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441 lines
10 KiB
441 lines
10 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Copyright (C) 2016 Imagination Technologies |
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* Author: Paul Burton <[email protected]> |
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*/ |
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#include <generated/utsrelease.h> |
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#include <linux/kernel.h> |
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#include <linux/io.h> |
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#include <linux/mfd/syscon.h> |
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#include <linux/module.h> |
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#include <linux/of_address.h> |
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#include <linux/of_platform.h> |
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#include <linux/platform_device.h> |
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#include <linux/regmap.h> |
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#include <linux/slab.h> |
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#include <linux/sysfs.h> |
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struct img_ascii_lcd_ctx; |
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/** |
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* struct img_ascii_lcd_config - Configuration information about an LCD model |
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* @num_chars: the number of characters the LCD can display |
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* @external_regmap: true if registers are in a system controller, else false |
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* @update: function called to update the LCD |
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*/ |
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struct img_ascii_lcd_config { |
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unsigned int num_chars; |
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bool external_regmap; |
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void (*update)(struct img_ascii_lcd_ctx *ctx); |
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}; |
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/** |
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* struct img_ascii_lcd_ctx - Private data structure |
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* @pdev: the ASCII LCD platform device |
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* @base: the base address of the LCD registers |
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* @regmap: the regmap through which LCD registers are accessed |
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* @offset: the offset within regmap to the start of the LCD registers |
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* @cfg: pointer to the LCD model configuration |
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* @message: the full message to display or scroll on the LCD |
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* @message_len: the length of the @message string |
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* @scroll_pos: index of the first character of @message currently displayed |
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* @scroll_rate: scroll interval in jiffies |
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* @timer: timer used to implement scrolling |
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* @curr: the string currently displayed on the LCD |
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*/ |
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struct img_ascii_lcd_ctx { |
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struct platform_device *pdev; |
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union { |
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void __iomem *base; |
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struct regmap *regmap; |
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}; |
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u32 offset; |
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const struct img_ascii_lcd_config *cfg; |
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char *message; |
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unsigned int message_len; |
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unsigned int scroll_pos; |
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unsigned int scroll_rate; |
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struct timer_list timer; |
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char curr[] __aligned(8); |
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}; |
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/* |
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* MIPS Boston development board |
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*/ |
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static void boston_update(struct img_ascii_lcd_ctx *ctx) |
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{ |
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ulong val; |
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#if BITS_PER_LONG == 64 |
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val = *((u64 *)&ctx->curr[0]); |
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__raw_writeq(val, ctx->base); |
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#elif BITS_PER_LONG == 32 |
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val = *((u32 *)&ctx->curr[0]); |
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__raw_writel(val, ctx->base); |
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val = *((u32 *)&ctx->curr[4]); |
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__raw_writel(val, ctx->base + 4); |
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#else |
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# error Not 32 or 64 bit |
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#endif |
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} |
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static struct img_ascii_lcd_config boston_config = { |
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.num_chars = 8, |
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.update = boston_update, |
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}; |
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/* |
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* MIPS Malta development board |
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*/ |
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static void malta_update(struct img_ascii_lcd_ctx *ctx) |
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{ |
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unsigned int i; |
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int err = 0; |
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for (i = 0; i < ctx->cfg->num_chars; i++) { |
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err = regmap_write(ctx->regmap, |
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ctx->offset + (i * 8), ctx->curr[i]); |
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if (err) |
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break; |
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} |
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if (unlikely(err)) |
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pr_err_ratelimited("Failed to update LCD display: %d\n", err); |
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} |
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static struct img_ascii_lcd_config malta_config = { |
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.num_chars = 8, |
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.external_regmap = true, |
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.update = malta_update, |
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}; |
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/* |
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* MIPS SEAD3 development board |
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*/ |
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enum { |
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SEAD3_REG_LCD_CTRL = 0x00, |
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#define SEAD3_REG_LCD_CTRL_SETDRAM BIT(7) |
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SEAD3_REG_LCD_DATA = 0x08, |
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SEAD3_REG_CPLD_STATUS = 0x10, |
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#define SEAD3_REG_CPLD_STATUS_BUSY BIT(0) |
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SEAD3_REG_CPLD_DATA = 0x18, |
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#define SEAD3_REG_CPLD_DATA_BUSY BIT(7) |
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}; |
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static int sead3_wait_sm_idle(struct img_ascii_lcd_ctx *ctx) |
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{ |
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unsigned int status; |
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int err; |
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do { |
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err = regmap_read(ctx->regmap, |
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ctx->offset + SEAD3_REG_CPLD_STATUS, |
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&status); |
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if (err) |
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return err; |
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} while (status & SEAD3_REG_CPLD_STATUS_BUSY); |
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return 0; |
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} |
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static int sead3_wait_lcd_idle(struct img_ascii_lcd_ctx *ctx) |
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{ |
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unsigned int cpld_data; |
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int err; |
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err = sead3_wait_sm_idle(ctx); |
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if (err) |
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return err; |
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do { |
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err = regmap_read(ctx->regmap, |
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ctx->offset + SEAD3_REG_LCD_CTRL, |
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&cpld_data); |
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if (err) |
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return err; |
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err = sead3_wait_sm_idle(ctx); |
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if (err) |
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return err; |
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err = regmap_read(ctx->regmap, |
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ctx->offset + SEAD3_REG_CPLD_DATA, |
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&cpld_data); |
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if (err) |
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return err; |
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} while (cpld_data & SEAD3_REG_CPLD_DATA_BUSY); |
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return 0; |
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} |
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static void sead3_update(struct img_ascii_lcd_ctx *ctx) |
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{ |
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unsigned int i; |
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int err = 0; |
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for (i = 0; i < ctx->cfg->num_chars; i++) { |
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err = sead3_wait_lcd_idle(ctx); |
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if (err) |
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break; |
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err = regmap_write(ctx->regmap, |
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ctx->offset + SEAD3_REG_LCD_CTRL, |
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SEAD3_REG_LCD_CTRL_SETDRAM | i); |
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if (err) |
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break; |
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err = sead3_wait_lcd_idle(ctx); |
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if (err) |
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break; |
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err = regmap_write(ctx->regmap, |
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ctx->offset + SEAD3_REG_LCD_DATA, |
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ctx->curr[i]); |
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if (err) |
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break; |
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} |
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if (unlikely(err)) |
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pr_err_ratelimited("Failed to update LCD display: %d\n", err); |
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} |
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static struct img_ascii_lcd_config sead3_config = { |
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.num_chars = 16, |
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.external_regmap = true, |
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.update = sead3_update, |
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}; |
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static const struct of_device_id img_ascii_lcd_matches[] = { |
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{ .compatible = "img,boston-lcd", .data = &boston_config }, |
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{ .compatible = "mti,malta-lcd", .data = &malta_config }, |
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{ .compatible = "mti,sead3-lcd", .data = &sead3_config }, |
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{ /* sentinel */ } |
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}; |
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MODULE_DEVICE_TABLE(of, img_ascii_lcd_matches); |
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/** |
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* img_ascii_lcd_scroll() - scroll the display by a character |
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* @t: really a pointer to the private data structure |
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* |
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* Scroll the current message along the LCD by one character, rearming the |
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* timer if required. |
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*/ |
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static void img_ascii_lcd_scroll(struct timer_list *t) |
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{ |
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struct img_ascii_lcd_ctx *ctx = from_timer(ctx, t, timer); |
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unsigned int i, ch = ctx->scroll_pos; |
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unsigned int num_chars = ctx->cfg->num_chars; |
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/* update the current message string */ |
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for (i = 0; i < num_chars;) { |
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/* copy as many characters from the string as possible */ |
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for (; i < num_chars && ch < ctx->message_len; i++, ch++) |
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ctx->curr[i] = ctx->message[ch]; |
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/* wrap around to the start of the string */ |
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ch = 0; |
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} |
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/* update the LCD */ |
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ctx->cfg->update(ctx); |
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/* move on to the next character */ |
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ctx->scroll_pos++; |
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ctx->scroll_pos %= ctx->message_len; |
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/* rearm the timer */ |
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if (ctx->message_len > ctx->cfg->num_chars) |
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mod_timer(&ctx->timer, jiffies + ctx->scroll_rate); |
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} |
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/** |
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* img_ascii_lcd_display() - set the message to be displayed |
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* @ctx: pointer to the private data structure |
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* @msg: the message to display |
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* @count: length of msg, or -1 |
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* |
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* Display a new message @msg on the LCD. @msg can be longer than the number of |
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* characters the LCD can display, in which case it will begin scrolling across |
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* the LCD display. |
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* |
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* Return: 0 on success, -ENOMEM on memory allocation failure |
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*/ |
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static int img_ascii_lcd_display(struct img_ascii_lcd_ctx *ctx, |
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const char *msg, ssize_t count) |
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{ |
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char *new_msg; |
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/* stop the scroll timer */ |
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del_timer_sync(&ctx->timer); |
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if (count == -1) |
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count = strlen(msg); |
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/* if the string ends with a newline, trim it */ |
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if (msg[count - 1] == '\n') |
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count--; |
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new_msg = devm_kmalloc(&ctx->pdev->dev, count + 1, GFP_KERNEL); |
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if (!new_msg) |
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return -ENOMEM; |
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memcpy(new_msg, msg, count); |
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new_msg[count] = 0; |
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if (ctx->message) |
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devm_kfree(&ctx->pdev->dev, ctx->message); |
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ctx->message = new_msg; |
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ctx->message_len = count; |
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ctx->scroll_pos = 0; |
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/* update the LCD */ |
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img_ascii_lcd_scroll(&ctx->timer); |
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return 0; |
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} |
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/** |
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* message_show() - read message via sysfs |
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* @dev: the LCD device |
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* @attr: the LCD message attribute |
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* @buf: the buffer to read the message into |
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* |
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* Read the current message being displayed or scrolled across the LCD display |
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* into @buf, for reads from sysfs. |
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* |
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* Return: the number of characters written to @buf |
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*/ |
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static ssize_t message_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct img_ascii_lcd_ctx *ctx = dev_get_drvdata(dev); |
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return sprintf(buf, "%s\n", ctx->message); |
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} |
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/** |
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* message_store() - write a new message via sysfs |
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* @dev: the LCD device |
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* @attr: the LCD message attribute |
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* @buf: the buffer containing the new message |
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* @count: the size of the message in @buf |
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* |
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* Write a new message to display or scroll across the LCD display from sysfs. |
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* |
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* Return: the size of the message on success, else -ERRNO |
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*/ |
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static ssize_t message_store(struct device *dev, struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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struct img_ascii_lcd_ctx *ctx = dev_get_drvdata(dev); |
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int err; |
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err = img_ascii_lcd_display(ctx, buf, count); |
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return err ?: count; |
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} |
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static DEVICE_ATTR_RW(message); |
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/** |
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* img_ascii_lcd_probe() - probe an LCD display device |
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* @pdev: the LCD platform device |
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* |
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* Probe an LCD display device, ensuring that we have the required resources in |
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* order to access the LCD & setting up private data as well as sysfs files. |
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* |
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* Return: 0 on success, else -ERRNO |
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*/ |
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static int img_ascii_lcd_probe(struct platform_device *pdev) |
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{ |
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const struct of_device_id *match; |
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const struct img_ascii_lcd_config *cfg; |
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struct img_ascii_lcd_ctx *ctx; |
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int err; |
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match = of_match_device(img_ascii_lcd_matches, &pdev->dev); |
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if (!match) |
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return -ENODEV; |
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cfg = match->data; |
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ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx) + cfg->num_chars, |
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GFP_KERNEL); |
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if (!ctx) |
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return -ENOMEM; |
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if (cfg->external_regmap) { |
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ctx->regmap = syscon_node_to_regmap(pdev->dev.parent->of_node); |
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if (IS_ERR(ctx->regmap)) |
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return PTR_ERR(ctx->regmap); |
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if (of_property_read_u32(pdev->dev.of_node, "offset", |
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&ctx->offset)) |
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return -EINVAL; |
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} else { |
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ctx->base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(ctx->base)) |
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return PTR_ERR(ctx->base); |
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} |
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ctx->pdev = pdev; |
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ctx->cfg = cfg; |
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ctx->message = NULL; |
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ctx->scroll_pos = 0; |
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ctx->scroll_rate = HZ / 2; |
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/* initialise a timer for scrolling the message */ |
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timer_setup(&ctx->timer, img_ascii_lcd_scroll, 0); |
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platform_set_drvdata(pdev, ctx); |
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/* display a default message */ |
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err = img_ascii_lcd_display(ctx, "Linux " UTS_RELEASE " ", -1); |
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if (err) |
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goto out_del_timer; |
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err = device_create_file(&pdev->dev, &dev_attr_message); |
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if (err) |
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goto out_del_timer; |
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return 0; |
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out_del_timer: |
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del_timer_sync(&ctx->timer); |
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return err; |
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} |
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/** |
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* img_ascii_lcd_remove() - remove an LCD display device |
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* @pdev: the LCD platform device |
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* |
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* Remove an LCD display device, freeing private resources & ensuring that the |
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* driver stops using the LCD display registers. |
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* |
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* Return: 0 |
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*/ |
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static int img_ascii_lcd_remove(struct platform_device *pdev) |
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{ |
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struct img_ascii_lcd_ctx *ctx = platform_get_drvdata(pdev); |
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device_remove_file(&pdev->dev, &dev_attr_message); |
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del_timer_sync(&ctx->timer); |
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return 0; |
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} |
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static struct platform_driver img_ascii_lcd_driver = { |
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.driver = { |
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.name = "img-ascii-lcd", |
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.of_match_table = img_ascii_lcd_matches, |
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}, |
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.probe = img_ascii_lcd_probe, |
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.remove = img_ascii_lcd_remove, |
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}; |
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module_platform_driver(img_ascii_lcd_driver); |
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MODULE_DESCRIPTION("Imagination Technologies ASCII LCD Display"); |
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MODULE_AUTHOR("Paul Burton <[email protected]>"); |
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MODULE_LICENSE("GPL");
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