *dev;
struct i2c_adapter adap;
- struct cros_ec_device *ec;

u16 remote_bus;

@@ -176,6 +176,7 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
{
struct ec_i2c_device *bus = adap->algo_data;
struct device *dev = bus->dev;
+ struct cros_ec_dev *ec = dev_get_drvdata(dev->parent);
const u16 bus_num = bus->remote_bus;
int request_len;
int response_len;
@@ -183,6 +184,16 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
int result;
struct cros_ec_command *msg;

+ if (!ec) {
+ dev_err(dev, "%s: ec is missing!\n", __func__);
+ return -EINVAL;
+ }
+
+ if (!ec->ec_dev) {
+ dev_err(dev, "%s: ec->ec_dev is missing!\n", __func__);
+ return -EINVAL;
+ }
+
request_len = ec_i2c_count_message(i2c_msgs, num);
if (request_len < 0) {
dev_warn(dev, "Error constructing message %d\n", request_len);
@@ -212,7 +223,7 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
msg->outsize = request_len;
msg->insize = response_len;

- result = cros_ec_cmd_xfer_status(bus->ec, msg);
+ result = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
if (result < 0) {
dev_err(dev, "Error transferring EC i2c message %d\n", result);
goto exit;
@@ -241,17 +252,11 @@ static const struct i2c_algorithm ec_i2c_algorithm = {

static int ec_i2c_probe(struct platform_device *pdev)
{
- struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
struct device *dev = &pdev->dev;
struct ec_i2c_device *bus = NULL;
u32 remote_bus;
int err;

- if (!ec->cmd_xfer) {
- dev_err(dev, "Missing sendrecv\n");
- return -EINVAL;
- }
-
bus = devm_kzalloc(dev, sizeof(*bus), GFP_KERNEL);
if (bus == NULL)
return -ENOMEM;
@@ -263,7 +268,6 @@ static int ec_i2c_probe(struct platform_device *pdev)
}
bus->remote_bus = remote_bus;

- bus->ec = ec;
bus->dev = dev;

bus->adap.owner = THIS_MODULE;
@@ -292,25 +296,11 @@ static int ec_i2c_remove(struct platform_device *dev)
return 0;
}

-static const struct of_device_id cros_ec_i2c_of_match[] = {
- { .compatible = "google,cros-ec-i2c-tunnel" },
- {},
-};
-MODULE_DEVICE_TABLE(of, cros_ec_i2c_of_match);
-
-static const struct acpi_device_id cros_ec_i2c_tunnel_acpi_id[] = {
- { "GOOG0012", 0 },
- { }
-};
-MODULE_DEVICE_TABLE(acpi, cros_ec_i2c_tunnel_acpi_id);
-
static struct platform_driver ec_i2c_tunnel_driver = {
.probe = ec_i2c_probe,
.remove = ec_i2c_remove,
.driver = {
.name = "cros-ec-i2c-tunnel",
- .acpi_match_table = ACPI_PTR(cros_ec_i2c_tunnel_acpi_id),
- .of_match_table = of_match_ptr(cros_ec_i2c_of_match),
},
};

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 1efdba18f20b..61b20e061f75 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -113,6 +113,18 @@ static const struct mfd_cell cros_ec_vbc_cells[] = {
{ .name = "cros-ec-vbc", }
};

+static struct mfd_cell_acpi_match cros_ec_i2c_tunnel_acpi_match = {
+ .pnpid = "GOOG0012"
+};
+
+static struct mfd_cell cros_ec_fw_cells[] = {
+ {
+ .name = "cros-ec-i2c-tunnel",
+ .acpi_match = &cros_ec_i2c_tunnel_acpi_match,
+ .of_compatible = "google,cros-ec-i2c-tunnel"
+ },
+};
+
int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
{
struct cros_ec_command *msg;
@@ -485,6 +497,13 @@ static int ec_device_probe(struct platform_device *pdev)
"failed to add cros-ec platform devices: %d\n",
retval);

+ retval = mfd_add_hotplug_devices(ec->dev, cros_ec_fw_cells,
+ ARRAY_SIZE(cros_ec_fw_cells));
+ if (retval)
+ dev_warn(ec->dev,
+ "failed to add cros-ec fw platform devices: %d\n",
+ retval);
+
/* Check whether this EC instance has a VBC NVRAM */
node = ec->ec_dev->dev->of_node;
if (of_property_read_bool(node, "google,has-vbc-nvram")) {
--
2.24.0.432.g9d3f5f5b63-goog