diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/auxdisplay/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/auxdisplay/Makefile | 1 | ||||
| -rw-r--r-- | drivers/auxdisplay/img-ascii-lcd.c | 443 |
3 files changed, 453 insertions, 0 deletions
diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig index c07e725ea93d..10e1b9eee10e 100644 --- a/drivers/auxdisplay/Kconfig +++ b/drivers/auxdisplay/Kconfig @@ -119,4 +119,13 @@ config CFAG12864B_RATE If you compile this as a module, you can still override this value using the module parameters. +config IMG_ASCII_LCD + tristate "Imagination Technologies ASCII LCD Display" + default y if MIPS_MALTA || MIPS_SEAD3 + select SYSCON + help + Enable this to support the simple ASCII LCD displays found on + development boards such as the MIPS Boston, MIPS Malta & MIPS SEAD3 + from Imagination Technologies. + endif # AUXDISPLAY diff --git a/drivers/auxdisplay/Makefile b/drivers/auxdisplay/Makefile index 8a8936a468b9..3127175c89df 100644 --- a/drivers/auxdisplay/Makefile +++ b/drivers/auxdisplay/Makefile @@ -4,3 +4,4 @@ obj-$(CONFIG_KS0108) += ks0108.o obj-$(CONFIG_CFAG12864B) += cfag12864b.o cfag12864bfb.o +obj-$(CONFIG_IMG_ASCII_LCD) += img-ascii-lcd.o diff --git a/drivers/auxdisplay/img-ascii-lcd.c b/drivers/auxdisplay/img-ascii-lcd.c new file mode 100644 index 000000000000..bf43b5d2aafc --- /dev/null +++ b/drivers/auxdisplay/img-ascii-lcd.c @@ -0,0 +1,443 @@ +/* + * Copyright (C) 2016 Imagination Technologies + * Author: Paul Burton <paul.burton@imgtec.com> + * + * 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 <generated/utsrelease.h> +#include <linux/kernel.h> +#include <linux/io.h> +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/slab.h> +#include <linux/sysfs.h> + +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 }, +}; + +/** + * 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--; + + 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); |