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[src/trunk]: src/sys/dev/i2c Add a driver for NXP PCA954x / PCA984x I2C switc...



details:   https://anonhg.NetBSD.org/src/rev/ba94039b3770
branches:  trunk
changeset: 948690:ba94039b3770
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Tue Dec 29 01:47:51 2020 +0000

description:
Add a driver for NXP PCA954x / PCA984x I2C switch / mux controllers.

diffstat:

 sys/dev/i2c/files.i2c   |    7 +-
 sys/dev/i2c/pcai2cmux.c |  354 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 360 insertions(+), 1 deletions(-)

diffs (truncated from 379 to 300 lines):

diff -r 404a9f534ccb -r ba94039b3770 sys/dev/i2c/files.i2c
--- a/sys/dev/i2c/files.i2c     Tue Dec 29 01:45:06 2020 +0000
+++ b/sys/dev/i2c/files.i2c     Tue Dec 29 01:47:51 2020 +0000
@@ -1,4 +1,4 @@
-#      $NetBSD: files.i2c,v 1.113 2020/12/28 20:29:57 thorpej Exp $
+#      $NetBSD: files.i2c,v 1.114 2020/12/29 01:47:51 thorpej Exp $
 
 obsolete defflag       opt_i2cbus.h            I2C_SCAN
 define i2cbus { }
@@ -370,6 +370,11 @@
 attach anxedp at iic
 file   dev/i2c/anxedp.c                        anxedp
 
+# NXP PCA954x / PCA984x I2C switch / mux controllers
+device pcaiicmux: i2cbus, i2cmux
+attach pcaiicmux at iic
+file   dev/i2c/pcai2cmux.c                     pcaiicmux
+
 # NXP PCA9685 16-channel, 12-bit PWM Fm+ LED controller
 device pcapwm: pwm
 attach pcapwm at iic
diff -r 404a9f534ccb -r ba94039b3770 sys/dev/i2c/pcai2cmux.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/sys/dev/i2c/pcai2cmux.c   Tue Dec 29 01:47:51 2020 +0000
@@ -0,0 +1,354 @@
+/*     $NetBSD: pcai2cmux.c,v 1.1 2020/12/29 01:47:51 thorpej Exp $    */
+
+/*-
+ * Copyright (c) 2020 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Jason R. Thorpe.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: pcai2cmux.c,v 1.1 2020/12/29 01:47:51 thorpej Exp $");
+
+/*
+ * Driver for NXP PCA954x / PCA984x I2C switches and multiplexers.
+ *
+ * There are two flavors of this device:
+ *
+ * - Multiplexers, which connect the upstream bus to one downstream bus
+ *   at a time.
+ *
+ * - Switches, which can connect the upstream bus to one or more downstream
+ *   busses at a time (which is useful when using an all-call address for
+ *   a large array of PCA9685 LED controllers, for example).
+ *
+ * Alas, the device tree bindings don't have anything specifically for
+ * switches, so we treat the switch variants as basic multiplexers,
+ * only enabling one downstream bus at a time.
+ *
+ * Note that some versions of these chips also have interrupt mux
+ * capability.  XXX We do not support this yet.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+
+#include <dev/fdt/fdtvar.h>
+#include <dev/i2c/i2cmuxvar.h>
+
+/* There are a maximum of 8 busses supported. */
+#define        PCAIICMUX_MAX_BUSSES    8
+
+struct pcaiicmux_type {
+       unsigned int    nchannels;      /* # of downstream channels */
+       uint8_t         enable_bit;     /* if 0, chip is switch type */
+};
+
+static const struct pcaiicmux_type mux2_type = {
+       .nchannels = 2,
+       .enable_bit = __BIT(2),
+};
+
+static const struct pcaiicmux_type switch2_type = {
+       .nchannels = 2,
+       .enable_bit = 0,
+};
+
+static const struct pcaiicmux_type mux4_type = {
+       .nchannels = 4,
+       .enable_bit = __BIT(2),
+};
+
+static const struct pcaiicmux_type switch4_type = {
+       .nchannels = 4,
+       .enable_bit = 0,
+};
+
+static const struct pcaiicmux_type mux8_type = {
+       .nchannels = 8,
+       .enable_bit = __BIT(3),
+};
+
+static const struct pcaiicmux_type switch8_type = {
+       .nchannels = 8,
+       .enable_bit = 0,
+};
+
+static const struct device_compatible_entry compat_data[] = {
+       /* PCA9540 - 2 channel i2c mux */
+       { .compat = "nxp,pca9540",
+         .data = (uintptr_t)&mux2_type },
+
+       /* PCA9542 - 2 channel i2c mux with interrupts */
+       { .compat = "nxp,pca9542",
+         .data = (uintptr_t)&mux2_type },
+
+       /* PCA9543 - 2 channel i2c switch with interrupts */
+       { .compat = "nxp,pca9543",
+         .data = (uintptr_t)&switch2_type },
+
+       /* PCA9544 - 4 channel i2c mux with interrupts */
+       { .compat = "nxp,pca9544",
+         .data = (uintptr_t)&mux4_type },
+
+       /* PCA9545 - 4 channel i2c switch with interrupts */
+       { .compat = "nxp,pca9545",
+         .data = (uintptr_t)&switch4_type },
+
+       /* PCA9546 - 4 channel i2c switch */
+       { .compat = "nxp,pca9546",
+         .data = (uintptr_t)&switch4_type },
+
+       /* PCA9547 - 8 channel i2c mux */
+       { .compat = "nxp,pca9547",
+         .data = (uintptr_t)&mux8_type },
+
+       /* PCA9548 - 8 channel i2c switch */
+       { .compat = "nxp,pca9548",
+         .data = (uintptr_t)&switch8_type },
+
+       /* PCA9846 - 4 channel i2c switch */
+       { .compat = "nxp,pca9846",
+         .data = (uintptr_t)&switch4_type },
+
+       /* PCA9847 - 8 channel i2c mux */
+       { .compat = "nxp,pca9847",
+         .data = (uintptr_t)&mux8_type },
+
+       /* PCA9848 - 8 channel i2c switch */
+       { .compat = "nxp,pca9848",
+         .data = (uintptr_t)&switch8_type },
+
+       /* PCA9849 - 4 channel i2c mux */
+       { .compat = "nxp,pca9849",
+         .data = (uintptr_t)&mux4_type },
+
+       { NULL }
+};
+
+struct pcaiicmux_softc {
+       struct iicmux_softc     sc_iicmux;
+
+       i2c_addr_t              sc_addr;
+       int                     sc_cur_value;
+
+       const struct pcaiicmux_type *sc_type;
+       struct fdtbus_gpio_pin *sc_reset_gpio;
+
+       bool                    sc_idle_disconnect;
+
+       struct pcaiicmux_bus_info {
+               uint8_t         enable_value;
+       } sc_bus_info[PCAIICMUX_MAX_BUSSES];
+};
+
+static int
+pcaiicmux_write(struct pcaiicmux_softc * const sc, uint8_t const val,
+    int const flags)
+{
+       if ((int)val == sc->sc_cur_value) {
+               return 0;
+       }
+       sc->sc_cur_value = (int)val;
+
+       int const error =
+           iic_smbus_send_byte(sc->sc_iicmux.sc_i2c_parent, sc->sc_addr, val,
+                               flags & ~I2C_F_SPEED);
+       if (error) {
+               sc->sc_cur_value = -1;
+       }
+
+       return error;
+}
+
+/*****************************************************************************/
+
+static void *
+pcaiicmux_get_mux_info(struct iicmux_softc * const iicmux)
+{
+       return container_of(iicmux, struct pcaiicmux_softc, sc_iicmux);
+}
+
+static void *
+pcaiicmux_get_bus_info(struct iicmux_bus * const bus)
+{
+       struct iicmux_softc * const iicmux = bus->mux;
+       struct pcaiicmux_softc * const sc = iicmux->sc_mux_data;
+       bus_addr_t addr;
+       int error;
+
+       if (bus->busidx >= sc->sc_type->nchannels) {
+               aprint_error_dev(iicmux->sc_dev,
+                   "device tree error: bus index %d out of range\n",
+                   bus->busidx);
+               return NULL;
+       }
+
+       struct pcaiicmux_bus_info * const bus_info =
+           &sc->sc_bus_info[bus->busidx];
+
+       error = fdtbus_get_reg(bus->phandle, 0, &addr, NULL);
+       if (error) {
+               aprint_error_dev(iicmux->sc_dev,
+                   "unable to get reg property for bus %d\n", bus->busidx);
+               return NULL;
+       }
+
+       if (addr >= sc->sc_type->nchannels) {
+               aprint_error_dev(iicmux->sc_dev,
+                   "device tree error: reg property %llu out of range\n",
+                   (unsigned long long)addr);
+               return NULL;
+       }
+
+       /*
+        * If it's a mux type, the enable value is the channel number
+        * (from the reg property) OR'd with the enable bit.
+        *
+        * If it's a switch type, the enable value is 1 << channel number
+        * (from the reg property).
+        */
+       if (sc->sc_type->enable_bit) {
+               bus_info->enable_value =
+                   (uint8_t)addr | sc->sc_type->enable_bit;
+       } else {
+               bus_info->enable_value = 1 << addr;
+       }
+
+       return bus_info;
+}
+
+static int
+pcaiicmux_acquire_bus(struct iicmux_bus * const bus, int const flags)
+{
+       struct pcaiicmux_softc * const sc = bus->mux->sc_mux_data;
+       struct pcaiicmux_bus_info * const bus_info = bus->bus_data;
+
+       return pcaiicmux_write(sc, bus_info->enable_value, flags);
+}
+
+static void
+pcaiicmux_release_bus(struct iicmux_bus * const bus, int const flags)
+{
+       struct pcaiicmux_softc * const sc = bus->mux->sc_mux_data;
+
+       if (sc->sc_idle_disconnect) {
+               (void) pcaiicmux_write(sc, 0, flags);
+       }
+}
+
+static const struct iicmux_config pcaiicmux_config = {
+       .desc = "PCA954x",
+       .get_mux_info = pcaiicmux_get_mux_info,
+       .get_bus_info = pcaiicmux_get_bus_info,
+       .acquire_bus = pcaiicmux_acquire_bus,
+       .release_bus = pcaiicmux_release_bus,
+};
+
+/*****************************************************************************/
+
+static const struct pcaiicmux_type *
+pcaiicmux_type_by_compat(const struct i2c_attach_args * const ia)
+{



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