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