Hi Heikki and Andy
[...]
> > > 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).
> > 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
> > return -ETIMEDOUT;
> >
> > > Something like:
> > >
> > > ...
> > > while (count--)
> > > status = ccg_read(uc, CCGX_RAB_INTR_REG, &data,
> sizeof(data));
> > > if (status < 0)
> > > return status;
> > > if (!data)
> > > return 0;
> > > }
> > >
> > > return -ETIMEDOUT;
> > >
> > > Or does the count of 10 have some specific meaning?
> > >
> > > > +}
> > > > +
> > > > +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));
> > > > + 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));
> > > > + 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);
> > > > + 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,
> > > > + IRQF_ONESHOT |
> > > IRQF_TRIGGER_HIGH,
> > > > + dev_name(dev), uc);
> > > > + if (status < 0) {
> > > > + dev_err(uc->dev, "request_threaded_irq failed - %d\n",
> > > status);
> > > > + 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));
> > > > + 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 <aj...@nvidia.com>");
> > > > +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.
> > >
> > > 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
