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![Geert Uytterhoeven](/assets/img/avatar_default.png)
Extract the character line display core support from the simple ASCII LCD driver for the MIPS Boston, Malta & SEAD3 development boards into its own subdriver, so it can be reused for other displays. As this moves the "message" device attribute in sysfs in a "linedisp.N" subdirectory, a symlink is added to preserve backwards compatibility. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
306 lines
7 KiB
C
306 lines
7 KiB
C
// 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 <paul.burton@mips.com>
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*/
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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 "line-display.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 linedisp *linedisp);
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};
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/**
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* struct img_ascii_lcd_ctx - Private data structure
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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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* @linedisp: line display structure
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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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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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struct linedisp linedisp;
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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 linedisp *linedisp)
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{
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struct img_ascii_lcd_ctx *ctx =
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container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
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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 linedisp *linedisp)
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{
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struct img_ascii_lcd_ctx *ctx =
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container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
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unsigned int i;
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int err = 0;
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for (i = 0; i < linedisp->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 linedisp *linedisp)
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{
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struct img_ascii_lcd_ctx *ctx =
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container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
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unsigned int i;
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int err = 0;
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for (i = 0; i < linedisp->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_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 device *dev = &pdev->dev;
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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, 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(dev, sizeof(*ctx) + cfg->num_chars, 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(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(dev->of_node, "offset", &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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err = linedisp_register(&ctx->linedisp, dev, cfg->num_chars, ctx->curr,
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cfg->update);
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if (err)
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return err;
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/* for backwards compatibility */
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err = compat_only_sysfs_link_entry_to_kobj(&dev->kobj,
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&ctx->linedisp.dev.kobj,
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"message", NULL);
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if (err)
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goto err_unregister;
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platform_set_drvdata(pdev, ctx);
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return 0;
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err_unregister:
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linedisp_unregister(&ctx->linedisp);
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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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sysfs_remove_link(&pdev->dev.kobj, "message");
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linedisp_unregister(&ctx->linedisp);
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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 <paul.burton@mips.com>");
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MODULE_LICENSE("GPL");
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