Hi Peter,
> >>> +static int ccg_read(struct ucsi_ccg *uc, u16 rab, u8 *data, u32
> >>> +len) {
> >>> + struct i2c_client *client = uc->client;
> >>> + unsigned char buf[2];
> >>> + struct i2c_msg msgs[] = {
> >>> + {
> >>> + .addr = client->addr,
> >>> + .flags = 0x0,
> >>> + .len = 0x2,
> >>
> >> sizeof(buf)?
> > ok
> >>
> >>> + .buf = buf,
> >>> + },
> >>> + {
> >>> + .addr = client->addr,
> >>> + .flags = I2C_M_RD,
> >>> + .buf = data,
> >>> + },
> >>> + };
> >>> + u32 rlen, rem_len = len;
> >>> + int status;
> >>> +
> >>
> >> If your target I2C adapter had supported larger reads, this would
> >> have been a single xfer instead of the loop, correct? I think this
> >> deserves a comment, and perhaps e.g. the eeprom drivers should be
> >> examined to see how they handle deficient I2C adapters (there is a
> >> module_param named io_limit in the at24 driver). Because it is a
> >> little bit sad to penalise all users just because you have an adapter with
> limitations.
> >> Or is this driver tied to that adapter?
> >> Anyway, I'm satisfied with a comment, as I don't care all that much.
> > I am thinking of moving the loop to the i2c driver.
>
> No, that will not work. The i2c driver cannot know how the splitting works,
> since how to split transfers will typically be different for different drivers
> needing large reads.
>
> You will have to do the split here in this driver.
Yes, I realized it later.
>
> >>> + while (rem_len > 0) {
> >>> + msgs[1].buf = &data[len - rem_len];
> >>> + rlen = min_t(u16, rem_len, 4);
> >>> + msgs[1].len = rlen;
> >>> + put_unaligned_le16(rab, buf);
> >>> + status = i2c_transfer(client->adapter, msgs,
> >> ARRAY_SIZE(msgs));
> >>> + if (status < 0) {
> >>> + dev_err(uc->dev, "i2c_transfer failed %d\n", status);
> >>> + return status;
> >>> + }
> >>> + rab += rlen;
> >>> + rem_len -= rlen;
> >>> + }
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static int ccg_write(struct ucsi_ccg *uc, u16 rab, u8 *data, u32
> >>> +len) {
> >>> + struct i2c_client *client = uc->client;
> >>> + unsigned char buf[2];
> >>> + struct i2c_msg msgs[] = {
> >>> + {
> >>> + .addr = client->addr,
> >>> + .flags = 0x0,
> >>> + .len = 0x2,
> >>
> >> sizeof(buf)?
> > ok
> >>
> >>> + .buf = buf,
> >>> + },
> >>> + {
> >>> + .addr = client->addr,
> >>> + .flags = 0x0,
> >>> + .buf = data,
> >>> + .len = len,
> >>> + },
> >>> + };
> >>> + int status;
> >>> +
> >>> + put_unaligned_le16(rab, buf);
> >>> + status = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
> >>> + if (status < 0) {
> >>> + dev_err(uc->dev, "i2c_transfer failed %d\n", status);
> >>> + return status;
> >>> + }
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static int ucsi_ccg_init(struct ucsi_ccg *uc) {
> >>> + struct device *dev = uc->dev;
> >>> + unsigned int count = 10;
> >>> + u8 data[64];
> >>> + int status;
> >>> +
> >>> + status = ccg_read(uc, CCGX_I2C_RAB_DEVICE_MODE, data,
> >> sizeof(data));
> >>> + if (status < 0)
> >>> + return status;
> >>> +
> >>> + dev_dbg(dev, "Silicon id %2ph", data +
> >> CCGX_I2C_RAB_READ_SILICON_ID);
> >>> + dev_dbg(dev, "FW1 version %8ph\n", data +
> >> CCGX_I2C_RAB_FW1_VERSION);
> >>> + dev_dbg(dev, "FW2 version %8ph\n", data +
> >> CCGX_I2C_RAB_FW2_VERSION);
> >>> +
> >>> + data[0] = CCGX_I2C_RAB_UCSI_CONTROL_STOP;
> >>> + status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
> >>> + if (status < 0)
> >>> + return status;
> >>> +
> >>> + data[0] = CCGX_I2C_RAB_UCSI_CONTROL_START;
> >>> + status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
> >>> + if (status < 0)
> >>> + return status;
> >>> +
> >>> + /*
> >>> + * Flush CCGx RESPONSE queue by acking interrupts
> >>> + * - above ucsi control register write will push response
> >>> + * which must be flushed
> >>> + * - affects f/w update which reads response register
> >>> + */
> >>> + data[0] = 0xff;
> >>> + do {
> >>> + status = ccg_write(uc, CCGX_I2C_RAB_INTR_REG, data, 0x1);
> >>> + if (status < 0)
> >>> + return status;
> >>> +
> >>> + usleep_range(10000, 11000);
> >>> +
> >>> + status = ccg_read(uc, CCGX_I2C_RAB_INTR_REG, data, 0x1);
> >>> + if (status < 0)
> >>> + return status;
> >>> + } while ((data[0] != 0x00) && count--);
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static int ucsi_ccg_send_data(struct ucsi_ccg *uc) {
> >>> + unsigned char buf1[USBC_MSG_OUT_SIZE];
> >>> + unsigned char buf2[USBC_CONTROL_SIZE];
> >>> + int status;
> >>> + u16 rab;
> >>> +
> >>> + memcpy(buf1, (u8 *)(uc->ppm.data) + USBC_MSG_OUT_OFFSET,
> >> sizeof(buf1));
> >>> + memcpy(buf2, (u8 *)(uc->ppm.data) + USBC_CONTROL_OFFSET,
> >>> +sizeof(buf2));
> >>
> >> Hmm, now that I see what this function does, instead of just seeing a
> >> bunch of magic numbers, I wonder why you make copies instead of
> >> feeding the correct section of the ppm.data buffer directly to
> >> ccg_write, like you do below for recv?
> > Ok, will fix.
>
> Hmm, now that I see this again, it makes me wonder why you complained
> about copying the buffer to fix the misunderstanding of the i2c_transfer
> interface, when you already copy the buffer in the first place?
Copy is indeed not needed. I will fix it in next version.
We will have to do copy in ccg_write()if we try to combine two write i2c_msg
into one and I want to rather stay with two i2c_msg to avoid copy.
Also master_xfer() will become tricky since rab write for read alsp has to go
first.
> >>> +
> >>> + rab = CCGX_I2C_RAB_UCSI_DATA_BLOCK(USBC_MSG_OUT_OFFSET);
> >>> + status = ccg_write(uc, rab, buf1, sizeof(buf1));
> >>> + if (status < 0)
> >>> + return status;
> >>> +
> >>> + rab = CCGX_I2C_RAB_UCSI_DATA_BLOCK(USBC_CONTROL_OFFSET);
> >>> + return ccg_write(uc, rab, buf2, sizeof(buf2)); }
> >>> +
> >>> +static int ucsi_ccg_recv_data(struct ucsi_ccg *uc) {
> >>> + u8 *ppm = (u8 *)uc->ppm.data;
> >>> + int status;
> >>> + u16 rab;
> >>> +
> >>> + rab = CCGX_I2C_RAB_UCSI_DATA_BLOCK(USBC_CCI_OFFSET);
> >>> + status = ccg_read(uc, rab, ppm + USBC_CCI_OFFSET, USBC_CCI_SIZE);
> >>> + if (status < 0)
> >>> + return status;
> >>> +
> >>> + rab = CCGX_I2C_RAB_UCSI_DATA_BLOCK(USBC_MSG_IN_OFFSET);
> >>> + return ccg_read(uc, rab, ppm + USBC_MSG_IN_OFFSET,
> >>> +USBC_MSG_IN_SIZE); }
> >>> +
> >>> +static int ucsi_ccg_ack_interrupt(struct ucsi_ccg *uc) {
> >>> + int status;
> >>> + unsigned char buf[1] = {0x0};
> >>
> >> The initializer can be dropped.
> > ok
> >>
> >>> +
> >>> + status = ccg_read(uc, CCGX_I2C_RAB_INTR_REG, buf, 0x1);
> >>
> >> sizeof(buf)?
> > ok
> >>
> >>> + if (status < 0)
> >>> + return status;
> >>> +
> >>> + return ccg_write(uc, CCGX_I2C_RAB_INTR_REG, buf, 0x1);
> >>
> >> sizeof(buf)?
> > ok
> >>
> >>> +}
> >>> +
> >>> +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;
> >>
> >> Wait a minute, ppm.data is allocated as a struct? And it's __packed!
> >> So, it's clearly intended to match something real. I didn't notice
> >> that before, but that means that all the new offsets and sizes
> >> defined in v10 are available with
> >> offsetof() and sizeof() which would be much neater than a bunch of defines.
> >> Sorry for not catching this earlier!
> >>
> >> See below for an example.
> > Sure.
> >>
> >>> +
> >>> + 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_I2C_RAB_UCSI_DATA_BLOCK(USBC_VERSION_OFFSET);
> >>> + status = ccg_read(uc, rab, (u8 *)(uc->ppm.data) +
> >> USBC_VERSION_OFFSET,
> >>> + USBC_VERSION_SIZE);
> >>
> >> E.g.
> >> rab = CCGX_I2C_RAB_UCSI_DATA_BLOCK(offsetof(struct ucsi_data,
> >> version));
> >> status = ccg_read(uc, rab, (u8 *)&uc->ppm.data->version,
> >> sizeof(uc->ppm.data->version));
> >>
> >> Hmm, but this highlights that you are not doing any endian conversion
> >> of the fields in that struct as you read/write it.
> >
> >> Do you need to in case you have an endian mismatch?
> > Looks like don't need it. I have tested it and it works as is.
>
> Yeah, but have you tested the driver on a machine with the other byte-sex?
No, I think better to convert to desired endian.
Thanks
Ajay
--
nvpublic
--
> Cheers,
> Peter
>
> > Thanks
> > Ajay
> >
> > --
> > nvpublic
> > --
> >>
> >> Cheers,
> >> Peter
> >>
> >>> + 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");
> >>>
> >
