To test SMBusAlert handlers, let the testunit be able to trigger
SMBusAlert interrupts. This new command needs a GPIO connected to the
SMBAlert# line.
Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/i2c/slave-testunit-backend.rst | 48 ++++++++++++++++
drivers/i2c/i2c-slave-testunit.c | 59 ++++++++++++++++++++
2 files changed, 107 insertions(+)
diff --git a/Documentation/i2c/slave-testunit-backend.rst b/Documentation/i2c/slave-testunit-backend.rst
index 3743188ecfc7..d752f433be07 100644
--- a/Documentation/i2c/slave-testunit-backend.rst
+++ b/Documentation/i2c/slave-testunit-backend.rst
@@ -185,3 +185,51 @@ default response::
# i2cset -y 0 0x30 4 0 0 i; i2cget -y 0 0x30
0x00
+
+0x05 SMBUS_ALERT_REQUEST
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. list-table::
+ :header-rows: 1
+
+ * - CMD
+ - DATAL
+ - DATAH
+ - DELAY
+
+ * - 0x05
+ - response value (7 MSBs interpreted as I2C address)
+ - currently unused
+ - n * 10ms
+
+This test raises an interrupt via the SMBAlert pin which the host controller
+must handle. The pin must be connected to the testunit as a GPIO. GPIO access
+is not allowed to sleep. Currently, this can only be described using firmware
+nodes. So, for devicetree, you would add something like this to the testunit
+node::
+
+ gpios = <&gpio1 24 GPIO_ACTIVE_LOW>;
+
+The following command will trigger the alert with a response of 0xc9 after 1
+second of delay::
+
+ # i2cset -y 0 0x30 5 0xc9 0x00 100 i
+
+If the host controller supports SMBusAlert, this message with debug level
+should appear::
+
+ smbus_alert 0-000c: SMBALERT# from dev 0x64, flag 1
+
+This message may appear more than once because the testunit is software not
+hardware and, thus, may not be able to react to the response of the host fast
+enough. The interrupt count should increase only by one, though::
+
+ # cat /proc/interrupts | grep smbus_alert
+ 93: 1 gpio-rcar 26 Edge smbus_alert
+
+If the host does not respond to the alert within 1 second, the test will be
+aborted and the testunit will report an error.
+
+For this test, the testunit will shortly drop its assigned address and listen
+on the SMBus Alert Response Address (0x0c). It will reassign its original
+address afterwards.
diff --git a/drivers/i2c/i2c-slave-testunit.c b/drivers/i2c/i2c-slave-testunit.c
index df54185e5e9a..9fe3150378e8 100644
--- a/drivers/i2c/i2c-slave-testunit.c
+++ b/drivers/i2c/i2c-slave-testunit.c
@@ -8,6 +8,8 @@
#include <generated/utsrelease.h>
#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/module.h>
@@ -22,6 +24,7 @@ enum testunit_cmds {
TU_CMD_SMBUS_HOST_NOTIFY,
TU_CMD_SMBUS_BLOCK_PROC_CALL,
TU_CMD_GET_VERSION_WITH_REP_START,
+ TU_CMD_SMBUS_ALERT_REQUEST,
TU_NUM_CMDS
};
@@ -44,10 +47,37 @@ struct testunit_data {
u8 read_idx;
struct i2c_client *client;
struct delayed_work worker;
+ struct gpio_desc *gpio;
+ struct completion alert_done;
};
static char tu_version_info[] = "v" UTS_RELEASE "\n\0";
+static int i2c_slave_testunit_smbalert_cb(struct i2c_client *client,
+ enum i2c_slave_event event, u8 *val)
+{
+ struct testunit_data *tu = i2c_get_clientdata(client);
+
+ switch (event) {
+ case I2C_SLAVE_READ_PROCESSED:
+ gpiod_set_value(tu->gpio, 0);
+ fallthrough;
+ case I2C_SLAVE_READ_REQUESTED:
+ *val = tu->regs[TU_REG_DATAL];
+ break;
+
+ case I2C_SLAVE_STOP:
+ complete(&tu->alert_done);
+ break;
+
+ case I2C_SLAVE_WRITE_REQUESTED:
+ case I2C_SLAVE_WRITE_RECEIVED:
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
static int i2c_slave_testunit_slave_cb(struct i2c_client *client,
enum i2c_slave_event event, u8 *val)
{
@@ -127,8 +157,10 @@ static int i2c_slave_testunit_slave_cb(struct i2c_client *client,
static void i2c_slave_testunit_work(struct work_struct *work)
{
struct testunit_data *tu = container_of(work, struct testunit_data, worker.work);
+ unsigned long time_left;
struct i2c_msg msg;
u8 msgbuf[256];
+ u16 orig_addr;
int ret = 0;
msg.addr = I2C_CLIENT_END;
@@ -150,6 +182,26 @@ static void i2c_slave_testunit_work(struct work_struct *work)
msgbuf[2] = tu->regs[TU_REG_DATAH];
break;
+ case TU_CMD_SMBUS_ALERT_REQUEST:
+ i2c_slave_unregister(tu->client);
+ orig_addr = tu->client->addr;
+ tu->client->addr = 0x0c;
+ ret = i2c_slave_register(tu->client, i2c_slave_testunit_smbalert_cb);
+ if (ret)
+ goto out_smbalert;
+
+ reinit_completion(&tu->alert_done);
+ gpiod_set_value(tu->gpio, 1);
+ time_left = wait_for_completion_timeout(&tu->alert_done, HZ);
+ if (!time_left)
+ ret = -ETIMEDOUT;
+
+ i2c_slave_unregister(tu->client);
+out_smbalert:
+ tu->client->addr = orig_addr;
+ i2c_slave_register(tu->client, i2c_slave_testunit_slave_cb);
+ break;
+
default:
break;
}
@@ -176,8 +228,15 @@ static int i2c_slave_testunit_probe(struct i2c_client *client)
tu->client = client;
i2c_set_clientdata(client, tu);
+ init_completion(&tu->alert_done);
INIT_DELAYED_WORK(&tu->worker, i2c_slave_testunit_work);
+ tu->gpio = devm_gpiod_get_index_optional(&client->dev, NULL, 0, GPIOD_OUT_LOW);
+ if (gpiod_cansleep(tu->gpio)) {
+ dev_err(&client->dev, "GPIO access which may sleep is not allowed\n");
+ return -EDEADLK;
+ }
+
if (sizeof(tu_version_info) > TU_VERSION_MAX_LENGTH)
tu_version_info[TU_VERSION_MAX_LENGTH - 1] = 0;
--
2.43.0
