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      1 /*	$NetBSD: bq4802_ebus.c,v 1.3 2026/07/07 12:33:39 jdc Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2026 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Julian Coleman.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: bq4802_ebus.c,v 1.3 2026/07/07 12:33:39 jdc Exp $");
     34 
     35 /* Clock driver for rtc/bq4802 (a Texas Instruments bq4802Y/bq4802LY). */
     36 
     37 #include <sys/param.h>
     38 #include <sys/device.h>
     39 #include <sys/proc.h>
     40 #include <sys/types.h>
     41 #include <sys/sysctl.h>
     42 
     43 #include <sys/bus.h>
     44 #include <machine/autoconf.h>
     45 
     46 #include <dev/clock_subr.h>
     47 #include <dev/ic/bq4802reg.h>
     48 
     49 #include <dev/ebus/ebusreg.h>
     50 #include <dev/ebus/ebusvar.h>
     51 
     52 
     53 struct bq4802rtc_softc {
     54 	device_t	sc_dev;
     55 
     56 	struct todr_chip_handle	sc_tch;
     57 
     58 	bus_space_tag_t		sc_bst;
     59 	bus_space_handle_t	sc_bsh;
     60 
     61 	int			sc_osc_stp;	/* Oscillator stop (sysctl) */
     62 };
     63 
     64 static int	bq4802rtc_ebus_match(device_t, cfdata_t, void *);
     65 static void	bq4802rtc_ebus_attach(device_t, device_t, void *);
     66 static int	bq4802_gettime_ymdhms(struct todr_chip_handle *,
     67 		    struct clock_ymdhms *);
     68 static int	bq4802_settime_ymdhms(struct todr_chip_handle *,
     69 		    struct clock_ymdhms *);
     70 static int	sysctl_bq4802_osc(SYSCTLFN_ARGS);
     71 
     72 CFATTACH_DECL_NEW(bq4802rtc_ebus, sizeof(struct bq4802rtc_softc),
     73     bq4802rtc_ebus_match, bq4802rtc_ebus_attach, NULL, NULL);
     74 
     75 /* Register read and write. */
     76 #define	bq4802_read(sc, reg) \
     77     bus_space_read_1(sc->sc_bst, sc->sc_bsh, reg)
     78 #define bq4802_write(sc, reg, val) \
     79     bus_space_write_1(sc->sc_bst, sc->sc_bsh, reg, val)
     80 
     81 static int
     82 bq4802rtc_ebus_match(device_t parent, cfdata_t cf, void *aux)
     83 {
     84 	struct ebus_attach_args *ea = aux;
     85 	char *compat;
     86 
     87 	if (strcmp("rtc", ea->ea_name) != 0)
     88 		return 0;
     89 
     90 	compat = prom_getpropstring(ea->ea_node, "compatible");
     91 	if (compat != NULL && !strcmp(compat, "bq4802"))
     92 		return 2;	/* We need a better match than 'rtc' */
     93 
     94 	return 0;
     95 }
     96 
     97 static void
     98 bq4802rtc_ebus_attach(device_t parent, device_t self, void *aux)
     99 {
    100 	struct bq4802rtc_softc *sc = device_private(self);
    101 	struct ebus_attach_args *ea = aux;
    102 	todr_chip_handle_t tch = &sc->sc_tch;
    103 	const struct sysctlnode *me = NULL, *node = NULL;
    104 	int sz;
    105 	uint8_t ctrl, new;
    106 
    107 	sc->sc_dev = self;
    108 	sc->sc_bst = ea->ea_bustag;
    109 
    110 	sz = ea->ea_reg[0].size;
    111 
    112 	if (bus_space_map(sc->sc_bst,
    113 			 EBUS_ADDR_FROM_REG(&ea->ea_reg[0]),
    114 			 sz, 0,
    115 			 &sc->sc_bsh) != 0) {
    116 		aprint_error(": can't map register\n");
    117 		return;
    118 	}
    119 
    120 	aprint_normal(": real time clock\n");
    121 
    122 	tch->todr_dev = self;
    123 	tch->todr_gettime_ymdhms = bq4802_gettime_ymdhms;
    124 	tch->todr_settime_ymdhms = bq4802_settime_ymdhms;
    125 
    126 	/* Setup: alarms off, disable DST, enable updates, 24-hour mode */
    127 	ctrl = bq4802_read(sc, BQ4802_CTRL);
    128 	if (ctrl & BQ4802_CTRL_STP)
    129 		sc->sc_osc_stp = 0;
    130 	else {
    131 		aprint_error_dev(self,
    132 		    "WARNING: oscillator is stopped (0x%02x)\n", ctrl);
    133 		sc->sc_osc_stp = 1;
    134 	}
    135 	new = ctrl & ~(BQ4802_CTRL_DSE | BQ4802_CTRL_UTI);
    136 	new = new | BQ4802_CTRL_24;
    137 	if (new != ctrl)
    138 		bq4802_write(sc, BQ4802_CTRL, ctrl);
    139 
    140 	todr_attach(tch);
    141 
    142 	/* Setup sysctl for the oscillator control */
    143 	sysctl_createv(NULL, 0, NULL, &me,
    144 	    CTLFLAG_READWRITE,
    145 	    CTLTYPE_NODE, device_xname(self), NULL,
    146 	    NULL, 0, NULL, 0,
    147 	    CTL_HW, CTL_CREATE, CTL_EOL);
    148 	if (me == NULL)
    149 		aprint_error_dev(self, "unable to add sysctl root\n");
    150 	else {
    151 		sysctl_createv(NULL, 0, NULL, &node,
    152 		    CTLFLAG_READWRITE | CTLFLAG_OWNDESC,
    153 		    CTLTYPE_INT, "stop_oscillator", "Stop the chip oscillator",
    154 		    sysctl_bq4802_osc, 1, (void *)sc, 0,
    155 		    CTL_HW, me->sysctl_num, CTL_CREATE, CTL_EOL);
    156 		if (node == NULL)
    157 			aprint_error_dev(self, "unable to add sysctl node\n");
    158 	}
    159 }
    160 
    161 static int
    162 bq4802_gettime_ymdhms(struct todr_chip_handle *todrch, struct clock_ymdhms *dt)
    163 {
    164 	struct bq4802rtc_softc *sc = device_private(todrch->todr_dev);
    165 	bq4802_regs regs;
    166 	uint64_t	val;
    167 	int s;
    168 
    169 	s = splclock();
    170 	BQ4802_GETTOD(sc, &regs);
    171 	splx(s);
    172 
    173 	dt->dt_sec = bcdtobin(regs[BQ4802_SEC]);
    174 	dt->dt_min = bcdtobin(regs[BQ4802_MIN]);
    175 	val = bcdtobin(regs[BQ4802_HOUR]);
    176 	if (val == 24)
    177 		val = 0;
    178 	dt->dt_hour = val;
    179 	dt->dt_wday = bcdtobin(regs[BQ4802_WDAY]);
    180 	dt->dt_day = bcdtobin(regs[BQ4802_DAY]);
    181 	dt->dt_mon = bcdtobin(regs[BQ4802_MONTH]);
    182 	val = bcdtobin(regs[BQ4802_YEAR]);
    183 	val += bcdtobin(regs[BQ4802_CENT]) * 100;
    184 	dt->dt_year = val;
    185 
    186 	return 0;
    187 }
    188 
    189 static int
    190 bq4802_settime_ymdhms(struct todr_chip_handle *todrch, struct clock_ymdhms *dt)
    191 {
    192 	struct bq4802rtc_softc *sc = device_private(todrch->todr_dev);
    193 	bq4802_regs regs;
    194 	uint8_t val;
    195 	int s;
    196 
    197 	regs[BQ4802_SEC] = bintobcd(dt->dt_sec);
    198 	regs[BQ4802_MIN] = bintobcd(dt->dt_min);
    199 	if (dt->dt_hour == 0)
    200 		val = 24;
    201 	else
    202 		val = dt->dt_hour;
    203 	regs[BQ4802_HOUR] = bintobcd(val);
    204 	regs[BQ4802_WDAY] = bintobcd(dt->dt_wday);
    205 	regs[BQ4802_DAY] = bintobcd(dt->dt_day);
    206 	regs[BQ4802_MONTH] = bintobcd(dt->dt_mon);
    207 	regs[BQ4802_YEAR] = bintobcd(dt->dt_year % 100);
    208 	regs[BQ4802_CENT] = bintobcd(dt->dt_year / 100);
    209 
    210 	s = splclock();
    211 	BQ4802_SETTOD(sc, &regs);
    212 	splx(s);
    213 
    214 	return 0;
    215 }
    216 
    217 static int
    218 sysctl_bq4802_osc(SYSCTLFN_ARGS)
    219 {
    220 	struct sysctlnode node = *rnode;
    221 	struct bq4802rtc_softc *sc = node.sysctl_data;
    222 	int stp;
    223 	uint8_t ctrl;
    224 
    225 	if (newp) {
    226 		/* write */
    227 		stp = sc->sc_osc_stp;
    228 		node.sysctl_data = &stp;
    229 		if (sysctl_lookup(SYSCTLFN_CALL(&node)) == 0) {
    230 			if (stp != 0 && stp != 1)
    231 				return EINVAL;
    232 
    233 			if (stp != sc->sc_osc_stp) {
    234 				sc->sc_osc_stp = stp;
    235 				ctrl = bq4802_read(sc, BQ4802_CTRL);
    236 				if (stp)
    237 					ctrl &= ~BQ4802_CTRL_STP;
    238 				else
    239 					ctrl |= BQ4802_CTRL_STP;
    240 				bq4802_write(sc, BQ4802_CTRL, ctrl);
    241 			}
    242 
    243 			return 0;
    244 		}
    245 		return EINVAL;
    246 	} else {
    247 		node.sysctl_data = &sc->sc_osc_stp;
    248 		node.sysctl_size = 4;
    249 		return (sysctl_lookup(SYSCTLFN_CALL(&node)));
    250 	}
    251 
    252 	return 0;
    253 }
    254 
    255 /*
    256 SYSCTL_SETUP(sysctl_bq4802_setup, "sysctl bq4802 subtree setup")
    257 {
    258 
    259 	sysctl_createv(NULL, 0, NULL, NULL,
    260 		       CTLFLAG_PERMANENT,
    261 		       CTLTYPE_NODE, "hw", NULL,
    262 		       NULL, 0, NULL, 0,
    263 		       CTL_HW, CTL_EOL);
    264 }
    265 */
    266