1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0
2c296d5f9SThomas Petazzoni #include <linux/export.h>
3c296d5f9SThomas Petazzoni #include <linux/errno.h>
4c440eee1SNishad Kamdar #include <linux/gpio/consumer.h>
5c296d5f9SThomas Petazzoni #include <linux/spi/spi.h>
6c296d5f9SThomas Petazzoni #include "fbtft.h"
7c296d5f9SThomas Petazzoni
fbtft_write_spi(struct fbtft_par * par,void * buf,size_t len)8c296d5f9SThomas Petazzoni int fbtft_write_spi(struct fbtft_par *par, void *buf, size_t len)
9c296d5f9SThomas Petazzoni {
10c296d5f9SThomas Petazzoni struct spi_transfer t = {
11c296d5f9SThomas Petazzoni .tx_buf = buf,
12c296d5f9SThomas Petazzoni .len = len,
13c296d5f9SThomas Petazzoni };
14c296d5f9SThomas Petazzoni struct spi_message m;
15c296d5f9SThomas Petazzoni
16c296d5f9SThomas Petazzoni fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
1727a0eb8fSJeremy Sowden "%s(len=%zu): ", __func__, len);
18c296d5f9SThomas Petazzoni
19c296d5f9SThomas Petazzoni if (!par->spi) {
20c296d5f9SThomas Petazzoni dev_err(par->info->device,
21c296d5f9SThomas Petazzoni "%s: par->spi is unexpectedly NULL\n", __func__);
22c296d5f9SThomas Petazzoni return -1;
23c296d5f9SThomas Petazzoni }
24c296d5f9SThomas Petazzoni
25c296d5f9SThomas Petazzoni spi_message_init(&m);
26c296d5f9SThomas Petazzoni spi_message_add_tail(&t, &m);
27c296d5f9SThomas Petazzoni return spi_sync(par->spi, &m);
28c296d5f9SThomas Petazzoni }
29c296d5f9SThomas Petazzoni EXPORT_SYMBOL(fbtft_write_spi);
30c296d5f9SThomas Petazzoni
31c296d5f9SThomas Petazzoni /**
32c296d5f9SThomas Petazzoni * fbtft_write_spi_emulate_9() - write SPI emulating 9-bit
33c296d5f9SThomas Petazzoni * @par: Driver data
34c296d5f9SThomas Petazzoni * @buf: Buffer to write
35c296d5f9SThomas Petazzoni * @len: Length of buffer (must be divisible by 8)
36c296d5f9SThomas Petazzoni *
37c296d5f9SThomas Petazzoni * When 9-bit SPI is not available, this function can be used to emulate that.
38c296d5f9SThomas Petazzoni * par->extra must hold a transformation buffer used for transfer.
39c296d5f9SThomas Petazzoni */
fbtft_write_spi_emulate_9(struct fbtft_par * par,void * buf,size_t len)40c296d5f9SThomas Petazzoni int fbtft_write_spi_emulate_9(struct fbtft_par *par, void *buf, size_t len)
41c296d5f9SThomas Petazzoni {
42c296d5f9SThomas Petazzoni u16 *src = buf;
43c296d5f9SThomas Petazzoni u8 *dst = par->extra;
44c296d5f9SThomas Petazzoni size_t size = len / 2;
45c296d5f9SThomas Petazzoni size_t added = 0;
46c296d5f9SThomas Petazzoni int bits, i, j;
47c296d5f9SThomas Petazzoni u64 val, dc, tmp;
48c296d5f9SThomas Petazzoni
49c296d5f9SThomas Petazzoni fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
5027a0eb8fSJeremy Sowden "%s(len=%zu): ", __func__, len);
51c296d5f9SThomas Petazzoni
52c296d5f9SThomas Petazzoni if (!par->extra) {
53c296d5f9SThomas Petazzoni dev_err(par->info->device, "%s: error: par->extra is NULL\n",
54c296d5f9SThomas Petazzoni __func__);
55c296d5f9SThomas Petazzoni return -EINVAL;
56c296d5f9SThomas Petazzoni }
57c296d5f9SThomas Petazzoni if ((len % 8) != 0) {
58c296d5f9SThomas Petazzoni dev_err(par->info->device,
59aed1c72eSHaneen Mohammed "error: len=%zu must be divisible by 8\n", len);
60c296d5f9SThomas Petazzoni return -EINVAL;
61c296d5f9SThomas Petazzoni }
62c296d5f9SThomas Petazzoni
63c296d5f9SThomas Petazzoni for (i = 0; i < size; i += 8) {
64c296d5f9SThomas Petazzoni tmp = 0;
65c296d5f9SThomas Petazzoni bits = 63;
66c296d5f9SThomas Petazzoni for (j = 0; j < 7; j++) {
67c296d5f9SThomas Petazzoni dc = (*src & 0x0100) ? 1 : 0;
68c296d5f9SThomas Petazzoni val = *src & 0x00FF;
69c296d5f9SThomas Petazzoni tmp |= dc << bits;
70c296d5f9SThomas Petazzoni bits -= 8;
71c296d5f9SThomas Petazzoni tmp |= val << bits--;
72c296d5f9SThomas Petazzoni src++;
73c296d5f9SThomas Petazzoni }
74c296d5f9SThomas Petazzoni tmp |= ((*src & 0x0100) ? 1 : 0);
75caaba677SJandy Gou *(__be64 *)dst = cpu_to_be64(tmp);
76c296d5f9SThomas Petazzoni dst += 8;
77c296d5f9SThomas Petazzoni *dst++ = (u8)(*src++ & 0x00FF);
78c296d5f9SThomas Petazzoni added++;
79c296d5f9SThomas Petazzoni }
80c296d5f9SThomas Petazzoni
81c296d5f9SThomas Petazzoni return spi_write(par->spi, par->extra, size + added);
82c296d5f9SThomas Petazzoni }
83c296d5f9SThomas Petazzoni EXPORT_SYMBOL(fbtft_write_spi_emulate_9);
84c296d5f9SThomas Petazzoni
fbtft_read_spi(struct fbtft_par * par,void * buf,size_t len)85c296d5f9SThomas Petazzoni int fbtft_read_spi(struct fbtft_par *par, void *buf, size_t len)
86c296d5f9SThomas Petazzoni {
87c296d5f9SThomas Petazzoni int ret;
88c296d5f9SThomas Petazzoni u8 txbuf[32] = { 0, };
89c296d5f9SThomas Petazzoni struct spi_transfer t = {
90c296d5f9SThomas Petazzoni .speed_hz = 2000000,
91c296d5f9SThomas Petazzoni .rx_buf = buf,
92c296d5f9SThomas Petazzoni .len = len,
93c296d5f9SThomas Petazzoni };
94c296d5f9SThomas Petazzoni struct spi_message m;
95c296d5f9SThomas Petazzoni
96c296d5f9SThomas Petazzoni if (!par->spi) {
97c296d5f9SThomas Petazzoni dev_err(par->info->device,
98c296d5f9SThomas Petazzoni "%s: par->spi is unexpectedly NULL\n", __func__);
99c296d5f9SThomas Petazzoni return -ENODEV;
100c296d5f9SThomas Petazzoni }
101c296d5f9SThomas Petazzoni
102c296d5f9SThomas Petazzoni if (par->startbyte) {
103c296d5f9SThomas Petazzoni if (len > 32) {
104c296d5f9SThomas Petazzoni dev_err(par->info->device,
105aed1c72eSHaneen Mohammed "len=%zu can't be larger than 32 when using 'startbyte'\n",
106aed1c72eSHaneen Mohammed len);
107c296d5f9SThomas Petazzoni return -EINVAL;
108c296d5f9SThomas Petazzoni }
109c296d5f9SThomas Petazzoni txbuf[0] = par->startbyte | 0x3;
110c296d5f9SThomas Petazzoni t.tx_buf = txbuf;
111c296d5f9SThomas Petazzoni fbtft_par_dbg_hex(DEBUG_READ, par, par->info->device, u8,
11227a0eb8fSJeremy Sowden txbuf, len, "%s(len=%zu) txbuf => ",
113333c7b94SLeonardo Brás __func__, len);
114c296d5f9SThomas Petazzoni }
115c296d5f9SThomas Petazzoni
116c296d5f9SThomas Petazzoni spi_message_init(&m);
117c296d5f9SThomas Petazzoni spi_message_add_tail(&t, &m);
118c296d5f9SThomas Petazzoni ret = spi_sync(par->spi, &m);
119c296d5f9SThomas Petazzoni fbtft_par_dbg_hex(DEBUG_READ, par, par->info->device, u8, buf, len,
12027a0eb8fSJeremy Sowden "%s(len=%zu) buf <= ", __func__, len);
121c296d5f9SThomas Petazzoni
122c296d5f9SThomas Petazzoni return ret;
123c296d5f9SThomas Petazzoni }
124c296d5f9SThomas Petazzoni EXPORT_SYMBOL(fbtft_read_spi);
125c296d5f9SThomas Petazzoni
126c296d5f9SThomas Petazzoni /*
127c296d5f9SThomas Petazzoni * Optimized use of gpiolib is twice as fast as no optimization
128c296d5f9SThomas Petazzoni * only one driver can use the optimized version at a time
129c296d5f9SThomas Petazzoni */
fbtft_write_gpio8_wr(struct fbtft_par * par,void * buf,size_t len)130c296d5f9SThomas Petazzoni int fbtft_write_gpio8_wr(struct fbtft_par *par, void *buf, size_t len)
131c296d5f9SThomas Petazzoni {
132c296d5f9SThomas Petazzoni u8 data;
133c296d5f9SThomas Petazzoni int i;
134c296d5f9SThomas Petazzoni #ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
135c296d5f9SThomas Petazzoni static u8 prev_data;
136c296d5f9SThomas Petazzoni #endif
137c296d5f9SThomas Petazzoni
138c296d5f9SThomas Petazzoni fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
13927a0eb8fSJeremy Sowden "%s(len=%zu): ", __func__, len);
140c296d5f9SThomas Petazzoni
141c296d5f9SThomas Petazzoni while (len--) {
142c296d5f9SThomas Petazzoni data = *(u8 *)buf;
143c296d5f9SThomas Petazzoni
144c296d5f9SThomas Petazzoni /* Start writing by pulling down /WR */
145*ec03c210SAndy Shevchenko gpiod_set_value(par->gpio.wr, 1);
146c296d5f9SThomas Petazzoni
147c296d5f9SThomas Petazzoni /* Set data */
148c296d5f9SThomas Petazzoni #ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
149c296d5f9SThomas Petazzoni if (data == prev_data) {
150*ec03c210SAndy Shevchenko gpiod_set_value(par->gpio.wr, 1); /* used as delay */
151c296d5f9SThomas Petazzoni } else {
152c296d5f9SThomas Petazzoni for (i = 0; i < 8; i++) {
153c296d5f9SThomas Petazzoni if ((data & 1) != (prev_data & 1))
154c440eee1SNishad Kamdar gpiod_set_value(par->gpio.db[i],
155248d8285SAya Mahfouz data & 1);
156c296d5f9SThomas Petazzoni data >>= 1;
157c296d5f9SThomas Petazzoni prev_data >>= 1;
158c296d5f9SThomas Petazzoni }
159c296d5f9SThomas Petazzoni }
160c296d5f9SThomas Petazzoni #else
161c296d5f9SThomas Petazzoni for (i = 0; i < 8; i++) {
162c440eee1SNishad Kamdar gpiod_set_value(par->gpio.db[i], data & 1);
163c296d5f9SThomas Petazzoni data >>= 1;
164c296d5f9SThomas Petazzoni }
165c296d5f9SThomas Petazzoni #endif
166c296d5f9SThomas Petazzoni
167c296d5f9SThomas Petazzoni /* Pullup /WR */
168*ec03c210SAndy Shevchenko gpiod_set_value(par->gpio.wr, 0);
169c296d5f9SThomas Petazzoni
170c296d5f9SThomas Petazzoni #ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
171c296d5f9SThomas Petazzoni prev_data = *(u8 *)buf;
172c296d5f9SThomas Petazzoni #endif
173c296d5f9SThomas Petazzoni buf++;
174c296d5f9SThomas Petazzoni }
175c296d5f9SThomas Petazzoni
176c296d5f9SThomas Petazzoni return 0;
177c296d5f9SThomas Petazzoni }
178c296d5f9SThomas Petazzoni EXPORT_SYMBOL(fbtft_write_gpio8_wr);
179c296d5f9SThomas Petazzoni
fbtft_write_gpio16_wr(struct fbtft_par * par,void * buf,size_t len)180c296d5f9SThomas Petazzoni int fbtft_write_gpio16_wr(struct fbtft_par *par, void *buf, size_t len)
181c296d5f9SThomas Petazzoni {
182c296d5f9SThomas Petazzoni u16 data;
183c296d5f9SThomas Petazzoni int i;
184c296d5f9SThomas Petazzoni #ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
185c296d5f9SThomas Petazzoni static u16 prev_data;
186c296d5f9SThomas Petazzoni #endif
187c296d5f9SThomas Petazzoni
188c296d5f9SThomas Petazzoni fbtft_par_dbg_hex(DEBUG_WRITE, par, par->info->device, u8, buf, len,
18927a0eb8fSJeremy Sowden "%s(len=%zu): ", __func__, len);
190c296d5f9SThomas Petazzoni
191c296d5f9SThomas Petazzoni while (len) {
192c296d5f9SThomas Petazzoni data = *(u16 *)buf;
193c296d5f9SThomas Petazzoni
194c296d5f9SThomas Petazzoni /* Start writing by pulling down /WR */
195*ec03c210SAndy Shevchenko gpiod_set_value(par->gpio.wr, 1);
196c296d5f9SThomas Petazzoni
197c296d5f9SThomas Petazzoni /* Set data */
198c296d5f9SThomas Petazzoni #ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
199c296d5f9SThomas Petazzoni if (data == prev_data) {
200*ec03c210SAndy Shevchenko gpiod_set_value(par->gpio.wr, 1); /* used as delay */
201c296d5f9SThomas Petazzoni } else {
202c296d5f9SThomas Petazzoni for (i = 0; i < 16; i++) {
203c296d5f9SThomas Petazzoni if ((data & 1) != (prev_data & 1))
204c440eee1SNishad Kamdar gpiod_set_value(par->gpio.db[i],
205248d8285SAya Mahfouz data & 1);
206c296d5f9SThomas Petazzoni data >>= 1;
207c296d5f9SThomas Petazzoni prev_data >>= 1;
208c296d5f9SThomas Petazzoni }
209c296d5f9SThomas Petazzoni }
210c296d5f9SThomas Petazzoni #else
211c296d5f9SThomas Petazzoni for (i = 0; i < 16; i++) {
212c440eee1SNishad Kamdar gpiod_set_value(par->gpio.db[i], data & 1);
213c296d5f9SThomas Petazzoni data >>= 1;
214c296d5f9SThomas Petazzoni }
215c296d5f9SThomas Petazzoni #endif
216c296d5f9SThomas Petazzoni
217c296d5f9SThomas Petazzoni /* Pullup /WR */
218*ec03c210SAndy Shevchenko gpiod_set_value(par->gpio.wr, 0);
219c296d5f9SThomas Petazzoni
220c296d5f9SThomas Petazzoni #ifndef DO_NOT_OPTIMIZE_FBTFT_WRITE_GPIO
221c296d5f9SThomas Petazzoni prev_data = *(u16 *)buf;
222c296d5f9SThomas Petazzoni #endif
223c296d5f9SThomas Petazzoni buf += 2;
224c296d5f9SThomas Petazzoni len -= 2;
225c296d5f9SThomas Petazzoni }
226c296d5f9SThomas Petazzoni
227c296d5f9SThomas Petazzoni return 0;
228c296d5f9SThomas Petazzoni }
229c296d5f9SThomas Petazzoni EXPORT_SYMBOL(fbtft_write_gpio16_wr);
230c296d5f9SThomas Petazzoni
fbtft_write_gpio16_wr_latched(struct fbtft_par * par,void * buf,size_t len)231c296d5f9SThomas Petazzoni int fbtft_write_gpio16_wr_latched(struct fbtft_par *par, void *buf, size_t len)
232c296d5f9SThomas Petazzoni {
233c296d5f9SThomas Petazzoni dev_err(par->info->device, "%s: function not implemented\n", __func__);
234c296d5f9SThomas Petazzoni return -1;
235c296d5f9SThomas Petazzoni }
236c296d5f9SThomas Petazzoni EXPORT_SYMBOL(fbtft_write_gpio16_wr_latched);
237