[src/trunk]: src/sys/dev/i2c Actually, the local mutex is unnecesary; the i2c...

[thorpej <thorpej%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f6b3a9db136d
branches:  trunk
changeset: 466504:f6b3a9db136d
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Mon Dec 23 19:20:18 2019 +0000

description:
Actually, the local mutex is unnecesary; the i2c bus lock is held
across all register r/m/w cycles, so we can just piggy back on that.
(I misread the code previously.)

diffstat:

 sys/dev/i2c/max77620.c |  20 ++------------------
 1 files changed, 2 insertions(+), 18 deletions(-)

diffs (89 lines):

diff -r c04b106aad76 -r f6b3a9db136d sys/dev/i2c/max77620.c
--- a/sys/dev/i2c/max77620.c    Mon Dec 23 19:12:22 2019 +0000
+++ b/sys/dev/i2c/max77620.c    Mon Dec 23 19:20:18 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: max77620.c,v 1.7 2019/12/23 18:49:13 thorpej Exp $ */
+/* $NetBSD: max77620.c,v 1.8 2019/12/23 19:20:18 thorpej Exp $ */
 
 /*-
  * Copyright (c) 2017 Jared McNeill <jmcneill%invisible.ca@localhost>
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: max77620.c,v 1.7 2019/12/23 18:49:13 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: max77620.c,v 1.8 2019/12/23 19:20:18 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -58,13 +58,6 @@
        i2c_tag_t       sc_i2c;
        i2c_addr_t      sc_addr;
        int             sc_phandle;
-
-       /*
-        * Locking order:
-        *
-        *      max77620 -> i2c
-        */
-       kmutex_t        sc_lock;
 };
 
 struct max77620_pin {
@@ -115,7 +108,6 @@
        uint32_t gpio;
 
        KASSERT(pin >= 0 && pin < MAX_GPIO_COUNT);
-       KASSERT(mutex_owned(&sc->sc_lock));
 
        gpio = I2C_READ(sc, MAX_GPIO_REG(pin));
 
@@ -170,11 +162,9 @@
        if (pin >= MAX_GPIO_COUNT)
                return NULL;
 
-       mutex_enter(&sc->sc_lock);
        I2C_LOCK(sc);
        error = max77620_gpio_config(sc, pin, flags);
        I2C_UNLOCK(sc);
-       mutex_exit(&sc->sc_lock);
 
        if (error != 0) {
                device_printf(dev, "bad pin %d config %#x\n", pin, flags);
@@ -196,11 +186,9 @@
        struct max77620_softc * const sc = device_private(dev);
        struct max77620_pin *gpin = priv;
 
-       mutex_enter(&sc->sc_lock);
        I2C_LOCK(sc);
        max77620_gpio_config(sc, gpin->pin_num, GPIO_PIN_INPUT|GPIO_PIN_OPENDRAIN);
        I2C_UNLOCK(sc);
-       mutex_exit(&sc->sc_lock);
 
        kmem_free(gpin, sizeof(*gpin));
 }
@@ -245,7 +233,6 @@
        if (!raw && gpin->pin_actlo)
                val = !val;
 
-       mutex_enter(&sc->sc_lock);
        I2C_LOCK(sc);
        gpio = I2C_READ(sc, MAX_GPIO_REG(gpin->pin_num));
        gpio &= ~MAX_GPIO_OUTPUT_VAL;
@@ -257,7 +244,6 @@
 #endif
        I2C_WRITE(sc, MAX_GPIO_REG(gpin->pin_num), gpio);
        I2C_UNLOCK(sc);
-       mutex_exit(&sc->sc_lock);
 }
 
 static struct fdtbus_gpio_controller_func max77620_gpio_funcs = {
@@ -297,8 +283,6 @@
        sc->sc_addr = ia->ia_addr;
        sc->sc_phandle = ia->ia_cookie;
 
-       mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
-
        aprint_naive("\n");
        aprint_normal(": MAX77620 Power Management IC\n");