diff options
Diffstat (limited to 'drivers/spi/spi-davinci.c')
| -rw-r--r-- | drivers/spi/spi-davinci.c | 1058 |
1 files changed, 1058 insertions, 0 deletions
diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c new file mode 100644 index 000000000..fda73221f --- /dev/null +++ b/drivers/spi/spi-davinci.c @@ -0,0 +1,1058 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2009 Texas Instruments. + * Copyright (C) 2010 EF Johnson Technologies + */ + +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/gpio/consumer.h> +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/platform_device.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/spi/spi.h> +#include <linux/spi/spi_bitbang.h> +#include <linux/slab.h> + +#include <linux/platform_data/spi-davinci.h> + +#define CS_DEFAULT 0xFF + +#define SPIFMT_PHASE_MASK BIT(16) +#define SPIFMT_POLARITY_MASK BIT(17) +#define SPIFMT_DISTIMER_MASK BIT(18) +#define SPIFMT_SHIFTDIR_MASK BIT(20) +#define SPIFMT_WAITENA_MASK BIT(21) +#define SPIFMT_PARITYENA_MASK BIT(22) +#define SPIFMT_ODD_PARITY_MASK BIT(23) +#define SPIFMT_WDELAY_MASK 0x3f000000u +#define SPIFMT_WDELAY_SHIFT 24 +#define SPIFMT_PRESCALE_SHIFT 8 + +/* SPIPC0 */ +#define SPIPC0_DIFUN_MASK BIT(11) /* MISO */ +#define SPIPC0_DOFUN_MASK BIT(10) /* MOSI */ +#define SPIPC0_CLKFUN_MASK BIT(9) /* CLK */ +#define SPIPC0_SPIENA_MASK BIT(8) /* nREADY */ + +#define SPIINT_MASKALL 0x0101035F +#define SPIINT_MASKINT 0x0000015F +#define SPI_INTLVL_1 0x000001FF +#define SPI_INTLVL_0 0x00000000 + +/* SPIDAT1 (upper 16 bit defines) */ +#define SPIDAT1_CSHOLD_MASK BIT(12) +#define SPIDAT1_WDEL BIT(10) + +/* SPIGCR1 */ +#define SPIGCR1_CLKMOD_MASK BIT(1) +#define SPIGCR1_MASTER_MASK BIT(0) +#define SPIGCR1_POWERDOWN_MASK BIT(8) +#define SPIGCR1_LOOPBACK_MASK BIT(16) +#define SPIGCR1_SPIENA_MASK BIT(24) + +/* SPIBUF */ +#define SPIBUF_TXFULL_MASK BIT(29) +#define SPIBUF_RXEMPTY_MASK BIT(31) + +/* SPIDELAY */ +#define SPIDELAY_C2TDELAY_SHIFT 24 +#define SPIDELAY_C2TDELAY_MASK (0xFF << SPIDELAY_C2TDELAY_SHIFT) +#define SPIDELAY_T2CDELAY_SHIFT 16 +#define SPIDELAY_T2CDELAY_MASK (0xFF << SPIDELAY_T2CDELAY_SHIFT) +#define SPIDELAY_T2EDELAY_SHIFT 8 +#define SPIDELAY_T2EDELAY_MASK (0xFF << SPIDELAY_T2EDELAY_SHIFT) +#define SPIDELAY_C2EDELAY_SHIFT 0 +#define SPIDELAY_C2EDELAY_MASK 0xFF + +/* Error Masks */ +#define SPIFLG_DLEN_ERR_MASK BIT(0) +#define SPIFLG_TIMEOUT_MASK BIT(1) +#define SPIFLG_PARERR_MASK BIT(2) +#define SPIFLG_DESYNC_MASK BIT(3) +#define SPIFLG_BITERR_MASK BIT(4) +#define SPIFLG_OVRRUN_MASK BIT(6) +#define SPIFLG_BUF_INIT_ACTIVE_MASK BIT(24) +#define SPIFLG_ERROR_MASK (SPIFLG_DLEN_ERR_MASK \ + | SPIFLG_TIMEOUT_MASK | SPIFLG_PARERR_MASK \ + | SPIFLG_DESYNC_MASK | SPIFLG_BITERR_MASK \ + | SPIFLG_OVRRUN_MASK) + +#define SPIINT_DMA_REQ_EN BIT(16) + +/* SPI Controller registers */ +#define SPIGCR0 0x00 +#define SPIGCR1 0x04 +#define SPIINT 0x08 +#define SPILVL 0x0c +#define SPIFLG 0x10 +#define SPIPC0 0x14 +#define SPIDAT1 0x3c +#define SPIBUF 0x40 +#define SPIDELAY 0x48 +#define SPIDEF 0x4c +#define SPIFMT0 0x50 + +#define DMA_MIN_BYTES 16 + +/* SPI Controller driver's private data. */ +struct davinci_spi { + struct spi_bitbang bitbang; + struct clk *clk; + + u8 version; + resource_size_t pbase; + void __iomem *base; + u32 irq; + struct completion done; + + const void *tx; + void *rx; + int rcount; + int wcount; + + struct dma_chan *dma_rx; + struct dma_chan *dma_tx; + + struct davinci_spi_platform_data pdata; + + void (*get_rx)(u32 rx_data, struct davinci_spi *); + u32 (*get_tx)(struct davinci_spi *); + + u8 *bytes_per_word; + + u8 prescaler_limit; +}; + +static struct davinci_spi_config davinci_spi_default_cfg; + +static void davinci_spi_rx_buf_u8(u32 data, struct davinci_spi *dspi) +{ + if (dspi->rx) { + u8 *rx = dspi->rx; + *rx++ = (u8)data; + dspi->rx = rx; + } +} + +static void davinci_spi_rx_buf_u16(u32 data, struct davinci_spi *dspi) +{ + if (dspi->rx) { + u16 *rx = dspi->rx; + *rx++ = (u16)data; + dspi->rx = rx; + } +} + +static u32 davinci_spi_tx_buf_u8(struct davinci_spi *dspi) +{ + u32 data = 0; + + if (dspi->tx) { + const u8 *tx = dspi->tx; + + data = *tx++; + dspi->tx = tx; + } + return data; +} + +static u32 davinci_spi_tx_buf_u16(struct davinci_spi *dspi) +{ + u32 data = 0; + + if (dspi->tx) { + const u16 *tx = dspi->tx; + + data = *tx++; + dspi->tx = tx; + } + return data; +} + +static inline void set_io_bits(void __iomem *addr, u32 bits) +{ + u32 v = ioread32(addr); + + v |= bits; + iowrite32(v, addr); +} + +static inline void clear_io_bits(void __iomem *addr, u32 bits) +{ + u32 v = ioread32(addr); + + v &= ~bits; + iowrite32(v, addr); +} + +/* + * Interface to control the chip select signal + */ +static void davinci_spi_chipselect(struct spi_device *spi, int value) +{ + struct davinci_spi *dspi; + struct davinci_spi_config *spicfg = spi->controller_data; + u8 chip_sel = spi->chip_select; + u16 spidat1 = CS_DEFAULT; + + dspi = spi_master_get_devdata(spi->master); + + /* program delay transfers if tx_delay is non zero */ + if (spicfg && spicfg->wdelay) + spidat1 |= SPIDAT1_WDEL; + + /* + * Board specific chip select logic decides the polarity and cs + * line for the controller + */ + if (spi->cs_gpiod) { + if (value == BITBANG_CS_ACTIVE) + gpiod_set_value(spi->cs_gpiod, 1); + else + gpiod_set_value(spi->cs_gpiod, 0); + } else { + if (value == BITBANG_CS_ACTIVE) { + if (!(spi->mode & SPI_CS_WORD)) + spidat1 |= SPIDAT1_CSHOLD_MASK; + spidat1 &= ~(0x1 << chip_sel); + } + } + + iowrite16(spidat1, dspi->base + SPIDAT1 + 2); +} + +/** + * davinci_spi_get_prescale - Calculates the correct prescale value + * @dspi: the controller data + * @max_speed_hz: the maximum rate the SPI clock can run at + * + * This function calculates the prescale value that generates a clock rate + * less than or equal to the specified maximum. + * + * Returns: calculated prescale value for easy programming into SPI registers + * or negative error number if valid prescalar cannot be updated. + */ +static inline int davinci_spi_get_prescale(struct davinci_spi *dspi, + u32 max_speed_hz) +{ + int ret; + + /* Subtract 1 to match what will be programmed into SPI register. */ + ret = DIV_ROUND_UP(clk_get_rate(dspi->clk), max_speed_hz) - 1; + + if (ret < dspi->prescaler_limit || ret > 255) + return -EINVAL; + + return ret; +} + +/** + * davinci_spi_setup_transfer - This functions will determine transfer method + * @spi: spi device on which data transfer to be done + * @t: spi transfer in which transfer info is filled + * + * This function determines data transfer method (8/16/32 bit transfer). + * It will also set the SPI Clock Control register according to + * SPI slave device freq. + */ +static int davinci_spi_setup_transfer(struct spi_device *spi, + struct spi_transfer *t) +{ + + struct davinci_spi *dspi; + struct davinci_spi_config *spicfg; + u8 bits_per_word = 0; + u32 hz = 0, spifmt = 0; + int prescale; + + dspi = spi_master_get_devdata(spi->master); + spicfg = spi->controller_data; + if (!spicfg) + spicfg = &davinci_spi_default_cfg; + + if (t) { + bits_per_word = t->bits_per_word; + hz = t->speed_hz; + } + + /* if bits_per_word is not set then set it default */ + if (!bits_per_word) + bits_per_word = spi->bits_per_word; + + /* + * Assign function pointer to appropriate transfer method + * 8bit, 16bit or 32bit transfer + */ + if (bits_per_word <= 8) { + dspi->get_rx = davinci_spi_rx_buf_u8; + dspi->get_tx = davinci_spi_tx_buf_u8; + dspi->bytes_per_word[spi->chip_select] = 1; + } else { + dspi->get_rx = davinci_spi_rx_buf_u16; + dspi->get_tx = davinci_spi_tx_buf_u16; + dspi->bytes_per_word[spi->chip_select] = 2; + } + + if (!hz) + hz = spi->max_speed_hz; + + /* Set up SPIFMTn register, unique to this chipselect. */ + + prescale = davinci_spi_get_prescale(dspi, hz); + if (prescale < 0) + return prescale; + + spifmt = (prescale << SPIFMT_PRESCALE_SHIFT) | (bits_per_word & 0x1f); + + if (spi->mode & SPI_LSB_FIRST) + spifmt |= SPIFMT_SHIFTDIR_MASK; + + if (spi->mode & SPI_CPOL) + spifmt |= SPIFMT_POLARITY_MASK; + + if (!(spi->mode & SPI_CPHA)) + spifmt |= SPIFMT_PHASE_MASK; + + /* + * Assume wdelay is used only on SPI peripherals that has this field + * in SPIFMTn register and when it's configured from board file or DT. + */ + if (spicfg->wdelay) + spifmt |= ((spicfg->wdelay << SPIFMT_WDELAY_SHIFT) + & SPIFMT_WDELAY_MASK); + + /* + * Version 1 hardware supports two basic SPI modes: + * - Standard SPI mode uses 4 pins, with chipselect + * - 3 pin SPI is a 4 pin variant without CS (SPI_NO_CS) + * (distinct from SPI_3WIRE, with just one data wire; + * or similar variants without MOSI or without MISO) + * + * Version 2 hardware supports an optional handshaking signal, + * so it can support two more modes: + * - 5 pin SPI variant is standard SPI plus SPI_READY + * - 4 pin with enable is (SPI_READY | SPI_NO_CS) + */ + + if (dspi->version == SPI_VERSION_2) { + + u32 delay = 0; + + if (spicfg->odd_parity) + spifmt |= SPIFMT_ODD_PARITY_MASK; + + if (spicfg->parity_enable) + spifmt |= SPIFMT_PARITYENA_MASK; + + if (spicfg->timer_disable) { + spifmt |= SPIFMT_DISTIMER_MASK; + } else { + delay |= (spicfg->c2tdelay << SPIDELAY_C2TDELAY_SHIFT) + & SPIDELAY_C2TDELAY_MASK; + delay |= (spicfg->t2cdelay << SPIDELAY_T2CDELAY_SHIFT) + & SPIDELAY_T2CDELAY_MASK; + } + + if (spi->mode & SPI_READY) { + spifmt |= SPIFMT_WAITENA_MASK; + delay |= (spicfg->t2edelay << SPIDELAY_T2EDELAY_SHIFT) + & SPIDELAY_T2EDELAY_MASK; + delay |= (spicfg->c2edelay << SPIDELAY_C2EDELAY_SHIFT) + & SPIDELAY_C2EDELAY_MASK; + } + + iowrite32(delay, dspi->base + SPIDELAY); + } + + iowrite32(spifmt, dspi->base + SPIFMT0); + + return 0; +} + +static int davinci_spi_of_setup(struct spi_device *spi) +{ + struct davinci_spi_config *spicfg = spi->controller_data; + struct device_node *np = spi->dev.of_node; + struct davinci_spi *dspi = spi_master_get_devdata(spi->master); + u32 prop; + + if (spicfg == NULL && np) { + spicfg = kzalloc(sizeof(*spicfg), GFP_KERNEL); + if (!spicfg) + return -ENOMEM; + *spicfg = davinci_spi_default_cfg; + /* override with dt configured values */ + if (!of_property_read_u32(np, "ti,spi-wdelay", &prop)) + spicfg->wdelay = (u8)prop; + spi->controller_data = spicfg; + + if (dspi->dma_rx && dspi->dma_tx) + spicfg->io_type = SPI_IO_TYPE_DMA; + } + + return 0; +} + +/** + * davinci_spi_setup - This functions will set default transfer method + * @spi: spi device on which data transfer to be done + * + * This functions sets the default transfer method. + */ +static int davinci_spi_setup(struct spi_device *spi) +{ + struct davinci_spi *dspi; + struct device_node *np = spi->dev.of_node; + bool internal_cs = true; + + dspi = spi_master_get_devdata(spi->master); + + if (!(spi->mode & SPI_NO_CS)) { + if (np && spi->cs_gpiod) + internal_cs = false; + + if (internal_cs) + set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select); + } + + if (spi->mode & SPI_READY) + set_io_bits(dspi->base + SPIPC0, SPIPC0_SPIENA_MASK); + + if (spi->mode & SPI_LOOP) + set_io_bits(dspi->base + SPIGCR1, SPIGCR1_LOOPBACK_MASK); + else + clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_LOOPBACK_MASK); + + return davinci_spi_of_setup(spi); +} + +static void davinci_spi_cleanup(struct spi_device *spi) +{ + struct davinci_spi_config *spicfg = spi->controller_data; + + spi->controller_data = NULL; + if (spi->dev.of_node) + kfree(spicfg); +} + +static bool davinci_spi_can_dma(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *xfer) +{ + struct davinci_spi_config *spicfg = spi->controller_data; + bool can_dma = false; + + if (spicfg) + can_dma = (spicfg->io_type == SPI_IO_TYPE_DMA) && + (xfer->len >= DMA_MIN_BYTES) && + !is_vmalloc_addr(xfer->rx_buf) && + !is_vmalloc_addr(xfer->tx_buf); + + return can_dma; +} + +static int davinci_spi_check_error(struct davinci_spi *dspi, int int_status) +{ + struct device *sdev = dspi->bitbang.master->dev.parent; + + if (int_status & SPIFLG_TIMEOUT_MASK) { + dev_err(sdev, "SPI Time-out Error\n"); + return -ETIMEDOUT; + } + if (int_status & SPIFLG_DESYNC_MASK) { + dev_err(sdev, "SPI Desynchronization Error\n"); + return -EIO; + } + if (int_status & SPIFLG_BITERR_MASK) { + dev_err(sdev, "SPI Bit error\n"); + return -EIO; + } + + if (dspi->version == SPI_VERSION_2) { + if (int_status & SPIFLG_DLEN_ERR_MASK) { + dev_err(sdev, "SPI Data Length Error\n"); + return -EIO; + } + if (int_status & SPIFLG_PARERR_MASK) { + dev_err(sdev, "SPI Parity Error\n"); + return -EIO; + } + if (int_status & SPIFLG_OVRRUN_MASK) { + dev_err(sdev, "SPI Data Overrun error\n"); + return -EIO; + } + if (int_status & SPIFLG_BUF_INIT_ACTIVE_MASK) { + dev_err(sdev, "SPI Buffer Init Active\n"); + return -EBUSY; + } + } + + return 0; +} + +/** + * davinci_spi_process_events - check for and handle any SPI controller events + * @dspi: the controller data + * + * This function will check the SPIFLG register and handle any events that are + * detected there + */ +static int davinci_spi_process_events(struct davinci_spi *dspi) +{ + u32 buf, status, errors = 0, spidat1; + + buf = ioread32(dspi->base + SPIBUF); + + if (dspi->rcount > 0 && !(buf & SPIBUF_RXEMPTY_MASK)) { + dspi->get_rx(buf & 0xFFFF, dspi); + dspi->rcount--; + } + + status = ioread32(dspi->base + SPIFLG); + + if (unlikely(status & SPIFLG_ERROR_MASK)) { + errors = status & SPIFLG_ERROR_MASK; + goto out; + } + + if (dspi->wcount > 0 && !(buf & SPIBUF_TXFULL_MASK)) { + spidat1 = ioread32(dspi->base + SPIDAT1); + dspi->wcount--; + spidat1 &= ~0xFFFF; + spidat1 |= 0xFFFF & dspi->get_tx(dspi); + iowrite32(spidat1, dspi->base + SPIDAT1); + } + +out: + return errors; +} + +static void davinci_spi_dma_rx_callback(void *data) +{ + struct davinci_spi *dspi = (struct davinci_spi *)data; + + dspi->rcount = 0; + + if (!dspi->wcount && !dspi->rcount) + complete(&dspi->done); +} + +static void davinci_spi_dma_tx_callback(void *data) +{ + struct davinci_spi *dspi = (struct davinci_spi *)data; + + dspi->wcount = 0; + + if (!dspi->wcount && !dspi->rcount) + complete(&dspi->done); +} + +/** + * davinci_spi_bufs - functions which will handle transfer data + * @spi: spi device on which data transfer to be done + * @t: spi transfer in which transfer info is filled + * + * This function will put data to be transferred into data register + * of SPI controller and then wait until the completion will be marked + * by the IRQ Handler. + */ +static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t) +{ + struct davinci_spi *dspi; + int data_type, ret = -ENOMEM; + u32 tx_data, spidat1; + u32 errors = 0; + struct davinci_spi_config *spicfg; + struct davinci_spi_platform_data *pdata; + + dspi = spi_master_get_devdata(spi->master); + pdata = &dspi->pdata; + spicfg = (struct davinci_spi_config *)spi->controller_data; + if (!spicfg) + spicfg = &davinci_spi_default_cfg; + + /* convert len to words based on bits_per_word */ + data_type = dspi->bytes_per_word[spi->chip_select]; + + dspi->tx = t->tx_buf; + dspi->rx = t->rx_buf; + dspi->wcount = t->len / data_type; + dspi->rcount = dspi->wcount; + + spidat1 = ioread32(dspi->base + SPIDAT1); + + clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK); + set_io_bits(dspi->base + SPIGCR1, SPIGCR1_SPIENA_MASK); + + reinit_completion(&dspi->done); + + if (!davinci_spi_can_dma(spi->master, spi, t)) { + if (spicfg->io_type != SPI_IO_TYPE_POLL) + set_io_bits(dspi->base + SPIINT, SPIINT_MASKINT); + /* start the transfer */ + dspi->wcount--; + tx_data = dspi->get_tx(dspi); + spidat1 &= 0xFFFF0000; + spidat1 |= tx_data & 0xFFFF; + iowrite32(spidat1, dspi->base + SPIDAT1); + } else { + struct dma_slave_config dma_rx_conf = { + .direction = DMA_DEV_TO_MEM, + .src_addr = (unsigned long)dspi->pbase + SPIBUF, + .src_addr_width = data_type, + .src_maxburst = 1, + }; + struct dma_slave_config dma_tx_conf = { + .direction = DMA_MEM_TO_DEV, + .dst_addr = (unsigned long)dspi->pbase + SPIDAT1, + .dst_addr_width = data_type, + .dst_maxburst = 1, + }; + struct dma_async_tx_descriptor *rxdesc; + struct dma_async_tx_descriptor *txdesc; + + dmaengine_slave_config(dspi->dma_rx, &dma_rx_conf); + dmaengine_slave_config(dspi->dma_tx, &dma_tx_conf); + + rxdesc = dmaengine_prep_slave_sg(dspi->dma_rx, + t->rx_sg.sgl, t->rx_sg.nents, DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!rxdesc) + goto err_desc; + + if (!t->tx_buf) { + /* To avoid errors when doing rx-only transfers with + * many SG entries (> 20), use the rx buffer as the + * dummy tx buffer so that dma reloads are done at the + * same time for rx and tx. + */ + t->tx_sg.sgl = t->rx_sg.sgl; + t->tx_sg.nents = t->rx_sg.nents; + } + + txdesc = dmaengine_prep_slave_sg(dspi->dma_tx, + t->tx_sg.sgl, t->tx_sg.nents, DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!txdesc) + goto err_desc; + + rxdesc->callback = davinci_spi_dma_rx_callback; + rxdesc->callback_param = (void *)dspi; + txdesc->callback = davinci_spi_dma_tx_callback; + txdesc->callback_param = (void *)dspi; + + if (pdata->cshold_bug) + iowrite16(spidat1 >> 16, dspi->base + SPIDAT1 + 2); + + dmaengine_submit(rxdesc); + dmaengine_submit(txdesc); + + dma_async_issue_pending(dspi->dma_rx); + dma_async_issue_pending(dspi->dma_tx); + + set_io_bits(dspi->base + SPIINT, SPIINT_DMA_REQ_EN); + } + + /* Wait for the transfer to complete */ + if (spicfg->io_type != SPI_IO_TYPE_POLL) { + if (wait_for_completion_timeout(&dspi->done, HZ) == 0) + errors = SPIFLG_TIMEOUT_MASK; + } else { + while (dspi->rcount > 0 || dspi->wcount > 0) { + errors = davinci_spi_process_events(dspi); + if (errors) + break; + cpu_relax(); + } + } + + clear_io_bits(dspi->base + SPIINT, SPIINT_MASKALL); + if (davinci_spi_can_dma(spi->master, spi, t)) + clear_io_bits(dspi->base + SPIINT, SPIINT_DMA_REQ_EN); + + clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_SPIENA_MASK); + set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK); + + /* + * Check for bit error, desync error,parity error,timeout error and + * receive overflow errors + */ + if (errors) { + ret = davinci_spi_check_error(dspi, errors); + WARN(!ret, "%s: error reported but no error found!\n", + dev_name(&spi->dev)); + return ret; + } + + if (dspi->rcount != 0 || dspi->wcount != 0) { + dev_err(&spi->dev, "SPI data transfer error\n"); + return -EIO; + } + + return t->len; + +err_desc: + return ret; +} + +/** + * dummy_thread_fn - dummy thread function + * @irq: IRQ number for this SPI Master + * @data: structure for SPI Master controller davinci_spi + * + * This is to satisfy the request_threaded_irq() API so that the irq + * handler is called in interrupt context. + */ +static irqreturn_t dummy_thread_fn(s32 irq, void *data) +{ + return IRQ_HANDLED; +} + +/** + * davinci_spi_irq - Interrupt handler for SPI Master Controller + * @irq: IRQ number for this SPI Master + * @data: structure for SPI Master controller davinci_spi + * + * ISR will determine that interrupt arrives either for READ or WRITE command. + * According to command it will do the appropriate action. It will check + * transfer length and if it is not zero then dispatch transfer command again. + * If transfer length is zero then it will indicate the COMPLETION so that + * davinci_spi_bufs function can go ahead. + */ +static irqreturn_t davinci_spi_irq(s32 irq, void *data) +{ + struct davinci_spi *dspi = data; + int status; + + status = davinci_spi_process_events(dspi); + if (unlikely(status != 0)) + clear_io_bits(dspi->base + SPIINT, SPIINT_MASKINT); + + if ((!dspi->rcount && !dspi->wcount) || status) + complete(&dspi->done); + + return IRQ_HANDLED; +} + +static int davinci_spi_request_dma(struct davinci_spi *dspi) +{ + struct device *sdev = dspi->bitbang.master->dev.parent; + + dspi->dma_rx = dma_request_chan(sdev, "rx"); + if (IS_ERR(dspi->dma_rx)) + return PTR_ERR(dspi->dma_rx); + + dspi->dma_tx = dma_request_chan(sdev, "tx"); + if (IS_ERR(dspi->dma_tx)) { + dma_release_channel(dspi->dma_rx); + return PTR_ERR(dspi->dma_tx); + } + + return 0; +} + +#if defined(CONFIG_OF) + +/* OF SPI data structure */ +struct davinci_spi_of_data { + u8 version; + u8 prescaler_limit; +}; + +static const struct davinci_spi_of_data dm6441_spi_data = { + .version = SPI_VERSION_1, + .prescaler_limit = 2, +}; + +static const struct davinci_spi_of_data da830_spi_data = { + .version = SPI_VERSION_2, + .prescaler_limit = 2, +}; + +static const struct davinci_spi_of_data keystone_spi_data = { + .version = SPI_VERSION_1, + .prescaler_limit = 0, +}; + +static const struct of_device_id davinci_spi_of_match[] = { + { + .compatible = "ti,dm6441-spi", + .data = &dm6441_spi_data, + }, + { + .compatible = "ti,da830-spi", + .data = &da830_spi_data, + }, + { + .compatible = "ti,keystone-spi", + .data = &keystone_spi_data, + }, + { }, +}; +MODULE_DEVICE_TABLE(of, davinci_spi_of_match); + +/** + * spi_davinci_get_pdata - Get platform data from DTS binding + * @pdev: ptr to platform data + * @dspi: ptr to driver data + * + * Parses and populates pdata in dspi from device tree bindings. + * + * NOTE: Not all platform data params are supported currently. + */ +static int spi_davinci_get_pdata(struct platform_device *pdev, + struct davinci_spi *dspi) +{ + struct device_node *node = pdev->dev.of_node; + struct davinci_spi_of_data *spi_data; + struct davinci_spi_platform_data *pdata; + unsigned int num_cs, intr_line = 0; + const struct of_device_id *match; + + pdata = &dspi->pdata; + + match = of_match_device(davinci_spi_of_match, &pdev->dev); + if (!match) + return -ENODEV; + + spi_data = (struct davinci_spi_of_data *)match->data; + + pdata->version = spi_data->version; + pdata->prescaler_limit = spi_data->prescaler_limit; + /* + * default num_cs is 1 and all chipsel are internal to the chip + * indicated by chip_sel being NULL or cs_gpios being NULL or + * set to -ENOENT. num-cs includes internal as well as gpios. + * indicated by chip_sel being NULL. GPIO based CS is not + * supported yet in DT bindings. + */ + num_cs = 1; + of_property_read_u32(node, "num-cs", &num_cs); + pdata->num_chipselect = num_cs; + of_property_read_u32(node, "ti,davinci-spi-intr-line", &intr_line); + pdata->intr_line = intr_line; + return 0; +} +#else +static int spi_davinci_get_pdata(struct platform_device *pdev, + struct davinci_spi *dspi) +{ + return -ENODEV; +} +#endif + +/** + * davinci_spi_probe - probe function for SPI Master Controller + * @pdev: platform_device structure which contains plateform specific data + * + * According to Linux Device Model this function will be invoked by Linux + * with platform_device struct which contains the device specific info. + * This function will map the SPI controller's memory, register IRQ, + * Reset SPI controller and setting its registers to default value. + * It will invoke spi_bitbang_start to create work queue so that client driver + * can register transfer method to work queue. + */ +static int davinci_spi_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct davinci_spi *dspi; + struct davinci_spi_platform_data *pdata; + struct resource *r; + int ret = 0; + u32 spipc0; + + master = spi_alloc_master(&pdev->dev, sizeof(struct davinci_spi)); + if (master == NULL) { + ret = -ENOMEM; + goto err; + } + + platform_set_drvdata(pdev, master); + + dspi = spi_master_get_devdata(master); + + if (dev_get_platdata(&pdev->dev)) { + pdata = dev_get_platdata(&pdev->dev); + dspi->pdata = *pdata; + } else { + /* update dspi pdata with that from the DT */ + ret = spi_davinci_get_pdata(pdev, dspi); + if (ret < 0) + goto free_master; + } + + /* pdata in dspi is now updated and point pdata to that */ + pdata = &dspi->pdata; + + dspi->bytes_per_word = devm_kcalloc(&pdev->dev, + pdata->num_chipselect, + sizeof(*dspi->bytes_per_word), + GFP_KERNEL); + if (dspi->bytes_per_word == NULL) { + ret = -ENOMEM; + goto free_master; + } + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (r == NULL) { + ret = -ENOENT; + goto free_master; + } + + dspi->pbase = r->start; + + dspi->base = devm_ioremap_resource(&pdev->dev, r); + if (IS_ERR(dspi->base)) { + ret = PTR_ERR(dspi->base); + goto free_master; + } + + init_completion(&dspi->done); + + ret = platform_get_irq(pdev, 0); + if (ret == 0) + ret = -EINVAL; + if (ret < 0) + goto free_master; + dspi->irq = ret; + + ret = devm_request_threaded_irq(&pdev->dev, dspi->irq, davinci_spi_irq, + dummy_thread_fn, 0, dev_name(&pdev->dev), dspi); + if (ret) + goto free_master; + + dspi->bitbang.master = master; + + dspi->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(dspi->clk)) { + ret = -ENODEV; + goto free_master; + } + ret = clk_prepare_enable(dspi->clk); + if (ret) + goto free_master; + + master->use_gpio_descriptors = true; + master->dev.of_node = pdev->dev.of_node; + master->bus_num = pdev->id; + master->num_chipselect = pdata->num_chipselect; + master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 16); + master->flags = SPI_MASTER_MUST_RX | SPI_MASTER_GPIO_SS; + master->setup = davinci_spi_setup; + master->cleanup = davinci_spi_cleanup; + master->can_dma = davinci_spi_can_dma; + + dspi->bitbang.chipselect = davinci_spi_chipselect; + dspi->bitbang.setup_transfer = davinci_spi_setup_transfer; + dspi->prescaler_limit = pdata->prescaler_limit; + dspi->version = pdata->version; + + dspi->bitbang.flags = SPI_NO_CS | SPI_LSB_FIRST | SPI_LOOP | SPI_CS_WORD; + if (dspi->version == SPI_VERSION_2) + dspi->bitbang.flags |= SPI_READY; + + dspi->bitbang.txrx_bufs = davinci_spi_bufs; + + ret = davinci_spi_request_dma(dspi); + if (ret == -EPROBE_DEFER) { + goto free_clk; + } else if (ret) { + dev_info(&pdev->dev, "DMA is not supported (%d)\n", ret); + dspi->dma_rx = NULL; + dspi->dma_tx = NULL; + } + + dspi->get_rx = davinci_spi_rx_buf_u8; + dspi->get_tx = davinci_spi_tx_buf_u8; + + /* Reset In/OUT SPI module */ + iowrite32(0, dspi->base + SPIGCR0); + udelay(100); + iowrite32(1, dspi->base + SPIGCR0); + + /* Set up SPIPC0. CS and ENA init is done in davinci_spi_setup */ + spipc0 = SPIPC0_DIFUN_MASK | SPIPC0_DOFUN_MASK | SPIPC0_CLKFUN_MASK; + iowrite32(spipc0, dspi->base + SPIPC0); + + if (pdata->intr_line) + iowrite32(SPI_INTLVL_1, dspi->base + SPILVL); + else + iowrite32(SPI_INTLVL_0, dspi->base + SPILVL); + + iowrite32(CS_DEFAULT, dspi->base + SPIDEF); + + /* master mode default */ + set_io_bits(dspi->base + SPIGCR1, SPIGCR1_CLKMOD_MASK); + set_io_bits(dspi->base + SPIGCR1, SPIGCR1_MASTER_MASK); + set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK); + + ret = spi_bitbang_start(&dspi->bitbang); + if (ret) + goto free_dma; + + dev_info(&pdev->dev, "Controller at 0x%p\n", dspi->base); + + return ret; + +free_dma: + if (dspi->dma_rx) { + dma_release_channel(dspi->dma_rx); + dma_release_channel(dspi->dma_tx); + } +free_clk: + clk_disable_unprepare(dspi->clk); +free_master: + spi_master_put(master); +err: + return ret; +} + +/** + * davinci_spi_remove - remove function for SPI Master Controller + * @pdev: platform_device structure which contains plateform specific data + * + * This function will do the reverse action of davinci_spi_probe function + * It will free the IRQ and SPI controller's memory region. + * It will also call spi_bitbang_stop to destroy the work queue which was + * created by spi_bitbang_start. + */ +static int davinci_spi_remove(struct platform_device *pdev) +{ + struct davinci_spi *dspi; + struct spi_master *master; + + master = platform_get_drvdata(pdev); + dspi = spi_master_get_devdata(master); + + spi_bitbang_stop(&dspi->bitbang); + + clk_disable_unprepare(dspi->clk); + + if (dspi->dma_rx) { + dma_release_channel(dspi->dma_rx); + dma_release_channel(dspi->dma_tx); + } + + spi_master_put(master); + return 0; +} + +static struct platform_driver davinci_spi_driver = { + .driver = { + .name = "spi_davinci", + .of_match_table = of_match_ptr(davinci_spi_of_match), + }, + .probe = davinci_spi_probe, + .remove = davinci_spi_remove, +}; +module_platform_driver(davinci_spi_driver); + +MODULE_DESCRIPTION("TI DaVinci SPI Master Controller Driver"); +MODULE_LICENSE("GPL"); |