395 строки
10 KiB
C
395 строки
10 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Nvidia GPU I2C controller Driver
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*
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* Copyright (C) 2018 NVIDIA Corporation. All rights reserved.
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* Author: Ajay Gupta <ajayg@nvidia.com>
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*/
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#include <linux/delay.h>
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#include <linux/i2c.h>
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#include <linux/interrupt.h>
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#include <linux/iopoll.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <linux/platform_device.h>
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#include <linux/pm.h>
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#include <linux/pm_runtime.h>
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#include <asm/unaligned.h>
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/* I2C definitions */
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#define I2C_MST_CNTL 0x00
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#define I2C_MST_CNTL_GEN_START BIT(0)
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#define I2C_MST_CNTL_GEN_STOP BIT(1)
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#define I2C_MST_CNTL_CMD_READ (1 << 2)
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#define I2C_MST_CNTL_CMD_WRITE (2 << 2)
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#define I2C_MST_CNTL_BURST_SIZE_SHIFT 6
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#define I2C_MST_CNTL_GEN_NACK BIT(28)
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#define I2C_MST_CNTL_STATUS GENMASK(30, 29)
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#define I2C_MST_CNTL_STATUS_OKAY (0 << 29)
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#define I2C_MST_CNTL_STATUS_NO_ACK (1 << 29)
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#define I2C_MST_CNTL_STATUS_TIMEOUT (2 << 29)
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#define I2C_MST_CNTL_STATUS_BUS_BUSY (3 << 29)
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#define I2C_MST_CNTL_CYCLE_TRIGGER BIT(31)
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#define I2C_MST_ADDR 0x04
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#define I2C_MST_I2C0_TIMING 0x08
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#define I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ 0x10e
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#define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT 16
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#define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX 255
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#define I2C_MST_I2C0_TIMING_TIMEOUT_CHECK BIT(24)
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#define I2C_MST_DATA 0x0c
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#define I2C_MST_HYBRID_PADCTL 0x20
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#define I2C_MST_HYBRID_PADCTL_MODE_I2C BIT(0)
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#define I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV BIT(14)
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#define I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV BIT(15)
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struct gpu_i2c_dev {
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struct device *dev;
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void __iomem *regs;
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struct i2c_adapter adapter;
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struct i2c_board_info *gpu_ccgx_ucsi;
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struct i2c_client *ccgx_client;
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};
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static void gpu_enable_i2c_bus(struct gpu_i2c_dev *i2cd)
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{
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u32 val;
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/* enable I2C */
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val = readl(i2cd->regs + I2C_MST_HYBRID_PADCTL);
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val |= I2C_MST_HYBRID_PADCTL_MODE_I2C |
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I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV |
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I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV;
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writel(val, i2cd->regs + I2C_MST_HYBRID_PADCTL);
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/* enable 100KHZ mode */
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val = I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ;
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val |= (I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX
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<< I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT);
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val |= I2C_MST_I2C0_TIMING_TIMEOUT_CHECK;
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writel(val, i2cd->regs + I2C_MST_I2C0_TIMING);
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}
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static int gpu_i2c_check_status(struct gpu_i2c_dev *i2cd)
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{
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u32 val;
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int ret;
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ret = readl_poll_timeout(i2cd->regs + I2C_MST_CNTL, val,
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!(val & I2C_MST_CNTL_CYCLE_TRIGGER) ||
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(val & I2C_MST_CNTL_STATUS) != I2C_MST_CNTL_STATUS_BUS_BUSY,
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500, 1000 * USEC_PER_MSEC);
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if (ret) {
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dev_err(i2cd->dev, "i2c timeout error %x\n", val);
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return -ETIMEDOUT;
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}
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val = readl(i2cd->regs + I2C_MST_CNTL);
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switch (val & I2C_MST_CNTL_STATUS) {
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case I2C_MST_CNTL_STATUS_OKAY:
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return 0;
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case I2C_MST_CNTL_STATUS_NO_ACK:
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return -ENXIO;
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case I2C_MST_CNTL_STATUS_TIMEOUT:
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return -ETIMEDOUT;
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default:
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return 0;
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}
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}
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static int gpu_i2c_read(struct gpu_i2c_dev *i2cd, u8 *data, u16 len)
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{
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int status;
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u32 val;
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val = I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_CMD_READ |
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(len << I2C_MST_CNTL_BURST_SIZE_SHIFT) |
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I2C_MST_CNTL_CYCLE_TRIGGER | I2C_MST_CNTL_GEN_NACK;
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writel(val, i2cd->regs + I2C_MST_CNTL);
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status = gpu_i2c_check_status(i2cd);
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if (status < 0)
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return status;
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val = readl(i2cd->regs + I2C_MST_DATA);
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switch (len) {
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case 1:
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data[0] = val;
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break;
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case 2:
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put_unaligned_be16(val, data);
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break;
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case 3:
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put_unaligned_be24(val, data);
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break;
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case 4:
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put_unaligned_be32(val, data);
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break;
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default:
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break;
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}
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return status;
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}
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static int gpu_i2c_start(struct gpu_i2c_dev *i2cd)
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{
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writel(I2C_MST_CNTL_GEN_START, i2cd->regs + I2C_MST_CNTL);
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return gpu_i2c_check_status(i2cd);
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}
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static int gpu_i2c_stop(struct gpu_i2c_dev *i2cd)
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{
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writel(I2C_MST_CNTL_GEN_STOP, i2cd->regs + I2C_MST_CNTL);
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return gpu_i2c_check_status(i2cd);
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}
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static int gpu_i2c_write(struct gpu_i2c_dev *i2cd, u8 data)
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{
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u32 val;
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writel(data, i2cd->regs + I2C_MST_DATA);
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val = I2C_MST_CNTL_CMD_WRITE | (1 << I2C_MST_CNTL_BURST_SIZE_SHIFT);
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writel(val, i2cd->regs + I2C_MST_CNTL);
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return gpu_i2c_check_status(i2cd);
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}
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static int gpu_i2c_master_xfer(struct i2c_adapter *adap,
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struct i2c_msg *msgs, int num)
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{
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struct gpu_i2c_dev *i2cd = i2c_get_adapdata(adap);
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int status, status2;
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bool send_stop = true;
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int i, j;
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/*
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* The controller supports maximum 4 byte read due to known
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* limitation of sending STOP after every read.
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*/
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pm_runtime_get_sync(i2cd->dev);
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for (i = 0; i < num; i++) {
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if (msgs[i].flags & I2C_M_RD) {
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/* program client address before starting read */
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writel(msgs[i].addr, i2cd->regs + I2C_MST_ADDR);
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/* gpu_i2c_read has implicit start */
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status = gpu_i2c_read(i2cd, msgs[i].buf, msgs[i].len);
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if (status < 0)
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goto exit;
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} else {
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u8 addr = i2c_8bit_addr_from_msg(msgs + i);
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status = gpu_i2c_start(i2cd);
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if (status < 0) {
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if (i == 0)
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send_stop = false;
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goto exit;
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}
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status = gpu_i2c_write(i2cd, addr);
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if (status < 0)
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goto exit;
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for (j = 0; j < msgs[i].len; j++) {
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status = gpu_i2c_write(i2cd, msgs[i].buf[j]);
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if (status < 0)
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goto exit;
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}
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}
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}
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send_stop = false;
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status = gpu_i2c_stop(i2cd);
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if (status < 0)
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goto exit;
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status = i;
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exit:
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if (send_stop) {
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status2 = gpu_i2c_stop(i2cd);
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if (status2 < 0)
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dev_err(i2cd->dev, "i2c stop failed %d\n", status2);
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}
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pm_runtime_mark_last_busy(i2cd->dev);
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pm_runtime_put_autosuspend(i2cd->dev);
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return status;
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}
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static const struct i2c_adapter_quirks gpu_i2c_quirks = {
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.max_read_len = 4,
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.max_comb_2nd_msg_len = 4,
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.flags = I2C_AQ_COMB_WRITE_THEN_READ,
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};
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static u32 gpu_i2c_functionality(struct i2c_adapter *adap)
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{
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return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
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}
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static const struct i2c_algorithm gpu_i2c_algorithm = {
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.master_xfer = gpu_i2c_master_xfer,
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.functionality = gpu_i2c_functionality,
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};
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/*
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* This driver is for Nvidia GPU cards with USB Type-C interface.
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* We want to identify the cards using vendor ID and class code only
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* to avoid dependency of adding product id for any new card which
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* requires this driver.
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* Currently there is no class code defined for UCSI device over PCI
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* so using UNKNOWN class for now and it will be updated when UCSI
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* over PCI gets a class code.
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* There is no other NVIDIA cards with UNKNOWN class code. Even if the
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* driver gets loaded for an undesired card then eventually i2c_read()
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* (initiated from UCSI i2c_client) will timeout or UCSI commands will
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* timeout.
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*/
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#define PCI_CLASS_SERIAL_UNKNOWN 0x0c80
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static const struct pci_device_id gpu_i2c_ids[] = {
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{ PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
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PCI_CLASS_SERIAL_UNKNOWN << 8, 0xffffff00},
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{ }
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};
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MODULE_DEVICE_TABLE(pci, gpu_i2c_ids);
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static const struct property_entry ccgx_props[] = {
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/* Use FW built for NVIDIA (nv) only */
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PROPERTY_ENTRY_U16("ccgx,firmware-build", ('n' << 8) | 'v'),
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{ }
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};
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static const struct software_node ccgx_node = {
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.properties = ccgx_props,
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};
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static int gpu_populate_client(struct gpu_i2c_dev *i2cd, int irq)
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{
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i2cd->gpu_ccgx_ucsi = devm_kzalloc(i2cd->dev,
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sizeof(*i2cd->gpu_ccgx_ucsi),
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GFP_KERNEL);
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if (!i2cd->gpu_ccgx_ucsi)
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return -ENOMEM;
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strlcpy(i2cd->gpu_ccgx_ucsi->type, "ccgx-ucsi",
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sizeof(i2cd->gpu_ccgx_ucsi->type));
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i2cd->gpu_ccgx_ucsi->addr = 0x8;
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i2cd->gpu_ccgx_ucsi->irq = irq;
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i2cd->gpu_ccgx_ucsi->swnode = &ccgx_node;
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i2cd->ccgx_client = i2c_new_client_device(&i2cd->adapter, i2cd->gpu_ccgx_ucsi);
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return PTR_ERR_OR_ZERO(i2cd->ccgx_client);
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}
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static int gpu_i2c_probe(struct pci_dev *pdev, const struct pci_device_id *id)
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{
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struct gpu_i2c_dev *i2cd;
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int status;
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i2cd = devm_kzalloc(&pdev->dev, sizeof(*i2cd), GFP_KERNEL);
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if (!i2cd)
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return -ENOMEM;
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i2cd->dev = &pdev->dev;
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dev_set_drvdata(&pdev->dev, i2cd);
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status = pcim_enable_device(pdev);
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if (status < 0) {
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dev_err(&pdev->dev, "pcim_enable_device failed %d\n", status);
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return status;
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}
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pci_set_master(pdev);
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i2cd->regs = pcim_iomap(pdev, 0, 0);
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if (!i2cd->regs) {
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dev_err(&pdev->dev, "pcim_iomap failed\n");
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return -ENOMEM;
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}
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status = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
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if (status < 0) {
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dev_err(&pdev->dev, "pci_alloc_irq_vectors err %d\n", status);
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return status;
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}
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gpu_enable_i2c_bus(i2cd);
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i2c_set_adapdata(&i2cd->adapter, i2cd);
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i2cd->adapter.owner = THIS_MODULE;
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strlcpy(i2cd->adapter.name, "NVIDIA GPU I2C adapter",
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sizeof(i2cd->adapter.name));
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i2cd->adapter.algo = &gpu_i2c_algorithm;
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i2cd->adapter.quirks = &gpu_i2c_quirks;
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i2cd->adapter.dev.parent = &pdev->dev;
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status = i2c_add_adapter(&i2cd->adapter);
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if (status < 0)
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goto free_irq_vectors;
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status = gpu_populate_client(i2cd, pdev->irq);
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if (status < 0) {
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dev_err(&pdev->dev, "gpu_populate_client failed %d\n", status);
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goto del_adapter;
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}
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pm_runtime_set_autosuspend_delay(&pdev->dev, 3000);
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pm_runtime_use_autosuspend(&pdev->dev);
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pm_runtime_put_autosuspend(&pdev->dev);
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pm_runtime_allow(&pdev->dev);
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return 0;
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del_adapter:
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i2c_del_adapter(&i2cd->adapter);
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free_irq_vectors:
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pci_free_irq_vectors(pdev);
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return status;
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}
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static void gpu_i2c_remove(struct pci_dev *pdev)
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{
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struct gpu_i2c_dev *i2cd = dev_get_drvdata(&pdev->dev);
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pm_runtime_get_noresume(i2cd->dev);
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i2c_del_adapter(&i2cd->adapter);
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pci_free_irq_vectors(pdev);
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}
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#define gpu_i2c_suspend NULL
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static __maybe_unused int gpu_i2c_resume(struct device *dev)
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{
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struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev);
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gpu_enable_i2c_bus(i2cd);
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/*
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* Runtime resume ccgx client so that it can see for any
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* connector change event. Old ccg firmware has known
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* issue of not triggering interrupt when a device is
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* connected to runtime resume the controller.
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*/
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pm_request_resume(&i2cd->ccgx_client->dev);
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return 0;
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}
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static UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, gpu_i2c_suspend, gpu_i2c_resume,
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NULL);
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static struct pci_driver gpu_i2c_driver = {
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.name = "nvidia-gpu",
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.id_table = gpu_i2c_ids,
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.probe = gpu_i2c_probe,
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.remove = gpu_i2c_remove,
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.driver = {
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.pm = &gpu_i2c_driver_pm,
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},
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};
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module_pci_driver(gpu_i2c_driver);
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MODULE_AUTHOR("Ajay Gupta <ajayg@nvidia.com>");
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MODULE_DESCRIPTION("Nvidia GPU I2C controller Driver");
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MODULE_LICENSE("GPL v2");
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