diff options
Diffstat (limited to 'drivers/auxdisplay/img-ascii-lcd.c')
| -rw-r--r-- | drivers/auxdisplay/img-ascii-lcd.c | 306 |
1 files changed, 306 insertions, 0 deletions
diff --git a/drivers/auxdisplay/img-ascii-lcd.c b/drivers/auxdisplay/img-ascii-lcd.c new file mode 100644 index 000000000..fa23e415f --- /dev/null +++ b/drivers/auxdisplay/img-ascii-lcd.c @@ -0,0 +1,306 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2016 Imagination Technologies + * Author: Paul Burton <paul.burton@mips.com> + */ + +#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 "line-display.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 linedisp *linedisp); +}; + +/** + * struct img_ascii_lcd_ctx - Private data structure + * @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 + * @linedisp: line display structure + * @curr: the string currently displayed on the LCD + */ +struct img_ascii_lcd_ctx { + union { + void __iomem *base; + struct regmap *regmap; + }; + u32 offset; + const struct img_ascii_lcd_config *cfg; + struct linedisp linedisp; + char curr[] __aligned(8); +}; + +/* + * MIPS Boston development board + */ + +static void boston_update(struct linedisp *linedisp) +{ + struct img_ascii_lcd_ctx *ctx = + container_of(linedisp, struct img_ascii_lcd_ctx, linedisp); + 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 linedisp *linedisp) +{ + struct img_ascii_lcd_ctx *ctx = + container_of(linedisp, struct img_ascii_lcd_ctx, linedisp); + unsigned int i; + int err = 0; + + for (i = 0; i < linedisp->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 linedisp *linedisp) +{ + struct img_ascii_lcd_ctx *ctx = + container_of(linedisp, struct img_ascii_lcd_ctx, linedisp); + unsigned int i; + int err = 0; + + for (i = 0; i < linedisp->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 */ } +}; +MODULE_DEVICE_TABLE(of, img_ascii_lcd_matches); + +/** + * 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 device *dev = &pdev->dev; + struct img_ascii_lcd_ctx *ctx; + int err; + + match = of_match_device(img_ascii_lcd_matches, dev); + if (!match) + return -ENODEV; + + cfg = match->data; + ctx = devm_kzalloc(dev, sizeof(*ctx) + cfg->num_chars, GFP_KERNEL); + if (!ctx) + return -ENOMEM; + + if (cfg->external_regmap) { + ctx->regmap = syscon_node_to_regmap(dev->parent->of_node); + if (IS_ERR(ctx->regmap)) + return PTR_ERR(ctx->regmap); + + if (of_property_read_u32(dev->of_node, "offset", &ctx->offset)) + return -EINVAL; + } else { + ctx->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(ctx->base)) + return PTR_ERR(ctx->base); + } + + err = linedisp_register(&ctx->linedisp, dev, cfg->num_chars, ctx->curr, + cfg->update); + if (err) + return err; + + /* for backwards compatibility */ + err = compat_only_sysfs_link_entry_to_kobj(&dev->kobj, + &ctx->linedisp.dev.kobj, + "message", NULL); + if (err) + goto err_unregister; + + platform_set_drvdata(pdev, ctx); + return 0; + +err_unregister: + linedisp_unregister(&ctx->linedisp); + 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); + + sysfs_remove_link(&pdev->dev.kobj, "message"); + linedisp_unregister(&ctx->linedisp); + 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 <paul.burton@mips.com>"); +MODULE_LICENSE("GPL"); |