drivers/auxdisplay/img-ascii-lcd.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016 Imagination Technologies
   4  * Author: Paul Burton <paul.burton@mips.com>
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/io.h>
   9 #include <linux/mfd/syscon.h>
  10 #include <linux/module.h>
  11 #include <linux/of.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/property.h>
  14 #include <linux/regmap.h>
  15 #include <linux/slab.h>
  16
  17 #include "line-display.h"
  18
  19 struct img_ascii_lcd_ctx;
  20
  21 /**
  22  * struct img_ascii_lcd_config - Configuration information about an LCD model
  23  * @num_chars: the number of characters the LCD can display
  24  * @external_regmap: true if registers are in a system controller, else false
  25  * @ops: character line display operations
  26  */
  27 struct img_ascii_lcd_config {
  28         unsigned int num_chars;
  29         bool external_regmap;
  30         const struct linedisp_ops ops;
  31 };
  32
  33 /**
  34  * struct img_ascii_lcd_ctx - Private data structure
  35  * @linedisp: line display structure
  36  * @base: the base address of the LCD registers
  37  * @regmap: the regmap through which LCD registers are accessed
  38  * @offset: the offset within regmap to the start of the LCD registers
  39  */
  40 struct img_ascii_lcd_ctx {
  41         struct linedisp linedisp;
  42         union {
  43                 void __iomem *base;
  44                 struct regmap *regmap;
  45         };
  46         u32 offset;
  47 };
  48
  49 /*
  50  * MIPS Boston development board
  51  */
  52
  53 static void boston_update(struct linedisp *linedisp)
  54 {
  55         struct img_ascii_lcd_ctx *ctx =
  56                 container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
  57         ulong val;
  58
  59 #if BITS_PER_LONG == 64
  60         val = *((u64 *)&linedisp->buf[0]);
  61         __raw_writeq(val, ctx->base);
  62 #elif BITS_PER_LONG == 32
  63         val = *((u32 *)&linedisp->buf[0]);
  64         __raw_writel(val, ctx->base);
  65         val = *((u32 *)&linedisp->buf[4]);
  66         __raw_writel(val, ctx->base + 4);
  67 #else
  68 # error Not 32 or 64 bit
  69 #endif
  70 }
  71
  72 static const struct img_ascii_lcd_config boston_config = {
  73         .num_chars = 8,
  74         .ops = {
  75                 .update = boston_update,
  76         },
  77 };
  78
  79 /*
  80  * MIPS Malta development board
  81  */
  82
  83 static void malta_update(struct linedisp *linedisp)
  84 {
  85         struct img_ascii_lcd_ctx *ctx =
  86                 container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
  87         unsigned int i;
  88         int err = 0;
  89
  90         for (i = 0; i < linedisp->num_chars; i++) {
  91                 err = regmap_write(ctx->regmap,
  92                                    ctx->offset + (i * 8), linedisp->buf[i]);
  93                 if (err)
  94                         break;
  95         }
  96
  97         if (unlikely(err))
  98                 pr_err_ratelimited("Failed to update LCD display: %d\n", err);
  99 }
 100
 101 static const struct img_ascii_lcd_config malta_config = {
 102         .num_chars = 8,
 103         .external_regmap = true,
 104         .ops = {
 105                 .update = malta_update,
 106         },
 107 };
 108
 109 /*
 110  * MIPS SEAD3 development board
 111  */
 112
 113 enum {
 114         SEAD3_REG_LCD_CTRL              = 0x00,
 115 #define SEAD3_REG_LCD_CTRL_SETDRAM      BIT(7)
 116         SEAD3_REG_LCD_DATA              = 0x08,
 117         SEAD3_REG_CPLD_STATUS           = 0x10,
 118 #define SEAD3_REG_CPLD_STATUS_BUSY      BIT(0)
 119         SEAD3_REG_CPLD_DATA             = 0x18,
 120 #define SEAD3_REG_CPLD_DATA_BUSY        BIT(7)
 121 };
 122
 123 static int sead3_wait_sm_idle(struct img_ascii_lcd_ctx *ctx)
 124 {
 125         unsigned int status;
 126         int err;
 127
 128         do {
 129                 err = regmap_read(ctx->regmap,
 130                                   ctx->offset + SEAD3_REG_CPLD_STATUS,
 131                                   &status);
 132                 if (err)
 133                         return err;
 134         } while (status & SEAD3_REG_CPLD_STATUS_BUSY);
 135
 136         return 0;
 137
 138 }
 139
 140 static int sead3_wait_lcd_idle(struct img_ascii_lcd_ctx *ctx)
 141 {
 142         unsigned int cpld_data;
 143         int err;
 144
 145         err = sead3_wait_sm_idle(ctx);
 146         if (err)
 147                 return err;
 148
 149         do {
 150                 err = regmap_read(ctx->regmap,
 151                                   ctx->offset + SEAD3_REG_LCD_CTRL,
 152                                   &cpld_data);
 153                 if (err)
 154                         return err;
 155
 156                 err = sead3_wait_sm_idle(ctx);
 157                 if (err)
 158                         return err;
 159
 160                 err = regmap_read(ctx->regmap,
 161                                   ctx->offset + SEAD3_REG_CPLD_DATA,
 162                                   &cpld_data);
 163                 if (err)
 164                         return err;
 165         } while (cpld_data & SEAD3_REG_CPLD_DATA_BUSY);
 166
 167         return 0;
 168 }
 169
 170 static void sead3_update(struct linedisp *linedisp)
 171 {
 172         struct img_ascii_lcd_ctx *ctx =
 173                 container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
 174         unsigned int i;
 175         int err = 0;
 176
 177         for (i = 0; i < linedisp->num_chars; i++) {
 178                 err = sead3_wait_lcd_idle(ctx);
 179                 if (err)
 180                         break;
 181
 182                 err = regmap_write(ctx->regmap,
 183                                    ctx->offset + SEAD3_REG_LCD_CTRL,
 184                                    SEAD3_REG_LCD_CTRL_SETDRAM | i);
 185                 if (err)
 186                         break;
 187
 188                 err = sead3_wait_lcd_idle(ctx);
 189                 if (err)
 190                         break;
 191
 192                 err = regmap_write(ctx->regmap,
 193                                    ctx->offset + SEAD3_REG_LCD_DATA,
 194                                    linedisp->buf[i]);
 195                 if (err)
 196                         break;
 197         }
 198
 199         if (unlikely(err))
 200                 pr_err_ratelimited("Failed to update LCD display: %d\n", err);
 201 }
 202
 203 static const struct img_ascii_lcd_config sead3_config = {
 204         .num_chars = 16,
 205         .external_regmap = true,
 206         .ops = {
 207                 .update = sead3_update,
 208         },
 209 };
 210
 211 static const struct of_device_id img_ascii_lcd_matches[] = {
 212         { .compatible = "img,boston-lcd", .data = &boston_config },
 213         { .compatible = "mti,malta-lcd", .data = &malta_config },
 214         { .compatible = "mti,sead3-lcd", .data = &sead3_config },
 215         { /* sentinel */ }
 216 };
 217 MODULE_DEVICE_TABLE(of, img_ascii_lcd_matches);
 218
 219 /**
 220  * img_ascii_lcd_probe() - probe an LCD display device
 221  * @pdev: the LCD platform device
 222  *
 223  * Probe an LCD display device, ensuring that we have the required resources in
 224  * order to access the LCD & setting up private data as well as sysfs files.
 225  *
 226  * Return: 0 on success, else -ERRNO
 227  */
 228 static int img_ascii_lcd_probe(struct platform_device *pdev)
 229 {
 230         struct device *dev = &pdev->dev;
 231         const struct img_ascii_lcd_config *cfg = device_get_match_data(dev);
 232         struct img_ascii_lcd_ctx *ctx;
 233         int err;
 234
 235         ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
 236         if (!ctx)
 237                 return -ENOMEM;
 238
 239         if (cfg->external_regmap) {
 240                 ctx->regmap = syscon_node_to_regmap(dev->parent->of_node);
 241                 if (IS_ERR(ctx->regmap))
 242                         return PTR_ERR(ctx->regmap);
 243
 244                 if (of_property_read_u32(dev->of_node, "offset", &ctx->offset))
 245                         return -EINVAL;
 246         } else {
 247                 ctx->base = devm_platform_ioremap_resource(pdev, 0);
 248                 if (IS_ERR(ctx->base))
 249                         return PTR_ERR(ctx->base);
 250         }
 251
 252         err = linedisp_register(&ctx->linedisp, dev, cfg->num_chars, &cfg->ops);
 253         if (err)
 254                 return err;
 255
 256         /* for backwards compatibility */
 257         err = compat_only_sysfs_link_entry_to_kobj(&dev->kobj,
 258                                                    &ctx->linedisp.dev.kobj,
 259                                                    "message", NULL);
 260         if (err)
 261                 goto err_unregister;
 262
 263         platform_set_drvdata(pdev, ctx);
 264         return 0;
 265
 266 err_unregister:
 267         linedisp_unregister(&ctx->linedisp);
 268         return err;
 269 }
 270
 271 /**
 272  * img_ascii_lcd_remove() - remove an LCD display device
 273  * @pdev: the LCD platform device
 274  *
 275  * Remove an LCD display device, freeing private resources & ensuring that the
 276  * driver stops using the LCD display registers.
 277  */
 278 static void img_ascii_lcd_remove(struct platform_device *pdev)
 279 {
 280         struct img_ascii_lcd_ctx *ctx = platform_get_drvdata(pdev);
 281
 282         sysfs_remove_link(&pdev->dev.kobj, "message");
 283         linedisp_unregister(&ctx->linedisp);
 284 }
 285
 286 static struct platform_driver img_ascii_lcd_driver = {
 287         .driver = {
 288                 .name           = "img-ascii-lcd",
 289                 .of_match_table = img_ascii_lcd_matches,
 290         },
 291         .probe  = img_ascii_lcd_probe,
 292         .remove = img_ascii_lcd_remove,
 293 };
 294 module_platform_driver(img_ascii_lcd_driver);
 295
 296 MODULE_DESCRIPTION("Imagination Technologies ASCII LCD Display");
 297 MODULE_AUTHOR("Paul Burton <paul.burton@mips.com>");
 298 MODULE_LICENSE("GPL");
 299 MODULE_IMPORT_NS("LINEDISP");