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DragonProbe/host/modules/i2c-dragonprobe.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for the Dragon Probe USB multitool: USB-I2C adapter
*
* Copyright (c) 2021 sys64738 and haskal
*
* Adapted from:
* i2c-dln2.c Copyright (c) 2014 Intel Corporation
* i2c-tiny-usb.c Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/platform_device.h>
#include <linux/acpi.h>
#if 0
#include <linux/mfd/dragonprobe.h>
#else
#include "dragonprobe.h"
#endif
#define HARDWARE_NAME "Dragon Probe"
#define DP_I2C_MAX_XFER_SIZE 64
#define DP_I2C_CMD_ECHO 0x00
#define DP_I2C_CMD_GET_FUNC 0x01
#define DP_I2C_CMD_SET_DELAY 0x02
#define DP_I2C_CMD_GET_STATUS 0x03
#define DP_I2C_CMD_DO_XFER 0x04
#define DP_I2C_CMD_DO_XFER_B 0x05
#define DP_I2C_CMD_DO_XFER_E 0x06
#define DP_I2C_CMD_DO_XFER_BE 0x07
#define DP_I2C_FLG_XFER_B 0x01
#define DP_I2C_FLG_XFER_E 0x02
#define DP_I2C_STAT_IDLE 0
#define DP_I2C_STAT_ACK 1
#define DP_I2C_STAT_NAK 2
static uint16_t delay = 10;
module_param(delay, ushort, 0);
MODULE_PARM_DESC(delay, "bit delay in microseconds (default is 10us for 100kHz)");
struct dp_i2c {
struct platform_device *pdev;
struct i2c_adapter adapter;
};
static int dp_i2c_read(struct dp_i2c *dpi, struct i2c_msg *msg, int cmd)
{
struct device *dev = &dpi->pdev->dev;
void *respbuf = NULL;
int ret, len;
uint8_t cmdbuf[1+2+2+2]; /* cmd, flags, addr, len */
cmdbuf[0] = cmd;
cmdbuf[1] = (msg->flags >> 0) & 0xff;
cmdbuf[2] = (msg->flags >> 8) & 0xff;
cmdbuf[3] = (msg->addr >> 0) & 0xff;
cmdbuf[4] = (msg->addr >> 8) & 0xff;
cmdbuf[5] = (msg->len >> 0) & 0xff;
cmdbuf[6] = (msg->len >> 8) & 0xff;
ret = dp_transfer(dpi->pdev, DP_CMD_MODE1_I2C, DP_XFER_FLAGS_PARSE_RESP,
cmdbuf, sizeof(cmdbuf), &respbuf, &len);
ret = dp_check_retval(ret, len, dev, "i2c read", true, -1, msg->len);
if (ret < 0 || !respbuf) goto err_free;
memcpy(msg->buf, respbuf, msg->len);
ret = len;
err_free:
if (respbuf) kfree(respbuf);
return ret;
}
static int dp_i2c_write(struct dp_i2c *dpi, struct i2c_msg *msg, int cmd)
{
struct device *dev = &dpi->pdev->dev;
uint8_t *cmdbuf;
int ret, len;
len = msg->len + 1+2+2+2; /* cmd, flags, addr, len */
cmdbuf = kzalloc(len, GFP_KERNEL);
if (!cmdbuf) return -ENOMEM;
cmdbuf[0] = cmd;
cmdbuf[1] = (msg->flags >> 0) & 0xff;
cmdbuf[2] = (msg->flags >> 8) & 0xff;
cmdbuf[3] = (msg->addr >> 0) & 0xff;
cmdbuf[4] = (msg->addr >> 8) & 0xff;
cmdbuf[5] = (msg->len >> 0) & 0xff;
cmdbuf[6] = (msg->len >> 8) & 0xff;
memcpy(&cmdbuf[7], msg->buf, msg->len);
ret = dp_write(dpi->pdev, DP_CMD_MODE1_I2C, cmdbuf, len);
ret = dp_check_retval(ret, len, dev, "i2c write", true, -1, -1);
if (ret < 0) goto err_free;
ret = msg->len;
err_free:
kfree(cmdbuf);
return ret;
}
static int dp_i2c_xfer(struct i2c_adapter *a, struct i2c_msg *msgs, int nmsg)
{
struct dp_i2c *dpi = i2c_get_adapdata(a);
struct device *dev = &dpi->pdev->dev;
struct i2c_msg *pmsg;
int i, ret, cmd, stlen;
uint8_t *status = NULL, i2ccmd;
for (i = 0; i < nmsg; ++i) {
cmd = DP_I2C_CMD_DO_XFER;
if (i == 0) cmd |= DP_I2C_FLG_XFER_B;
if (i == nmsg-1) cmd |= DP_I2C_FLG_XFER_E;
pmsg = &msgs[i];
dev_dbg(&a->dev,
" %d: %s (flags %04x) %d bytes to 0x%02x\n",
i, pmsg->flags & I2C_M_RD ? "read" : "write",
pmsg->flags, pmsg->len, pmsg->addr);
if (pmsg->flags & I2C_M_RD) {
ret = dp_i2c_read(dpi, pmsg, cmd);
if (ret < 0) goto err_ret;
if (ret != pmsg->len) {
dev_err(dev, "xfer rd: bad length %d vs %d\n", ret, pmsg->len);
ret = -EMSGSIZE;
goto err_ret;
}
} else {
ret = dp_i2c_write(dpi, pmsg, cmd);
if (ret < 0) goto err_ret;
if (ret != pmsg->len) {
dev_err(dev, "xfer wr: bad length %d vs %d\n", ret, pmsg->len);
ret = -EMSGSIZE;
goto err_ret;
}
}
/* read status */
i2ccmd = DP_I2C_CMD_GET_STATUS;
ret = dp_transfer(dpi->pdev, DP_CMD_MODE1_I2C, DP_XFER_FLAGS_PARSE_RESP,
&i2ccmd, sizeof(i2ccmd), (void**)&status, &stlen);
ret = dp_check_retval(ret, stlen, dev, "i2c stat", true, sizeof(*status), sizeof(*status));
if (ret < 0 || !status) goto err_ret;
dev_dbg(&a->dev, " status = %d\n", *status);
if (*status == DP_I2C_STAT_NAK) {
ret = -ENXIO;
goto err_ret;
}
}
ret = i;
err_ret:
if (status) kfree(status);
return ret;
}
static uint32_t dp_i2c_func(struct i2c_adapter *a)
{
struct dp_i2c *dpi = i2c_get_adapdata(a);
struct device *dev = /*&dpi->pdev->dev;*/ &a->dev;
uint32_t func = 0;
int len, ret;
uint8_t i2ccmd = DP_I2C_CMD_GET_FUNC;
uint8_t *fbuf = NULL;
ret = dp_transfer(dpi->pdev, DP_CMD_MODE1_I2C, DP_XFER_FLAGS_PARSE_RESP,
&i2ccmd, sizeof(i2ccmd), (void**)&fbuf, &len);
ret = dp_check_retval(ret, len, dev, "i2c get_func", true, sizeof(func), sizeof(func));
if (ret < 0 || !fbuf) return 0;
func = (uint32_t)fbuf[0] | ((uint32_t)fbuf[1] << 8)
| ((uint32_t)fbuf[2] << 16) | ((uint32_t)fbuf[3] << 24);
dev_dbg(dev, "I2C functionality: 0x%08x\n", func);
kfree(fbuf);
return func;
}
static const struct i2c_algorithm dp_i2c_algo = {
.master_xfer = dp_i2c_xfer,
.functionality = dp_i2c_func
};
static const struct i2c_adapter_quirks dp_i2c_quirks = {
.max_read_len = DP_I2C_MAX_XFER_SIZE,
.max_write_len = DP_I2C_MAX_XFER_SIZE,
};
static int dp_i2c_check_hw(struct platform_device *pdev)
{
/*
* 1. check if mode 1 is available
* 2. check mode 1 version
* 3. check if mode 1 has the I2C feature
* 4. test the echo I2C command
*/
struct device *dev = &pdev->dev;
uint16_t m1ver;
uint8_t curmode, m1feat, echoval;
const int ver_min = 0x0010, ver_max = 0x0010;
uint8_t i2ccmd[2];
int ret = 0, len;
uint8_t *buf = NULL;
ret = dp_transfer(pdev, DP_CMD_CFG_GET_CUR_MODE,
DP_XFER_FLAGS_PARSE_RESP, NULL, 0, (void**)&buf, &len);
ret = dp_check_retval(ret, len, dev, "i2c test 1", true, sizeof(curmode), sizeof(curmode));
if (ret < 0 || !buf) goto out;
curmode = buf[0];
kfree(buf); buf = NULL;
if (curmode != 0x1) {
dev_err(dev, "device must be in mode 1 for I2C to work, but it is in mode %d\n", curmode);
ret = -EIO;
goto out;
}
ret = dp_transfer(pdev, (1<<4) | DP_CMD_MODE_GET_VERSION,
DP_XFER_FLAGS_PARSE_RESP, NULL, 0, (void**)&buf, &len);
ret = dp_check_retval(ret, len, dev, "i2c test 2", true, sizeof(m1ver), sizeof(m1ver));
if (ret < 0 || !buf) goto out;
m1ver = (uint16_t)buf[0] | ((uint16_t)buf[1] << 8);
kfree(buf); buf = NULL;
if (m1ver > ver_max || m1ver < ver_min) {
dev_err(dev, "bad mode 1 version %04x on device, must be between %04x and %04x\n",
m1ver, ver_min, ver_max);
ret = -EIO;
goto out;
}
ret = dp_transfer(pdev, (1<<4) | DP_CMD_MODE_GET_FEATURES,
DP_XFER_FLAGS_PARSE_RESP, NULL, 0, (void**)&buf, &len);
ret = dp_check_retval(ret, len, dev, "i2c test 3", true, sizeof(m1feat), sizeof(m1feat));
if (ret < 0 || !buf) goto out;
m1feat = buf[0];
kfree(buf); buf = NULL;
if (!(m1feat & DP_FEATURE_MODE1_I2C)) {
dev_err(dev, "device's mode 1 does not support I2C\n");
ret = -EIO;
goto out;
}
echoval = 0x42;
i2ccmd[0] = DP_I2C_CMD_ECHO;
i2ccmd[1] = ~echoval;
ret = dp_transfer(pdev, (1<<4) | DP_CMD_MODE1_I2C,
DP_XFER_FLAGS_PARSE_RESP, i2ccmd, sizeof(i2ccmd), (void**)&buf, &len);
ret = dp_check_retval(ret, len, dev, "i2c test", true, sizeof(echoval), sizeof(echoval));
if (ret < 0 || !buf) goto out;
echoval = buf[0];
kfree(buf); buf = NULL;
if (echoval != i2ccmd[1]) {
dev_err(dev, "I2C echo test command not functional\n");
ret = -EIO;
goto out;
}
ret = 0;
out:
if (buf) kfree(buf);
return ret;
}
static int dp_i2c_set_delay(struct platform_device *pdev, uint16_t us)
{
struct device *dev = &pdev->dev;
uint8_t i2ccmd[3];
int ret = 0;
i2ccmd[0] = DP_I2C_CMD_SET_DELAY;
i2ccmd[1] = (us >> 0) & 0xff;
i2ccmd[2] = (us >> 8) & 0xff;
ret = dp_write(pdev, (1<<4) | DP_CMD_MODE1_I2C, i2ccmd, sizeof(i2ccmd));
dev_dbg(dev, "set delay to %hu us, result %d\n", us, ret);
ret = dp_check_retval(ret, -1, dev, "i2c set delay", true, -1, -1);
return ret;
}
static int dp_i2c_probe(struct platform_device *pdev)
{
int ret, hwnlen;
struct dp_i2c *dpi;
struct device *dev = &pdev->dev;
void *hwname;
char namebuf[64];
ret = dp_i2c_check_hw(pdev);
if (ret) return -ENODEV;
ret = dp_i2c_set_delay(pdev, delay);
if (ret) {
dev_err(dev, "failed to set I2C speed: %d\n", ret);
return ret;
}
dpi = devm_kzalloc(dev, sizeof(*dpi), GFP_KERNEL);
if (!dpi) return -ENOMEM;
dpi->pdev = pdev;
dpi->adapter.owner = THIS_MODULE;
dpi->adapter.class = I2C_CLASS_HWMON;
dpi->adapter.algo = &dp_i2c_algo;
dpi->adapter.quirks = &dp_i2c_quirks; /* TODO: is this needed? probably... */
dpi->adapter.dev.of_node = dev->of_node;
i2c_set_adapdata(&dpi->adapter, dpi);
/* get device name, for adapter name */
ret = dp_transfer(pdev, DP_CMD_CFG_GET_INFOSTR,
DP_XFER_FLAGS_PARSE_RESP, NULL, 0, (void**)&hwname, &hwnlen);
ret = dp_check_retval(ret, hwnlen, dev, "probe: get name", true, -1, sizeof(namebuf)-1);
if (ret < 0 || !hwname) return -EIO;
memcpy(namebuf, hwname, hwnlen);
namebuf[hwnlen] = 0;
kfree(hwname);
snprintf(dpi->adapter.name, sizeof(dpi->adapter.name),
HARDWARE_NAME " '%s' at %s", namebuf, dev_name(pdev->dev.parent));
platform_set_drvdata(pdev, dpi);
ret = i2c_add_adapter(&dpi->adapter);
if (!ret) {
dev_info(dev, HARDWARE_NAME " I2C device driver at i2c-%d, %s\n",
dpi->adapter.nr, dpi->adapter.name);
}
return ret;
}
static int dp_i2c_remove(struct platform_device *pdev)
{
struct dp_i2c *dpi = platform_get_drvdata(pdev);
i2c_del_adapter(&dpi->adapter);
return 0;
}
static struct platform_driver dp_i2c_drv = {
.driver.name = "dragonprobe-i2c",
.probe = dp_i2c_probe,
.remove = dp_i2c_remove
};
module_platform_driver(dp_i2c_drv);
MODULE_AUTHOR("sys64738 <sys64738@disroot.org>");
MODULE_AUTHOR("haskal <haskal@awoo.systems>");
MODULE_DESCRIPTION("I2C interface driver for the " HARDWARE_NAME " USB multitool");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:dragonprobe-i2c");
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