1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * MIPI Camera Control Interface (CCI) register access helpers.
4 *
5 * Copyright (C) 2023 Hans de Goede <hansg@kernel.org>
6 */
7
8 #include <linux/bitfield.h>
9 #include <linux/delay.h>
10 #include <linux/dev_printk.h>
11 #include <linux/module.h>
12 #include <linux/regmap.h>
13 #include <linux/types.h>
14
15 #include <asm/unaligned.h>
16
17 #include <media/v4l2-cci.h>
18
cci_read(struct regmap * map,u32 reg,u64 * val,int * err)19 int cci_read(struct regmap *map, u32 reg, u64 *val, int *err)
20 {
21 bool little_endian;
22 unsigned int len;
23 u8 buf[8];
24 int ret;
25
26 /*
27 * TODO: Fix smatch. Assign *val to 0 here in order to avoid
28 * failing a smatch check on caller when the caller proceeds to
29 * read *val without initialising it on caller's side. *val is set
30 * to a valid value whenever this function returns 0 but smatch
31 * can't figure that out currently.
32 */
33 *val = 0;
34
35 if (err && *err)
36 return *err;
37
38 little_endian = reg & CCI_REG_LE;
39 len = CCI_REG_WIDTH_BYTES(reg);
40 reg = CCI_REG_ADDR(reg);
41
42 ret = regmap_bulk_read(map, reg, buf, len);
43 if (ret) {
44 dev_err(regmap_get_device(map), "Error reading reg 0x%04x: %d\n",
45 reg, ret);
46 goto out;
47 }
48
49 switch (len) {
50 case 1:
51 *val = buf[0];
52 break;
53 case 2:
54 if (little_endian)
55 *val = get_unaligned_le16(buf);
56 else
57 *val = get_unaligned_be16(buf);
58 break;
59 case 3:
60 if (little_endian)
61 *val = get_unaligned_le24(buf);
62 else
63 *val = get_unaligned_be24(buf);
64 break;
65 case 4:
66 if (little_endian)
67 *val = get_unaligned_le32(buf);
68 else
69 *val = get_unaligned_be32(buf);
70 break;
71 case 8:
72 if (little_endian)
73 *val = get_unaligned_le64(buf);
74 else
75 *val = get_unaligned_be64(buf);
76 break;
77 default:
78 dev_err(regmap_get_device(map), "Error invalid reg-width %u for reg 0x%04x\n",
79 len, reg);
80 ret = -EINVAL;
81 break;
82 }
83
84 out:
85 if (ret && err)
86 *err = ret;
87
88 return ret;
89 }
90 EXPORT_SYMBOL_GPL(cci_read);
91
cci_write(struct regmap * map,u32 reg,u64 val,int * err)92 int cci_write(struct regmap *map, u32 reg, u64 val, int *err)
93 {
94 bool little_endian;
95 unsigned int len;
96 u8 buf[8];
97 int ret;
98
99 if (err && *err)
100 return *err;
101
102 little_endian = reg & CCI_REG_LE;
103 len = CCI_REG_WIDTH_BYTES(reg);
104 reg = CCI_REG_ADDR(reg);
105
106 switch (len) {
107 case 1:
108 buf[0] = val;
109 break;
110 case 2:
111 if (little_endian)
112 put_unaligned_le16(val, buf);
113 else
114 put_unaligned_be16(val, buf);
115 break;
116 case 3:
117 if (little_endian)
118 put_unaligned_le24(val, buf);
119 else
120 put_unaligned_be24(val, buf);
121 break;
122 case 4:
123 if (little_endian)
124 put_unaligned_le32(val, buf);
125 else
126 put_unaligned_be32(val, buf);
127 break;
128 case 8:
129 if (little_endian)
130 put_unaligned_le64(val, buf);
131 else
132 put_unaligned_be64(val, buf);
133 break;
134 default:
135 dev_err(regmap_get_device(map), "Error invalid reg-width %u for reg 0x%04x\n",
136 len, reg);
137 ret = -EINVAL;
138 goto out;
139 }
140
141 ret = regmap_bulk_write(map, reg, buf, len);
142 if (ret)
143 dev_err(regmap_get_device(map), "Error writing reg 0x%04x: %d\n",
144 reg, ret);
145
146 out:
147 if (ret && err)
148 *err = ret;
149
150 return ret;
151 }
152 EXPORT_SYMBOL_GPL(cci_write);
153
cci_update_bits(struct regmap * map,u32 reg,u64 mask,u64 val,int * err)154 int cci_update_bits(struct regmap *map, u32 reg, u64 mask, u64 val, int *err)
155 {
156 u64 readval;
157 int ret;
158
159 ret = cci_read(map, reg, &readval, err);
160 if (ret)
161 return ret;
162
163 val = (readval & ~mask) | (val & mask);
164
165 return cci_write(map, reg, val, err);
166 }
167 EXPORT_SYMBOL_GPL(cci_update_bits);
168
cci_multi_reg_write(struct regmap * map,const struct cci_reg_sequence * regs,unsigned int num_regs,int * err)169 int cci_multi_reg_write(struct regmap *map, const struct cci_reg_sequence *regs,
170 unsigned int num_regs, int *err)
171 {
172 unsigned int i;
173 int ret;
174
175 for (i = 0; i < num_regs; i++) {
176 ret = cci_write(map, regs[i].reg, regs[i].val, err);
177 if (ret)
178 return ret;
179 }
180
181 return 0;
182 }
183 EXPORT_SYMBOL_GPL(cci_multi_reg_write);
184
185 #if IS_ENABLED(CONFIG_V4L2_CCI_I2C)
devm_cci_regmap_init_i2c(struct i2c_client * client,int reg_addr_bits)186 struct regmap *devm_cci_regmap_init_i2c(struct i2c_client *client,
187 int reg_addr_bits)
188 {
189 struct regmap_config config = {
190 .reg_bits = reg_addr_bits,
191 .val_bits = 8,
192 .reg_format_endian = REGMAP_ENDIAN_BIG,
193 .disable_locking = true,
194 };
195
196 return devm_regmap_init_i2c(client, &config);
197 }
198 EXPORT_SYMBOL_GPL(devm_cci_regmap_init_i2c);
199 #endif
200
201 MODULE_LICENSE("GPL");
202 MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>");
203 MODULE_DESCRIPTION("MIPI Camera Control Interface (CCI) support");
204