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.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, 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         type *buf = (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] = (type)va_arg(args, unsigned int);            \
  26                 }                                                             \
  27                 va_end(args);                                                 \
  28                 fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par, par->info->device, type, buf, len, "%s: ", __func__);   \
  29         }                                                                     \
  30                                                                               \
  31         va_start(args, len);                                                  \
  32                                                                               \
  33         if (par->startbyte) {                                                 \
  34                 *(u8 *)par->buf = par->startbyte;                             \
  35                 buf = (type *)(par->buf + 1);                                 \
  36                 offset = 1;                                                   \
  37         }                                                                     \
  38                                                                               \
  39         *buf = modifier((type)va_arg(args, unsigned int));                    \
  40         ret = fbtft_write_buf_dc(par, par->buf, sizeof(type) + offset, 0);    \
  41         if (ret < 0)                                                          \
  42                 goto out;                                                     \
  43         len--;                                                                \
  44                                                                               \
  45         if (par->startbyte)                                                   \
  46                 *(u8 *)par->buf = par->startbyte | 0x2;                       \
  47                                                                               \
  48         if (len) {                                                            \
  49                 i = len;                                                      \
  50                 while (i--)                                                   \
  51                         *buf++ = modifier((type)va_arg(args, unsigned int));  \
  52                 fbtft_write_buf_dc(par, par->buf,                             \
  53                                    len * (sizeof(type) + offset), 1);         \
  54         }                                                                     \
  55 out:                                                                          \
  56         va_end(args);                                                         \
  57 }                                                                             \
  58 EXPORT_SYMBOL(func);
  59
  60 define_fbtft_write_reg(fbtft_write_reg8_bus8, u8, )
  61 define_fbtft_write_reg(fbtft_write_reg16_bus8, u16, cpu_to_be16)
  62 define_fbtft_write_reg(fbtft_write_reg16_bus16, u16, )
  63
  64 void fbtft_write_reg8_bus9(struct fbtft_par *par, int len, ...)
  65 {
  66         va_list args;
  67         int i, ret;
  68         int pad = 0;
  69         u16 *buf = (u16 *)par->buf;
  70
  71         if (unlikely(par->debug & DEBUG_WRITE_REGISTER)) {
  72                 va_start(args, len);
  73                 for (i = 0; i < len; i++)
  74                         *(((u8 *)buf) + i) = (u8)va_arg(args, unsigned int);
  75                 va_end(args);
  76                 fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par,
  77                         par->info->device, u8, buf, len, "%s: ", __func__);
  78         }
  79         if (len <= 0)
  80                 return;
  81
  82         if (par->spi && (par->spi->bits_per_word == 8)) {
  83                 /* we're emulating 9-bit, pad start of buffer with no-ops
  84                  * (assuming here that zero is a no-op)
  85                  */
  86                 pad = (len % 4) ? 4 - (len % 4) : 0;
  87                 for (i = 0; i < pad; i++)
  88                         *buf++ = 0x000;
  89         }
  90
  91         va_start(args, len);
  92         *buf++ = (u8)va_arg(args, unsigned int);
  93         i = len - 1;
  94         while (i--) {
  95                 *buf = (u8)va_arg(args, unsigned int);
  96                 *buf++ |= 0x100; /* dc=1 */
  97         }
  98         va_end(args);
  99         ret = par->fbtftops.write(par, par->buf, (len + pad) * sizeof(u16));
 100         if (ret < 0) {
 101                 dev_err(par->info->device,
 102                         "write() failed and returned %d\n", ret);
 103                 return;
 104         }
 105 }
 106 EXPORT_SYMBOL(fbtft_write_reg8_bus9);
 107
 108 /*****************************************************************************
 109  *
 110  *   int (*write_vmem)(struct fbtft_par *par);
 111  *
 112  *****************************************************************************/
 113
 114 /* 16 bit pixel over 8-bit databus */
 115 int fbtft_write_vmem16_bus8(struct fbtft_par *par, size_t offset, size_t len)
 116 {
 117         u16 *vmem16;
 118         __be16 *txbuf16 = par->txbuf.buf;
 119         size_t remain;
 120         size_t to_copy;
 121         size_t tx_array_size;
 122         int i;
 123         int ret = 0;
 124         size_t startbyte_size = 0;
 125
 126         fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s(offset=%zu, len=%zu)\n",
 127                 __func__, offset, len);
 128
 129         remain = len / 2;
 130         vmem16 = (u16 *)(par->info->screen_buffer + offset);
 131
 132         if (par->gpio.dc != -1)
 133                 gpio_set_value(par->gpio.dc, 1);
 134
 135         /* non buffered write */
 136         if (!par->txbuf.buf)
 137                 return par->fbtftops.write(par, vmem16, len);
 138
 139         /* buffered write */
 140         tx_array_size = par->txbuf.len / 2;
 141
 142         if (par->startbyte) {
 143                 txbuf16 = par->txbuf.buf + 1;
 144                 tx_array_size -= 2;
 145                 *(u8 *)(par->txbuf.buf) = par->startbyte | 0x2;
 146                 startbyte_size = 1;
 147         }
 148
 149         while (remain) {
 150                 to_copy = min(tx_array_size, remain);
 151                 dev_dbg(par->info->device, "    to_copy=%zu, remain=%zu\n",
 152                                                 to_copy, remain - to_copy);
 153
 154                 for (i = 0; i < to_copy; i++)
 155                         txbuf16[i] = cpu_to_be16(vmem16[i]);
 156
 157                 vmem16 = vmem16 + to_copy;
 158                 ret = par->fbtftops.write(par, par->txbuf.buf,
 159                                                 startbyte_size + to_copy * 2);
 160                 if (ret < 0)
 161                         return ret;
 162                 remain -= to_copy;
 163         }
 164
 165         return ret;
 166 }
 167 EXPORT_SYMBOL(fbtft_write_vmem16_bus8);
 168
 169 /* 16 bit pixel over 9-bit SPI bus: dc + high byte, dc + low byte */
 170 int fbtft_write_vmem16_bus9(struct fbtft_par *par, size_t offset, size_t len)
 171 {
 172         u8 *vmem8;
 173         u16 *txbuf16 = par->txbuf.buf;
 174         size_t remain;
 175         size_t to_copy;
 176         size_t tx_array_size;
 177         int i;
 178         int ret = 0;
 179
 180         fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s(offset=%zu, len=%zu)\n",
 181                 __func__, offset, len);
 182
 183         if (!par->txbuf.buf) {
 184                 dev_err(par->info->device, "%s: txbuf.buf is NULL\n", __func__);
 185                 return -1;
 186         }
 187
 188         remain = len;
 189         vmem8 = par->info->screen_buffer + offset;
 190
 191         tx_array_size = par->txbuf.len / 2;
 192
 193         while (remain) {
 194                 to_copy = min(tx_array_size, remain);
 195                 dev_dbg(par->info->device, "    to_copy=%zu, remain=%zu\n",
 196                                                 to_copy, remain - to_copy);
 197
 198 #ifdef __LITTLE_ENDIAN
 199                 for (i = 0; i < to_copy; i += 2) {
 200                         txbuf16[i]     = 0x0100 | vmem8[i + 1];
 201                         txbuf16[i + 1] = 0x0100 | vmem8[i];
 202                 }
 203 #else
 204                 for (i = 0; i < to_copy; i++)
 205                         txbuf16[i]   = 0x0100 | vmem8[i];
 206 #endif
 207                 vmem8 = vmem8 + to_copy;
 208                 ret = par->fbtftops.write(par, par->txbuf.buf, to_copy * 2);
 209                 if (ret < 0)
 210                         return ret;
 211                 remain -= to_copy;
 212         }
 213
 214         return ret;
 215 }
 216 EXPORT_SYMBOL(fbtft_write_vmem16_bus9);
 217
 218 int fbtft_write_vmem8_bus8(struct fbtft_par *par, size_t offset, size_t len)
 219 {
 220         dev_err(par->info->device, "%s: function not implemented\n", __func__);
 221         return -1;
 222 }
 223 EXPORT_SYMBOL(fbtft_write_vmem8_bus8);
 224
 225 /* 16 bit pixel over 16-bit databus */
 226 int fbtft_write_vmem16_bus16(struct fbtft_par *par, size_t offset, size_t len)
 227 {
 228         u16 *vmem16;
 229
 230         fbtft_par_dbg(DEBUG_WRITE_VMEM, par, "%s(offset=%zu, len=%zu)\n",
 231                 __func__, offset, len);
 232
 233         vmem16 = (u16 *)(par->info->screen_buffer + offset);
 234
 235         /* no need for buffered write with 16-bit bus */
 236         return fbtft_write_buf_dc(par, vmem16, len, 1);
 237 }
 238 EXPORT_SYMBOL(fbtft_write_vmem16_bus16);