Re: [PATCH v6 2/2] usb: typec: ucsi: add support for Cypress CCGx

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On Thu, Sep 6, 2018 at 1:22 AM Ajay Gupta <ajayg@xxxxxxxxxx> 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.
>

FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

for either version you choose (stack or heap).

> Signed-off-by: Ajay Gupta <ajayg@xxxxxxxxxx>
> ---
> 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
>
>  drivers/usb/typec/ucsi/Kconfig    |  10 +
>  drivers/usb/typec/ucsi/Makefile   |   2 +
>  drivers/usb/typec/ucsi/ucsi_ccg.c | 382 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 394 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..65292bf
> --- /dev/null
> +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
> @@ -0,0 +1,382 @@
> +// 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;
> +       struct i2c_msg *msgs;
> +       u32 rlen, rem_len = len;
> +       int status;
> +
> +       buf = kzalloc(2, GFP_KERNEL);
> +       if (!buf)
> +               return -ENOMEM;
> +
> +       msgs = kcalloc(2, sizeof(struct i2c_msg), GFP_KERNEL);
> +       if (!msgs) {
> +               kfree(buf);
> +               return -ENOMEM;
> +       }
> +
> +       msgs[0].addr = client->addr;
> +       msgs[0].len = 2;
> +       msgs[0].buf = buf;
> +       msgs[1].addr = client->addr;
> +       msgs[1].flags = I2C_M_RD;
> +
> +       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, 2);
> +               if (status < 0) {
> +                       dev_err(uc->dev, "i2c_transfer failed %d", status);
> +                       kfree(buf);
> +                       kfree(msgs);
> +                       return status;
> +               }
> +               rab += rlen;
> +               rem_len -= rlen;
> +       }
> +
> +       kfree(buf);
> +       kfree(msgs);
> +       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;
> +       struct i2c_msg *msgs;
> +       int status;
> +
> +       buf = kzalloc(2, GFP_KERNEL);
> +       if (!buf)
> +               return -ENOMEM;
> +
> +       msgs = kcalloc(3, sizeof(struct i2c_msg), GFP_KERNEL);
> +       if (!msgs) {
> +               kfree(buf);
> +               return -ENOMEM;
> +       }
> +
> +       msgs[0].addr = client->addr;
> +       msgs[0].len = 2;
> +       msgs[0].buf = buf;
> +       msgs[1].addr = client->addr;
> +       msgs[1].len = len;
> +       msgs[1].buf = data;
> +       msgs[2].addr = client->addr;
> +       msgs[2].flags = I2C_M_STOP;
> +
> +       put_unaligned_le16(rab, buf);
> +       status = i2c_transfer(client->adapter, msgs, 3);
> +       if (status < 0) {
> +               dev_err(uc->dev, "i2c_transfer failed %d", status);
> +               kfree(buf);
> +               kfree(msgs);
> +               return status;
> +       }
> +
> +       kfree(buf);
> +       kfree(msgs);
> +       return 0;
> +}
> +
> +static int ucsi_ccg_init(struct ucsi_ccg *uc)
> +{
> +       struct device *dev = uc->dev;
> +       unsigned int count = 10;
> +       u8 *data;
> +       int status;
> +
> +       data = kzalloc(64, GFP_KERNEL);
> +       if (!data)
> +               return -ENOMEM;
> +
> +       /*
> +        * 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;
> +
> +       status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
> +       if (status < 0)
> +               goto free_mem;
> +
> +       memset(data, 0, 64);
> +       status = ccg_read(uc, CCGX_I2C_RAB_DEVICE_MODE, data, sizeof(data));
> +       if (status < 0)
> +               goto free_mem;
> +
> +       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;
> +       status = ccg_read(uc, CCGX_I2C_RAB_RESPONSE_REG, data, 0x2);
> +       if (status < 0)
> +               goto free_mem;
> +
> +       data[0] = CCGX_I2C_RAB_UCSI_CONTROL_STOP;
> +       status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
> +       if (status < 0)
> +               goto free_mem;
> +
> +       data[0] = CCGX_I2C_RAB_UCSI_CONTROL_START;
> +       status = ccg_write(uc, CCGX_I2C_RAB_UCSI_CONTROL, data, 0x1);
> +       if (status < 0)
> +               goto free_mem;
> +
> +       /*
> +        * 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)
> +                       goto free_mem;
> +
> +               usleep_range(10000, 11000);
> +
> +               status = ccg_read(uc, CCGX_I2C_RAB_INTR_REG, data, 0x1);
> +               if (status < 0)
> +                       goto free_mem;
> +       } while ((data[0] != 0x00) && count--);
> +
> +free_mem:
> +       kfree(data);
> +       return status;
> +}
> +
> +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;
> +       unsigned char *buf2;
> +
> +       buf1 = kzalloc(16, GFP_KERNEL);
> +       if (!buf1)
> +               return -ENOMEM;
> +
> +       buf2 = kzalloc(8, GFP_KERNEL);
> +       if (!buf2) {
> +               kfree(buf1);
> +               return -ENOMEM;
> +       }
> +
> +       memcpy(buf1, ((const void *)uc->ppm.data) + 0x20, 16);
> +       memcpy(buf2, ((const void *)uc->ppm.data) + 0x8, 8);
> +
> +       status = ccg_write(uc, *(u16 *)buf, buf1, 16);
> +       if (status < 0)
> +               goto free_mem;
> +
> +       status = ccg_write(uc, *(u16 *)(buf + 2), buf2, 8);
> +
> +free_mem:
> +       kfree(buf1);
> +       kfree(buf2);
> +       return status;
> +}
> +
> +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);
> +       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;
> +
> +       buf2 = kzalloc(1, GFP_KERNEL);
> +       if (!buf2)
> +               return -ENOMEM;
> +
> +       status = ccg_read(uc, *(u16 *)buf, buf2, 0x1);
> +       if (status < 0)
> +               goto free_mem;
> +
> +       status = ccg_write(uc, *(u16 *)buf, buf2, 0x1);
> +
> +free_mem:
> +       kfree(buf2);
> +       return status;
> +}
> +
> +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");
> --
> 2.7.4
>


-- 
With Best Regards,
Andy Shevchenko



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