Hi Heikki and Andy
[...]

quoted

quoted

Shouldn't you return -ETIMEDOUT if count == 0?

Yes. Good catch. Does the below fix looks ok?

        do {
                status = ccg_write(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));
                if (status < 0)
                        return status;

                usleep_range(10000, 11000);

                status = ccg_read(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));
                if (status < 0)
                        return status;

                if (!data)
                        return 0;
        } while (data && count--);

Doesn't that condition break out of the loop immediately?

How? I didn't get your point? We want to break out when data is
zero (interrupt status cleared).

quoted

Ah, I see, but why you not reorganize it to put this into do-while loop?

We actually need to check data after reading it so will reorganize accordingly.
do {
	read
	check for data and break out if (!data)
	write
	sleep
} while (--count);

Thanks
Ajay
-nvpublic

quoted

        return -ETIMEDOUT;

quoted

Something like:

        ...
        while (count--)
		status = ccg_read(uc, CCGX_RAB_INTR_REG, &data,

sizeof(data));

quoted

quoted

		if (status < 0)
			return status;
                if (!data)
                        return 0;
	}

        return -ETIMEDOUT;

Or does the count of 10 have some specific meaning?

quoted

+}
+
+static int ucsi_ccg_send_data(struct ucsi_ccg *uc) {
+	u8 *ppm = (u8 *)uc->ppm.data;
+	int status;
+	u16 rab;
+
+	rab = CCGX_RAB_UCSI_DATA_BLOCK(offsetof(struct ucsi_data,

message_out));

quoted

+	status = ccg_write(uc, rab, ppm +
+			   offsetof(struct ucsi_data, message_out),
+			   sizeof(uc->ppm.data->message_out));
+	if (status < 0)
+		return status;
+
+	rab = CCGX_RAB_UCSI_DATA_BLOCK(offsetof(struct ucsi_data, ctrl));
+	return ccg_write(uc, rab, ppm + offsetof(struct ucsi_data, ctrl),
+			 sizeof(uc->ppm.data->ctrl));
+}
+
+static int ucsi_ccg_recv_data(struct ucsi_ccg *uc) {
+	u8 *ppm = (u8 *)uc->ppm.data;
+	int status;
+	u16 rab;
+
+	rab = CCGX_RAB_UCSI_DATA_BLOCK(offsetof(struct ucsi_data, cci));
+	status = ccg_read(uc, rab, ppm + offsetof(struct ucsi_data, cci),
+			  sizeof(uc->ppm.data->cci));
+	if (status < 0)
+		return status;
+
+	rab = CCGX_RAB_UCSI_DATA_BLOCK(offsetof(struct ucsi_data,

message_in));

quoted

+	return ccg_read(uc, rab, ppm + offsetof(struct ucsi_data, message_in),
+			sizeof(uc->ppm.data->message_in));
+}
+
+static int ucsi_ccg_ack_interrupt(struct ucsi_ccg *uc) {
+	int status;
+	unsigned char data;
+
+	status = ccg_read(uc, CCGX_RAB_INTR_REG, &data, sizeof(data));
+	if (status < 0)
+		return status;
+
+	return ccg_write(uc, CCGX_RAB_INTR_REG, &data, sizeof(data)); }
+
+static int ucsi_ccg_sync(struct ucsi_ppm *ppm) {
+	struct ucsi_ccg *uc = container_of(ppm, struct ucsi_ccg, ppm);
+	int status;
+
+	status = ucsi_ccg_recv_data(uc);
+	if (status < 0)
+		return status;
+
+	/* ack interrupt to allow next command to run */
+	return ucsi_ccg_ack_interrupt(uc); }
+
+static int ucsi_ccg_cmd(struct ucsi_ppm *ppm, struct ucsi_control
+*ctrl) {
+	struct ucsi_ccg *uc = container_of(ppm, struct ucsi_ccg, ppm);
+
+	ppm->data->ctrl.raw_cmd = ctrl->raw_cmd;
+	return ucsi_ccg_send_data(uc);
+}
+
+static irqreturn_t ccg_irq_handler(int irq, void *data) {
+	struct ucsi_ccg *uc = data;
+
+	ucsi_notify(uc->ucsi);
+
+	return IRQ_HANDLED;
+}
+
+static int ucsi_ccg_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id) {
+	struct device *dev = &client->dev;
+	struct ucsi_ccg *uc;
+	int status;
+	u16 rab;
+
+	uc = devm_kzalloc(dev, sizeof(*uc), GFP_KERNEL);
+	if (!uc)
+		return -ENOMEM;
+
+	uc->ppm.data = devm_kzalloc(dev, sizeof(struct ucsi_data),

GFP_KERNEL);

quoted

+	if (!uc->ppm.data)
+		return -ENOMEM;
+
+	uc->ppm.cmd = ucsi_ccg_cmd;
+	uc->ppm.sync = ucsi_ccg_sync;
+	uc->dev = dev;
+	uc->client = client;
+
+	/* reset ccg device and initialize ucsi */
+	status = ucsi_ccg_init(uc);
+	if (status < 0) {
+		dev_err(uc->dev, "ucsi_ccg_init failed - %d\n", status);
+		return status;
+	}
+
+	uc->irq = client->irq;
+
+	status = devm_request_threaded_irq(dev, uc->irq, NULL,

ccg_irq_handler,

quoted

+					   IRQF_ONESHOT |

IRQF_TRIGGER_HIGH,

quoted

+					   dev_name(dev), uc);
+	if (status < 0) {
+		dev_err(uc->dev, "request_threaded_irq failed - %d\n",

status);

quoted

+		return status;
+	}
+
+	uc->ucsi = ucsi_register_ppm(dev, &uc->ppm);
+	if (IS_ERR(uc->ucsi)) {
+		dev_err(uc->dev, "ucsi_register_ppm failed\n");
+		return PTR_ERR(uc->ucsi);
+	}
+
+	rab = CCGX_RAB_UCSI_DATA_BLOCK(offsetof(struct ucsi_data,

version));

quoted

+	status = ccg_read(uc, rab, (u8 *)(uc->ppm.data) +
+			  offsetof(struct ucsi_data, version),
+			  sizeof(uc->ppm.data->version));
+	if (status < 0) {
+		ucsi_unregister_ppm(uc->ucsi);
+		return status;
+	}
+
+	i2c_set_clientdata(client, uc);
+	return 0;
+}
+
+static int ucsi_ccg_remove(struct i2c_client *client) {
+	struct ucsi_ccg *uc = i2c_get_clientdata(client);
+
+	ucsi_unregister_ppm(uc->ucsi);
+
+	return 0;
+}
+
+static const struct i2c_device_id ucsi_ccg_device_id[] = {
+	{"ccgx-ucsi", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ucsi_ccg_device_id);
+
+static struct i2c_driver ucsi_ccg_driver = {
+	.driver = {
+		.name = "ucsi_ccg",
+	},
+	.probe = ucsi_ccg_probe,
+	.remove = ucsi_ccg_remove,
+	.id_table = ucsi_ccg_device_id,
+};
+
+module_i2c_driver(ucsi_ccg_driver);
+
+MODULE_AUTHOR("Ajay Gupta [off-list ref]");
+MODULE_DESCRIPTION("UCSI driver for Cypress CCGx Type-C
+controller"); MODULE_LICENSE("GPL v2");

I'm still worried about how this driver works on other platforms. It
just looks like you have written ccg_read/write() functions for only your

I2C host.

quoted

quoted

I would feel much more comfortable with this if you for example used
those
i2c_smbus_read/write*() helpers instead of raw i2c_transfer().
I would expect them to force you to write your i2c host driver, as
well as this driver, in a more generic fashion.

I2c_smbus_read/write*() will not work with Cypress CCGx controller
since CCGx requires 2 byte of command for any read/write transaction.
I2c_smbus_read/write*() APIs support only 1 byte of command.

OK, got it.


thanks,

--
heikki