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// 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.h>
#include <linux/platform_device.h>
#include <linux/property.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)
{
struct device *dev = &pdev->dev;
const struct img_ascii_lcd_config *cfg = device_get_match_data(dev);
struct img_ascii_lcd_ctx *ctx;
int err;
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");
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