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