[src/thorpej-i2c-spi-conf]: src/sys/dev/spi If we were directly configured us...

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

details:   https://anonhg.NetBSD.org/src/rev/d4a84ec6a5fd
branches:  thorpej-i2c-spi-conf
changeset: 983393:d4a84ec6a5fd
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Wed May 19 13:40:56 2021 +0000

description:
If we were directly configured using the platform device tree, consult
the device tree for our reference voltage and make the vref sysctl read-only
in that case.  Implement this for the Device Tree bindings for this device
(the "vref-supply" property points to the regulator providing the reference
voltage).

diffstat:

 sys/dev/spi/mcp3k.c |  87 +++++++++++++++++++++++++++++++++++++++++++++++-----
 1 files changed, 78 insertions(+), 9 deletions(-)

diffs (146 lines):

diff -r e8ff00f7741a -r d4a84ec6a5fd sys/dev/spi/mcp3k.c
--- a/sys/dev/spi/mcp3k.c       Wed May 19 13:23:23 2021 +0000
+++ b/sys/dev/spi/mcp3k.c       Wed May 19 13:40:56 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mcp3k.c,v 1.2.36.2 2021/05/19 03:46:26 thorpej Exp $ */
+/*     $NetBSD: mcp3k.c,v 1.2.36.3 2021/05/19 13:40:56 thorpej Exp $ */
 
 /*-
  * Copyright (c) 2015 The NetBSD Foundation, Inc.
@@ -45,6 +45,8 @@
  * MPC3302/3304: http://ww1.microchip.com/downloads/en/DeviceDoc/21697F.pdf
  */
 
+#include "opt_fdt.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/device.h>
@@ -55,6 +57,10 @@
 #include <dev/sysmon/sysmonvar.h>
 #include <dev/spi/spivar.h>
 
+#ifdef FDT
+#include <dev/fdt/fdtvar.h>
+#endif /* FDT */
+
 #define M3K_MAX_SENSORS                16              /* 8 single-ended & 8 diff. */
 
 /* mcp3x0x model description */
@@ -77,6 +83,9 @@
        const struct mcp3kadc_model     *sc_model;
        uint32_t                        sc_adc_max;
        int32_t                         sc_vref_mv;
+#ifdef FDT
+       struct fdtbus_regulator         *sc_vref_supply;
+#endif
 
        struct sysmon_envsys            *sc_sme;
        envsys_data_t                   sc_sensors[M3K_MAX_SENSORS];
@@ -247,14 +256,58 @@
        return rv;
 }
 
+#ifdef FDT
+static bool
+mcp3kadc_vref_fdt(struct mcp3kadc_softc *sc)
+{
+       devhandle_t devhandle = device_handle(sc->sc_dev);
+       int phandle = devhandle_to_of(devhandle);
+       int error;
+       u_int uvolts;
+
+       sc->sc_vref_supply = fdtbus_regulator_acquire(phandle, "vref-supply");
+       if (sc->sc_vref_supply == NULL) {
+               aprint_error_dev(sc->sc_dev,
+                   "unable to acquire \"vref-supply\"\n");
+               return false;
+       }
+
+       error = fdtbus_regulator_enable(sc->sc_vref_supply);
+       if (error) {
+               aprint_error_dev(sc->sc_dev,
+                   "failed to enable \"vref-supply\" (error = %d)\n",
+                   error);
+               return false;
+       }
+
+       error = fdtbus_regulator_get_voltage(sc->sc_vref_supply, &uvolts);
+       if (error) {
+               aprint_error_dev(sc->sc_dev,
+                   "unable to get \"vref-supply\" voltage (error = %d)\n",
+                   error);
+               (void) fdtbus_regulator_disable(sc->sc_vref_supply);
+               return false;
+       }
+
+       /*
+        * Device tree property is uV, convert to mV that we use
+        * internally.
+        */
+       sc->sc_vref_mv = uvolts / 1000;
+       return true;
+}
+#endif /* FDT */
+
 static void
 mcp3kadc_attach(device_t parent, device_t self, void *aux)
 {
        const struct sysctlnode *rnode, *node;
        struct spi_attach_args *sa = aux;
        struct mcp3kadc_softc *sc = device_private(self);
+       devhandle_t devhandle = device_handle(self);
        const struct mcp3kadc_model *model;
        int ch, i, error;
+       bool vref_read_only;
 
        sc->sc_dev = self;
        sc->sc_sh = sa->sa_handle;
@@ -277,13 +330,27 @@
                return;
        }
 
-       /*
-        * XXX Get vref-supply from device tree and make the sysctl
-        * XXX read-only in that case.
-        */
-       /* set a default Vref in mV according to the chip's ADC resolution */
-       sc->sc_vref_mv = 1 << ((model->flags & M3K_SIGNED) ?
-           model->bits - 1 : model->bits);
+       vref_read_only = false;
+       switch (devhandle_type(devhandle)) {
+#ifdef FDT
+       case DEVHANDLE_TYPE_OF:
+               vref_read_only = mcp3kadc_vref_fdt(sc);
+               if (! vref_read_only) {
+                       /* Error already displayed. */
+                       return;
+               }
+               break;
+#endif /* FDT */
+       default:
+               /*
+                * set a default Vref in mV according to the chip's ADC
+                * resolution
+                */
+               sc->sc_vref_mv = 1 << ((model->flags & M3K_SIGNED) ?
+                   model->bits - 1 : model->bits);
+               break;
+       }
+
 
        /* remember maximum value for this ADC - also used for masking */
        sc->sc_adc_max = (1 << model->bits) - 1;
@@ -338,9 +405,11 @@
            NULL, 0, NULL, 0,
            CTL_HW, CTL_CREATE, CTL_EOL);
 
+       const int ctlflag = vref_read_only ? CTLFLAG_READONLY
+                                          : CTLFLAG_READWRITE;
        if (rnode != NULL)
                sysctl_createv(NULL, 0, NULL, &node,
-                   CTLFLAG_READWRITE | CTLFLAG_OWNDESC,
+                   ctlflag | CTLFLAG_OWNDESC,
                    CTLTYPE_INT, "vref",
                    SYSCTL_DESCR("ADC reference voltage"),
                    sysctl_mcp3kadc_vref, 0, (void *)sc, 0,