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      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 (at) 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 
     43 static const struct device_compatible_entry compat_data[] = {
     44 	{ .compat = "mmc-pwrseq-emmc" },
     45 	DEVICE_COMPAT_EOL
     46 };
     47 
     48 struct mmcpwrseq_emmc_softc {
     49 	device_t sc_dev;
     50 	int sc_phandle;
     51 	struct fdtbus_gpio_pin *sc_pin;
     52 };
     53 
     54 static void
     55 mmcpwrseq_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 
     65 static const struct fdtbus_mmc_pwrseq_func mmcpwrseq_emmc_funcs = {
     66 	.reset = mmcpwrseq_emmc_reset,
     67 };
     68 
     69 static int
     70 mmcpwrseq_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 
     77 static void
     78 mmcpwrseq_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 
     99 static int
    100 mmcpwrseq_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 
    110 CFATTACH_DECL_NEW(mmcpwrseq_emmc, sizeof(struct mmcpwrseq_emmc_softc),
    111 	mmcpwrseq_emmc_match, mmcpwrseq_emmc_attach, mmcpwrseq_emmc_detach, NULL);
    112