From 3d16973f771a957d0afd58551b43b861eacc3127 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Wed, 14 Aug 2024 20:22:09 +0200 Subject: [PATCH] i2c: testunit: add SMBusAlert trigger 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 --- 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 #include +#include +#include #include #include #include @@ -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;