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
aspeed_sig_desc_print_val(const struct aspeed_sig_desc * desc,bool enable,u32 rv)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 * aspeed_sig_desc_eval() - Query the enabled or disabled state of a signal
25 * descriptor.
26 *
27 * @desc: The signal descriptor of interest
28 * @enabled: True to query the enabled state, false to query disabled state
29 * @map: The IP block's regmap instance
30 *
31 * Return: 1 if the descriptor's bitfield is configured to the state
32 * selected by @enabled, 0 if not, and less than zero if an unrecoverable
33 * failure occurred
34 *
35 * Evaluation of descriptor state is non-trivial in that it is not a binary
36 * outcome: The bitfields can be greater than one bit in size and thus can take
37 * a value that is neither the enabled nor disabled state recorded in the
38 * descriptor (typically this means a different function to the one of interest
39 * is enabled). Thus we must explicitly test for either condition as required.
40 */
aspeed_sig_desc_eval(const struct aspeed_sig_desc * desc,bool enabled,struct regmap * map)41 int aspeed_sig_desc_eval(const struct aspeed_sig_desc *desc,
42 bool enabled, struct regmap *map)
43 {
44 int ret;
45 unsigned int raw;
46 u32 want;
47
48 if (!map)
49 return -ENODEV;
50
51 ret = regmap_read(map, desc->reg, &raw);
52 if (ret)
53 return ret;
54
55 aspeed_sig_desc_print_val(desc, enabled, raw);
56 want = enabled ? desc->enable : desc->disable;
57
58 return ((raw & desc->mask) >> __ffs(desc->mask)) == want;
59 }
60
61 /**
62 * aspeed_sig_expr_eval - Query the enabled or disabled state for a
63 * mux function's signal on a pin
64 *
65 * @ctx: The driver context for the pinctrl IP
66 * @expr: An expression controlling the signal for a mux function on a pin
67 * @enabled: True to query the enabled state, false to query disabled state
68 *
69 * Return: 1 if the expression composed by @enabled evaluates true, 0 if not,
70 * and less than zero if an unrecoverable failure occurred.
71 *
72 * A mux function is enabled or disabled if the function's signal expression
73 * for each pin in the function's pin group evaluates true for the desired
74 * state. An signal expression evaluates true if all of its associated signal
75 * descriptors evaluate true for the desired state.
76 *
77 * If an expression's state is described by more than one bit, either through
78 * multi-bit bitfields in a single signal descriptor or through multiple signal
79 * descriptors of a single bit then it is possible for the expression to be in
80 * neither the enabled nor disabled state. Thus we must explicitly test for
81 * either condition as required.
82 */
aspeed_sig_expr_eval(struct aspeed_pinmux_data * ctx,const struct aspeed_sig_expr * expr,bool enabled)83 int aspeed_sig_expr_eval(struct aspeed_pinmux_data *ctx,
84 const struct aspeed_sig_expr *expr, bool enabled)
85 {
86 int ret;
87 int i;
88
89 if (ctx->ops->eval)
90 return ctx->ops->eval(ctx, expr, enabled);
91
92 for (i = 0; i < expr->ndescs; i++) {
93 const struct aspeed_sig_desc *desc = &expr->descs[i];
94
95 ret = aspeed_sig_desc_eval(desc, enabled, ctx->maps[desc->ip]);
96 if (ret <= 0)
97 return ret;
98 }
99
100 return 1;
101 }
102