100 lines
3.2 KiB
C
100 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* Copyright (C) 2019 IBM Corp. */
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/* Pieces to enable drivers to implement the .set callback */
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#include "pinmux-aspeed.h"
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static const char *const aspeed_pinmux_ips[] = {
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[ASPEED_IP_SCU] = "SCU",
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[ASPEED_IP_GFX] = "GFX",
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[ASPEED_IP_LPC] = "LPC",
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};
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static inline void aspeed_sig_desc_print_val(
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const struct aspeed_sig_desc *desc, bool enable, u32 rv)
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{
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pr_debug("Want %s%X[0x%08X]=0x%X, got 0x%X from 0x%08X\n",
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aspeed_pinmux_ips[desc->ip], desc->reg,
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desc->mask, enable ? desc->enable : desc->disable,
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(rv & desc->mask) >> __ffs(desc->mask), rv);
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}
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/**
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* Query the enabled or disabled state of a signal descriptor
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*
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* @desc: The signal descriptor of interest
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* @enabled: True to query the enabled state, false to query disabled state
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* @map: The IP block's regmap instance
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*
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* Return: 1 if the descriptor's bitfield is configured to the state
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* selected by @enabled, 0 if not, and less than zero if an unrecoverable
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* failure occurred
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*
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* Evaluation of descriptor state is non-trivial in that it is not a binary
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* outcome: The bitfields can be greater than one bit in size and thus can take
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* a value that is neither the enabled nor disabled state recorded in the
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* descriptor (typically this means a different function to the one of interest
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* is enabled). Thus we must explicitly test for either condition as required.
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*/
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int aspeed_sig_desc_eval(const struct aspeed_sig_desc *desc,
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bool enabled, struct regmap *map)
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{
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int ret;
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unsigned int raw;
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u32 want;
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if (!map)
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return -ENODEV;
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ret = regmap_read(map, desc->reg, &raw);
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if (ret)
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return ret;
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aspeed_sig_desc_print_val(desc, enabled, raw);
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want = enabled ? desc->enable : desc->disable;
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return ((raw & desc->mask) >> __ffs(desc->mask)) == want;
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}
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/**
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* Query the enabled or disabled state for a mux function's signal on a pin
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*
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* @ctx: The driver context for the pinctrl IP
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* @expr: An expression controlling the signal for a mux function on a pin
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* @enabled: True to query the enabled state, false to query disabled state
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*
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* Return: 1 if the expression composed by @enabled evaluates true, 0 if not,
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* and less than zero if an unrecoverable failure occurred.
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*
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* A mux function is enabled or disabled if the function's signal expression
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* for each pin in the function's pin group evaluates true for the desired
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* state. An signal expression evaluates true if all of its associated signal
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* descriptors evaluate true for the desired state.
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*
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* If an expression's state is described by more than one bit, either through
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* multi-bit bitfields in a single signal descriptor or through multiple signal
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* descriptors of a single bit then it is possible for the expression to be in
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* neither the enabled nor disabled state. Thus we must explicitly test for
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* either condition as required.
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*/
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int aspeed_sig_expr_eval(struct aspeed_pinmux_data *ctx,
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const struct aspeed_sig_expr *expr, bool enabled)
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{
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int ret;
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int i;
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if (ctx->ops->eval)
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return ctx->ops->eval(ctx, expr, enabled);
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for (i = 0; i < expr->ndescs; i++) {
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const struct aspeed_sig_desc *desc = &expr->descs[i];
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ret = aspeed_sig_desc_eval(desc, enabled, ctx->maps[desc->ip]);
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if (ret <= 0)
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return ret;
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}
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return 1;
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}
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