synth.c

 1// SPDX-License-Identifier: GPL-2.0-only
 2
 3#include <linux/bitfield.h>
 4#include <linux/cleanup.h>
 5#include <linux/dev_printk.h>
 6#include <linux/string.h>
 7#include <linux/string_choices.h>
 8#include <linux/types.h>
 9
10#include "core.h"
11#include "synth.h"
12
13/**
14 * zl3073x_synth_state_fetch - fetch synth state from hardware
15 * @zldev: pointer to zl3073x_dev structure
16 * @index: synth index to fetch state for
17 *
18 * Function fetches state of the given synthesizer from the hardware and
19 * stores it for later use.
20 *
21 * Return: 0 on success, <0 on error
22 */
23int zl3073x_synth_state_fetch(struct zl3073x_dev *zldev, u8 index)
24{
25	struct zl3073x_synth *synth = &zldev->synth[index];
26	int rc;
27
28	/* Read synth control register */
29	rc = zl3073x_read_u8(zldev, ZL_REG_SYNTH_CTRL(index), &synth->ctrl);
30	if (rc)
31		return rc;
32
33	guard(mutex)(&zldev->multiop_lock);
34
35	/* Read synth configuration */
36	rc = zl3073x_mb_op(zldev, ZL_REG_SYNTH_MB_SEM, ZL_SYNTH_MB_SEM_RD,
37			   ZL_REG_SYNTH_MB_MASK, BIT(index));
38	if (rc)
39		return rc;
40
41	/* The output frequency is determined by the following formula:
42	 * base * multiplier * numerator / denominator
43	 *
44	 * Read registers with these values
45	 */
46	rc = zl3073x_read_u16(zldev, ZL_REG_SYNTH_FREQ_BASE, &synth->freq_base);
47	if (rc)
48		return rc;
49
50	rc = zl3073x_read_u32(zldev, ZL_REG_SYNTH_FREQ_MULT, &synth->freq_mult);
51	if (rc)
52		return rc;
53
54	rc = zl3073x_read_u16(zldev, ZL_REG_SYNTH_FREQ_M, &synth->freq_m);
55	if (rc)
56		return rc;
57
58	rc = zl3073x_read_u16(zldev, ZL_REG_SYNTH_FREQ_N, &synth->freq_n);
59	if (rc)
60		return rc;
61
62	/* Check denominator for zero to avoid div by 0 */
63	if (!synth->freq_n) {
64		dev_err(zldev->dev,
65			"Zero divisor for SYNTH%u retrieved from device\n",
66			index);
67		return -EINVAL;
68	}
69
70	dev_dbg(zldev->dev, "SYNTH%u frequency: %u Hz\n", index,
71		zl3073x_synth_freq_get(synth));
72
73	return rc;
74}
75
76/**
77 * zl3073x_synth_state_get - get current synth state
78 * @zldev: pointer to zl3073x_dev structure
79 * @index: synth index to get state for
80 *
81 * Return: pointer to given synth state
82 */
83const struct zl3073x_synth *zl3073x_synth_state_get(struct zl3073x_dev *zldev,
84						    u8 index)
85{
86	return &zldev->synth[index];
87}