85 lines
2.2 KiB
C
85 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-3.0-only
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#include <stdbool.h>
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#include <common/macro.h>
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#include <ec/ps2.h>
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#define PS2(NUM) { \
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.control = &PSCTL ## NUM, \
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.interrupt = &PSINT ## NUM, \
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.status = &PSSTS ## NUM, \
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.data = &PSDAT ## NUM, \
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}
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#define PS2_TIMEOUT 10000
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#define PSSTS_TIMEOUT_ERR BIT(6)
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#define PSSTS_FRAME_ERR BIT(5)
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#define PSSTS_PARITY_ERR BIT(4)
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#define PSSTS_ALL_ERR (PSSTS_TIMEOUT_ERR | PSSTS_FRAME_ERR | PSSTS_PARITY_ERR)
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#define PSSTS_DONE BIT(3)
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struct Ps2 __code PS2_1 = PS2(1);
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struct Ps2 __code PS2_2 = PS2(2);
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struct Ps2 __code PS2_3 = PS2(3);
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void ps2_reset(struct Ps2 * ps2) {
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// Reset interface to defaults
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*(ps2->control) = 1;
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// Clear status
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*(ps2->status) = *(ps2->status);
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}
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static int ps2_transaction(struct Ps2 * ps2, uint8_t * data, int length, bool read) {
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int i;
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for (i = 0; i < length; i++) {
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if (read) {
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// Begin read
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*(ps2->control) = 0x07;
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} else {
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// Begin write
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*(ps2->control) = 0x0D;
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*(ps2->data) = data[i];
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// Pull data line low
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*(ps2->control) = 0x0C;
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// Pull clock line high
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*(ps2->control) = 0x0E;
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}
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uint32_t timeout;
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for (timeout = PS2_TIMEOUT; timeout > 0; timeout--) {
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uint8_t status = *(ps2->status);
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// If an error happened, clear status and return the error
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if (status & PSSTS_ALL_ERR) {
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ps2_reset(ps2);
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return -(int)status;
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}
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// If transaction is done, break
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if (status & PSSTS_DONE) {
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break;
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}
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}
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// If a timeout happened, return the error
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if (timeout == 0) {
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ps2_reset(ps2);
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return -0x1000;
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}
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if (read) {
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data[i] = *(ps2->data);
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}
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// Set interface to defaults
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ps2_reset(ps2);
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}
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return i;
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}
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int ps2_read(struct Ps2 * ps2, uint8_t * data, int length) {
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return ps2_transaction(ps2, data, length, true);
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}
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int ps2_write(struct Ps2 * ps2, uint8_t * data, int length) {
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return ps2_transaction(ps2, data, length, false);
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}
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