diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/blackfin/Kconfig | 10 | ||||
| -rw-r--r-- | arch/blackfin/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/blackfin/kernel/pwm.c | 100 |
3 files changed, 111 insertions, 0 deletions
diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig index d619b17c441..c7476295de8 100644 --- a/arch/blackfin/Kconfig +++ b/arch/blackfin/Kconfig @@ -953,6 +953,16 @@ config BFIN_GPTIMERS To compile this driver as a module, choose M here: the module will be called gptimers. +config HAVE_PWM + tristate "Enable PWM API support" + depends on BFIN_GPTIMERS + help + Enable support for the Pulse Width Modulation framework (as + found in linux/pwm.h). + + To compile this driver as a module, choose M here: the module + will be called pwm. + choice prompt "Uncached DMA region" default DMA_UNCACHED_1M diff --git a/arch/blackfin/kernel/Makefile b/arch/blackfin/kernel/Makefile index d550b24d9e9..b7bdc42fe1a 100644 --- a/arch/blackfin/kernel/Makefile +++ b/arch/blackfin/kernel/Makefile @@ -21,6 +21,7 @@ obj-$(CONFIG_FUNCTION_TRACER) += ftrace-entry.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o CFLAGS_REMOVE_ftrace.o = -pg +obj-$(CONFIG_HAVE_PWM) += pwm.o obj-$(CONFIG_IPIPE) += ipipe.o obj-$(CONFIG_BFIN_GPTIMERS) += gptimers.o obj-$(CONFIG_CPLB_INFO) += cplbinfo.o diff --git a/arch/blackfin/kernel/pwm.c b/arch/blackfin/kernel/pwm.c new file mode 100644 index 00000000000..33f5942733b --- /dev/null +++ b/arch/blackfin/kernel/pwm.c @@ -0,0 +1,100 @@ +/* + * Blackfin Pulse Width Modulation (PWM) core + * + * Copyright (c) 2011 Analog Devices Inc. + * + * Licensed under the GPL-2 or later. + */ + +#include <linux/module.h> +#include <linux/pwm.h> +#include <linux/slab.h> + +#include <asm/gptimers.h> +#include <asm/portmux.h> + +struct pwm_device { + unsigned id; + unsigned short pin; +}; + +static const unsigned short pwm_to_gptimer_per[] = { + P_TMR0, P_TMR1, P_TMR2, P_TMR3, P_TMR4, P_TMR5, + P_TMR6, P_TMR7, P_TMR8, P_TMR9, P_TMR10, P_TMR11, +}; + +struct pwm_device *pwm_request(int pwm_id, const char *label) +{ + struct pwm_device *pwm; + int ret; + + /* XXX: pwm_id really should be unsigned */ + if (pwm_id < 0) + return NULL; + + pwm = kzalloc(sizeof(*pwm), GFP_KERNEL); + if (!pwm) + return pwm; + + pwm->id = pwm_id; + if (pwm->id >= ARRAY_SIZE(pwm_to_gptimer_per)) + goto err; + + pwm->pin = pwm_to_gptimer_per[pwm->id]; + ret = peripheral_request(pwm->pin, label); + if (ret) + goto err; + + return pwm; + err: + kfree(pwm); + return NULL; +} +EXPORT_SYMBOL(pwm_request); + +void pwm_free(struct pwm_device *pwm) +{ + peripheral_free(pwm->pin); + kfree(pwm); +} +EXPORT_SYMBOL(pwm_free); + +int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) +{ + unsigned long period, duty; + unsigned long long val; + + if (duty_ns < 0 || duty_ns > period_ns) + return -EINVAL; + + val = (unsigned long long)get_sclk() * period_ns; + do_div(val, NSEC_PER_SEC); + period = val; + + val = (unsigned long long)period * duty_ns; + do_div(val, period_ns); + duty = period - val; + + if (duty >= period) + duty = period - 1; + + set_gptimer_config(pwm->id, TIMER_MODE_PWM | TIMER_PERIOD_CNT); + set_gptimer_pwidth(pwm->id, duty); + set_gptimer_period(pwm->id, period); + + return 0; +} +EXPORT_SYMBOL(pwm_config); + +int pwm_enable(struct pwm_device *pwm) +{ + enable_gptimer(pwm->id); + return 0; +} +EXPORT_SYMBOL(pwm_enable); + +void pwm_disable(struct pwm_device *pwm) +{ + disable_gptimer(pwm->id); +} +EXPORT_SYMBOL(pwm_disable); |