/************************************************************************************ * configs/sam4l-xplained/src/sam_spi.c * * Copyright (C) 2013 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ************************************************************************************/ /************************************************************************************ * Included Files ************************************************************************************/ #include #include #include #include #include #include #include "sam_gpio.h" #include "sam_spi.h" #include "sam4l-xplained.h" #ifdef CONFIG_SAM34_SPI /************************************************************************************ * Definitions ************************************************************************************/ /* Enables debug output from this file (needs CONFIG_DEBUG too) */ #undef SPI_DEBUG /* Define to enable debug */ #undef SPI_VERBOSE /* Define to enable verbose debug */ #ifdef SPI_DEBUG # define spidbg lldbg # ifdef SPI_VERBOSE # define spivdbg lldbg # else # define spivdbg(x...) # endif #else # undef SPI_VERBOSE # define spidbg(x...) # define spivdbg(x...) #endif /************************************************************************************ * Private Functions ************************************************************************************/ /************************************************************************************ * Public Functions ************************************************************************************/ /************************************************************************************ * Name: sam_spiinitialize * * Description: * Called to configure SPI chip select GPIO pins for the SAM3U10E-EVAL board. * ************************************************************************************/ void weak_function sam_spiinitialize(void) { /* The ZigBee module connects used NPCS0. However, there is not yet any * ZigBee support. */ /* The touchscreen connects using NPCS2 (PC14). */ #if defined(CONFIG_INPUT) && defined(CONFIG_INPUT_ADS7843E) sam_configgpio(GPIO_TSC_NPCS2); #endif } /**************************************************************************** * Name: sam_spicsnumber, sam_spiselect, sam_spistatus, and sam_spicmddata * * Description: * These external functions must be provided by board-specific logic. They * include: * * o sam_spicsnumber and sam_spiselect which are helper functions to * manage the board-specific aspects of the unique SAM3U chip select * architecture. * o sam_spistatus and sam_spicmddata: Implementations of the status * and cmddata methods of the SPI interface defined by struct spi_ops_ * (see include/nuttx/spi.h). All other methods including * up_spiinitialize()) are provided by common SAM3U logic. * * To use this common SPI logic on your board: * * 1. Provide logic in sam_boardinitialize() to configure SPI chip select * pins. * 2. Provide sam_spicsnumber(), sam_spiselect() and sam_spistatus() * functions in your board-specific logic. These functions will perform * chip selection and status operations using GPIOs in the way your board * is configured. * 2. If CONFIG_SPI_CMDDATA is defined in the NuttX configuration, provide * sam_spicmddata() functions in your board-specific logic. This * function will perform cmd/data selection operations using GPIOs in * the way your board is configured. * 3. Add a call to up_spiinitialize() in your low level application * initialization logic * 4. The handle returned by up_spiinitialize() may then be used to bind the * SPI driver to higher level logic (e.g., calling * mmcsd_spislotinitialize(), for example, will bind the SPI driver to * the SPI MMC/SD driver). * ****************************************************************************/ /**************************************************************************** * Name: sam_spicsnumber * * Description: * The SAM3U has 4 CS registers for controlling device features. This * function must be provided by board-specific code. Given a logical device * ID, this function returns a number from 0 to 3 that identifies one of * these SAM3U CS resources. * * Input Parameters: * devid - Identifies the (logical) device * * Returned Values: * On success, a CS number from 0 to 3 is returned; A negated errno may * be returned on a failure. * ****************************************************************************/ int sam_spicsnumber(enum spi_dev_e devid) { int cs = -EINVAL; #if defined(CONFIG_INPUT) && defined(CONFIG_INPUT_ADS7843E) if (devid == SPIDEV_TOUCHSCREEN) { /* Assert the CS pin to the OLED display */ cs = 2; } #endif spidbg("devid: %d CS: %d\n", (int)devid, cs); return cs; } /**************************************************************************** * Name: sam_spiselect * * Description: * PIO chip select pins may be programmed by the board specific logic in * one of two different ways. First, the pins may be programmed as SPI * peripherals. In that case, the pins are completely controlled by the * SPI driver. This method still needs to be provided, but it may be only * a stub. * * An alternative way to program the PIO chip select pins is as a normal * GPIO output. In that case, the automatic control of the CS pins is * bypassed and this function must provide control of the chip select. * NOTE: In this case, the GPIO output pin does *not* have to be the * same as the NPCS pin normal associated with the chip select number. * * Input Parameters: * devid - Identifies the (logical) device * selected - TRUE:Select the device, FALSE:De-select the device * * Returned Values: * None * ****************************************************************************/ void sam_spiselect(enum spi_dev_e devid, bool selected) { /* The touchscreen chip select is implemented as a GPIO OUTPUT that must * be controlled by this function. This is because the ADS7843E driver * must be able to sample the device BUSY GPIO input between SPI transfers. * However, the AD7843E will tri-state the BUSY input whenever the chip * select is de-asserted. So the only option is to control the chip select * manually and hold it low throughout the SPI transfer. */ #if defined(CONFIG_INPUT) && defined(CONFIG_INPUT_ADS7843E) if (devid == SPIDEV_TOUCHSCREEN) { sam_gpiowrite(GPIO_TSC_NPCS2, !selected); } #endif } /**************************************************************************** * Name: sam_spistatus * * Description: * Return status information associated with the SPI device. * * Input Parameters: * devid - Identifies the (logical) device * * Returned Values: * Bit-encoded SPI status (see include/nuttx/spi.h. * ****************************************************************************/ uint8_t sam_spistatus(FAR struct spi_dev_s *dev, enum spi_dev_e devid) { return 0; } #endif /* CONFIG_SAM34_SPI */