1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Copyright (C) 2019 IBM Corp. */
3
4 /* Pieces to enable drivers to implement the .set callback */
5
6 #include "pinmux-aspeed.h"
7
8 static const char *const aspeed_pinmux_ips[] = {
9 [ASPEED_IP_SCU] = "SCU",
10 [ASPEED_IP_GFX] = "GFX",
11 [ASPEED_IP_LPC] = "LPC",
12 };
13
14 static inline void aspeed_sig_desc_print_val(
15 const struct aspeed_sig_desc *desc, bool enable, u32 rv)
16 {
17 pr_debug("Want %s%X[0x%08X]=0x%X, got 0x%X from 0x%08X\n",
18 aspeed_pinmux_ips[desc->ip], desc->reg,
19 desc->mask, enable ? desc->enable : desc->disable,
20 (rv & desc->mask) >> __ffs(desc->mask), rv);
21 }
22
23 /**
24 * Query the enabled or disabled state of a signal descriptor
25 *
26 * @desc: The signal descriptor of interest
27 * @enabled: True to query the enabled state, false to query disabled state
28 * @map: The IP block's regmap instance
29 *
30 * Return: 1 if the descriptor's bitfield is configured to the state
31 * selected by @enabled, 0 if not, and less than zero if an unrecoverable
32 * failure occurred
33 *
34 * Evaluation of descriptor state is non-trivial in that it is not a binary
35 * outcome: The bitfields can be greater than one bit in size and thus can take
36 * a value that is neither the enabled nor disabled state recorded in the
37 * descriptor (typically this means a different function to the one of interest
38 * is enabled). Thus we must explicitly test for either condition as required.
39 */
40 int aspeed_sig_desc_eval(const struct aspeed_sig_desc *desc,
41 bool enabled, struct regmap *map)
42 {
43 int ret;
44 unsigned int raw;
45 u32 want;
46
47 if (!map)
48 return -ENODEV;
49
50 ret = regmap_read(map, desc->reg, &raw);
51 if (ret)
52 return ret;
53
54 aspeed_sig_desc_print_val(desc, enabled, raw);
55 want = enabled ? desc->enable : desc->disable;
56
57 return ((raw & desc->mask) >> __ffs(desc->mask)) == want;
58 }
59
60 /**
61 * Query the enabled or disabled state for a mux function's signal on a pin
62 *
63 * @ctx: The driver context for the pinctrl IP
64 * @expr: An expression controlling the signal for a mux function on a pin
65 * @enabled: True to query the enabled state, false to query disabled state
66 *
67 * Return: 1 if the expression composed by @enabled evaluates true, 0 if not,
68 * and less than zero if an unrecoverable failure occurred.
69 *
70 * A mux function is enabled or disabled if the function's signal expression
71 * for each pin in the function's pin group evaluates true for the desired
72 * state. An signal expression evaluates true if all of its associated signal
73 * descriptors evaluate true for the desired state.
74 *
75 * If an expression's state is described by more than one bit, either through
76 * multi-bit bitfields in a single signal descriptor or through multiple signal
77 * descriptors of a single bit then it is possible for the expression to be in
78 * neither the enabled nor disabled state. Thus we must explicitly test for
79 * either condition as required.
80 */
81 int aspeed_sig_expr_eval(struct aspeed_pinmux_data *ctx,
82 const struct aspeed_sig_expr *expr, bool enabled)
83 {
84 int ret;
85 int i;
86
87 if (ctx->ops->eval)
88 return ctx->ops->eval(ctx, expr, enabled);
89
90 for (i = 0; i < expr->ndescs; i++) {
91 const struct aspeed_sig_desc *desc = &expr->descs[i];
92
93 ret = aspeed_sig_desc_eval(desc, enabled, ctx->maps[desc->ip]);
94 if (ret <= 0)
95 return ret;
96 }
97
98 return 1;
99 }