drivers/staging/fbtft/fbtft-bus.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/export.h>
   3 #include <linux/errno.h>
   4 #include <linux/gpio/consumer.h>
   5 #include <linux/spi/spi.h>
   6 #include "fbtft.h"
   7
   8 /*****************************************************************************
   9  *
  10  *   void (*write_reg)(struct fbtft_par *par, int len, ...);
  11  *
  12  *****************************************************************************/
  13
  14 #define define_fbtft_write_reg(func, buffer_type, data_type, modifier)        \
  15 void func(struct fbtft_par *par, int len, ...)                                \
  16 {                                                                             \
  17         va_list args;                                                         \
  18         int i, ret;                                                           \
  19         int offset = 0;                                                       \
  20         buffer_type *buf = (buffer_type *)par->buf;                           \
  21                                                                               \
  22         if (unlikely(par->debug & DEBUG_WRITE_REGISTER)) {                    \
  23                 va_start(args, len);                                          \
  24                 for (i = 0; i < len; i++) {                                   \
  25                         buf[i] = modifier((data_type)va_arg(args,             \
  26                                                             unsigned int));   \
  27                 }                                                             \
  28                 va_end(args);                                                 \
  29                 fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par,                  \
  30                                   par->info->device, buffer_type, buf, len,   \
  31                                   "%s: ", __func__);                          \
  32         }                                                                     \
  33                                                                               \
  34         va_start(args, len);                                                  \
  35                                                                               \
  36         if (par->startbyte) {                                                 \
  37                 *(u8 *)par->buf = par->startbyte;                             \
  38                 buf = (buffer_type *)(par->buf + 1);                          \
  39                 offset = 1;                                                   \
  40         }                                                                     \
  41                                                                               \
  42         *buf = modifier((data_type)va_arg(args, unsigned int));               \
  43         ret = fbtft_write_buf_dc(par, par->buf, sizeof(data_type) + offset,   \
  44                                  0);                                          \
  45         if (ret < 0)                                                          \
  46                 goto out;                                                     \
  47         len--;                                                                \
  48                                                                               \
  49         if (par->startbyte)                                                   \
  50                 *(u8 *)par->buf = par->startbyte | 0x2;                       \
  51                                                                               \
  52         if (len) {                                                            \
  53                 i = len;                                                      \
  54                 while (i--)                                                   \
  55                         *buf++ = modifier((data_type)va_arg(args,             \
  56                                                             unsigned int));   \
  57                 fbtft_write_buf_dc(par, par->buf,                             \
  58                                    len * (sizeof(data_type) + offset), 1);    \
  59         }                                                                     \
  60 out:                                                                          \
  61         va_end(args);                                                         \
  62 }                                                                             \
  63 EXPORT_SYMBOL(func);
  64
  65 define_fbtft_write_reg(fbtft_write_reg8_bus8, u8, u8, )
  66 define_fbtft_write_reg(fbtft_write_reg16_bus8, __be16, u16, cpu_to_be16)
  67 define_fbtft_write_reg(fbtft_write_reg16_bus16, u16, u16, )
  68
  69 void fbtft_write_reg8_bus9(struct fbtft_par *par, int len, ...)
  70 {
  71         va_list args;
  72         int i, ret;
  73         int pad = 0;
  74         u16 *buf = (u16 *)par->buf;
  75
  76         if (unlikely(par->debug & DEBUG_WRITE_REGISTER)) {
  77                 va_start(args, len);
  78                 for (i = 0; i < len; i++)
  79                         *(((u8 *)buf) + i) = (u8)va_arg(args, unsigned int);
  80                 va_end(args);
  81                 fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par,
  82                                   par->info->device, u8, buf, len, "%s: ",
  83                                   __func__);
  84         }
  85         if (len <= 0)
  86                 return;
  87
  88         if (par->spi && (par->spi->bits_per_word == 8)) {
  89                 /* we're emulating 9-bit, pad start of buffer with no-ops
  90                  * (assuming here that zero is a no-op)
  91                  */
  92                 pad = (len % 4) ? 4 - (len % 4) : 0;
  93                 for (i = 0; i < pad; i++)
  94                         *buf++ = 0x000;
  95         }
  96
  97         va_start(args, len);
  98         *buf++ = (u8)va_arg(args, unsigned int);
  99         i = len - 1;
 100         while (i--) {
 101                 *buf = (u8)va_arg(args, unsigned int);
 102                 *buf++ |= 0x100; /* dc=1 */
 103         }
 104         va_end(args);
 105         ret = par->fbtftops.write(par, par->buf, (len + pad) * sizeof(u16));
 106         if (ret < 0) {
 107                 dev_err(par->info->device,
 108                         "write() failed and returned %d\n", ret);
 109                 return;
 110         }
 111 }
 112 EXPORT_SYMBOL(fbtft_write_reg8_bus9);
 113
 114 /*****************************************************************************
 115  *
 116  *   int (*write_vmem)(struct fbtft_par *par);
 117  *
 118  *****************************************************************************/
 119
 120 /* 16 bit pixel over 8-bit databus */
 121 int fbtft_write_vmem16_bus8(struct fbtft_par *par, size_t offset, size_t len)
 122 {
 123         u16 *vmem16;
 124         __be16 *txbuf16 = par->txbuf.buf;
 125         size_t remain;
 126         size_t to_copy;
 127         size_t tx_array_size;
 128         int i;
 129         int ret = 0;
 130         size_t startbyte_size = 0;
 131
 132         remain = len / 2;
 133         vmem16 = (u16 *)(par->info->screen_buffer + offset);
 134
 135         gpiod_set_value(par->gpio.dc, 1);
 136
 137         /* non buffered write */
 138         if (!par->txbuf.buf)
 139                 return par->fbtftops.write(par, vmem16, len);
 140
 141         /* buffered write */
 142         tx_array_size = par->txbuf.len / 2;
 143
 144         if (par->startbyte) {
 145                 txbuf16 = par->txbuf.buf + 1;
 146                 tx_array_size -= 2;
 147                 *(u8 *)(par->txbuf.buf) = par->startbyte | 0x2;
 148                 startbyte_size = 1;
 149         }
 150
 151         while (remain) {
 152                 to_copy = min(tx_array_size, remain);
 153                 dev_dbg(par->info->device, "to_copy=%zu, remain=%zu\n",
 154                         to_copy, remain - to_copy);
 155
 156                 for (i = 0; i < to_copy; i++)
 157                         txbuf16[i] = cpu_to_be16(vmem16[i]);
 158
 159                 vmem16 = vmem16 + to_copy;
 160                 ret = par->fbtftops.write(par, par->txbuf.buf,
 161                                                 startbyte_size + to_copy * 2);
 162                 if (ret < 0)
 163                         return ret;
 164                 remain -= to_copy;
 165         }
 166
 167         return ret;
 168 }
 169 EXPORT_SYMBOL(fbtft_write_vmem16_bus8);
 170
 171 /* 16 bit pixel over 9-bit SPI bus: dc + high byte, dc + low byte */
 172 int fbtft_write_vmem16_bus9(struct fbtft_par *par, size_t offset, size_t len)
 173 {
 174         u8 *vmem8;
 175         u16 *txbuf16 = par->txbuf.buf;
 176         size_t remain;
 177         size_t to_copy;
 178         size_t tx_array_size;
 179         int i;
 180         int ret = 0;
 181
 182         if (!par->txbuf.buf) {
 183                 dev_err(par->info->device, "%s: txbuf.buf is NULL\n", __func__);
 184                 return -1;
 185         }
 186
 187         remain = len;
 188         vmem8 = par->info->screen_buffer + offset;
 189
 190         tx_array_size = par->txbuf.len / 2;
 191
 192         while (remain) {
 193                 to_copy = min(tx_array_size, remain);
 194                 dev_dbg(par->info->device, "to_copy=%zu, remain=%zu\n",
 195                         to_copy, remain - to_copy);
 196
 197 #ifdef __LITTLE_ENDIAN
 198                 for (i = 0; i < to_copy; i += 2) {
 199                         txbuf16[i]     = 0x0100 | vmem8[i + 1];
 200                         txbuf16[i + 1] = 0x0100 | vmem8[i];
 201                 }
 202 #else
 203                 for (i = 0; i < to_copy; i++)
 204                         txbuf16[i]   = 0x0100 | vmem8[i];
 205 #endif
 206                 vmem8 = vmem8 + to_copy;
 207                 ret = par->fbtftops.write(par, par->txbuf.buf, to_copy * 2);
 208                 if (ret < 0)
 209                         return ret;
 210                 remain -= to_copy;
 211         }
 212
 213         return ret;
 214 }
 215 EXPORT_SYMBOL(fbtft_write_vmem16_bus9);
 216
 217 int fbtft_write_vmem8_bus8(struct fbtft_par *par, size_t offset, size_t len)
 218 {
 219         dev_err(par->info->device, "%s: function not implemented\n", __func__);
 220         return -1;
 221 }
 222 EXPORT_SYMBOL(fbtft_write_vmem8_bus8);
 223
 224 /* 16 bit pixel over 16-bit databus */
 225 int fbtft_write_vmem16_bus16(struct fbtft_par *par, size_t offset, size_t len)
 226 {
 227         u16 *vmem16;
 228
 229         vmem16 = (u16 *)(par->info->screen_buffer + offset);
 230
 231         /* no need for buffered write with 16-bit bus */
 232         return fbtft_write_buf_dc(par, vmem16, len, 1);
 233 }
 234 EXPORT_SYMBOL(fbtft_write_vmem16_bus16);