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 #ifndef _V4L2_CCI_H
8 #define _V4L2_CCI_H
9
10 #include <linux/bitfield.h>
11 #include <linux/bits.h>
12 #include <linux/types.h>
13
14 struct i2c_client;
15 struct regmap;
16
17 /**
18 * struct cci_reg_sequence - An individual write from a sequence of CCI writes
19 *
20 * @reg: Register address, use CCI_REG#() macros to encode reg width
21 * @val: Register value
22 *
23 * Register/value pairs for sequences of writes.
24 */
25 struct cci_reg_sequence {
26 u32 reg;
27 u64 val;
28 };
29
30 /*
31 * Macros to define register address with the register width encoded
32 * into the higher bits.
33 */
34 #define CCI_REG_ADDR_MASK GENMASK(15, 0)
35 #define CCI_REG_WIDTH_SHIFT 16
36 #define CCI_REG_WIDTH_MASK GENMASK(19, 16)
37 /*
38 * Private CCI register flags, for the use of drivers.
39 */
40 #define CCI_REG_PRIVATE_SHIFT 28U
41 #define CCI_REG_PRIVATE_MASK GENMASK(31U, CCI_REG_PRIVATE_SHIFT)
42
43 #define CCI_REG_WIDTH_BYTES(x) FIELD_GET(CCI_REG_WIDTH_MASK, x)
44 #define CCI_REG_WIDTH(x) (CCI_REG_WIDTH_BYTES(x) << 3)
45 #define CCI_REG_ADDR(x) FIELD_GET(CCI_REG_ADDR_MASK, x)
46 #define CCI_REG_LE BIT(20)
47
48 #define CCI_REG8(x) ((1 << CCI_REG_WIDTH_SHIFT) | (x))
49 #define CCI_REG16(x) ((2 << CCI_REG_WIDTH_SHIFT) | (x))
50 #define CCI_REG24(x) ((3 << CCI_REG_WIDTH_SHIFT) | (x))
51 #define CCI_REG32(x) ((4 << CCI_REG_WIDTH_SHIFT) | (x))
52 #define CCI_REG64(x) ((8 << CCI_REG_WIDTH_SHIFT) | (x))
53 #define CCI_REG16_LE(x) (CCI_REG_LE | (2U << CCI_REG_WIDTH_SHIFT) | (x))
54 #define CCI_REG24_LE(x) (CCI_REG_LE | (3U << CCI_REG_WIDTH_SHIFT) | (x))
55 #define CCI_REG32_LE(x) (CCI_REG_LE | (4U << CCI_REG_WIDTH_SHIFT) | (x))
56 #define CCI_REG64_LE(x) (CCI_REG_LE | (8U << CCI_REG_WIDTH_SHIFT) | (x))
57
58 /**
59 * cci_read() - Read a value from a single CCI register
60 *
61 * @map: Register map to read from
62 * @reg: Register address to read, use CCI_REG#() macros to encode reg width
63 * @val: Pointer to store read value
64 * @err: Optional pointer to store errors, if a previous error is set
65 * then the read will be skipped
66 *
67 * Return: %0 on success or a negative error code on failure.
68 */
69 int cci_read(struct regmap *map, u32 reg, u64 *val, int *err);
70
71 /**
72 * cci_write() - Write a value to a single CCI register
73 *
74 * @map: Register map to write to
75 * @reg: Register address to write, use CCI_REG#() macros to encode reg width
76 * @val: Value to be written
77 * @err: Optional pointer to store errors, if a previous error is set
78 * then the write will be skipped
79 *
80 * Return: %0 on success or a negative error code on failure.
81 */
82 int cci_write(struct regmap *map, u32 reg, u64 val, int *err);
83
84 /**
85 * cci_update_bits() - Perform a read/modify/write cycle on
86 * a single CCI register
87 *
88 * @map: Register map to update
89 * @reg: Register address to update, use CCI_REG#() macros to encode reg width
90 * @mask: Bitmask to change
91 * @val: New value for bitmask
92 * @err: Optional pointer to store errors, if a previous error is set
93 * then the update will be skipped
94 *
95 * Note this uses read-modify-write to update the bits, atomicity with regards
96 * to other cci_*() register access functions is NOT guaranteed.
97 *
98 * Return: %0 on success or a negative error code on failure.
99 */
100 int cci_update_bits(struct regmap *map, u32 reg, u64 mask, u64 val, int *err);
101
102 /**
103 * cci_multi_reg_write() - Write multiple registers to the device
104 *
105 * @map: Register map to write to
106 * @regs: Array of structures containing register-address, -value pairs to be
107 * written, register-addresses use CCI_REG#() macros to encode reg width
108 * @num_regs: Number of registers to write
109 * @err: Optional pointer to store errors, if a previous error is set
110 * then the write will be skipped
111 *
112 * Write multiple registers to the device where the set of register, value
113 * pairs are supplied in any order, possibly not all in a single range.
114 *
115 * Use of the CCI_REG#() macros to encode reg width is mandatory.
116 *
117 * For raw lists of register-address, -value pairs with only 8 bit
118 * wide writes regmap_multi_reg_write() can be used instead.
119 *
120 * Return: %0 on success or a negative error code on failure.
121 */
122 int cci_multi_reg_write(struct regmap *map, const struct cci_reg_sequence *regs,
123 unsigned int num_regs, int *err);
124
125 #if IS_ENABLED(CONFIG_V4L2_CCI_I2C)
126 /**
127 * devm_cci_regmap_init_i2c() - Create regmap to use with cci_*() register
128 * access functions
129 *
130 * @client: i2c_client to create the regmap for
131 * @reg_addr_bits: register address width to use (8 or 16)
132 *
133 * Note the memory for the created regmap is devm() managed, tied to the client.
134 *
135 * Return: %0 on success or a negative error code on failure.
136 */
137 struct regmap *devm_cci_regmap_init_i2c(struct i2c_client *client,
138 int reg_addr_bits);
139 #endif
140
141 #endif
142
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