// SPDX-License-Identifier: GPL-2.0
/*
* Nvidia GPU I2C controller Driver
*
* Copyright (C) 2018 NVIDIA Corporation. All rights reserved.
* Author: Ajay Gupta <[email protected]>
*/
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/power_supply.h>
#include <linux/unaligned.h>
#include "i2c-ccgx-ucsi.h"
/* I2C definitions */
#define I2C_MST_CNTL 0x00
#define I2C_MST_CNTL_GEN_START BIT(0)
#define I2C_MST_CNTL_GEN_STOP BIT(1)
#define I2C_MST_CNTL_CMD_READ (1 << 2)
#define I2C_MST_CNTL_CMD_WRITE (2 << 2)
#define I2C_MST_CNTL_BURST_SIZE_SHIFT 6
#define I2C_MST_CNTL_GEN_NACK BIT(28)
#define I2C_MST_CNTL_STATUS GENMASK(30, 29)
#define I2C_MST_CNTL_STATUS_OKAY (0 << 29)
#define I2C_MST_CNTL_STATUS_NO_ACK (1 << 29)
#define I2C_MST_CNTL_STATUS_TIMEOUT (2 << 29)
#define I2C_MST_CNTL_STATUS_BUS_BUSY (3 << 29)
#define I2C_MST_CNTL_CYCLE_TRIGGER BIT(31)
#define I2C_MST_ADDR 0x04
#define I2C_MST_I2C0_TIMING 0x08
#define I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ 0x10e
#define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT 16
#define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX 255
#define I2C_MST_I2C0_TIMING_TIMEOUT_CHECK BIT(24)
#define I2C_MST_DATA 0x0c
#define I2C_MST_HYBRID_PADCTL 0x20
#define I2C_MST_HYBRID_PADCTL_MODE_I2C BIT(0)
#define I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV BIT(14)
#define I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV BIT(15)
struct gpu_i2c_dev {
struct device *dev;
void __iomem *regs;
struct i2c_adapter adapter;
struct i2c_board_info *gpu_ccgx_ucsi;
struct i2c_client *ccgx_client;
};
static void gpu_enable_i2c_bus(struct gpu_i2c_dev *i2cd)
{
u32 val;
/* enable I2C */
val = readl(i2cd->regs + I2C_MST_HYBRID_PADCTL);
val |= I2C_MST_HYBRID_PADCTL_MODE_I2C |
I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV |
I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV;
writel(val, i2cd->regs + I2C_MST_HYBRID_PADCTL);
/* enable 100KHZ mode */
val = I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ;
val |= (I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX
<< I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT);
val |= I2C_MST_I2C0_TIMING_TIMEOUT_CHECK;
writel(val, i2cd->regs + I2C_MST_I2C0_TIMING);
}
static int gpu_i2c_check_status(struct gpu_i2c_dev *i2cd)
{
u32 val;
int ret;
ret = readl_poll_timeout(i2cd->regs + I2C_MST_CNTL, val,
!(val & I2C_MST_CNTL_CYCLE_TRIGGER) ||
(val & I2C_MST_CNTL_STATUS) != I2C_MST_CNTL_STATUS_BUS_BUSY,
500, 1000 * USEC_PER_MSEC);
if (ret) {
dev_err(i2cd->dev, "i2c timeout error %x\n", val);
return -ETIMEDOUT;
}
val = readl(i2cd->regs + I2C_MST_CNTL);
switch (val & I2C_MST_CNTL_STATUS) {
case I2C_MST_CNTL_STATUS_OKAY:
return 0;
case I2C_MST_CNTL_STATUS_NO_ACK:
return -ENXIO;
case I2C_MST_CNTL_STATUS_TIMEOUT:
return -ETIMEDOUT;
default:
return 0;
}
}
static int gpu_i2c_read(struct gpu_i2c_dev *i2cd, u8 *data, u16 len)
{
int status;
u32 val;
val = I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_CMD_READ |
(len << I2C_MST_CNTL_BURST_SIZE_SHIFT) |
I2C_MST_CNTL_CYCLE_TRIGGER | I2C_MST_CNTL_GEN_NACK;
writel(val, i2cd->regs + I2C_MST_CNTL);
status = gpu_i2c_check_status(i2cd);
if (status < 0)
return status;
val = readl(i2cd->regs + I2C_MST_DATA);
switch (len) {
case 1:
data[0] = val;
break;
case 2:
put_unaligned_be16(val, data);
break;
case 3:
put_unaligned_be24(val, data);
break;
case 4:
put_unaligned_be32(val, data);
break;
default:
break;
}
return status;
}
static int gpu_i2c_start(struct gpu_i2c_dev *i2cd)
{
writel(I2C_MST_CNTL_GEN_START, i2cd->regs + I2C_MST_CNTL);
return gpu_i2c_check_status(i2cd);
}
static int gpu_i2c_stop(struct gpu_i2c_dev *i2cd)
{
writel(I2C_MST_CNTL_GEN_STOP, i2cd->regs + I2C_MST_CNTL);
return gpu_i2c_check_status(i2cd);
}
static int gpu_i2c_write(struct gpu_i2c_dev *i2cd, u8 data)
{
u32 val;
writel(data, i2cd->regs + I2C_MST_DATA);
val = I2C_MST_CNTL_CMD_WRITE | (1 << I2C_MST_CNTL_BURST_SIZE_SHIFT);
writel(val, i2cd->regs + I2C_MST_CNTL);
return gpu_i2c_check_status(i2cd);
}
static int gpu_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
struct gpu_i2c_dev *i2cd = i2c_get_adapdata(adap);
int status, status2;
bool send_stop = true;
int i, j;
/*
* The controller supports maximum 4 byte read due to known
* limitation of sending STOP after every read.
*/
pm_runtime_get_sync(i2cd->dev);
for (i = 0; i < num; i++) {
if (msgs[i].flags & I2C_M_RD) {
/* program client address before starting read */
writel(msgs[i].addr, i2cd->regs + I2C_MST_ADDR);
/* gpu_i2c_read has implicit start */
status = gpu_i2c_read(i2cd, msgs[i].buf, msgs[i].len);
if (status < 0)
goto exit;
} else {
u8 addr = i2c_8bit_addr_from_msg(msgs + i);
status = gpu_i2c_start(i2cd);
if (status < 0) {
if (i == 0)
send_stop = false;
goto exit;
}
status = gpu_i2c_write(i2cd, addr);
if (status < 0)
goto exit;
for (j = 0; j < msgs[i].len; j++) {
status = gpu_i2c_write(i2cd, msgs[i].buf[j]);
if (status < 0)
goto exit;
}
}
}
send_stop = false;
status = gpu_i2c_stop(i2cd);
if (status < 0)
goto exit;
status = i;
exit:
if (send_stop) {
status2 = gpu_i2c_stop(i2cd);
if (status2 < 0)
dev_err(i2cd->dev, "i2c stop failed %d\n", status2);
}
pm_runtime_mark_last_busy(i2cd->dev);
pm_runtime_put_autosuspend(i2cd->dev);
return status;
}
static const struct i2c_adapter_quirks gpu_i2c_quirks = {
.max_read_len = 4,
.max_comb_2nd_msg_len = 4,
.flags = I2C_AQ_COMB_WRITE_THEN_READ,
};
static u32 gpu_i2c_functionality(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm gpu_i2c_algorithm = {
.xfer = gpu_i2c_xfer,
.functionality = gpu_i2c_functionality,
};
/*
* This driver is for Nvidia GPU cards with USB Type-C interface.
* We want to identify the cards using vendor ID and class code only
* to avoid dependency of adding product id for any new card which
* requires this driver.
* Currently there is no class code defined for UCSI device over PCI
* so using UNKNOWN class for now and it will be updated when UCSI
* over PCI gets a class code.
* There is no other NVIDIA cards with UNKNOWN class code. Even if the
* driver gets loaded for an undesired card then eventually i2c_read()
* (initiated from UCSI i2c_client) will timeout or UCSI commands will
* timeout.
*/
#define PCI_CLASS_SERIAL_UNKNOWN 0x0c80
static const struct pci_device_id gpu_i2c_ids[] = {
{ PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
PCI_CLASS_SERIAL_UNKNOWN << 8, 0xffffff00},
{ }
};
MODULE_DEVICE_TABLE(pci, gpu_i2c_ids);
static const struct property_entry ccgx_props[] = {
/* Use FW built for NVIDIA GPU only */
PROPERTY_ENTRY_STRING("firmware-name", "nvidia,gpu"),
/* USB-C doesn't power the system */
PROPERTY_ENTRY_U8("scope", POWER_SUPPLY_SCOPE_DEVICE),
{ }
};
static const struct software_node ccgx_node = {
.properties = ccgx_props,
};
static int gpu_i2c_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
struct device *dev = &pdev->dev;
struct gpu_i2c_dev *i2cd;
int status;
i2cd = devm_kzalloc(dev, sizeof(*i2cd), GFP_KERNEL);
if (!i2cd)
return -ENOMEM;
i2cd->dev = dev;
dev_set_drvdata(dev, i2cd);
status = pcim_enable_device(pdev);
if (status < 0)
return dev_err_probe(dev, status, "pcim_enable_device failed\n");
pci_set_master(pdev);
i2cd->regs = pcim_iomap(pdev, 0, 0);
if (!i2cd->regs)
return dev_err_probe(dev, -ENOMEM, "pcim_iomap failed\n");
status = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
if (status < 0)
return dev_err_probe(dev, status, "pci_alloc_irq_vectors err\n");
gpu_enable_i2c_bus(i2cd);
i2c_set_adapdata(&i2cd->adapter, i2cd);
i2cd->adapter.owner = THIS_MODULE;
strscpy(i2cd->adapter.name, "NVIDIA GPU I2C adapter",
sizeof(i2cd->adapter.name));
i2cd->adapter.algo = &gpu_i2c_algorithm;
i2cd->adapter.quirks = &gpu_i2c_quirks;
i2cd->adapter.dev.parent = dev;
status = i2c_add_adapter(&i2cd->adapter);
if (status < 0)
goto free_irq_vectors;
i2cd->ccgx_client = i2c_new_ccgx_ucsi(&i2cd->adapter, pdev->irq, &ccgx_node);
if (IS_ERR(i2cd->ccgx_client)) {
status = dev_err_probe(dev, PTR_ERR(i2cd->ccgx_client), "register UCSI failed\n");
goto del_adapter;
}
pm_runtime_set_autosuspend_delay(dev, 3000);
pm_runtime_use_autosuspend(dev);
pm_runtime_put_autosuspend(dev);
pm_runtime_allow(dev);
return 0;
del_adapter:
i2c_del_adapter(&i2cd->adapter);
free_irq_vectors:
pci_free_irq_vectors(pdev);
return status;
}
static void gpu_i2c_remove(struct pci_dev *pdev)
{
struct gpu_i2c_dev *i2cd = pci_get_drvdata(pdev);
pm_runtime_get_noresume(i2cd->dev);
i2c_del_adapter(&i2cd->adapter);
pci_free_irq_vectors(pdev);
}
#define gpu_i2c_suspend NULL
static __maybe_unused int gpu_i2c_resume(struct device *dev)
{
struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev);
gpu_enable_i2c_bus(i2cd);
/*
* Runtime resume ccgx client so that it can see for any
* connector change event. Old ccg firmware has known
* issue of not triggering interrupt when a device is
* connected to runtime resume the controller.
*/
pm_request_resume(&i2cd->ccgx_client->dev);
return 0;
}
static UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, gpu_i2c_suspend, gpu_i2c_resume,
NULL);
static struct pci_driver gpu_i2c_driver = {
.name = "nvidia-gpu",
.id_table = gpu_i2c_ids,
.probe = gpu_i2c_probe,
.remove = gpu_i2c_remove,
.driver = {
.pm = &gpu_i2c_driver_pm,
},
};
module_pci_driver(gpu_i2c_driver);
MODULE_AUTHOR("Ajay Gupta <[email protected]>");
MODULE_DESCRIPTION("Nvidia GPU I2C controller Driver");
MODULE_LICENSE("GPL v2");
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