// SPDX-License-Identifier: GPL-2.0-only /* * Driver for Cirrus Logic EP93xx SPI controller. * * Copyright (C) 2010-2011 Mika Westerberg * * Explicit FIFO handling code was inspired by amba-pl022 driver. * * Chip select support using other than built-in GPIOs by H. Hartley Sweeten. * * For more information about the SPI controller see documentation on Cirrus * Logic web site: * https://www.cirrus.com/en/pubs/manual/EP93xx_Users_Guide_UM1.pdf */ #include <linux/io.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/delay.h> #include <linux/device.h> #include <linux/dmaengine.h> #include <linux/bitops.h> #include <linux/interrupt.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/sched.h> #include <linux/scatterlist.h> #include <linux/spi/spi.h> #include <linux/platform_data/dma-ep93xx.h> #include <linux/platform_data/spi-ep93xx.h> #define SSPCR0 … #define SSPCR0_SPO … #define SSPCR0_SPH … #define SSPCR0_SCR_SHIFT … #define SSPCR1 … #define SSPCR1_RIE … #define SSPCR1_TIE … #define SSPCR1_RORIE … #define SSPCR1_LBM … #define SSPCR1_SSE … #define SSPCR1_MS … #define SSPCR1_SOD … #define SSPDR … #define SSPSR … #define SSPSR_TFE … #define SSPSR_TNF … #define SSPSR_RNE … #define SSPSR_RFF … #define SSPSR_BSY … #define SSPCPSR … #define SSPIIR … #define SSPIIR_RIS … #define SSPIIR_TIS … #define SSPIIR_RORIS … #define SSPICR … /* timeout in milliseconds */ #define SPI_TIMEOUT … /* maximum depth of RX/TX FIFO */ #define SPI_FIFO_SIZE … /** * struct ep93xx_spi - EP93xx SPI controller structure * @clk: clock for the controller * @mmio: pointer to ioremap()'d registers * @sspdr_phys: physical address of the SSPDR register * @tx: current byte in transfer to transmit * @rx: current byte in transfer to receive * @fifo_level: how full is FIFO (%0..%SPI_FIFO_SIZE - %1). Receiving one * frame decreases this level and sending one frame increases it. * @dma_rx: RX DMA channel * @dma_tx: TX DMA channel * @dma_rx_data: RX parameters passed to the DMA engine * @dma_tx_data: TX parameters passed to the DMA engine * @rx_sgt: sg table for RX transfers * @tx_sgt: sg table for TX transfers * @zeropage: dummy page used as RX buffer when only TX buffer is passed in by * the client */ struct ep93xx_spi { … }; /* converts bits per word to CR0.DSS value */ #define bits_per_word_to_dss(bpw) … /** * ep93xx_spi_calc_divisors() - calculates SPI clock divisors * @host: SPI host * @rate: desired SPI output clock rate * @div_cpsr: pointer to return the cpsr (pre-scaler) divider * @div_scr: pointer to return the scr divider */ static int ep93xx_spi_calc_divisors(struct spi_controller *host, u32 rate, u8 *div_cpsr, u8 *div_scr) { … } static int ep93xx_spi_chip_setup(struct spi_controller *host, struct spi_device *spi, struct spi_transfer *xfer) { … } static void ep93xx_do_write(struct spi_controller *host) { … } static void ep93xx_do_read(struct spi_controller *host) { … } /** * ep93xx_spi_read_write() - perform next RX/TX transfer * @host: SPI host * * This function transfers next bytes (or half-words) to/from RX/TX FIFOs. If * called several times, the whole transfer will be completed. Returns * %-EINPROGRESS when current transfer was not yet completed otherwise %0. * * When this function is finished, RX FIFO should be empty and TX FIFO should be * full. */ static int ep93xx_spi_read_write(struct spi_controller *host) { … } static enum dma_transfer_direction ep93xx_dma_data_to_trans_dir(enum dma_data_direction dir) { … } /** * ep93xx_spi_dma_prepare() - prepares a DMA transfer * @host: SPI host * @dir: DMA transfer direction * * Function configures the DMA, maps the buffer and prepares the DMA * descriptor. Returns a valid DMA descriptor in case of success and ERR_PTR * in case of failure. */ static struct dma_async_tx_descriptor * ep93xx_spi_dma_prepare(struct spi_controller *host, enum dma_data_direction dir) { … } /** * ep93xx_spi_dma_finish() - finishes with a DMA transfer * @host: SPI host * @dir: DMA transfer direction * * Function finishes with the DMA transfer. After this, the DMA buffer is * unmapped. */ static void ep93xx_spi_dma_finish(struct spi_controller *host, enum dma_data_direction dir) { … } static void ep93xx_spi_dma_callback(void *callback_param) { … } static int ep93xx_spi_dma_transfer(struct spi_controller *host) { … } static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id) { … } static int ep93xx_spi_transfer_one(struct spi_controller *host, struct spi_device *spi, struct spi_transfer *xfer) { … } static int ep93xx_spi_prepare_message(struct spi_controller *host, struct spi_message *msg) { … } static int ep93xx_spi_prepare_hardware(struct spi_controller *host) { … } static int ep93xx_spi_unprepare_hardware(struct spi_controller *host) { … } static bool ep93xx_spi_dma_filter(struct dma_chan *chan, void *filter_param) { … } static int ep93xx_spi_setup_dma(struct ep93xx_spi *espi) { … } static void ep93xx_spi_release_dma(struct ep93xx_spi *espi) { … } static int ep93xx_spi_probe(struct platform_device *pdev) { … } static void ep93xx_spi_remove(struct platform_device *pdev) { … } static struct platform_driver ep93xx_spi_driver = …; module_platform_driver(…) …; MODULE_DESCRIPTION(…) …; MODULE_AUTHOR(…) …; MODULE_LICENSE(…) …; MODULE_ALIAS(…) …;
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