> Date: Sun, 6 Oct 2019 23:32:07 +0200
> From: Krystian Lewandowski <k.lewandow...@me.com>
>
> Good evening Mark, tech@,
> I was trying to enable brightness control on Pinebook, so it could be set via:
> wsconsctl display.brightness=N%.
>
> I added sxipwm and pwmbl drivers. First relies on "pwm" bindings,
> 2nd - on "pwm-backlight".
>
> I had it working for some time now. For PWM, I tried to replicate SPI approach
> (spivar.h, pwm parent device, etc.).
> With latest pwm_... support all these are no longer necessary and I updated my
> sxipwm so pwm_... functions are now used.
>
> I'm quite happy with sxipwm, pwmbl also does work for me but I didn't know how
> to properly use it in simplefb. You can see nasty approach in the patch.
> Do you have any suggestion how it should be done?
>
> Device tree related parts:
> pwm: pwm@1c21400 {
> compatible = "allwinner,sun50i-a64-pwm",
> "allwinner,sun5i-a13-pwm";
> reg = <0x01c21400 0x400>;
> clocks = <&osc24M>;
> pinctrl-names = "default";
> pinctrl-0 = <&pwm_pin>;
> #pwm-cells = <3>;
> [...]
>
> pwm_pin: pwm_pin {
> pins = "PD22";
> function = "pwm";
> };
>
> backlight: backlight {
> compatible = "pwm-backlight";
> pwms = <&pwm 0 50000 0>;
> brightness-levels = <0 5 10 15 20 30 40 55 70 85 100>;
> default-brightness-level = <2>;
> enable-gpios = <&pio 3 23 GPIO_ACTIVE_HIGH>; /* PD23 */
> power-supply = <&vdd_bl>;
> }
Cool.
The idea is that pwmbl(4) should implement pwmbl_get_param() and
pwmbl_set_para() functions and set the ws_get_param and ws_set_param
global function parameters like we do in dev/acpi/acpivout.c. And
have simplefb(4) call these function pointers if they're set.
But before that can be done on arm64 those function pointers need to
be moved since dev/pci/vga_pci.c isn't included in the arm64 kernel.
I'll see if I can get that fixed.
> Index: sys/arch/arm64/conf/GENERIC
> ===================================================================
> RCS file: /cvs/src/sys/arch/arm64/conf/GENERIC,v
> retrieving revision 1.126
> diff -u -p -r1.126 GENERIC
> --- sys/arch/arm64/conf/GENERIC 30 Sep 2019 20:48:15 -0000 1.126
> +++ sys/arch/arm64/conf/GENERIC 6 Oct 2019 21:04:59 -0000
> @@ -105,6 +105,7 @@ option WSDISPLAY_DEFAULTSCREENS=6 # init
>
> simplefb* at fdt?
> wsdisplay* at simplefb?
> +pwmbl* at fdt? # PWM backlight
>
> radeondrm* at pci?
> drm* at radeondrm?
> @@ -203,6 +204,7 @@ sdmmc* at sximmc? # SD/MMC bus
> sxisyscon* at fdt? early 1 # System controller
> sxitemp* at fdt? # Temperature sensor
> sxitwi* at fdt? # I2C controller
> +sxipwm* at fdt? # PWM controller
> iic* at sxitwi? # I2C bus
> dwxe* at fdt?
>
> Index: sys/dev/fdt/files.fdt
> ===================================================================
> RCS file: /cvs/src/sys/dev/fdt/files.fdt,v
> retrieving revision 1.95
> diff -u -p -r1.95 files.fdt
> --- sys/dev/fdt/files.fdt 30 Sep 2019 20:44:13 -0000 1.95
> +++ sys/dev/fdt/files.fdt 6 Oct 2019 21:05:05 -0000
> @@ -48,6 +48,14 @@ device sxitwi: i2cbus
> attach sxitwi at fdt
> file dev/fdt/sxitwi.c sxitwi
>
> +device sxipwm
> +attach sxipwm at fdt
> +file dev/fdt/sxipwm.c sxipwm
> +
> +device pwmbl
> +attach pwmbl at fdt
> +file dev/fdt/pwmbl.c pwmbl
> +
> device axppmic
> attach axppmic at i2c
> attach axppmic at rsb with axppmic_rsb
> @@ -205,7 +213,7 @@ attach rkgpio at fdt
> file dev/fdt/rkgpio.c rkgpio
>
> device rkiic: i2cbus
> -attach rkiic at fdt
> +attach rkiic at fdt
> file dev/fdt/rkiic.c rkiic
>
> device rkpmic
> Index: sys/dev/fdt/pwmbl.c
> ===================================================================
> RCS file: sys/dev/fdt/pwmbl.c
> diff -N sys/dev/fdt/pwmbl.c
> --- /dev/null 1 Jan 1970 00:00:00 -0000
> +++ sys/dev/fdt/pwmbl.c 6 Oct 2019 21:05:07 -0000
> @@ -0,0 +1,219 @@
> +/* $OpenBSD$ */
> +/*
> + * Copyright (c) 2019 Krystian Lewandowski
> + *
> + * 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/malloc.h>
> +
> +#include <machine/fdt.h>
> +#include <machine/bus.h>
> +
> +#include <dev/ofw/openfirm.h>
> +#include <dev/ofw/ofw_gpio.h>
> +#include <dev/ofw/ofw_misc.h>
> +
> +#include <dev/wscons/wsconsio.h>
> +
> +struct pwmbl_softc {
> + struct device sc_dev;
> + uint32_t *sc_pwm;
> + uint32_t sc_period;
> + uint32_t sc_flags;
> + uint32_t sc_nlevels;
> + uint32_t *sc_levels;
> + uint32_t sc_def_level;
> +};
> +
> +extern int (*simplefb_read_cmd)(u_long, caddr_t);
> +extern int (*simplefb_write_cmd)(u_long, caddr_t);
> +
> +struct pwmbl_softc *sc_pwmbl;
> +int pwmbl_match(struct device *, void *, void *);
> +void pwmbl_attach(struct device *, struct device *, void *);
> +int pwmbl_get_brightness(void *, uint32_t *);
> +int pwmbl_set_brightness(void *, uint32_t);
> +
> +int pwmbl_simplefb_read_cmd(ulong, caddr_t);
> +int pwmbl_simplefb_write_cmd(ulong, caddr_t);
> +
> +struct cfattach pwmbl_ca = {
> + sizeof (struct pwmbl_softc), pwmbl_match, pwmbl_attach
> +};
> +
> +struct cfdriver pwmbl_cd = {
> + NULL, "pwmbl", DV_DULL
> +};
> +
> +int
> +pwmbl_match(struct device *parent, void *match, void *aux)
> +{
> + struct fdt_attach_args *faa = aux;
> +
> + return OF_is_compatible(faa->fa_node, "pwm-backlight");
> +}
> +
> +void
> +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 len;
> +
> + len = OF_getproplen(faa->fa_node, "pwms");
> + if (len <= 12) {
> + printf(": no pwm\n");
> + return;
> + }
> +
> + sc->sc_pwm = malloc(len, M_DEVBUF, M_WAITOK);
> + OF_getpropintarray(faa->fa_node, "pwms", sc->sc_pwm, len);
> +
> + sc->sc_period = sc->sc_pwm[2];
> + if(len >= 16) {
> + sc->sc_flags = sc->sc_pwm[3];
> + } else {
> + sc->sc_flags = 0;
> + }
> +
> + len = OF_getproplen(faa->fa_node, "enable-gpios");
> + if (len < 0) {
> + printf(": no gpio\n");
> + return;
> + }
> +
> + gpios = malloc(len, M_TEMP, M_WAITOK);
> + OF_getpropintarray(faa->fa_node, "enable-gpios", gpios, len);
> + gpio_controller_config_pin(&gpios[0], GPIO_CONFIG_OUTPUT);
> + gpio_controller_set_pin(&gpios[0], 1);
> + free(gpios, M_TEMP, len);
> +
> + len = OF_getproplen(faa->fa_node, "brightness-levels");
> + if (len < 0) {
> + printf(": no brightness levels\n");
> + return;
> + }
> +
> + printf("\n");
> +
> + sc->sc_levels = malloc(len, M_DEVBUF, M_WAITOK);
> + OF_getpropintarray(faa->fa_node, "brightness-levels",
> + sc->sc_levels, len);
> + sc->sc_nlevels = len / sizeof(uint32_t);
> +
> + sc->sc_def_level = OF_getpropint(faa->fa_node,
> "default-brightness-level",
> + sc->sc_levels[sc->sc_nlevels-1]);
> +
> + // TODO: let simplefb to manage brightness via pwmbl
> + sc_pwmbl = sc;
> + simplefb_read_cmd = pwmbl_simplefb_read_cmd;
> + simplefb_write_cmd = pwmbl_simplefb_write_cmd;
> +}
> +
> +int
> +pwmbl_get_brightness(void *cookie, uint32_t *level) {
> + struct pwmbl_softc *sc = cookie;
> + struct pwm_state ps;
> + uint32_t bl_val;
> + int i;
> +
> + if (pwm_get_state(sc->sc_pwm, &ps))
> + return EINVAL;
> +
> + bl_val = (ps.ps_pulse_width * sc->sc_levels[sc->sc_nlevels - 1]) /
> sc->sc_period;
> +
> + for (i = 0; i < sc->sc_nlevels; i++) {
> + if (bl_val <= sc->sc_levels[i]) {
> + *level = i;
> + break;
> + }
> + }
> +
> + return 0;
> +}
> +
> +int
> +pwmbl_set_brightness(void *cookie, uint32_t level) {
> + struct pwmbl_softc *sc = cookie;
> + struct pwm_state ps;
> +
> + if (pwm_init_state(sc->sc_pwm, &ps))
> + return EINVAL;
> +
> + ps.ps_period = sc->sc_period;
> + ps.ps_flags = sc->sc_flags;
> + ps.ps_enabled = 1;
> + ps.ps_pulse_width = (sc->sc_period * sc->sc_levels[level]) /
> sc->sc_levels[sc->sc_nlevels - 1];
> + return pwm_set_state(sc->sc_pwm, &ps);
> +}
> +
> +// TODO: find a better way for simplefb to manage brightness via pwmbl
> +int
> +pwmbl_simplefb_read_cmd(ulong cmd, caddr_t data)
> +{
> + struct wsdisplay_param *dp = (struct wsdisplay_param *)data;
> + struct pwmbl_softc *sc = (struct pwmbl_softc *)sc_pwmbl;
> + uint32_t level;
> +
> + switch (cmd) {
> + case WSDISPLAYIO_GETPARAM:
> + switch (dp->param) {
> + case WSDISPLAYIO_PARAM_BRIGHTNESS:
> + dp->min = sc->sc_levels[0];
> + dp->max = sc->sc_levels[sc->sc_nlevels - 1];
> +
> + if (pwmbl_get_brightness(sc, &level) >= 0) {
> + dp->curval = sc->sc_levels[level];
> + return 0;
> + }
> + break;
> + }
> + break;
> + default:
> + return -1;
> + }
> + return -1;
> +}
> +
> +int
> +pwmbl_simplefb_write_cmd(ulong cmd, caddr_t data)
> +{
> + struct wsdisplay_param *dp = (struct wsdisplay_param *)data;
> + struct pwmbl_softc *sc = (struct pwmbl_softc *)sc_pwmbl;
> + u_int i;
> +
> + switch (cmd) {
> + case WSDISPLAYIO_SETPARAM:
> + switch (dp->param) {
> + case WSDISPLAYIO_PARAM_BRIGHTNESS:
> + for (i = 0; i < sc->sc_nlevels; i++) {
> + if (dp->curval <= sc->sc_levels[i])
> + break;
> + }
> +
> + if (pwmbl_set_brightness(sc, i) >= 0)
> + return 0;
> + break;
> + }
> + break;
> + default:
> + return -1;
> + }
> + return -1;
> +}
> Index: sys/dev/fdt/simplefb.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/fdt/simplefb.c,v
> retrieving revision 1.5
> diff -u -p -r1.5 simplefb.c
> --- sys/dev/fdt/simplefb.c 27 Aug 2018 09:30:07 -0000 1.5
> +++ sys/dev/fdt/simplefb.c 6 Oct 2019 21:05:10 -0000
> @@ -72,6 +72,9 @@ struct simplefb_softc {
> psize_t sc_psize;
> };
>
> +int (*simplefb_read_cmd)(u_long, caddr_t);
> +int (*simplefb_write_cmd)(u_long, caddr_t);
> +
> struct rasops_info simplefb_ri;
> struct wsscreen_descr simplefb_wsd = { "std" };
> struct wsdisplay_charcell simplefb_bs[SIMPLEFB_WIDTH * SIMPLEFB_HEIGHT];
> @@ -230,9 +233,32 @@ int
> simplefb_wsioctl(void *v, u_long cmd, caddr_t data, int flag, struct proc *p)
> {
> struct rasops_info *ri = v;
> + struct wsdisplay_param *dp = (struct wsdisplay_param *)data;
> struct wsdisplay_fbinfo *wdf;
>
> switch (cmd) {
> + case WSDISPLAYIO_GETPARAM:
> + switch (dp->param) {
> + case WSDISPLAYIO_PARAM_BRIGHTNESS:
> + if (simplefb_read_cmd) {
> + return simplefb_read_cmd(cmd, data);
> + }
> + break;
> + default:
> + return -1;
> + }
> + break;
> + case WSDISPLAYIO_SETPARAM:
> + switch (dp->param) {
> + case WSDISPLAYIO_PARAM_BRIGHTNESS:
> + if (simplefb_write_cmd) {
> + return simplefb_write_cmd(cmd, data);
> + }
> + break;
> + default:
> + return -1;
> + }
> + break;
> case WSDISPLAYIO_GTYPE:
> *(int *)data = WSDISPLAY_TYPE_EFIFB;
> return 0;
> Index: sys/dev/fdt/sxipwm.c
> ===================================================================
> RCS file: sys/dev/fdt/sxipwm.c
> diff -N sys/dev/fdt/sxipwm.c
> --- /dev/null 1 Jan 1970 00:00:00 -0000
> +++ sys/dev/fdt/sxipwm.c 6 Oct 2019 21:05:13 -0000
> @@ -0,0 +1,250 @@
> +/* $OpenBSD$ */
> +/*
> + * Copyright (c) 2019 Krystian Lewandowski
> + *
> + * 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/malloc.h>
> +
> +#include <machine/fdt.h>
> +#include <machine/bus.h>
> +
> +#include <dev/ofw/openfirm.h>
> +#include <dev/ofw/ofw_clock.h>
> +#include <dev/ofw/ofw_misc.h>
> +#include <dev/ofw/ofw_pinctrl.h>
> +#include <dev/ofw/fdt.h>
> +
> +#define PWM_CTRL_REG 0x0
> +#define PWM_CH0_PERIOD 0x4
> +#define PWM_CH0_PRESCAL 0xf
> +
> +#define PWM0_RDY (1 << 28)
> +#define SCLK_CH0_GATING (1 << 6)
> +#define PWM_CH0_ACT_STA (1 << 5)
> +#define PWM_CH0_EN (1 << 4)
> +
> +#define PWM_CH0_CYCLES_SHIFT 16
> +#define PWM_CH0_ACT_CYCLES_SHIFT 0
> +#define PWM_CH0_CYCLES_MAX 0xffff
> +
> +#define NS_PER_S 1000000000
> +
> +#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 sxipwm_prescaler {
> + uint32_t divider;
> + uint8_t mask;
> +};
> +
> +struct sxipwm_prescaler a64_prescalers[] = {
> + { 1, 0xf },
> + { 120, 0x0 },
> + { 180, 0x1 },
> + { 240, 0x2 },
> + { 360, 0x3 },
> + { 480, 0x4 },
> + { 12000, 0x8 },
> + { 24000, 0x9 },
> + { 36000, 0xa },
> + { 48000, 0xb },
> + { 72000, 0xc },
> + { 0 }
> +};
> +
> +struct sxipwm_softc {
> + struct device sc_dev;
> + bus_space_tag_t sc_iot;
> + bus_space_handle_t sc_ioh;
> +
> + struct sxipwm_prescaler *sc_prescalers;
> + uint32_t sc_clkin;
> + struct pwm_device sc_pd;
> +};
> +
> +int sxipwm_match(struct device *, void *, void *);
> +void sxipwm_attach(struct device *, struct device *, void *);
> +int sxipwm_get_state(void *, uint32_t *, struct pwm_state *);
> +int sxipwm_set_state(void *, uint32_t *, struct pwm_state *);
> +
> +struct cfattach sxipwm_ca = {
> + sizeof (struct sxipwm_softc), sxipwm_match, sxipwm_attach
> +};
> +
> +struct cfdriver sxipwm_cd = {
> + NULL, "sxipwm", DV_DULL
> +};
> +
> +int
> +sxipwm_match(struct device *parent, void *match, void *aux)
> +{
> + struct fdt_attach_args *faa = aux;
> +
> + return OF_is_compatible(faa->fa_node, "allwinner,sun50i-a64-pwm");
> +}
> +
> +void
> +sxipwm_attach(struct device *parent, struct device *self, void *aux)
> +{
> + struct sxipwm_softc *sc = (struct sxipwm_softc *)self;
> + struct fdt_attach_args *faa = aux;
> +
> + if (faa->fa_nreg < 1) {
> + printf(": no registers\n");
> + return;
> + }
> +
> + sc->sc_clkin = clock_get_frequency_idx(faa->fa_node, 0);
> + if (sc->sc_clkin == 0) {
> + printf(": no clock\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");
> +
> + pinctrl_byname(faa->fa_node, "default");
> +
> + clock_enable_all(faa->fa_node);
> + reset_deassert_all(faa->fa_node);
> +
> + if (OF_is_compatible(faa->fa_node, "allwinner,sun50i-a64-pwm")) {
> + sc->sc_prescalers = a64_prescalers;
> + }
> +
> + if (sc->sc_prescalers == NULL)
> + return;
> +
> + sc->sc_pd.pd_node = faa->fa_node;
> + sc->sc_pd.pd_cookie = sc;
> + sc->sc_pd.pd_get_state = sxipwm_get_state;
> + sc->sc_pd.pd_set_state = sxipwm_set_state;
> +
> + pwm_register(&sc->sc_pd);
> +}
> +
> +int
> +sxipwm_get_state(void *cookie, uint32_t *cells, struct pwm_state *ps)
> +{
> + struct sxipwm_softc *sc = cookie;
> + uint32_t idx = cells[0];
> + uint32_t ctrl_reg, ch_period_reg;
> + uint16_t cycles, act_cycles;
> + uint32_t rate;
> + int i, prescaler;
> +
> + if (idx != 0)
> + return EINVAL;
> +
> + ctrl_reg = HREAD4(sc, PWM_CTRL_REG);
> + ch_period_reg = HREAD4(sc, PWM_CH0_PERIOD);
> +
> + prescaler = -1;
> + for (i = 0; sc->sc_prescalers[i].divider; i++) {
> + if ((ctrl_reg & PWM_CH0_PRESCAL) == sc->sc_prescalers[i].mask) {
> + prescaler = i;
> + }
> + }
> +
> + if (prescaler < 0)
> + return EINVAL;
> +
> + rate = sc->sc_clkin / sc->sc_prescalers[prescaler].divider;
> + cycles = ((ch_period_reg >> PWM_CH0_CYCLES_SHIFT) + 1 ) &
> PWM_CH0_CYCLES_MAX;
> + act_cycles = (ch_period_reg >> PWM_CH0_ACT_CYCLES_SHIFT) &
> PWM_CH0_CYCLES_MAX;
> +
> + memset(ps, 0, sizeof(struct pwm_state));
> + ps->ps_period = NS_PER_S / (rate / cycles);
> + ps->ps_pulse_width = NS_PER_S / (rate / act_cycles);
> + ps->ps_enabled = (ctrl_reg & (PWM_CH0_EN | SCLK_CH0_GATING)) ==
> (PWM_CH0_EN | SCLK_CH0_GATING);
> +
> + return 0;
> +}
> +
> +int
> +sxipwm_set_state(void *cookie, uint32_t *cells, struct pwm_state *ps)
> +{
> + struct sxipwm_softc *sc = cookie;
> + uint32_t idx = cells[0];
> + uint32_t reg, period_freq, duty_freq, rate;
> + uint16_t cycles, act_cycles;
> + int i, prescaler;
> +
> + period_freq = NS_PER_S / ps->ps_period;
> + duty_freq = NS_PER_S / (ps->ps_pulse_width ? ps->ps_pulse_width : 1);
> +
> + if (idx != 0)
> + return EINVAL;
> +
> + if (period_freq > sc->sc_clkin)
> + return EINVAL;
> +
> + if (duty_freq < period_freq)
> + return EINVAL;
> +
> + prescaler = -1;
> + for (i = 0; sc->sc_prescalers[i].divider; i++) {
> + rate = sc->sc_clkin / (period_freq *
> sc->sc_prescalers[i].divider);
> + if ((rate - 1) < PWM_CH0_CYCLES_MAX) {
> + prescaler = i;
> + break;
> + }
> + }
> +
> + if (prescaler < 0)
> + return EINVAL;
> +
> + reg = HREAD4(sc, PWM_CTRL_REG);
> +
> + if (reg & PWM0_RDY)
> + return EBUSY;
> +
> + if (ps->ps_enabled) {
> + reg |= (PWM_CH0_EN | SCLK_CH0_GATING);
> + } else {
> + reg &= ~(PWM_CH0_EN | SCLK_CH0_GATING);
> + }
> +
> + if (ps->ps_flags & PWM_POLARITY_INVERTED) {
> + reg &= ~PWM_CH0_ACT_STA;
> + } else {
> + reg |= PWM_CH0_ACT_STA;
> + }
> +
> + reg &= ~PWM_CH0_PRESCAL;
> + reg |= sc->sc_prescalers[prescaler].mask;
> + HWRITE4(sc, PWM_CTRL_REG, reg);
> +
> + rate = sc->sc_clkin / sc->sc_prescalers[prescaler].divider;
> + cycles = rate / period_freq;
> + act_cycles = rate / duty_freq;
> +
> + reg = ((cycles - 1) << PWM_CH0_CYCLES_SHIFT) |
> + (act_cycles << PWM_CH0_ACT_CYCLES_SHIFT);
> + HWRITE4(sc, PWM_CH0_PERIOD, reg);
> +
> + return 0;
> +}
>
>
