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// SPDX-License-Identifier: GPL-2.0
#include <linux/export.h>
#include <linux/errno.h>
#include <linux/gpio/consumer.h>
#include <linux/spi/spi.h>
#include "fbtft.h"
int fbtft_write_spi(struct fbtft_par *par, void *buf, size_t len)
{
struct spi_transfer t = {
.tx_buf = buf,
.len = len,
};
struct spi_message m;
fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
"%s(len=%d): ", __func__, len);
if (!par->spi) {
dev_err(par->info->device,
"%s: par->spi is unexpectedly NULL\n", __func__);
return -1;
}
spi_message_init(&m);
spi_message_add_tail(&t, &m);
return spi_sync(par->spi, &m);
}
EXPORT_SYMBOL(fbtft_write_spi);
/**
* fbtft_write_spi_emulate_9() - write SPI emulating 9-bit
* @par: Driver data
* @buf: Buffer to write
* @len: Length of buffer (must be divisible by 8)
*
* When 9-bit SPI is not available, this function can be used to emulate that.
* par->extra must hold a transformation buffer used for transfer.
*/
int fbtft_write_spi_emulate_9(struct fbtft_par *par, void *buf, size_t len)
{
u16 *src = buf;
u8 *dst = par->extra;
size_t size = len / 2;
size_t added = 0;
int bits, i, j;
u64 val, dc, tmp;
fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
"%s(len=%d): ", __func__, len);
if (!par->extra) {
dev_err(par->info->device, "%s: error: par->extra is NULL\n",
__func__);
return -EINVAL;
}
if ((len % 8) != 0) {
dev_err(par->info->device,
"error: len=%zu must be divisible by 8\n", len);
return -EINVAL;
}
for (i = 0; i < size; i += 8) {
tmp = 0;
bits = 63;
for (j = 0; j < 7; j++) {
dc = (*src & 0x0100) ? 1 : 0;
val = *src & 0x00FF;
tmp |= dc << bits;
bits -= 8;
tmp |= val << bits--;
src++;
}
tmp |= ((*src & 0x0100) ? 1 : 0);
*(__be64 *)dst = cpu_to_be64(tmp);
dst += 8;
*dst++ = (u8)(*src++ & 0x00FF);
added++;
}
return spi_write(par->spi, par->extra, size + added);
}
EXPORT_SYMBOL(fbtft_write_spi_emulate_9);
int fbtft_read_spi(struct fbtft_par *par, void *buf, size_t len)
{
int ret;
u8 txbuf[32] = { 0, };
struct spi_transfer t = {
.speed_hz = 2000000,
.rx_buf = buf,
.len = len,
};
struct spi_message m;
if (!par->spi) {
dev_err(par->info->device,
"%s: par->spi is unexpectedly NULL\n", __func__);
return -ENODEV;
}
if (par->startbyte) {
if (len > 32) {
dev_err(par->info->device,
"len=%zu can't be larger than 32 when using 'startbyte'\n",
len);
return -EINVAL;
}
txbuf[0] = par->startbyte | 0x3;
t.tx_buf = txbuf;
fbtft_par_dbg_hex(DEBUG_READ, par, par->info->device, u8,
txbuf, len, "%s(len=%d) txbuf => ",
__func__, len);
}
spi_message_init(&m);
spi_message_add_tail(&t, &m);
ret = spi_sync(par->spi, &m);
fbtft_par_dbg_hex(DEBUG_READ, par, par->info->device, u8, buf, len,
"%s(len=%d) buf <= ", __func__, len);
return ret;
}
EXPORT_SYMBOL(fbtft_read_spi);
/*
* Optimized use of gpiolib is twice as fast as no optimization
* only one driver can use the optimized version at a time
*/
int fbtft_write_gpio8_wr(struct fbtft_par *par, void *buf, size_t len)
{
u8 data;
int i;
#ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
static u8 prev_data;
#endif
fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
"%s(len=%d): ", __func__, len);
while (len--) {
data = *(u8 *)buf;
/* Start writing by pulling down /WR */
gpiod_set_value(par->gpio.wr, 0);
/* Set data */
#ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
if (data == prev_data) {
gpiod_set_value(par->gpio.wr, 0); /* used as delay */
} else {
for (i = 0; i < 8; i++) {
if ((data & 1) != (prev_data & 1))
gpiod_set_value(par->gpio.db[i],
data & 1);
data >>= 1;
prev_data >>= 1;
}
}
#else
for (i = 0; i < 8; i++) {
gpiod_set_value(par->gpio.db[i], data & 1);
data >>= 1;
}
#endif
/* Pullup /WR */
gpiod_set_value(par->gpio.wr, 1);
#ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
prev_data = *(u8 *)buf;
#endif
buf++;
}
return 0;
}
EXPORT_SYMBOL(fbtft_write_gpio8_wr);
int fbtft_write_gpio16_wr(struct fbtft_par *par, void *buf, size_t len)
{
u16 data;
int i;
#ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
static u16 prev_data;
#endif
fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
"%s(len=%d): ", __func__, len);
while (len) {
data = *(u16 *)buf;
/* Start writing by pulling down /WR */
gpiod_set_value(par->gpio.wr, 0);
/* Set data */
#ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
if (data == prev_data) {
gpiod_set_value(par->gpio.wr, 0); /* used as delay */
} else {
for (i = 0; i < 16; i++) {
if ((data & 1) != (prev_data & 1))
gpiod_set_value(par->gpio.db[i],
data & 1);
data >>= 1;
prev_data >>= 1;
}
}
#else
for (i = 0; i < 16; i++) {
gpiod_set_value(par->gpio.db[i], data & 1);
data >>= 1;
}
#endif
/* Pullup /WR */
gpiod_set_value(par->gpio.wr, 1);
#ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
prev_data = *(u16 *)buf;
#endif
buf += 2;
len -= 2;
}
return 0;
}
EXPORT_SYMBOL(fbtft_write_gpio16_wr);
int fbtft_write_gpio16_wr_latched(struct fbtft_par *par, void *buf, size_t len)
{
dev_err(par->info->device, "%s: function not implemented\n", __func__);
return -1;
}
EXPORT_SYMBOL(fbtft_write_gpio16_wr_latched);
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