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![Andy Shevchenko](/assets/img/avatar_default.png)
There is no need to duplicate what SPI core already does, i.e. mapping buffers for DMA capable transfers. Remove all related pices of code. Note, that code, besides its redundancy, was buggy: DMA address potentially can be 0, SPI slave device has nothing to do with DMA capable device properties and DMA mask in particular. Suggested-by: Noralf Trønnes <noralf@tronnes.org> Acked-by: Noralf Trønnes <noralf@tronnes.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
234 lines
5.1 KiB
C
234 lines
5.1 KiB
C
#include <linux/export.h>
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#include <linux/errno.h>
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#include <linux/gpio.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=%d): ", __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=%d): ", __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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*(u64 *)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=%d) txbuf => ", __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=%d) 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=%d): ", __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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gpio_set_value(par->gpio.wr, 0);
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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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gpio_set_value(par->gpio.wr, 0); /* 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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gpio_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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gpio_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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gpio_set_value(par->gpio.wr, 1);
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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=%d): ", __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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gpio_set_value(par->gpio.wr, 0);
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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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gpio_set_value(par->gpio.wr, 0); /* 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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gpio_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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gpio_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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gpio_set_value(par->gpio.wr, 1);
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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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