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Added the ability to select the i2c speed at startup #10

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Added the ability to select the i2c speed at startup #10

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8 changes: 6 additions & 2 deletions i2c-ch341-usb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@
#include <linux/types.h>
#include <linux/usb.h>

#define DRV_VERSION "1.1"
#define DRV_VERSION "1.2"

#define CH341_I2C_LOW_SPEED 0 // low speed - 20kHz
#define CH341_I2C_STANDARD_SPEED 1 // standard speed - 100kHz
Expand All @@ -39,6 +39,10 @@
#define CH341_CMD_I2C_STM_SET 0x60
#define CH341_CMD_I2C_STM_END 0x00

static uint speed = CH341_I2C_STANDARD_SPEED; // Sets default speed as CH341_I2C_STANDARD_SPEED (100kHz)
module_param(speed, uint, 0644);
MODULE_PARM_DESC(speed, "I2C speed mode: 0=20kHz, 1=100kHz, 2=400kHz, 3=750kHz");

/* Structure to hold all of our device specific stuff */
struct i2c_ch341_usb {
struct usb_device *usb_dev; /* the usb device for this device */
Expand Down Expand Up @@ -282,7 +286,7 @@ static int i2c_ch341_usb_probe(struct usb_interface *iface,

/* set ch341 i2c speed */
dev->out_buf[0] = CH341_CMD_I2C_STREAM;
dev->out_buf[1] = CH341_CMD_I2C_STM_SET | CH341_I2C_STANDARD_SPEED;
dev->out_buf[1] = CH341_CMD_I2C_STM_SET | speed;
dev->out_buf[2] = CH341_CMD_I2C_STM_END;
retval = ch341_xfer(dev, 3, 0);
if (retval < 0) {
Expand Down