1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2016 Imagination Technologies
4 * Author: Paul Burton <paul.burton@mips.com>
5 */
6
7#include <linux/kernel.h>
8#include <linux/io.h>
9#include <linux/mfd/syscon.h>
10#include <linux/module.h>
11#include <linux/of.h>
12#include <linux/platform_device.h>
13#include <linux/property.h>
14#include <linux/regmap.h>
15#include <linux/slab.h>
16
17#include "line-display.h"
18
19struct img_ascii_lcd_ctx;
20
21/**
22 * struct img_ascii_lcd_config - Configuration information about an LCD model
23 * @num_chars: the number of characters the LCD can display
24 * @external_regmap: true if registers are in a system controller, else false
25 * @ops: character line display operations
26 */
27struct img_ascii_lcd_config {
28	unsigned int num_chars;
29	bool external_regmap;
30	const struct linedisp_ops ops;
31};
32
33/**
34 * struct img_ascii_lcd_ctx - Private data structure
35 * @linedisp: line display structure
36 * @base: the base address of the LCD registers
37 * @regmap: the regmap through which LCD registers are accessed
38 * @offset: the offset within regmap to the start of the LCD registers
39 * @cfg: pointer to the LCD model configuration
40 */
41struct img_ascii_lcd_ctx {
42	struct linedisp linedisp;
43	union {
44		void __iomem *base;
45		struct regmap *regmap;
46	};
47	u32 offset;
48	const struct img_ascii_lcd_config *cfg;
49};
50
51/*
52 * MIPS Boston development board
53 */
54
55static void boston_update(struct linedisp *linedisp)
56{
57	struct img_ascii_lcd_ctx *ctx =
58		container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
59	ulong val;
60
61#if BITS_PER_LONG == 64
62	val = *((u64 *)&linedisp->buf[0]);
63	__raw_writeq(val, ctx->base);
64#elif BITS_PER_LONG == 32
65	val = *((u32 *)&linedisp->buf[0]);
66	__raw_writel(val, ctx->base);
67	val = *((u32 *)&linedisp->buf[4]);
68	__raw_writel(val, ctx->base + 4);
69#else
70# error Not 32 or 64 bit
71#endif
72}
73
74static struct img_ascii_lcd_config boston_config = {
75	.num_chars = 8,
76	.ops = {
77		.update = boston_update,
78	},
79};
80
81/*
82 * MIPS Malta development board
83 */
84
85static void malta_update(struct linedisp *linedisp)
86{
87	struct img_ascii_lcd_ctx *ctx =
88		container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
89	unsigned int i;
90	int err = 0;
91
92	for (i = 0; i < linedisp->num_chars; i++) {
93		err = regmap_write(ctx->regmap,
94				   ctx->offset + (i * 8), linedisp->buf[i]);
95		if (err)
96			break;
97	}
98
99	if (unlikely(err))
100		pr_err_ratelimited("Failed to update LCD display: %d\n", err);
101}
102
103static struct img_ascii_lcd_config malta_config = {
104	.num_chars = 8,
105	.external_regmap = true,
106	.ops = {
107		.update = malta_update,
108	},
109};
110
111/*
112 * MIPS SEAD3 development board
113 */
114
115enum {
116	SEAD3_REG_LCD_CTRL		= 0x00,
117#define SEAD3_REG_LCD_CTRL_SETDRAM	BIT(7)
118	SEAD3_REG_LCD_DATA		= 0x08,
119	SEAD3_REG_CPLD_STATUS		= 0x10,
120#define SEAD3_REG_CPLD_STATUS_BUSY	BIT(0)
121	SEAD3_REG_CPLD_DATA		= 0x18,
122#define SEAD3_REG_CPLD_DATA_BUSY	BIT(7)
123};
124
125static int sead3_wait_sm_idle(struct img_ascii_lcd_ctx *ctx)
126{
127	unsigned int status;
128	int err;
129
130	do {
131		err = regmap_read(ctx->regmap,
132				  ctx->offset + SEAD3_REG_CPLD_STATUS,
133				  &status);
134		if (err)
135			return err;
136	} while (status & SEAD3_REG_CPLD_STATUS_BUSY);
137
138	return 0;
139
140}
141
142static int sead3_wait_lcd_idle(struct img_ascii_lcd_ctx *ctx)
143{
144	unsigned int cpld_data;
145	int err;
146
147	err = sead3_wait_sm_idle(ctx);
148	if (err)
149		return err;
150
151	do {
152		err = regmap_read(ctx->regmap,
153				  ctx->offset + SEAD3_REG_LCD_CTRL,
154				  &cpld_data);
155		if (err)
156			return err;
157
158		err = sead3_wait_sm_idle(ctx);
159		if (err)
160			return err;
161
162		err = regmap_read(ctx->regmap,
163				  ctx->offset + SEAD3_REG_CPLD_DATA,
164				  &cpld_data);
165		if (err)
166			return err;
167	} while (cpld_data & SEAD3_REG_CPLD_DATA_BUSY);
168
169	return 0;
170}
171
172static void sead3_update(struct linedisp *linedisp)
173{
174	struct img_ascii_lcd_ctx *ctx =
175		container_of(linedisp, struct img_ascii_lcd_ctx, linedisp);
176	unsigned int i;
177	int err = 0;
178
179	for (i = 0; i < linedisp->num_chars; i++) {
180		err = sead3_wait_lcd_idle(ctx);
181		if (err)
182			break;
183
184		err = regmap_write(ctx->regmap,
185				   ctx->offset + SEAD3_REG_LCD_CTRL,
186				   SEAD3_REG_LCD_CTRL_SETDRAM | i);
187		if (err)
188			break;
189
190		err = sead3_wait_lcd_idle(ctx);
191		if (err)
192			break;
193
194		err = regmap_write(ctx->regmap,
195				   ctx->offset + SEAD3_REG_LCD_DATA,
196				   linedisp->buf[i]);
197		if (err)
198			break;
199	}
200
201	if (unlikely(err))
202		pr_err_ratelimited("Failed to update LCD display: %d\n", err);
203}
204
205static struct img_ascii_lcd_config sead3_config = {
206	.num_chars = 16,
207	.external_regmap = true,
208	.ops = {
209		.update = sead3_update,
210	},
211};
212
213static const struct of_device_id img_ascii_lcd_matches[] = {
214	{ .compatible = "img,boston-lcd", .data = &boston_config },
215	{ .compatible = "mti,malta-lcd", .data = &malta_config },
216	{ .compatible = "mti,sead3-lcd", .data = &sead3_config },
217	{ /* sentinel */ }
218};
219MODULE_DEVICE_TABLE(of, img_ascii_lcd_matches);
220
221/**
222 * img_ascii_lcd_probe() - probe an LCD display device
223 * @pdev: the LCD platform device
224 *
225 * Probe an LCD display device, ensuring that we have the required resources in
226 * order to access the LCD & setting up private data as well as sysfs files.
227 *
228 * Return: 0 on success, else -ERRNO
229 */
230static int img_ascii_lcd_probe(struct platform_device *pdev)
231{
232	struct device *dev = &pdev->dev;
233	const struct img_ascii_lcd_config *cfg = device_get_match_data(dev);
234	struct img_ascii_lcd_ctx *ctx;
235	int err;
236
237	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
238	if (!ctx)
239		return -ENOMEM;
240
241	if (cfg->external_regmap) {
242		ctx->regmap = syscon_node_to_regmap(dev->parent->of_node);
243		if (IS_ERR(ctx->regmap))
244			return PTR_ERR(ctx->regmap);
245
246		if (of_property_read_u32(dev->of_node, "offset", &ctx->offset))
247			return -EINVAL;
248	} else {
249		ctx->base = devm_platform_ioremap_resource(pdev, 0);
250		if (IS_ERR(ctx->base))
251			return PTR_ERR(ctx->base);
252	}
253
254	err = linedisp_register(&ctx->linedisp, dev, cfg->num_chars, &cfg->ops);
255	if (err)
256		return err;
257
258	/* for backwards compatibility */
259	err = compat_only_sysfs_link_entry_to_kobj(&dev->kobj,
260						   &ctx->linedisp.dev.kobj,
261						   "message", NULL);
262	if (err)
263		goto err_unregister;
264
265	platform_set_drvdata(pdev, ctx);
266	return 0;
267
268err_unregister:
269	linedisp_unregister(&ctx->linedisp);
270	return err;
271}
272
273/**
274 * img_ascii_lcd_remove() - remove an LCD display device
275 * @pdev: the LCD platform device
276 *
277 * Remove an LCD display device, freeing private resources & ensuring that the
278 * driver stops using the LCD display registers.
279 */
280static void img_ascii_lcd_remove(struct platform_device *pdev)
281{
282	struct img_ascii_lcd_ctx *ctx = platform_get_drvdata(pdev);
283
284	sysfs_remove_link(&pdev->dev.kobj, "message");
285	linedisp_unregister(&ctx->linedisp);
286}
287
288static struct platform_driver img_ascii_lcd_driver = {
289	.driver = {
290		.name		= "img-ascii-lcd",
291		.of_match_table	= img_ascii_lcd_matches,
292	},
293	.probe	= img_ascii_lcd_probe,
294	.remove_new = img_ascii_lcd_remove,
295};
296module_platform_driver(img_ascii_lcd_driver);
297
298MODULE_DESCRIPTION("Imagination Technologies ASCII LCD Display");
299MODULE_AUTHOR("Paul Burton <paul.burton@mips.com>");
300MODULE_LICENSE("GPL");
301MODULE_IMPORT_NS(LINEDISP);
302