On 2018-09-07 01:56, 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
>
> drivers/usb/typec/ucsi/Kconfig | 10 ++
> drivers/usb/typec/ucsi/Makefile | 2 +
> drivers/usb/typec/ucsi/ucsi_ccg.c | 335 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 347 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..387b6fd
> --- /dev/null
> +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
> @@ -0,0 +1,335 @@
> +// 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 0xf000
> +
> +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,
> + .buf = buf,
> + },
> + {
> + .addr = client->addr,
> + .flags = I2C_M_RD,
> + .buf = data,
> + },
> + };
> + u32 rlen, rem_len = len;
> + int status;
> +
> + 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);
Why not simply do whichever is correct of
buf[0] = rab >> 8;
buf[1] = rab;
and
buf[0] = rab;
buf[1] = rab >> 8;
and feed rab as a cpu-native value and get rid of the endianess crap.
> + 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,
> + .buf = buf,
> + },
> + {
> + .addr = client->addr,
> + .flags = 0x0,
> + .buf = data,
> + .len = len,
> + },
> + };
> + int status;
> +
> + put_unaligned_le16(rab, buf);
Dito.
> + 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;
> +
> + /*
> + * Selectively issue device reset
> + * - if RESPONSE register is RESET_COMPLETE, do not issue device reset
> + * (will cause usb device disconnect / reconnect)
> + * - if RESPONSE register is not RESET_COMPLETE, issue device reset
> + * (causes PPC to resync device connect state by re-issuing
> + * set mux command)
> + */
> + data[0] = 0x00;
> + data[1] = 0x00;
Why do you need these assigments? Will not ccg_read just overwrite this
anyway?
> +
> + status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
> + if (status < 0)
> + return status;
> +
> + memset(data, 0, sizeof(data));
Dito.
> + 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] = 0x0;
> + data[1] = 0x0;
Dito.
> + status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
> + if (status < 0)
> + return status;
> +
> + 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)
> +{
> + int status;
> + unsigned char buf[4] = {
> + 0x20, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> + 0x8, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> + };
> + unsigned char buf1[16];
> + unsigned char buf2[8];
> +
> + memcpy(buf1, ((const void *)uc->ppm.data) + 0x20, sizeof(buf1));
> + memcpy(buf2, ((const void *)uc->ppm.data) + 0x8, sizeof(buf2));
> +
> + status = ccg_write(uc, *(u16 *)buf, buf1, sizeof(buf1));
This seems to be endian-dependent. May I suggest that you do as suggested
above for ccg_read, and then somthing like
#define CCGX_I2C_RAB_USCI_DATA_BLOCK(xxx) (0xf000 | ((xxx) & <mask>))
where you of course use an appropriate value for <mask> (perhaps 0xff, or
0xfff, what do I know) and a better name for the field than xxx (perhaps
len, what do I know), and then finally do
status = ccg_write(uc, CCGX_I2C_RAB_USCI_DATA_BLOCK(0x20), ...
Also, the 0x20 and 0x8 are repeated and are some magic numbers that
really should be given a name or some explanation. They appear to be
data lengths, but again, what do I know?
> + if (status < 0)
> + return status;
> +
> + return ccg_write(uc, *(u16 *)(buf + 2), buf2, sizeof(buf2));
> +}
> +
> +static int ucsi_ccg_recv_data(struct ucsi_ccg *uc)
> +{
> + u8 *ppm = (u8 *)uc->ppm.data;
> + int status;
> + unsigned char buf[6] = {
> + 0x0, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> + 0x4, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> + 0x10, CCGX_I2C_RAB_UCSI_DATA_BLOCK >> 8,
> + };
> +
> + status = ccg_read(uc, *(u16 *)buf, ppm, 0x2);
There are plenty magic numbers, but this call does not follow the
pattern. Should perhaps buf[0] be 0x2, or should perhaps the
last 0x2 argument be 0x0? All other ...DATA_BLOCK calls seem to
have the len in the other byte of the rab argument. Why does
this call not follow the pattern?
> + if (status < 0)
> + return status;
> +
> + status = ccg_read(uc, *(u16 *)(buf + 2), ppm + 0x4, 0x4);
> + if (status < 0)
> + return status;
> +
> + return ccg_read(uc, *(u16 *)(buf + 4), ppm + 0x10, 0x10);
> +}
> +
> +static int ucsi_ccg_ack_interrupt(struct ucsi_ccg *uc)
> +{
> + int status;
> + unsigned char buf[2] = {
> + CCGX_I2C_RAB_INTR_REG, CCGX_I2C_RAB_INTR_REG >> 8};
> + unsigned char buf2[1] = {0x0};
> +
> + status = ccg_read(uc, *(u16 *)buf, buf2, 0x1);
This becomes
status = ccg_read(uc, CCGX_I2C_RAB_INTR_REG, buf2, 0x1);
and you can drop the buf variable (or perhaps rename buf2 to buf)
[time passes]
Hmm, you already do it like that in ucsi_ccg_init, so this function
can be cleaned up regardless of any endian cleanup.
Cheers,
Peter
> + if (status < 0)
> + return status;
> +
> + return ccg_write(uc, *(u16 *)buf, buf2, 0x1);
> +}
> +
> +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;
> +
> + 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);
> + }
> +
> + 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");
>
