[PATCH 1/2] GPIO Driver
Steve B
sbattazzo at gmail.com
Wed Jul 1 03:20:02 UTC 2015
After this is sorted into the right place it would be great to see GPIO
IRQs included. I got an IRQ working by just writing to the correct memory
locations from application code (posted the source to users list last
week), but I think Andre's API does have some hooks for that (seemed that
way when I last looked). So it should not be too challenging to add that
feature. If you don't have time to get to it then I will volunteer to do it
once there is a patch that Gedare is happy with.
Steve
On Tue, Jun 30, 2015 at 9:53 AM, Gedare Bloom <gedare at gwu.edu> wrote:
> I don't think we want the shared code in cpukit but rather in
> libbsp/shared.. Also, I think Andre shall commit the shared code, so
> perhaps you should focus on just getting a localized solution working
> in the beagleboard BSP
>
> On Tue, Jun 30, 2015 at 5:46 AM, Ketul Shah <ketulshah1993 at gmail.com>
> wrote:
> > diff --git a/cpukit/include/rtems/gpio.h b/cpukit/include/rtems/gpio.h
> > new file mode 100644
> > index 0000000..3d68c39
> > --- /dev/null
> > +++ b/cpukit/include/rtems/gpio.h
> > @@ -0,0 +1,64 @@
> > +/**
> > + * @file rtems/gpio.h
> > + *
> > + * @brief Global GPIO definitions.
> > + *
> > + * This include the generalized definitions for GPIO
> > + */
> > +
> > +/**
> > + * Copyright (c) 2015 Ketul Shah <ketulshah1993 at gmail.com>
> > + *
> > + * The license and distribution terms for this file may be
> > + * found in the file LICENSE in this distribution or at
> > + * http://www.rtems.org/license/LICENSE.
> > + */
> > +
> > +#ifndef _RTEMS_GPIO_H
> > +#define _RTEMS_GPIO_H
> > +
> > +#ifdef __cplusplus
> > +extern "C" {
> > +#endif /* __cplusplus */
> > +
> > +/* Returned Error Codes by function */
> > +#define GPIO_SUCCESSFUL 0 /* operation is OK */
> > +#define GPIO_UNKNOWN_PIN 1 /* pin not known by bsp */
> > +#define GPIO_UNCONFIGURED_PIN 2 /* pin unable to configure */
> > +#define GPIO_MISCONFIGURED_PIN 3 /* pin configuration can't match
> operation */
> > +
> > +/* Possible GPIO Pin States */
> > +#define GPIO_PIN_STATE_UNCONFIGURED 0
> > +#define GPIO_PIN_STATE_DIGITAL_OUT 1
> > +#define GPIO_PIN_STATE_DIGITAL_IN 2
> > +
> > +/**
> > + * @brief Structure contains all the required members for GPIO access.
> > + */
> > +typedef struct
> > +{
> > + int pin_number;/* The pin number. */
> > + void* platform; /* Opaque hardware specific set up details. */
> > +} gpio_pin_handle;
> > +
> > +/**
> > + * @brief Initializes the GPIO API.
> > + */
> > +extern void rtems_gpio_initialize(void);
> > +/**
> > + * @brief Selects a GPIO pin for a digital output.
> > + */
> > +extern int rtems_gpio_configure_pin_digital_out(
> > + gpio_pin_handle *, unsigned int );
> > +/**
> > + * @brief Turns on the given pin.
> > + */
> > +extern int rtems_gpio_digital_set(gpio_pin_handle *);
> > +/**
> > + * @brief Turns off the given pin.
> > + */
> > +extern int rtems_gpio_digital_clear(gpio_pin_handle *);
> > +/**
> > + * @brief currently configured pin is released and made UNCONFIGURED.
> > + */
> > +extern int rtems_gpio_release_pin(gpio_pin_handle *);
> > \ No newline at end of file
> >
> > diff --git a/c/src/lib/libbsp/arm/beagle/gpio/gpio.c
> b/c/src/lib/libbsp/arm/beagle/gpio/gpio.c
> > new file mode 100644
> > index 0000000..541d456
> > --- /dev/null
> > +++ b/c/src/lib/libbsp/arm/beagle/gpio/gpio.c
> > @@ -0,0 +1,210 @@
> > +/**
> > + * @file
> > + *
> > + * @ingroup arm_beagle
> > + *
> > + * @brief Global BSP definitions.
> > + */
> > +
> > +/**
> > + * Copyright (c) 2015 Ketul Shah <ketulshah1993 at gmail.com>
> > + *
> > + * The license and distribution terms for this file may be
> > + * found in the file LICENSE in this distribution or at
> > + * http://www.rtems.org/license/LICENSE.
> > + */
> > +
> > +#include <libcpu/am335x.h>
> > +#include <rtems.h>
> > +#include <rtems/gpio.h>
> > +#include <bsp/irq.h>
> > +#include <bsp/beagleboneblack.h>
> > +#include <bsp.h>
> > +#include <stdlib.h>
> > +#include <stdint.h>
> > +#include <assert.h>
> > +
> > +/**
> > + * @brief GPIO API mutex atributes.
> > + */
> > +#define MUTEX_ATRIBUTES \
> > + ( RTEMS_LOCAL \
> > + | RTEMS_PRIORITY \
> > + | RTEMS_BINARY_SEMAPHORE \
> > + | RTEMS_INHERIT_PRIORITY \
> > + | RTEMS_NO_PRIORITY_CEILING \
> > + )
> > +
> > +#define OBTAIN_LOCK(s) if(rtems_semaphore_obtain(s,
> \
> > + RTEMS_WAIT,
> \
> > + RTEMS_NO_TIMEOUT
> \
> > + ) !=
> RTEMS_SUCCESSFUL) \
> > + printf("Semaphore not obtained\n");
> > +
> > +#define RELEASE_LOCK(s) if(rtems_semaphore_release(s) !=
> RTEMS_SUCCESSFUL) \
> > + printf("Semaphore not released\n");
> > +
> > +/* GPIO bank pin number as per TRM of AM335X */
> > +static unsigned int gpio_bank_pin[GPIO_PIN_COUNT];
> > +/* GPIO bank determines register of AM335X */
> > +static unsigned int gpio_bank[GPIO_PIN_COUNT];
> > +/* Pin states for all GPIO pins*/
> > +static unsigned int gpio_pin_state[GPIO_PIN_COUNT];
> > +/* Variable for gpio initialization */
> > +static bool is_initialized = false;
> > +/* Total number of gpio banks */
> > +static int gpio_bank_count = GPIO_PIN_COUNT / GPIO_PINS_PER_BANK;
> > +/* Semaphore for avoiding race condition */
> > +static rtems_id bank_lock;
> > +
> > +static const uint32_t gpio_bank_addrs[] =
> > + { AM335X_GPIO0, AM335X_GPIO1, AM335X_GPIO2, AM335X_GPIO3 };
> > +
> > +static uint32_t inline get_pin_mask(unsigned int pin_number)
> > +{
> > + return (1UL << gpio_bank_pin[pin_number]);
> > +}
> > +
> > +static void inline reg_update_set(unsigned int pin_number,uint32_t reg)
> > +{
> > + uint32_t gpioreg=gpio_bank[pin_number]+reg;
> > + uint32_t gpioreg_val=mmio_read(gpioreg);
> > + gpioreg_val |= get_pin_mask(pin_number);
> > + mmio_write(gpioreg, gpioreg_val);
> > +}
> > +
> > +static void inline reg_update_unset(unsigned int pin_number,uint32_t
> reg)
> > +{
> > + uint32_t gpioreg=gpio_bank[pin_number]+reg;
> > + uint32_t gpioreg_val=mmio_read(gpioreg);
> > + gpioreg_val &= ~get_pin_mask(pin_number);
> > + mmio_write(gpioreg, gpioreg_val);
> > +}
> > +
> > +/**
> > + * @brief Initializes the GPIO API.
> > + * Allocates space to gpio_pin_state and sets pin state as
> UNCONFIGURED.
> > + * Creates Semaphore for avoiding any race condition.
> > + * If the API has already been initialized silently exits.
> > + */
> > +void rtems_gpio_initialize(void)
> > +{
> > + int i;
> > + rtems_status_code status;
> > + if ( is_initialized )
> > + return;
> > +
> > + is_initialized = true;
> > + for ( i = 0; i < GPIO_PIN_COUNT; ++i ) {
> > + gpio_pin_state[i] = GPIO_PIN_STATE_UNCONFIGURED;
> > + }
> > + /* Create GPIO bank Semaphores */
> > + status = rtems_semaphore_create(
> > + rtems_build_name('G', 'L', 'C', 'K'),
> > + 1,
> > + MUTEX_ATRIBUTES,
> > + 0,
> > + &bank_lock
> > + );
> > + if (status != RTEMS_SUCCESSFUL){
> > + printf("Semaphore not created\n");
> > + }
> > +}
> > +
> > +/**
> > + * @brief Configures a GPIO pin to perform a digital output.
> > + *
> > + * @retval GPIO_SUCCESSFUL Pin was configured successfully as output.
> > + * @retval GPIO_UNKNOWN_PIN Pin is invalid or unknown.
> > + * @retval GPIO_MISCONFIGURED_PIN Pin is already configured for another
> state.
> > + */
> > +int rtems_gpio_configure_pin_digital_out(
> > + gpio_pin_handle *gpio_pin_assign,unsigned int pin_number){
> > +
> > + OBTAIN_LOCK(bank_lock);
> > + if (pin_number >= GPIO_PIN_COUNT || pin_number < 0){
> > + RELEASE_LOCK(bank_lock);
> > + return GPIO_UNKNOWN_PIN;
> > + }
> > + if (
> > + gpio_pin_state[gpio_pin_assign->pin_number] !=
> GPIO_PIN_STATE_UNCONFIGURED &&
> > + gpio_pin_state[gpio_pin_assign->pin_number] !=
> GPIO_PIN_STATE_DIGITAL_OUT){
> > + RELEASE_LOCK(bank_lock);
> > + return GPIO_MISCONFIGURED_PIN;
> > + }
> > +
> > + gpio_pin_state[gpio_pin_assign->pin_number] =
> GPIO_PIN_STATE_DIGITAL_OUT;
> > + gpio_pin_assign->pin_number = pin_number;
> > + gpio_bank_pin[pin_number] = pin_number % GPIO_PINS_PER_BANK;
> > + gpio_bank[pin_number] =
> gpio_bank_addrs[pin_number/GPIO_PINS_PER_BANK];
> > +
> > + reg_update_unset(gpio_pin_assign->pin_number,AM335X_GPIO_OE);
> > +
> > + RELEASE_LOCK(bank_lock);
> > + return GPIO_SUCCESSFUL;
> > +}
> > +
> > +/**
> > + * @brief Gives an output GPIO pin the logical value of 1.
> > + * @retval GPIO_SUCCESSFUL Pin was set successfully.
> > + * @retval GPIO_MISCONFIGURED_PIN The received pin is not configured
> > + * for digital output.
> > + */
> > +int rtems_gpio_digital_set(gpio_pin_handle *gpio_pin_assign){
> > +
> > + OBTAIN_LOCK(bank_lock);
> > + if (
> > + gpio_pin_state[gpio_pin_assign->pin_number] !=
> GPIO_PIN_STATE_DIGITAL_OUT){
> > + RELEASE_LOCK(bank_lock);
> > + return GPIO_MISCONFIGURED_PIN;
> > + }
> > +
> > + reg_update_set(gpio_pin_assign->pin_number,AM335X_GPIO_DATAOUT);
> > +
> > + RELEASE_LOCK(bank_lock);
> > + return GPIO_SUCCESSFUL;
> > +}
> > +
> > +/**
> > + * @brief Gives an output GPIO pin the logical value of 0.
> > + * @retval GPIO_SUCCESSFUL Pin was cleared successfully.
> > + * @retval GPIO_MISCONFIGURED_PIN The received pin is not configured
> > + * for digital output.
> > + */
> > +int rtems_gpio_digital_clear(gpio_pin_handle *gpio_pin_assign){
> > +
> > + OBTAIN_LOCK(bank_lock);
> > + if (
> > + gpio_pin_state[gpio_pin_assign->pin_number] ==
> GPIO_PIN_STATE_DIGITAL_OUT){
> > + RELEASE_LOCK(bank_lock);
> > + return GPIO_MISCONFIGURED_PIN ;
> > + }
> > +
> > + reg_update_unset(gpio_pin_assign->pin_number,AM335X_GPIO_DATAOUT);
> > +
> > + RELEASE_LOCK(bank_lock);
> > + return GPIO_SUCCESSFUL;
> > +}
> > +/**
> > + * @brief Releases currently configured pin and makes unused for
> repurposing.
> > + * @retval GPIO_SUCCESSFUL Pin was released successfully or it is
> already
> > + * UNCONFIGURED state.
> > + *
> > + */
> > +int rtems_gpio_release_pin(gpio_pin_handle *gpio_pin_assign){
> > +
> > + OBTAIN_LOCK(bank_lock);
> > + if (
> > + gpio_pin_state[gpio_pin_assign->pin_number] ==
> GPIO_PIN_STATE_UNCONFIGURED){
> > + RELEASE_LOCK(bank_lock);
> > + return GPIO_SUCCESSFUL;
> > + }
> > +
> > + OBTAIN_LOCK(bank_lock);
> > +
> > + gpio_pin_state[gpio_pin_assign->pin_number] =
> GPIO_PIN_STATE_UNCONFIGURED;
> > + reg_update_set(gpio_pin_assign->pin_number,AM335X_GPIO_OE);
> > +
> > + RELEASE_LOCK(bank_lock);
> > + return GPIO_SUCCESSFUL;
> > +}
> > \ No newline at end of file
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