mmc_pwrseq_emmc.c revision 1.2 
1/* $NetBSD: mmc_pwrseq_emmc.c,v 1.2 2021/01/27 03:10:21 thorpej Exp $ */
2
3/*-
4 * Copyright (c) 2019 Jared McNeill <jmcneill@invisible.ca>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__KERNEL_RCSID(0, "$NetBSD: mmc_pwrseq_emmc.c,v 1.2 2021/01/27 03:10:21 thorpej Exp $");
31
32#include <sys/param.h>
33#include <sys/kernel.h>
34#include <sys/device.h>
35#include <sys/systm.h>
36#include <sys/proc.h>
37#include <sys/gpio.h>
38
39#include <dev/fdt/fdtvar.h>
40
41#define	MMCPWRSEQ_MAX_PINS	32
42
43static const struct device_compatible_entry compat_data[] = {
44	{ .compat = "mmc-pwrseq-emmc" },
45	DEVICE_COMPAT_EOL
46};
47
48struct mmcpwrseq_emmc_softc {
49	device_t sc_dev;
50	int sc_phandle;
51	struct fdtbus_gpio_pin *sc_pin;
52};
53
54static void
55mmcpwrseq_emmc_reset(device_t dev)
56{
57	struct mmcpwrseq_emmc_softc * const sc = device_private(dev);
58
59	fdtbus_gpio_write(sc->sc_pin, 1);
60	delay(1);
61	fdtbus_gpio_write(sc->sc_pin, 0);
62	delay(200);
63}
64
65static const struct fdtbus_mmc_pwrseq_func mmcpwrseq_emmc_funcs = {
66	.reset = mmcpwrseq_emmc_reset,
67};
68
69static int
70mmcpwrseq_emmc_match(device_t parent, cfdata_t cf, void *aux)
71{
72	struct fdt_attach_args * const faa = aux;
73
74	return of_compatible_match(faa->faa_phandle, compat_data);
75}
76
77static void
78mmcpwrseq_emmc_attach(device_t parent, device_t self, void *aux)
79{
80	struct mmcpwrseq_emmc_softc * const sc = device_private(self);
81	struct fdt_attach_args * const faa = aux;
82	const int phandle = faa->faa_phandle;
83
84	sc->sc_dev = self;
85	sc->sc_phandle = phandle;
86
87	sc->sc_pin = fdtbus_gpio_acquire_index(phandle, "reset-gpios", 0, GPIO_PIN_OUTPUT);
88	if (sc->sc_pin == NULL) {
89		aprint_error(": couldn't get reset GPIO\n");
90		return;
91	}
92
93	aprint_naive("\n");
94	aprint_normal(": eMMC hardware reset provider\n");
95
96	fdtbus_register_mmc_pwrseq(self, phandle, &mmcpwrseq_emmc_funcs);
97}
98
99static int
100mmcpwrseq_emmc_detach(device_t self, int flags)
101{
102	struct mmcpwrseq_emmc_softc * const sc = device_private(self);
103
104	if (sc->sc_pin != NULL)
105		mmcpwrseq_emmc_reset(self);
106
107	return 0;
108}
109
110CFATTACH_DECL_NEW(mmcpwrseq_emmc, sizeof(struct mmcpwrseq_emmc_softc),
111	mmcpwrseq_emmc_match, mmcpwrseq_emmc_attach, mmcpwrseq_emmc_detach, NULL);
112