On May 22, 2016 2:32:59 AM PDT, "jeffrey.lin" [off-list ref] wrote:

Hi Dmitry:

+static int raydium_i2c_read_message(struct i2c_client *client,
+				    u32 addr, void *data, size_t len)
+{
+	__be32 be_addr;
+	size_t xfer_len;
+	int error;
+
+	while (len) {
+		xfer_len = min_t(size_t, len, RM_MAX_READ_SIZE);
+
+		be_addr = cpu_to_be32(addr);
+
+		error = raydium_i2c_send(client, RM_CMD_BANK_SWITCH,
+					 &be_addr, sizeof(be_addr));
+		if (!error)
+			error = raydium_i2c_read(client, (be_addr >> 24) & 0xff,
+						 data, xfer_len);
+		if (error)
+			return error;
+
+		len -= xfer_len;
+		data += xfer_len;
+		addr += xfer_len;
+	}
+
+	return 0;
+}
I change access address method of touch MCU direct mode so that I can
change raydium i2c driver as below.

static int raydium_i2c_read_message(struct i2c_client *client,
			    u32 addr, void *data, size_t len)
{
__le32 le_addr;
size_t xfer_len;
u32 shift_addr;
int error;

while (len) {
	xfer_len = min_t(size_t, len, RM_MAX_READ_SIZE);

	le_addr = cpu_to_le32(addr);

	shift_addr = le_addr >> 8;/*send the first 3rd byte addr.*/
	error = raydium_i2c_send(client, RM_CMD_BANK_SWITCH,
				 &shift_addr, sizeof(le_addr));
	if (!error)/*read from last byte addr.*/
		error = raydium_i2c_read(client, le_addr & 0xff,
					 data, xfer_len);
	if (error)
		return error;

	len -= xfer_len;
	data += xfer_len;
	addr += xfer_len;
}

return 0;
}
Is this okay? If okay, I will use this form update one new patch.

Why? It has the same problem - you can not do calculations on a variable in fixed endianness, because you do not know if your code will run on big or little endian CPU.

Doesn't my version of the code work?

quoted

quoted

static int raydium_i2c_fw_write_page(struct i2c_client *client,
				     u16 page_idx, const void *data, size_t len)
{
	u8 buf[RM_BL_WRT_LEN];
	u8 pkg_idx = 1;
	size_t xfer_len;
	int error;

	while (len) {
		xfer_len = min_t(size_t, len, RM_BL_WRT_PKG_SIZE);
		buf[BL_HEADER] = RM_CMD_BOOT_PAGE_WRT;
		/*FIXME,Touch MCU need zero index as start page*/
		buf[BL_PAGE_STR] = page_idx ? 0xff : 0;
		buf[BL_PKG_IDX] = pkg_idx++;

		memcpy(&buf[BL_DATA_STR], data, xfer_len);

		if (len < RM_BL_WRT_PKG_SIZE) {
			buf[BL_PKG_IDX] = 4;

quoted

Why 4???

4 is trigger index for write flash. Our page write size is 128 bytes,
but in order to meet maximum I2C bus read/write byte limite and need
fill full all pages of 128 bytes. So that I split 128 bytes to "4"
section, and start burning flash if touch MCU get index "4". 

That is not the best way of handling this. What if you get 2 blocks of RM_BL_WRT_PKG_SIZE data worth? You will never get to index 4. You should be tracking number of bytes received and do flash when you get full page.

Hi Jeffrey,
Thanks.

-- 
Dmitry