On 2018-09-08 02:09, Ajay Gupta wrote:
> Latest NVIDIA GPU cards have a Cypress CCGx Type-C controller
> over I2C interface.
>
> This UCSI I2C driver uses I2C bus driver interface for communicating
> with Type-C controller.
>
> Signed-off-by: Ajay Gupta <ajayg@xxxxxxxxxx>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
> Changes from v1 -> v2
> Fixed identation in drivers/usb/typec/ucsi/Kconfig
> Changes from v2 -> v3
> Fixed most of comments from Heikki
> Rename ucsi_i2c_ccg.c -> ucsi_ccg.c
> Changes from v3 -> v4
> Fixed comments from Andy
> Changes from v4 -> v5
> Fixed comments from Andy
> Changes from v5 -> v6
> Fixed review comments from Greg
> Changes from v6 -> v7
> None
> Changes from v7 -> v8
> Fixed review comments from Peter
> - Removed empty STOP message
> - Using stack memory for i2c_transfer()
> Changes from v8 -> v9
> None
> Changes from v9 -> v10
> Fixed review comments from Peter
> - Use UCSI macros
> - Cleanups
>
> drivers/usb/typec/ucsi/Kconfig | 10 ++
> drivers/usb/typec/ucsi/Makefile | 2 +
> drivers/usb/typec/ucsi/ucsi_ccg.c | 324 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 336 insertions(+)
> create mode 100644 drivers/usb/typec/ucsi/ucsi_ccg.c
>
> diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig
> index e36d6c7..7811888 100644
> --- a/drivers/usb/typec/ucsi/Kconfig
> +++ b/drivers/usb/typec/ucsi/Kconfig
> @@ -23,6 +23,16 @@ config TYPEC_UCSI
>
> if TYPEC_UCSI
>
> +config UCSI_CCG
> + tristate "UCSI Interface Driver for Cypress CCGx"
> + depends on I2C
> + help
> + This driver enables UCSI support on platforms that expose a
> + Cypress CCGx Type-C controller over I2C interface.
> +
> + To compile the driver as a module, choose M here: the module will be
> + called ucsi_ccg.
> +
> config UCSI_ACPI
> tristate "UCSI ACPI Interface Driver"
> depends on ACPI
> diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile
> index 7afbea5..2f4900b 100644
> --- a/drivers/usb/typec/ucsi/Makefile
> +++ b/drivers/usb/typec/ucsi/Makefile
> @@ -8,3 +8,5 @@ typec_ucsi-y := ucsi.o
> typec_ucsi-$(CONFIG_TRACING) += trace.o
>
> obj-$(CONFIG_UCSI_ACPI) += ucsi_acpi.o
> +
> +obj-$(CONFIG_UCSI_CCG) += ucsi_ccg.o
> diff --git a/drivers/usb/typec/ucsi/ucsi_ccg.c b/drivers/usb/typec/ucsi/ucsi_ccg.c
> new file mode 100644
> index 0000000..c346e6a
> --- /dev/null
> +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
> @@ -0,0 +1,324 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * UCSI driver for Cypress CCGx Type-C controller
> + *
> + * Copyright (C) 2017-2018 NVIDIA Corporation. All rights reserved.
> + * Author: Ajay Gupta <ajayg@xxxxxxxxxx>
> + *
> + * Some code borrowed from drivers/usb/typec/ucsi/ucsi_acpi.c
> + */
> +#include <linux/acpi.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +
> +#include <asm/unaligned.h>
> +#include "ucsi.h"
> +
> +struct ucsi_ccg {
> + struct device *dev;
> + struct ucsi *ucsi;
> + struct ucsi_ppm ppm;
> + struct i2c_client *client;
> + int irq;
> +};
> +
> +#define CCGX_I2C_RAB_DEVICE_MODE 0x00
> +#define CCGX_I2C_RAB_READ_SILICON_ID 0x2
> +#define CCGX_I2C_RAB_INTR_REG 0x06
> +#define CCGX_I2C_RAB_FW1_VERSION 0x28
> +#define CCGX_I2C_RAB_FW2_VERSION 0x20
> +#define CCGX_I2C_RAB_UCSI_CONTROL 0x39
> +#define CCGX_I2C_RAB_UCSI_CONTROL_START BIT(0)
> +#define CCGX_I2C_RAB_UCSI_CONTROL_STOP BIT(1)
> +#define CCGX_I2C_RAB_RESPONSE_REG 0x7E
> +#define CCGX_I2C_RAB_UCSI_DATA_BLOCK(offset) (0xf000 | ((offset) & 0xff))
> +
> +#define USBC_VERSION_OFFSET (0x0)
> +#define USBC_VERSION_SIZE (2)
> +#define USBC_CCI_OFFSET (0x4)
> +#define USBC_CCI_SIZE (4)
> +#define USBC_CONTROL_OFFSET (0x8)
> +#define USBC_CONTROL_SIZE (8)
> +#define USBC_MSG_IN_OFFSET (0x10)
> +#define USBC_MSG_IN_SIZE (16)
> +#define USBC_MSG_OUT_OFFSET (0x20)
> +#define USBC_MSG_OUT_SIZE (16)
> +
> +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)?
> + .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.
> + 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)?
> + .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?
> +
> + 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.
> +
> + status = ccg_read(uc, CCGX_I2C_RAB_INTR_REG, buf, 0x1);
sizeof(buf)?
> + if (status < 0)
> + return status;
> +
> + return ccg_write(uc, CCGX_I2C_RAB_INTR_REG, buf, 0x1);
sizeof(buf)?
> +}
> +
> +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.
> +
> + 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?
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 <ajayg@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("UCSI driver for Cypress CCGx Type-C controller");
> +MODULE_LICENSE("GPL v2");
>
