/* * Copyright (C) 2016 Imagination Technologies * Author: Paul Burton * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. */ #include #include #include #include #include #include #include #include #include #include #include struct img_ascii_lcd_ctx; /** * struct img_ascii_lcd_config - Configuration information about an LCD model * @num_chars: the number of characters the LCD can display * @external_regmap: true if registers are in a system controller, else false * @update: function called to update the LCD */ struct img_ascii_lcd_config { unsigned int num_chars; bool external_regmap; void (*update)(struct img_ascii_lcd_ctx *ctx); }; /** * struct img_ascii_lcd_ctx - Private data structure * @pdev: the ASCII LCD platform device * @base: the base address of the LCD registers * @regmap: the regmap through which LCD registers are accessed * @offset: the offset within regmap to the start of the LCD registers * @cfg: pointer to the LCD model configuration * @message: the full message to display or scroll on the LCD * @message_len: the length of the @message string * @scroll_pos: index of the first character of @message currently displayed * @scroll_rate: scroll interval in jiffies * @timer: timer used to implement scrolling * @curr: the string currently displayed on the LCD */ struct img_ascii_lcd_ctx { struct platform_device *pdev; union { void __iomem *base; struct regmap *regmap; }; u32 offset; const struct img_ascii_lcd_config *cfg; char *message; unsigned int message_len; unsigned int scroll_pos; unsigned int scroll_rate; struct timer_list timer; char curr[] __aligned(8); }; /* * MIPS Boston development board */ static void boston_update(struct img_ascii_lcd_ctx *ctx) { ulong val; #if BITS_PER_LONG == 64 val = *((u64 *)&ctx->curr[0]); __raw_writeq(val, ctx->base); #elif BITS_PER_LONG == 32 val = *((u32 *)&ctx->curr[0]); __raw_writel(val, ctx->base); val = *((u32 *)&ctx->curr[4]); __raw_writel(val, ctx->base + 4); #else # error Not 32 or 64 bit #endif } static struct img_ascii_lcd_config boston_config = { .num_chars = 8, .update = boston_update, }; /* * MIPS Malta development board */ static void malta_update(struct img_ascii_lcd_ctx *ctx) { unsigned int i; int err; for (i = 0; i < ctx->cfg->num_chars; i++) { err = regmap_write(ctx->regmap, ctx->offset + (i * 8), ctx->curr[i]); if (err) break; } if (unlikely(err)) pr_err_ratelimited("Failed to update LCD display: %d\n", err); } static struct img_ascii_lcd_config malta_config = { .num_chars = 8, .external_regmap = true, .update = malta_update, }; /* * MIPS SEAD3 development board */ enum { SEAD3_REG_LCD_CTRL = 0x00, #define SEAD3_REG_LCD_CTRL_SETDRAM BIT(7) SEAD3_REG_LCD_DATA = 0x08, SEAD3_REG_CPLD_STATUS = 0x10, #define SEAD3_REG_CPLD_STATUS_BUSY BIT(0) SEAD3_REG_CPLD_DATA = 0x18, #define SEAD3_REG_CPLD_DATA_BUSY BIT(7) }; static int sead3_wait_sm_idle(struct img_ascii_lcd_ctx *ctx) { unsigned int status; int err; do { err = regmap_read(ctx->regmap, ctx->offset + SEAD3_REG_CPLD_STATUS, &status); if (err) return err; } while (status & SEAD3_REG_CPLD_STATUS_BUSY); return 0; } static int sead3_wait_lcd_idle(struct img_ascii_lcd_ctx *ctx) { unsigned int cpld_data; int err; err = sead3_wait_sm_idle(ctx); if (err) return err; do { err = regmap_read(ctx->regmap, ctx->offset + SEAD3_REG_LCD_CTRL, &cpld_data); if (err) return err; err = sead3_wait_sm_idle(ctx); if (err) return err; err = regmap_read(ctx->regmap, ctx->offset + SEAD3_REG_CPLD_DATA, &cpld_data); if (err) return err; } while (cpld_data & SEAD3_REG_CPLD_DATA_BUSY); return 0; } static void sead3_update(struct img_ascii_lcd_ctx *ctx) { unsigned int i; int err; for (i = 0; i < ctx->cfg->num_chars; i++) { err = sead3_wait_lcd_idle(ctx); if (err) break; err = regmap_write(ctx->regmap, ctx->offset + SEAD3_REG_LCD_CTRL, SEAD3_REG_LCD_CTRL_SETDRAM | i); if (err) break; err = sead3_wait_lcd_idle(ctx); if (err) break; err = regmap_write(ctx->regmap, ctx->offset + SEAD3_REG_LCD_DATA, ctx->curr[i]); if (err) break; } if (unlikely(err)) pr_err_ratelimited("Failed to update LCD display: %d\n", err); } static struct img_ascii_lcd_config sead3_config = { .num_chars = 16, .external_regmap = true, .update = sead3_update, }; static const struct of_device_id img_ascii_lcd_matches[] = { { .compatible = "img,boston-lcd", .data = &boston_config }, { .compatible = "mti,malta-lcd", .data = &malta_config }, { .compatible = "mti,sead3-lcd", .data = &sead3_config }, { /* sentinel */ } }; /** * img_ascii_lcd_scroll() - scroll the display by a character * @arg: really a pointer to the private data structure * * Scroll the current message along the LCD by one character, rearming the * timer if required. */ static void img_ascii_lcd_scroll(unsigned long arg) { struct img_ascii_lcd_ctx *ctx = (struct img_ascii_lcd_ctx *)arg; unsigned int i, ch = ctx->scroll_pos; unsigned int num_chars = ctx->cfg->num_chars; /* update the current message string */ for (i = 0; i < num_chars;) { /* copy as many characters from the string as possible */ for (; i < num_chars && ch < ctx->message_len; i++, ch++) ctx->curr[i] = ctx->message[ch]; /* wrap around to the start of the string */ ch = 0; } /* update the LCD */ ctx->cfg->update(ctx); /* move on to the next character */ ctx->scroll_pos++; ctx->scroll_pos %= ctx->message_len; /* rearm the timer */ if (ctx->message_len > ctx->cfg->num_chars) mod_timer(&ctx->timer, jiffies + ctx->scroll_rate); } /** * img_ascii_lcd_display() - set the message to be displayed * @ctx: pointer to the private data structure * @msg: the message to display * @count: length of msg, or -1 * * Display a new message @msg on the LCD. @msg can be longer than the number of * characters the LCD can display, in which case it will begin scrolling across * the LCD display. * * Return: 0 on success, -ENOMEM on memory allocation failure */ static int img_ascii_lcd_display(struct img_ascii_lcd_ctx *ctx, const char *msg, ssize_t count) { char *new_msg; /* stop the scroll timer */ del_timer_sync(&ctx->timer); if (count == -1) count = strlen(msg); /* if the string ends with a newline, trim it */ if (msg[count - 1] == '\n') count--; if (!count) { /* clear the LCD */ devm_kfree(&ctx->pdev->dev, ctx->message); ctx->message = NULL; ctx->message_len = 0; memset(ctx->curr, ' ', ctx->cfg->num_chars); ctx->cfg->update(ctx); return 0; } new_msg = devm_kmalloc(&ctx->pdev->dev, count + 1, GFP_KERNEL); if (!new_msg) return -ENOMEM; memcpy(new_msg, msg, count); new_msg[count] = 0; if (ctx->message) devm_kfree(&ctx->pdev->dev, ctx->message); ctx->message = new_msg; ctx->message_len = count; ctx->scroll_pos = 0; /* update the LCD */ img_ascii_lcd_scroll((unsigned long)ctx); return 0; } /** * message_show() - read message via sysfs * @dev: the LCD device * @attr: the LCD message attribute * @buf: the buffer to read the message into * * Read the current message being displayed or scrolled across the LCD display * into @buf, for reads from sysfs. * * Return: the number of characters written to @buf */ static ssize_t message_show(struct device *dev, struct device_attribute *attr, char *buf) { struct img_ascii_lcd_ctx *ctx = dev_get_drvdata(dev); return sprintf(buf, "%s\n", ctx->message); } /** * message_store() - write a new message via sysfs * @dev: the LCD device * @attr: the LCD message attribute * @buf: the buffer containing the new message * @count: the size of the message in @buf * * Write a new message to display or scroll across the LCD display from sysfs. * * Return: the size of the message on success, else -ERRNO */ static ssize_t message_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct img_ascii_lcd_ctx *ctx = dev_get_drvdata(dev); int err; err = img_ascii_lcd_display(ctx, buf, count); return err ?: count; } static DEVICE_ATTR_RW(message); /** * img_ascii_lcd_probe() - probe an LCD display device * @pdev: the LCD platform device * * Probe an LCD display device, ensuring that we have the required resources in * order to access the LCD & setting up private data as well as sysfs files. * * Return: 0 on success, else -ERRNO */ static int img_ascii_lcd_probe(struct platform_device *pdev) { const struct of_device_id *match; const struct img_ascii_lcd_config *cfg; struct img_ascii_lcd_ctx *ctx; struct resource *res; int err; match = of_match_device(img_ascii_lcd_matches, &pdev->dev); if (!match) return -ENODEV; cfg = match->data; ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx) + cfg->num_chars, GFP_KERNEL); if (!ctx) return -ENOMEM; if (cfg->external_regmap) { ctx->regmap = syscon_node_to_regmap(pdev->dev.parent->of_node); if (IS_ERR(ctx->regmap)) return PTR_ERR(ctx->regmap); if (of_property_read_u32(pdev->dev.of_node, "offset", &ctx->offset)) return -EINVAL; } else { res = platform_get_resource(pdev, IORESOURCE_MEM, 0); ctx->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(ctx->base)) return PTR_ERR(ctx->base); } ctx->pdev = pdev; ctx->cfg = cfg; ctx->message = NULL; ctx->scroll_pos = 0; ctx->scroll_rate = HZ / 2; /* initialise a timer for scrolling the message */ init_timer(&ctx->timer); ctx->timer.function = img_ascii_lcd_scroll; ctx->timer.data = (unsigned long)ctx; platform_set_drvdata(pdev, ctx); /* display a default message */ err = img_ascii_lcd_display(ctx, "Linux " UTS_RELEASE " ", -1); if (err) goto out_del_timer; err = device_create_file(&pdev->dev, &dev_attr_message); if (err) goto out_del_timer; return 0; out_del_timer: del_timer_sync(&ctx->timer); return err; } /** * img_ascii_lcd_remove() - remove an LCD display device * @pdev: the LCD platform device * * Remove an LCD display device, freeing private resources & ensuring that the * driver stops using the LCD display registers. * * Return: 0 */ static int img_ascii_lcd_remove(struct platform_device *pdev) { struct img_ascii_lcd_ctx *ctx = platform_get_drvdata(pdev); device_remove_file(&pdev->dev, &dev_attr_message); del_timer_sync(&ctx->timer); return 0; } static struct platform_driver img_ascii_lcd_driver = { .driver = { .name = "img-ascii-lcd", .of_match_table = img_ascii_lcd_matches, }, .probe = img_ascii_lcd_probe, .remove = img_ascii_lcd_remove, }; module_platform_driver(img_ascii_lcd_driver); MODULE_DESCRIPTION("Imagination Technologies ASCII LCD Display"); MODULE_AUTHOR("Paul Burton "); MODULE_LICENSE("GPL");