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max77620.c revision 1.7 
      1 /* $NetBSD: max77620.c,v 1.7 2019/12/23 18:49:13 thorpej Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2017 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: max77620.c,v 1.7 2019/12/23 18:49:13 thorpej Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/systm.h>
     34 #include <sys/mutex.h>
     35 #include <sys/kernel.h>
     36 #include <sys/device.h>
     37 #include <sys/conf.h>
     38 #include <sys/bus.h>
     39 #include <sys/kmem.h>
     40 #include <sys/gpio.h>
     41 
     42 #include <dev/i2c/i2cvar.h>
     43 
     44 #include <dev/fdt/fdtvar.h>
     45 
     46 #define	MAX_GPIO_REG(n)		(0x36 + (n))
     47 #define	 MAX_GPIO_DEBOUNCE	__BITS(7,6)
     48 #define	 MAX_GPIO_INT		__BITS(5,4)
     49 #define	 MAX_GPIO_OUTPUT_VAL	__BIT(3)
     50 #define	 MAX_GPIO_INPUT_VAL	__BIT(2)
     51 #define	 MAX_GPIO_DIR		__BIT(1)
     52 #define	 MAX_GPIO_DRV		__BIT(0)
     53 
     54 #define	MAX_GPIO_COUNT		8
     55 
     56 struct max77620_softc {
     57 	device_t	sc_dev;
     58 	i2c_tag_t	sc_i2c;
     59 	i2c_addr_t	sc_addr;
     60 	int		sc_phandle;
     61 
     62 	/*
     63 	 * Locking order:
     64 	 *
     65 	 *	max77620 -> i2c
     66 	 */
     67 	kmutex_t	sc_lock;
     68 };
     69 
     70 struct max77620_pin {
     71 	struct max77620_softc	*pin_sc;
     72 	int			pin_num;
     73 	int			pin_flags;
     74 	bool			pin_actlo;
     75 };
     76 
     77 static const struct device_compatible_entry compat_data[] = {
     78 	{ "maxim,max77620",		0 },
     79 	{ NULL,				0 }
     80 };
     81 
     82 static uint8_t
     83 max77620_read(struct max77620_softc *sc, uint8_t reg, int flags)
     84 {
     85 	uint8_t val = 0;
     86 	int error;
     87 
     88 	error = iic_exec(sc->sc_i2c, I2C_OP_READ_WITH_STOP, sc->sc_addr,
     89 	    &reg, 1, &val, 1, flags);
     90 	if (error != 0)
     91 		aprint_error_dev(sc->sc_dev, "error reading reg %#x: %d\n", reg, error);
     92 
     93 	return val;
     94 }
     95 
     96 static void
     97 max77620_write(struct max77620_softc *sc, uint8_t reg, uint8_t val, int flags)
     98 {
     99 	int error;
    100 
    101 	error = iic_exec(sc->sc_i2c, I2C_OP_WRITE_WITH_STOP, sc->sc_addr,
    102 	    &reg, 1, &val, 1, flags);
    103 	if (error != 0)
    104 		aprint_error_dev(sc->sc_dev, "error writing reg %#x: %d\n", reg, error);
    105 }
    106 
    107 #define	I2C_READ(sc, reg)	max77620_read((sc), (reg), 0)
    108 #define	I2C_WRITE(sc, reg, val)	max77620_write((sc), (reg), (val), 0)
    109 #define	I2C_LOCK(sc)		iic_acquire_bus((sc)->sc_i2c, 0)
    110 #define	I2C_UNLOCK(sc)		iic_release_bus((sc)->sc_i2c, 0)
    111 
    112 static int
    113 max77620_gpio_config(struct max77620_softc *sc, int pin, int flags)
    114 {
    115 	uint32_t gpio;
    116 
    117 	KASSERT(pin >= 0 && pin < MAX_GPIO_COUNT);
    118 	KASSERT(mutex_owned(&sc->sc_lock));
    119 
    120 	gpio = I2C_READ(sc, MAX_GPIO_REG(pin));
    121 
    122 	switch (flags & (GPIO_PIN_INPUT|GPIO_PIN_OUTPUT)) {
    123 	case GPIO_PIN_INPUT:
    124 		gpio |= MAX_GPIO_DIR;
    125 		break;
    126 	case GPIO_PIN_OUTPUT:
    127 		gpio &= ~MAX_GPIO_DIR;
    128 		break;
    129 	default:
    130 		return EINVAL;
    131 	}
    132 
    133 	switch (flags & (GPIO_PIN_PUSHPULL|GPIO_PIN_OPENDRAIN)) {
    134 	case GPIO_PIN_PUSHPULL:
    135 		gpio |= MAX_GPIO_DRV;
    136 		break;
    137 	case GPIO_PIN_OPENDRAIN:
    138 		gpio &= ~MAX_GPIO_DRV;
    139 		break;
    140 	default:
    141 		return EINVAL;
    142 	}
    143 
    144 	I2C_WRITE(sc, MAX_GPIO_REG(pin), gpio);
    145 
    146 	return 0;
    147 }
    148 
    149 static void *
    150 max77620_gpio_acquire(device_t dev, const void *data, size_t len, int flags)
    151 {
    152 	struct max77620_softc * const sc = device_private(dev);
    153 	struct max77620_pin *gpin;
    154 	const u_int *gpio = data;
    155 	int error;
    156 
    157 	if (len != 12)
    158 		return NULL;
    159 
    160 	const uint8_t pin = be32toh(gpio[1]) & 0xff;
    161 	const bool actlo = (be32toh(gpio[2]) & __BIT(0)) != 0;
    162 	const bool pushpull = (be32toh(gpio[2]) & __BIT(1)) == 0;
    163 	const bool opendrain = (be32toh(gpio[2]) & __BIT(2)) != 0;
    164 
    165 	if (pushpull)
    166 		flags |= GPIO_PIN_PUSHPULL;
    167 	if (opendrain)
    168 		flags |= GPIO_PIN_OPENDRAIN;
    169 
    170 	if (pin >= MAX_GPIO_COUNT)
    171 		return NULL;
    172 
    173 	mutex_enter(&sc->sc_lock);
    174 	I2C_LOCK(sc);
    175 	error = max77620_gpio_config(sc, pin, flags);
    176 	I2C_UNLOCK(sc);
    177 	mutex_exit(&sc->sc_lock);
    178 
    179 	if (error != 0) {
    180 		device_printf(dev, "bad pin %d config %#x\n", pin, flags);
    181 		return NULL;
    182 	}
    183 
    184 	gpin = kmem_zalloc(sizeof(*gpin), KM_SLEEP);
    185 	gpin->pin_sc = sc;
    186 	gpin->pin_num = pin;
    187 	gpin->pin_flags = flags;
    188 	gpin->pin_actlo = actlo;
    189 
    190 	return gpin;
    191 }
    192 
    193 static void
    194 max77620_gpio_release(device_t dev, void *priv)
    195 {
    196 	struct max77620_softc * const sc = device_private(dev);
    197 	struct max77620_pin *gpin = priv;
    198 
    199 	mutex_enter(&sc->sc_lock);
    200 	I2C_LOCK(sc);
    201 	max77620_gpio_config(sc, gpin->pin_num, GPIO_PIN_INPUT|GPIO_PIN_OPENDRAIN);
    202 	I2C_UNLOCK(sc);
    203 	mutex_exit(&sc->sc_lock);
    204 
    205 	kmem_free(gpin, sizeof(*gpin));
    206 }
    207 
    208 static int
    209 max77620_gpio_read(device_t dev, void *priv, bool raw)
    210 {
    211 	struct max77620_softc * const sc = device_private(dev);
    212 	struct max77620_pin *gpin = priv;
    213 	uint8_t gpio;
    214 	int val;
    215 
    216 	/*
    217 	 * Performing a register read only; no need to acquire
    218 	 * the max77620 lock.
    219 	 */
    220 
    221 	I2C_LOCK(sc);
    222 	gpio = I2C_READ(sc, MAX_GPIO_REG(gpin->pin_num));
    223 	I2C_UNLOCK(sc);
    224 
    225 	val = __SHIFTOUT(gpio, MAX_GPIO_INPUT_VAL);
    226 	if (!raw && gpin->pin_actlo)
    227 		val = !val;
    228 
    229 #ifdef MAX77620_DEBUG
    230 	device_printf(sc->sc_dev, "GPIO%d rd %02x (%d %d)\n",
    231 	    gpin->pin_num, gpio,
    232 	    (int)__SHIFTOUT(gpio, MAX_GPIO_INPUT_VAL), val);
    233 #endif
    234 
    235 	return val;
    236 }
    237 
    238 static void
    239 max77620_gpio_write(device_t dev, void *priv, int val, bool raw)
    240 {
    241 	struct max77620_softc * const sc = device_private(dev);
    242 	struct max77620_pin *gpin = priv;
    243 	uint8_t gpio;
    244 
    245 	if (!raw && gpin->pin_actlo)
    246 		val = !val;
    247 
    248 	mutex_enter(&sc->sc_lock);
    249 	I2C_LOCK(sc);
    250 	gpio = I2C_READ(sc, MAX_GPIO_REG(gpin->pin_num));
    251 	gpio &= ~MAX_GPIO_OUTPUT_VAL;
    252 	gpio |= __SHIFTIN(val, MAX_GPIO_OUTPUT_VAL);
    253 #ifdef MAX77620_DEBUG
    254 	device_printf(sc->sc_dev, "GPIO%d wr %02x -> %02x\n",
    255 	    gpin->pin_num,
    256 	    I2C_READ(sc, MAX_GPIO_REG(gpin->pin_num)), gpio);
    257 #endif
    258 	I2C_WRITE(sc, MAX_GPIO_REG(gpin->pin_num), gpio);
    259 	I2C_UNLOCK(sc);
    260 	mutex_exit(&sc->sc_lock);
    261 }
    262 
    263 static struct fdtbus_gpio_controller_func max77620_gpio_funcs = {
    264 	.acquire = max77620_gpio_acquire,
    265 	.release = max77620_gpio_release,
    266 	.read = max77620_gpio_read,
    267 	.write = max77620_gpio_write,
    268 };
    269 
    270 static void
    271 max77620_gpio_attach(struct max77620_softc *sc)
    272 {
    273 	fdtbus_register_gpio_controller(sc->sc_dev, sc->sc_phandle,
    274 	    &max77620_gpio_funcs);
    275 }
    276 
    277 static int
    278 max77620_match(device_t parent, cfdata_t match, void *aux)
    279 {
    280 	struct i2c_attach_args *ia = aux;
    281 	int match_result;
    282 
    283 	if (iic_use_direct_match(ia, match, compat_data, &match_result))
    284 		return match_result;
    285 
    286 	return 0;
    287 }
    288 
    289 static void
    290 max77620_attach(device_t parent, device_t self, void *aux)
    291 {
    292 	struct max77620_softc * const sc = device_private(self);
    293 	struct i2c_attach_args *ia = aux;
    294 
    295 	sc->sc_dev = self;
    296 	sc->sc_i2c = ia->ia_tag;
    297 	sc->sc_addr = ia->ia_addr;
    298 	sc->sc_phandle = ia->ia_cookie;
    299 
    300 	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
    301 
    302 	aprint_naive("\n");
    303 	aprint_normal(": MAX77620 Power Management IC\n");
    304 
    305 	max77620_gpio_attach(sc);
    306 }
    307 
    308 CFATTACH_DECL_NEW(max77620pmic, sizeof(struct max77620_softc),
    309     max77620_match, max77620_attach, NULL, NULL);
    310