--- /dev/null
+/*
+ * drivers/spi/spi-fsl-dspi.c
+ *
+ * Copyright 2013 Freescale Semiconductor, Inc.
+ *
+ * Freescale DSPI driver
+ * This file contains a driver for the Freescale DSPI
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/errno.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/pm_runtime.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#define DRIVER_NAME "fsl-dspi"
+
+#define TRAN_STATE_RX_VOID 0x01
+#define TRAN_STATE_TX_VOID 0x02
+#define TRAN_STATE_WORD_ODD_NUM 0x04
+
+#define DSPI_FIFO_SIZE 4
+
+#define SPI_MCR 0x00
+#define SPI_MCR_MASTER (1 << 31)
+#define SPI_MCR_PCSIS (0x3F << 16)
+#define SPI_MCR_CLR_TXF (1 << 11)
+#define SPI_MCR_CLR_RXF (1 << 10)
+
+#define SPI_TCR 0x08
+
+#define SPI_CTAR(x) (0x0c + (x * 4))
+#define SPI_CTAR_FMSZ(x) (((x) & 0x0000000f) << 27)
+#define SPI_CTAR_CPOL(x) ((x) << 26)
+#define SPI_CTAR_CPHA(x) ((x) << 25)
+#define SPI_CTAR_LSBFE(x) ((x) << 24)
+#define SPI_CTAR_PCSSCR(x) (((x) & 0x00000003) << 22)
+#define SPI_CTAR_PASC(x) (((x) & 0x00000003) << 20)
+#define SPI_CTAR_PDT(x) (((x) & 0x00000003) << 18)
+#define SPI_CTAR_PBR(x) (((x) & 0x00000003) << 16)
+#define SPI_CTAR_CSSCK(x) (((x) & 0x0000000f) << 12)
+#define SPI_CTAR_ASC(x) (((x) & 0x0000000f) << 8)
+#define SPI_CTAR_DT(x) (((x) & 0x0000000f) << 4)
+#define SPI_CTAR_BR(x) ((x) & 0x0000000f)
+
+#define SPI_CTAR0_SLAVE 0x0c
+
+#define SPI_SR 0x2c
+#define SPI_SR_EOQF 0x10000000
+
+#define SPI_RSER 0x30
+#define SPI_RSER_EOQFE 0x10000000
+
+#define SPI_PUSHR 0x34
+#define SPI_PUSHR_CONT (1 << 31)
+#define SPI_PUSHR_CTAS(x) (((x) & 0x00000007) << 28)
+#define SPI_PUSHR_EOQ (1 << 27)
+#define SPI_PUSHR_CTCNT (1 << 26)
+#define SPI_PUSHR_PCS(x) (((1 << x) & 0x0000003f) << 16)
+#define SPI_PUSHR_TXDATA(x) ((x) & 0x0000ffff)
+
+#define SPI_PUSHR_SLAVE 0x34
+
+#define SPI_POPR 0x38
+#define SPI_POPR_RXDATA(x) ((x) & 0x0000ffff)
+
+#define SPI_TXFR0 0x3c
+#define SPI_TXFR1 0x40
+#define SPI_TXFR2 0x44
+#define SPI_TXFR3 0x48
+#define SPI_RXFR0 0x7c
+#define SPI_RXFR1 0x80
+#define SPI_RXFR2 0x84
+#define SPI_RXFR3 0x88
+
+#define SPI_FRAME_BITS(bits) SPI_CTAR_FMSZ((bits) - 1)
+#define SPI_FRAME_BITS_MASK SPI_CTAR_FMSZ(0xf)
+#define SPI_FRAME_BITS_16 SPI_CTAR_FMSZ(0xf)
+#define SPI_FRAME_BITS_8 SPI_CTAR_FMSZ(0x7)
+
+#define SPI_CS_INIT 0x01
+#define SPI_CS_ASSERT 0x02
+#define SPI_CS_DROP 0x04
+
+struct chip_data {
+ u32 mcr_val;
+ u32 ctar_val;
+ u16 void_write_data;
+};
+
+struct fsl_dspi {
+ struct spi_bitbang bitbang;
+ struct platform_device *pdev;
+
+ void *base;
+ int irq;
+ struct clk *clk;
+
+ struct spi_transfer *cur_transfer;
+ struct chip_data *cur_chip;
+ size_t len;
+ void *tx;
+ void *tx_end;
+ void *rx;
+ void *rx_end;
+ char dataflags;
+ u8 cs;
+ u16 void_write_data;
+
+ wait_queue_head_t waitq;
+ u32 waitflags;
+};
+
+static inline int is_double_byte_mode(struct fsl_dspi *dspi)
+{
+ return ((readl(dspi->base + SPI_CTAR(dspi->cs)) & SPI_FRAME_BITS_MASK)
+ == SPI_FRAME_BITS(8)) ? 0 : 1;
+}
+
+static void set_bit_mode(struct fsl_dspi *dspi, unsigned char bits)
+{
+ u32 temp;
+
+ temp = readl(dspi->base + SPI_CTAR(dspi->cs));
+ temp &= ~SPI_FRAME_BITS_MASK;
+ temp |= SPI_FRAME_BITS(bits);
+ writel(temp, dspi->base + SPI_CTAR(dspi->cs));
+}
+
+static void hz_to_spi_baud(char *pbr, char *br, int speed_hz,
+ unsigned long clkrate)
+{
+ /* Valid baud rate pre-scaler values */
+ int pbr_tbl[4] = {2, 3, 5, 7};
+ int brs[16] = { 2, 4, 6, 8,
+ 16, 32, 64, 128,
+ 256, 512, 1024, 2048,
+ 4096, 8192, 16384, 32768 };
+ int temp, i = 0, j = 0;
+
+ temp = clkrate / 2 / speed_hz;
+
+ for (i = 0; i < ARRAY_SIZE(pbr_tbl); i++)
+ for (j = 0; j < ARRAY_SIZE(brs); j++) {
+ if (pbr_tbl[i] * brs[j] >= temp) {
+ *pbr = i;
+ *br = j;
+ return;
+ }
+ }
+
+ pr_warn("Can not find valid buad rate,speed_hz is %d,clkrate is %ld\
+ ,we use the max prescaler value.\n", speed_hz, clkrate);
+ *pbr = ARRAY_SIZE(pbr_tbl) - 1;
+ *br = ARRAY_SIZE(brs) - 1;
+}
+
+static int dspi_transfer_write(struct fsl_dspi *dspi)
+{
+ int tx_count = 0;
+ int tx_word;
+ u16 d16;
+ u8 d8;
+ u32 dspi_pushr = 0;
+ int first = 1;
+
+ tx_word = is_double_byte_mode(dspi);
+
+ /* If we are in word mode, but only have a single byte to transfer
+ * then switch to byte mode temporarily. Will switch back at the
+ * end of the transfer.
+ */
+ if (tx_word && (dspi->len == 1)) {
+ dspi->dataflags |= TRAN_STATE_WORD_ODD_NUM;
+ set_bit_mode(dspi, 8);
+ tx_word = 0;
+ }
+
+ while (dspi->len && (tx_count < DSPI_FIFO_SIZE)) {
+ if (tx_word) {
+ if (dspi->len == 1)
+ break;
+
+ if (!(dspi->dataflags & TRAN_STATE_TX_VOID)) {
+ d16 = *(u16 *)dspi->tx;
+ dspi->tx += 2;
+ } else {
+ d16 = dspi->void_write_data;
+ }
+
+ dspi_pushr = SPI_PUSHR_TXDATA(d16) |
+ SPI_PUSHR_PCS(dspi->cs) |
+ SPI_PUSHR_CTAS(dspi->cs) |
+ SPI_PUSHR_CONT;
+
+ dspi->len -= 2;
+ } else {
+ if (!(dspi->dataflags & TRAN_STATE_TX_VOID)) {
+
+ d8 = *(u8 *)dspi->tx;
+ dspi->tx++;
+ } else {
+ d8 = (u8)dspi->void_write_data;
+ }
+
+ dspi_pushr = SPI_PUSHR_TXDATA(d8) |
+ SPI_PUSHR_PCS(dspi->cs) |
+ SPI_PUSHR_CTAS(dspi->cs) |
+ SPI_PUSHR_CONT;
+
+ dspi->len--;
+ }
+
+ if (dspi->len == 0 || tx_count == DSPI_FIFO_SIZE - 1) {
+ /* last transfer in the transfer */
+ dspi_pushr |= SPI_PUSHR_EOQ;
+ } else if (tx_word && (dspi->len == 1))
+ dspi_pushr |= SPI_PUSHR_EOQ;
+
+ if (first) {
+ first = 0;
+ dspi_pushr |= SPI_PUSHR_CTCNT; /* clear counter */
+ }
+
+ writel(dspi_pushr, dspi->base + SPI_PUSHR);
+ tx_count++;
+ }
+
+ return tx_count * (tx_word + 1);
+}
+
+static int dspi_transfer_read(struct fsl_dspi *dspi)
+{
+ int rx_count = 0;
+ int rx_word = is_double_byte_mode(dspi);
+ u16 d;
+ while ((dspi->rx < dspi->rx_end)
+ && (rx_count < DSPI_FIFO_SIZE)) {
+ if (rx_word) {
+ if ((dspi->rx_end - dspi->rx) == 1)
+ break;
+
+ d = SPI_POPR_RXDATA(readl(dspi->base + SPI_POPR));
+
+ if (!(dspi->dataflags & TRAN_STATE_RX_VOID))
+ *(u16 *)dspi->rx = d;
+ dspi->rx += 2;
+
+ } else {
+ d = SPI_POPR_RXDATA(readl(dspi->base + SPI_POPR));
+ if (!(dspi->dataflags & TRAN_STATE_RX_VOID))
+ *(u8 *)dspi->rx = d;
+ dspi->rx++;
+ }
+ rx_count++;
+ }
+
+ return rx_count;
+}
+
+static int dspi_txrx_transfer(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct fsl_dspi *dspi = spi_master_get_devdata(spi->master);
+ dspi->cur_transfer = t;
+ dspi->cur_chip = spi_get_ctldata(spi);
+ dspi->cs = spi->chip_select;
+ dspi->void_write_data = dspi->cur_chip->void_write_data;
+
+ dspi->dataflags = 0;
+ dspi->tx = (void *)t->tx_buf;
+ dspi->tx_end = dspi->tx + t->len;
+ dspi->rx = t->rx_buf;
+ dspi->rx_end = dspi->rx + t->len;
+ dspi->len = t->len;
+
+ if (!dspi->rx)
+ dspi->dataflags |= TRAN_STATE_RX_VOID;
+
+ if (!dspi->tx)
+ dspi->dataflags |= TRAN_STATE_TX_VOID;
+
+ writel(dspi->cur_chip->mcr_val, dspi->base + SPI_MCR);
+ writel(dspi->cur_chip->ctar_val, dspi->base + SPI_CTAR(dspi->cs));
+ writel(SPI_RSER_EOQFE, dspi->base + SPI_RSER);
+
+ if (t->speed_hz)
+ writel(dspi->cur_chip->ctar_val,
+ dspi->base + SPI_CTAR(dspi->cs));
+
+ dspi_transfer_write(dspi);
+
+ if (wait_event_interruptible(dspi->waitq, dspi->waitflags))
+ dev_err(&dspi->pdev->dev, "wait transfer complete fail!\n");
+ dspi->waitflags = 0;
+
+ return t->len - dspi->len;
+}
+
+static void dspi_chipselect(struct spi_device *spi, int value)
+{
+ struct fsl_dspi *dspi = spi_master_get_devdata(spi->master);
+ u32 pushr = readl(dspi->base + SPI_PUSHR);
+
+ switch (value) {
+ case BITBANG_CS_ACTIVE:
+ pushr |= SPI_PUSHR_CONT;
+ case BITBANG_CS_INACTIVE:
+ pushr &= ~SPI_PUSHR_CONT;
+ }
+
+ writel(pushr, dspi->base + SPI_PUSHR);
+}
+
+static int dspi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct chip_data *chip;
+ struct fsl_dspi *dspi = spi_master_get_devdata(spi->master);
+ unsigned char br = 0, pbr = 0, fmsz = 0;
+
+ /* Only alloc on first setup */
+ chip = spi_get_ctldata(spi);
+ if (chip == NULL) {
+ chip = kcalloc(1, sizeof(struct chip_data), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+ }
+
+ chip->mcr_val = SPI_MCR_MASTER | SPI_MCR_PCSIS |
+ SPI_MCR_CLR_TXF | SPI_MCR_CLR_RXF;
+ if ((spi->bits_per_word >= 4) && (spi->bits_per_word <= 16)) {
+ fmsz = spi->bits_per_word - 1;
+ } else {
+ pr_err("Invalid wordsize\n");
+ kfree(chip);
+ return -ENODEV;
+ }
+
+ chip->void_write_data = 0;
+
+ hz_to_spi_baud(&pbr, &br,
+ spi->max_speed_hz, clk_get_rate(dspi->clk));
+
+ chip->ctar_val = SPI_CTAR_FMSZ(fmsz)
+ | SPI_CTAR_CPOL(spi->mode & SPI_CPOL ? 1 : 0)
+ | SPI_CTAR_CPHA(spi->mode & SPI_CPHA ? 1 : 0)
+ | SPI_CTAR_LSBFE(spi->mode & SPI_LSB_FIRST ? 1 : 0)
+ | SPI_CTAR_PBR(pbr)
+ | SPI_CTAR_BR(br);
+
+ spi_set_ctldata(spi, chip);
+
+ return 0;
+}
+
+static int dspi_setup(struct spi_device *spi)
+{
+ if (!spi->max_speed_hz)
+ return -EINVAL;
+
+ if (!spi->bits_per_word)
+ spi->bits_per_word = 8;
+
+ return dspi_setup_transfer(spi, NULL);
+}
+
+static irqreturn_t dspi_interrupt(int irq, void *dev_id)
+{
+ struct fsl_dspi *dspi = (struct fsl_dspi *)dev_id;
+
+ writel(SPI_SR_EOQF, dspi->base + SPI_SR);
+
+ dspi_transfer_read(dspi);
+
+ if (!dspi->len) {
+ if (dspi->dataflags & TRAN_STATE_WORD_ODD_NUM)
+ set_bit_mode(dspi, 16);
+ dspi->waitflags = 1;
+ wake_up_interruptible(&dspi->waitq);
+ } else {
+ dspi_transfer_write(dspi);
+
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_HANDLED;
+}
+
+static struct of_device_id fsl_dspi_dt_ids[] = {
+ { .compatible = "fsl,vf610-dspi", .data = NULL, },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, fsl_dspi_dt_ids);
+
+#ifdef CONFIG_PM_SLEEP
+static int dspi_suspend(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct fsl_dspi *dspi = spi_master_get_devdata(master);
+
+ spi_master_suspend(master);
+ clk_disable_unprepare(dspi->clk);
+
+ return 0;
+}
+
+static int dspi_resume(struct device *dev)
+{
+
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct fsl_dspi *dspi = spi_master_get_devdata(master);
+
+ clk_prepare_enable(dspi->clk);
+ spi_master_resume(master);
+
+ return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops dspi_pm = {
+ SET_SYSTEM_SLEEP_PM_OPS(dspi_suspend, dspi_resume)
+};
+
+static int dspi_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct spi_master *master;
+ struct fsl_dspi *dspi;
+ struct resource *res;
+ int ret = 0, cs_num, bus_num;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(struct fsl_dspi));
+ if (!master)
+ return -ENOMEM;
+
+ dspi = spi_master_get_devdata(master);
+ dspi->pdev = pdev;
+ dspi->bitbang.master = spi_master_get(master);
+ dspi->bitbang.chipselect = dspi_chipselect;
+ dspi->bitbang.setup_transfer = dspi_setup_transfer;
+ dspi->bitbang.txrx_bufs = dspi_txrx_transfer;
+ dspi->bitbang.master->setup = dspi_setup;
+ dspi->bitbang.master->dev.of_node = pdev->dev.of_node;
+
+ master->mode_bits = SPI_CPOL | SPI_CPHA;
+ master->bits_per_word_mask = SPI_BPW_MASK(4) | SPI_BPW_MASK(8) |
+ SPI_BPW_MASK(16);
+
+ ret = of_property_read_u32(np, "spi-num-chipselects", &cs_num);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "can't get spi-num-chipselects\n");
+ goto out_master_put;
+ }
+ master->num_chipselect = cs_num;
+
+ ret = of_property_read_u32(np, "bus-num", &bus_num);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "can't get bus-num\n");
+ goto out_master_put;
+ }
+ master->bus_num = bus_num;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "can't get platform resource\n");
+ ret = -EINVAL;
+ goto out_master_put;
+ }
+
+ dspi->base = devm_ioremap_resource(&pdev->dev, res);
+ if (!dspi->base) {
+ ret = -EINVAL;
+ goto out_master_put;
+ }
+
+ dspi->irq = platform_get_irq(pdev, 0);
+ if (dspi->irq < 0) {
+ dev_err(&pdev->dev, "can't get platform irq\n");
+ ret = dspi->irq;
+ goto out_master_put;
+ }
+
+ ret = devm_request_irq(&pdev->dev, dspi->irq, dspi_interrupt, 0,
+ pdev->name, dspi);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Unable to attach DSPI interrupt\n");
+ goto out_master_put;
+ }
+
+ dspi->clk = devm_clk_get(&pdev->dev, "dspi");
+ if (IS_ERR(dspi->clk)) {
+ ret = PTR_ERR(dspi->clk);
+ dev_err(&pdev->dev, "unable to get clock\n");
+ goto out_master_put;
+ }
+ clk_prepare_enable(dspi->clk);
+
+ init_waitqueue_head(&dspi->waitq);
+ platform_set_drvdata(pdev, dspi);
+
+ ret = spi_bitbang_start(&dspi->bitbang);
+ if (ret != 0) {
+ dev_err(&pdev->dev, "Problem registering DSPI master\n");
+ goto out_clk_put;
+ }
+
+ pr_info(KERN_INFO "Freescale DSPI master initialized\n");
+ return ret;
+
+out_clk_put:
+ clk_disable_unprepare(dspi->clk);
+out_master_put:
+ spi_master_put(master);
+ platform_set_drvdata(pdev, NULL);
+
+ return ret;
+}
+
+static int dspi_remove(struct platform_device *pdev)
+{
+ struct fsl_dspi *dspi = platform_get_drvdata(pdev);
+
+ /* Disconnect from the SPI framework */
+ spi_bitbang_stop(&dspi->bitbang);
+ spi_master_put(dspi->bitbang.master);
+
+ return 0;
+}
+
+static struct platform_driver fsl_dspi_driver = {
+ .driver.name = DRIVER_NAME,
+ .driver.of_match_table = fsl_dspi_dt_ids,
+ .driver.owner = THIS_MODULE,
+ .driver.pm = &dspi_pm,
+ .probe = dspi_probe,
+ .remove = dspi_remove,
+};
+module_platform_driver(fsl_dspi_driver);
+
+MODULE_DESCRIPTION("Freescale DSPI Controller Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);
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