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