Add bcmtemp(4), a driver for the temperature sensor on the Raspberry Pi.

1 files changed, 124 insertions, 0 deletions

diff --git a/sys/dev/fdt/bcm2835_temp.c b/sys/dev/fdt/bcm2835_temp.c
new file mode 100644
index 00000000000..c5aab990656
--- /dev/null
+++ b/sys/dev/fdt/bcm2835_temp.c
@@ -0,0 +1,124 @@
+/*	$OpenBSD: bcm2835_temp.c,v 1.1 2018/02/24 11:06:59 kettenis Exp $	*/
+/*
+ * Copyright (c) 2018 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/sensors.h>
+
+#include <machine/bus.h>
+#include <machine/fdt.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/fdt.h>
+
+/* Registers */
+#define TS_TSENSCTL		0x0000
+#define TS_TSENSSTAT		0x0004
+#define  TS_TSENSSTAT_VALID	(1 << 10)
+#define  TS_TSENSSTAT_DATA(x)	((x) & 0x3ff)
+
+#define HREAD4(sc, reg)							\
+	(bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
+#define HWRITE4(sc, reg, val)						\
+	bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
+
+struct bcmtemp_softc {
+	struct device		sc_dev;
+	bus_space_tag_t		sc_iot;
+	bus_space_handle_t	sc_ioh;
+
+	int32_t			sc_slope;
+	int32_t			sc_offset;
+
+	struct ksensor		sc_sensor;
+	struct ksensordev	sc_sensordev;
+};
+
+int	bcmtemp_match(struct device *, void *, void *);
+void	bcmtemp_attach(struct device *, struct device *, void *);
+
+struct cfattach	bcmtemp_ca = {
+	sizeof (struct bcmtemp_softc), bcmtemp_match, bcmtemp_attach
+};
+
+struct cfdriver bcmtemp_cd = {
+	NULL, "bcmtemp", DV_DULL
+};
+
+void	bcmtemp_refresh_sensors(void *);
+
+int
+bcmtemp_match(struct device *parent, void *match, void *aux)
+{
+	struct fdt_attach_args *faa = aux;
+
+	return (OF_is_compatible(faa->fa_node, "brcm,bcm2836-thermal") ||
+	    OF_is_compatible(faa->fa_node, "brcm,bcm2837-thermal"));
+}
+
+void
+bcmtemp_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct bcmtemp_softc *sc = (struct bcmtemp_softc *)self;
+	struct fdt_attach_args *faa = aux;
+
+	if (faa->fa_nreg < 1) {
+		printf(": no registers\n");
+		return;
+	}
+
+	sc->sc_iot = faa->fa_iot;
+	if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
+	    faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
+		printf(": can't map registers\n");
+		return;
+	}
+
+	printf("\n");
+
+	/* XXX fetch these from /thermal-zones. */
+	sc->sc_slope = -538;
+	if (OF_is_compatible(faa->fa_node, "brcm,bcm2836-thermal"))
+		sc->sc_offset = 407000;
+	else
+		sc->sc_offset = 412000;
+
+	/* Register sensors. */
+	strlcpy(sc->sc_sensordev.xname, sc->sc_dev.dv_xname,
+	    sizeof(sc->sc_sensordev.xname));
+	sc->sc_sensor.type = SENSOR_TEMP;
+	sc->sc_sensor.flags = SENSOR_FINVALID;
+	sensor_attach(&sc->sc_sensordev, &sc->sc_sensor);
+	sensordev_install(&sc->sc_sensordev);
+	sensor_task_register(sc, bcmtemp_refresh_sensors, 5);
+}
+
+void
+bcmtemp_refresh_sensors(void *arg)
+{
+	struct bcmtemp_softc *sc = arg;
+	int32_t code, temp;
+
+	code = HREAD4(sc, TS_TSENSSTAT);
+	temp = sc->sc_offset + TS_TSENSSTAT_DATA(code) * sc->sc_slope;
+	sc->sc_sensor.value = 273150000 + 1000 * temp;
+	if (code & TS_TSENSSTAT_VALID)
+		sc->sc_sensor.flags &= ~SENSOR_FINVALID;
+	else
+		sc->sc_sensor.flags |= SENSOR_FINVALID;
+}