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
19 struct 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 */
27 struct 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 */
41 struct 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
boston_update(struct linedisp * linedisp)55 static 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
74 static 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
malta_update(struct linedisp * linedisp)85 static 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
103 static 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
115 enum {
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
sead3_wait_sm_idle(struct img_ascii_lcd_ctx * ctx)125 static 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
sead3_wait_lcd_idle(struct img_ascii_lcd_ctx * ctx)142 static 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
sead3_update(struct linedisp * linedisp)172 static 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
205 static struct img_ascii_lcd_config sead3_config = {
206 .num_chars = 16,
207 .external_regmap = true,
208 .ops = {
209 .update = sead3_update,
210 },
211 };
212
213 static 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 };
219 MODULE_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 */
img_ascii_lcd_probe(struct platform_device * pdev)230 static 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
268 err_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 */
img_ascii_lcd_remove(struct platform_device * pdev)280 static 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
288 static 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 };
296 module_platform_driver(img_ascii_lcd_driver);
297
298 MODULE_DESCRIPTION("Imagination Technologies ASCII LCD Display");
299 MODULE_AUTHOR("Paul Burton <paul.burton@mips.com>");
300 MODULE_LICENSE("GPL");
301 MODULE_IMPORT_NS(LINEDISP);
302