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SubjectRe: [PATCH] driver: input :touchscreen : add Raydium I2C touch driver
On Wed, May 18, 2016 at 12:07:02AM +0800, jeffrey.lin 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, addr & 0xff,
> > > data, xfer_len);
> > Change as:
> > if (!error)
> > error = raydium_i2c_read(client, (be_addr >> 24) & 0xff,
> > data, xfer_len);
>
> >I think it is the same on LE, and I suspect it will not work correctly
> >on BE... You want to have the 8 least significant bits of the bank to be
> >used as the address, right?

> This function work correctly with the kernel 3.18 of chromebook in my
> hand. Raydium touch direct access mode can recieve the BE address

That is because it is a little-endian device.

>
> after bank switch command 0xaa. For example, if we'll read 10 bytes
> data begin on 0x12345678. We need send the command sequences as 0xaa->
> 0x12->0x34->0x56-> 0x78 and then recive 10 bytes from 0x78.
>

Right. So the thing is - on any architecture, be it little- or
big-endian, expression "value & 0xff" will extract the 8 least
significant bits from the value, while "(value >> 24) & 0xff" will
extract the most significant bits (assuming that the value is 32 bits). So with your example if you do
cpu_to_be32() on LE architecture it will actually reshuffle the bytes so
that former LSB will become MSB and then you will extract that MSB and
use it. On BE arches cpu_to_be32() is a noop, so addr and be_addr will
have the same value, and your expression will produce 0x12 and not 0x78
as you expect. On the other hand, doing "addr & 0xff" will produce 0x78
regardless of endianness.

> > 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;
> > u8 div_cnt;
> > size_t xfer_len;
> > int error;
> > int i;
> >
> > div_cnt = len % RM_BL_WRT_PKG_SIZE ?
> > len / RM_BL_WRT_PKG_SIZE + 1:len / RM_BL_WRT_PKG_SIZE;
> >
> >Drop this. BTW, if you ever need it we have DIV_ROUND_UP macro.
>
> >
> > for (i = 0; i < div_cnt; i++) {
> >
> > 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);
> >
> > /* we need to pad to full page size */
> > if (len < RM_BL_WRT_PKG_SIZE)
> > memset(&buf[BL_DATA_STR] + len, 0xff,
> > RM_BL_WRT_PKG_SIZE - len);
> >
> > if (len == 0)
> > memset(buf + BL_DATA_STR, 0xff, RM_BL_WRT_PKG_SIZE);
> > else if (len < RM_BL_WRT_PKG_SIZE)
> > memset(buf + BL_DATA_STR + xfer_len, 0xff,
> > RM_BL_WRT_PKG_SIZE - xfer_len);
> >
> > error = raydium_i2c_write_object(client, buf, RM_BL_WRT_LEN,
> > RAYDIUM_WAIT_READY);
> > if (error) {
> > dev_err(&client->dev,
> > "page write command failed for page %d, chunk %d: %d\n",
> > page_idx, pkg_idx, error);
> > return error;
> > }
> > data += RM_BL_WRT_PKG_SIZE;
> > len -= RM_BL_WRT_PKG_SIZE;
> > }
> >
> > return error;
> > }
> Modify as below.
>
> 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;

Why 4???

> memset(buf + BL_DATA_STR + xfer_len, 0xff,
> RM_BL_WRT_PKG_SIZE - xfer_len);
> }
>
> error = raydium_i2c_write_object(client, buf, RM_BL_WRT_LEN,
> RAYDIUM_WAIT_READY);
> if (error) {
> dev_err(&client->dev,
> "page write command failed for page %d, chunk %d: %d\n",
> page_idx, pkg_idx, error);
> return error;
> }
> data += xfer_len;
> len -= xfer_len;
> }
>
> return error;
> >
> > >static void raydium_mt_event(struct raydium_data *ts)
> > >{
> > > int i;
> > > int error;
> > memory allocate
> > ts->report_data = kmalloc(ts->report_size, GFP_KERNEL);
> > if (!ts->report_data)
> > return;
> >
> >I thought I was allocating it after I queried the touchscreen
> >parameters... If not it was oversight. I do not think we should be
> >doing this on every interrupt, so please do the allocation in ->probe()
> >code.
> Move memory allocate to raydium_i2c_probe().

Thanks.

--
Dmitry

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