[PATCH 1/2] GPIO Driver
Gedare Bloom
gedare at gwu.edu
Tue Jun 30 16:53:32 UTC 2015
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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