When the fdt does not provide a list of brightness states, pwmbl(4)

builds a 256 state ramp (i.e. state[i] = i with 0 <= i < 256).

Change the logic to not need to malloc an array of values in this case,
since they are trivially known.

test&ok patrick@

diff --git a/sys/dev/fdt/pwmbl.c b/sys/dev/fdt/pwmbl.c
index 51e279f..08b63f7 100644 (file)
--- a/sys/dev/fdt/pwmbl.c
+++ b/sys/dev/fdt/pwmbl.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: pwmbl.c,v 1.6 2021/10/24 17:52:26 mpi Exp $   */
+/*     $OpenBSD: pwmbl.c,v 1.7 2022/11/14 07:22:44 miod Exp $  */
 /*
  * Copyright (c) 2019 Krystian Lewandowski
  * Copyright (c) 2019 Mark Kettenis <kettenis@openbsd.org>
@@ -35,7 +35,7 @@ struct pwmbl_softc {
        struct device           sc_dev;
        uint32_t                *sc_pwm;
        int                     sc_pwm_len;
-       uint32_t                *sc_levels;
+       uint32_t                *sc_levels;     /* NULL if simple ramp */
        int                     sc_nlevels;
        uint32_t                sc_max_level;
        uint32_t                sc_def_level;
@@ -73,7 +73,7 @@ pwmbl_attach(struct device *parent, struct device *self, void *aux)
        struct pwmbl_softc *sc = (struct pwmbl_softc *)self;
        struct fdt_attach_args *faa = aux;
        uint32_t *gpios;
-       int i, len;
+       int len;
 
        len = OF_getproplen(faa->fa_node, "pwms");
        if (len < 0) {
@@ -95,7 +95,7 @@ pwmbl_attach(struct device *parent, struct device *self, void *aux)
        }
 
        len = OF_getproplen(faa->fa_node, "brightness-levels");
-       if (len > 0) {
+       if (len >= (int)sizeof(uint32_t)) {
                sc->sc_levels = malloc(len, M_DEVBUF, M_WAITOK);
                OF_getpropintarray(faa->fa_node, "brightness-levels",
                    sc->sc_levels, len);
@@ -107,13 +107,9 @@ pwmbl_attach(struct device *parent, struct device *self, void *aux)
                        sc->sc_def_level = sc->sc_nlevels - 1;
                sc->sc_def_level = sc->sc_levels[sc->sc_def_level];
        } else {
+               /* No levels, assume a simple 0..255 ramp. */
                sc->sc_nlevels = 256;
-               sc->sc_levels = mallocarray(sc->sc_nlevels,
-                   sizeof(uint32_t), M_DEVBUF, M_WAITOK);
-               for (i = 0; i < sc->sc_nlevels; i++)
-                       sc->sc_levels[i] = i;
-               sc->sc_max_level = sc->sc_levels[sc->sc_nlevels - 1];
-               sc->sc_def_level = sc->sc_levels[sc->sc_nlevels - 1];
+               sc->sc_max_level = sc->sc_def_level = sc->sc_nlevels - 1;
        }
 
        printf("\n");
@@ -144,6 +140,9 @@ pwmbl_find_brightness(struct pwmbl_softc *sc, uint32_t level)
        uint32_t mid;
        int i;
 
+       if (sc->sc_levels == NULL)
+               return level < sc->sc_nlevels ? level : sc->sc_nlevels - 1;
+
        for (i = 0; i < sc->sc_nlevels - 1; i++) {
                mid = (sc->sc_levels[i] + sc->sc_levels[i + 1]) / 2;
                if (sc->sc_levels[i] <= level && level <= mid)