/* * Driver for Atmel AT32 and AT91 SPI Controllers * * Copyright (C) 2006 Atmel Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* SPI register offsets */ #define SPI_CR 0x0000 #define SPI_MR 0x0004 #define SPI_RDR 0x0008 #define SPI_TDR 0x000c #define SPI_SR 0x0010 #define SPI_IER 0x0014 #define SPI_IDR 0x0018 #define SPI_IMR 0x001c #define SPI_CSR0 0x0030 #define SPI_CSR1 0x0034 #define SPI_CSR2 0x0038 #define SPI_CSR3 0x003c #define SPI_VERSION 0x00fc #define SPI_RPR 0x0100 #define SPI_RCR 0x0104 #define SPI_TPR 0x0108 #define SPI_TCR 0x010c #define SPI_RNPR 0x0110 #define SPI_RNCR 0x0114 #define SPI_TNPR 0x0118 #define SPI_TNCR 0x011c #define SPI_PTCR 0x0120 #define SPI_PTSR 0x0124 /* Bitfields in CR */ #define SPI_SPIEN_OFFSET 0 #define SPI_SPIEN_SIZE 1 #define SPI_SPIDIS_OFFSET 1 #define SPI_SPIDIS_SIZE 1 #define SPI_SWRST_OFFSET 7 #define SPI_SWRST_SIZE 1 #define SPI_LASTXFER_OFFSET 24 #define SPI_LASTXFER_SIZE 1 /* Bitfields in MR */ #define SPI_MSTR_OFFSET 0 #define SPI_MSTR_SIZE 1 #define SPI_PS_OFFSET 1 #define SPI_PS_SIZE 1 #define SPI_PCSDEC_OFFSET 2 #define SPI_PCSDEC_SIZE 1 #define SPI_FDIV_OFFSET 3 #define SPI_FDIV_SIZE 1 #define SPI_MODFDIS_OFFSET 4 #define SPI_MODFDIS_SIZE 1 #define SPI_WDRBT_OFFSET 5 #define SPI_WDRBT_SIZE 1 #define SPI_LLB_OFFSET 7 #define SPI_LLB_SIZE 1 #define SPI_PCS_OFFSET 16 #define SPI_PCS_SIZE 4 #define SPI_DLYBCS_OFFSET 24 #define SPI_DLYBCS_SIZE 8 /* Bitfields in RDR */ #define SPI_RD_OFFSET 0 #define SPI_RD_SIZE 16 /* Bitfields in TDR */ #define SPI_TD_OFFSET 0 #define SPI_TD_SIZE 16 /* Bitfields in SR */ #define SPI_RDRF_OFFSET 0 #define SPI_RDRF_SIZE 1 #define SPI_TDRE_OFFSET 1 #define SPI_TDRE_SIZE 1 #define SPI_MODF_OFFSET 2 #define SPI_MODF_SIZE 1 #define SPI_OVRES_OFFSET 3 #define SPI_OVRES_SIZE 1 #define SPI_ENDRX_OFFSET 4 #define SPI_ENDRX_SIZE 1 #define SPI_ENDTX_OFFSET 5 #define SPI_ENDTX_SIZE 1 #define SPI_RXBUFF_OFFSET 6 #define SPI_RXBUFF_SIZE 1 #define SPI_TXBUFE_OFFSET 7 #define SPI_TXBUFE_SIZE 1 #define SPI_NSSR_OFFSET 8 #define SPI_NSSR_SIZE 1 #define SPI_TXEMPTY_OFFSET 9 #define SPI_TXEMPTY_SIZE 1 #define SPI_SPIENS_OFFSET 16 #define SPI_SPIENS_SIZE 1 /* Bitfields in CSR0 */ #define SPI_CPOL_OFFSET 0 #define SPI_CPOL_SIZE 1 #define SPI_NCPHA_OFFSET 1 #define SPI_NCPHA_SIZE 1 #define SPI_CSAAT_OFFSET 3 #define SPI_CSAAT_SIZE 1 #define SPI_BITS_OFFSET 4 #define SPI_BITS_SIZE 4 #define SPI_SCBR_OFFSET 8 #define SPI_SCBR_SIZE 8 #define SPI_DLYBS_OFFSET 16 #define SPI_DLYBS_SIZE 8 #define SPI_DLYBCT_OFFSET 24 #define SPI_DLYBCT_SIZE 8 /* Bitfields in RCR */ #define SPI_RXCTR_OFFSET 0 #define SPI_RXCTR_SIZE 16 /* Bitfields in TCR */ #define SPI_TXCTR_OFFSET 0 #define SPI_TXCTR_SIZE 16 /* Bitfields in RNCR */ #define SPI_RXNCR_OFFSET 0 #define SPI_RXNCR_SIZE 16 /* Bitfields in TNCR */ #define SPI_TXNCR_OFFSET 0 #define SPI_TXNCR_SIZE 16 /* Bitfields in PTCR */ #define SPI_RXTEN_OFFSET 0 #define SPI_RXTEN_SIZE 1 #define SPI_RXTDIS_OFFSET 1 #define SPI_RXTDIS_SIZE 1 #define SPI_TXTEN_OFFSET 8 #define SPI_TXTEN_SIZE 1 #define SPI_TXTDIS_OFFSET 9 #define SPI_TXTDIS_SIZE 1 /* Constants for BITS */ #define SPI_BITS_8_BPT 0 #define SPI_BITS_9_BPT 1 #define SPI_BITS_10_BPT 2 #define SPI_BITS_11_BPT 3 #define SPI_BITS_12_BPT 4 #define SPI_BITS_13_BPT 5 #define SPI_BITS_14_BPT 6 #define SPI_BITS_15_BPT 7 #define SPI_BITS_16_BPT 8 /* Bit manipulation macros */ #define SPI_BIT(name) \ (1 << SPI_##name##_OFFSET) #define SPI_BF(name, value) \ (((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET) #define SPI_BFEXT(name, value) \ (((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1)) #define SPI_BFINS(name, value, old) \ (((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \ | SPI_BF(name, value)) /* Register access macros */ #define spi_readl(port, reg) \ __raw_readl((port)->regs + SPI_##reg) #define spi_writel(port, reg, value) \ __raw_writel((value), (port)->regs + SPI_##reg) /* use PIO for small transfers, avoiding DMA setup/teardown overhead and * cache operations; better heuristics consider wordsize and bitrate. */ #define DMA_MIN_BYTES 16 struct atmel_spi_dma { struct dma_chan *chan_rx; struct dma_chan *chan_tx; struct scatterlist sgrx; struct scatterlist sgtx; struct dma_async_tx_descriptor *data_desc_rx; struct dma_async_tx_descriptor *data_desc_tx; struct at_dma_slave dma_slave; }; struct atmel_spi_caps { bool is_spi2; bool has_wdrbt; bool has_dma_support; }; /* * The core SPI transfer engine just talks to a register bank to set up * DMA transfers; transfer queue progress is driven by IRQs. The clock * framework provides the base clock, subdivided for each spi_device. */ struct atmel_spi { spinlock_t lock; unsigned long flags; phys_addr_t phybase; void __iomem *regs; int irq; struct clk *clk; struct platform_device *pdev; struct spi_device *stay; u8 stopping; struct list_head queue; struct tasklet_struct tasklet; struct spi_transfer *current_transfer; unsigned long current_remaining_bytes; struct spi_transfer *next_transfer; unsigned long next_remaining_bytes; int done_status; /* scratch buffer */ void *buffer; dma_addr_t buffer_dma; struct atmel_spi_caps caps; bool use_dma; bool use_pdc; /* dmaengine data */ struct atmel_spi_dma dma; }; /* Controller-specific per-slave state */ struct atmel_spi_device { unsigned int npcs_pin; u32 csr; }; #define BUFFER_SIZE PAGE_SIZE #define INVALID_DMA_ADDRESS 0xffffffff /* * Version 2 of the SPI controller has * - CR.LASTXFER * - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero) * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs) * - SPI_CSRx.CSAAT * - SPI_CSRx.SBCR allows faster clocking */ static bool atmel_spi_is_v2(struct atmel_spi *as) { return as->caps.is_spi2; } /* * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby * they assume that spi slave device state will not change on deselect, so * that automagic deselection is OK. ("NPCSx rises if no data is to be * transmitted") Not so! Workaround uses nCSx pins as GPIOs; or newer * controllers have CSAAT and friends. * * Since the CSAAT functionality is a bit weird on newer controllers as * well, we use GPIO to control nCSx pins on all controllers, updating * MR.PCS to avoid confusing the controller. Using GPIOs also lets us * support active-high chipselects despite the controller's belief that * only active-low devices/systems exists. * * However, at91rm9200 has a second erratum whereby nCS0 doesn't work * right when driven with GPIO. ("Mode Fault does not allow more than one * Master on Chip Select 0.") No workaround exists for that ... so for * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH, * and (c) will trigger that first erratum in some cases. */ static void cs_activate(struct atmel_spi *as, struct spi_device *spi) { struct atmel_spi_device *asd = spi->controller_state; unsigned active = spi->mode & SPI_CS_HIGH; u32 mr; if (atmel_spi_is_v2(as)) { spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr); /* For the low SPI version, there is a issue that PDC transfer * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS */ spi_writel(as, CSR0, asd->csr); if (as->caps.has_wdrbt) { spi_writel(as, MR, SPI_BF(PCS, ~(0x01 << spi->chip_select)) | SPI_BIT(WDRBT) | SPI_BIT(MODFDIS) | SPI_BIT(MSTR)); } else { spi_writel(as, MR, SPI_BF(PCS, ~(0x01 << spi->chip_select)) | SPI_BIT(MODFDIS) | SPI_BIT(MSTR)); } mr = spi_readl(as, MR); gpio_set_value(asd->npcs_pin, active); } else { u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0; int i; u32 csr; /* Make sure clock polarity is correct */ for (i = 0; i < spi->master->num_chipselect; i++) { csr = spi_readl(as, CSR0 + 4 * i); if ((csr ^ cpol) & SPI_BIT(CPOL)) spi_writel(as, CSR0 + 4 * i, csr ^ SPI_BIT(CPOL)); } mr = spi_readl(as, MR); mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr); if (spi->chip_select != 0) gpio_set_value(asd->npcs_pin, active); spi_writel(as, MR, mr); } dev_dbg(&spi->dev, "activate %u%s, mr %08x\n", asd->npcs_pin, active ? " (high)" : "", mr); } static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi) { struct atmel_spi_device *asd = spi->controller_state; unsigned active = spi->mode & SPI_CS_HIGH; u32 mr; /* only deactivate *this* device; sometimes transfers to * another device may be active when this routine is called. */ mr = spi_readl(as, MR); if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) { mr = SPI_BFINS(PCS, 0xf, mr); spi_writel(as, MR, mr); } dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n", asd->npcs_pin, active ? " (low)" : "", mr); if (atmel_spi_is_v2(as) || spi->chip_select != 0) gpio_set_value(asd->npcs_pin, !active); } static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock) { spin_lock_irqsave(&as->lock, as->flags); } static void atmel_spi_unlock(struct atmel_spi *as) __releases(&as->lock) { spin_unlock_irqrestore(&as->lock, as->flags); } static inline bool atmel_spi_use_dma(struct atmel_spi *as, struct spi_transfer *xfer) { return as->use_dma && xfer->len >= DMA_MIN_BYTES; } static inline int atmel_spi_xfer_is_last(struct spi_message *msg, struct spi_transfer *xfer) { return msg->transfers.prev == &xfer->transfer_list; } static inline int atmel_spi_xfer_can_be_chained(struct spi_transfer *xfer) { return xfer->delay_usecs == 0 && !xfer->cs_change; } static int atmel_spi_dma_slave_config(struct atmel_spi *as, struct dma_slave_config *slave_config, u8 bits_per_word) { int err = 0; if (bits_per_word > 8) { slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES; slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES; } else { slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; } slave_config->dst_addr = (dma_addr_t)as->phybase + SPI_TDR; slave_config->src_addr = (dma_addr_t)as->phybase + SPI_RDR; slave_config->src_maxburst = 1; slave_config->dst_maxburst = 1; slave_config->device_fc = false; slave_config->direction = DMA_MEM_TO_DEV; if (dmaengine_slave_config(as->dma.chan_tx, slave_config)) { dev_err(&as->pdev->dev, "failed to configure tx dma channel\n"); err = -EINVAL; } slave_config->direction = DMA_DEV_TO_MEM; if (dmaengine_slave_config(as->dma.chan_rx, slave_config)) { dev_err(&as->pdev->dev, "failed to configure rx dma channel\n"); err = -EINVAL; } return err; } static bool filter(struct dma_chan *chan, void *pdata) { struct atmel_spi_dma *sl_pdata = pdata; struct at_dma_slave *sl; if (!sl_pdata) return false; sl = &sl_pdata->dma_slave; if (sl->dma_dev == chan->device->dev) { chan->private = sl; return true; } else { return false; } } static int atmel_spi_configure_dma(struct atmel_spi *as) { struct dma_slave_config slave_config; struct device *dev = &as->pdev->dev; int err; dma_cap_mask_t mask; dma_cap_zero(mask); dma_cap_set(DMA_SLAVE, mask); as->dma.chan_tx = dma_request_slave_channel_compat(mask, filter, &as->dma, dev, "tx"); if (!as->dma.chan_tx) { dev_err(dev, "DMA TX channel not available, SPI unable to use DMA\n"); err = -EBUSY; goto error; } as->dma.chan_rx = dma_request_slave_channel_compat(mask, filter, &as->dma, dev, "rx"); if (!as->dma.chan_rx) { dev_err(dev, "DMA RX channel not available, SPI unable to use DMA\n"); err = -EBUSY; goto error; } err = atmel_spi_dma_slave_config(as, &slave_config, 8); if (err) goto error; dev_info(&as->pdev->dev, "Using %s (tx) and %s (rx) for DMA transfers\n", dma_chan_name(as->dma.chan_tx), dma_chan_name(as->dma.chan_rx)); return 0; error: if (as->dma.chan_rx) dma_release_channel(as->dma.chan_rx); if (as->dma.chan_tx) dma_release_channel(as->dma.chan_tx); return err; } static void atmel_spi_stop_dma(struct atmel_spi *as) { if (as->dma.chan_rx) as->dma.chan_rx->device->device_control(as->dma.chan_rx, DMA_TERMINATE_ALL, 0); if (as->dma.chan_tx) as->dma.chan_tx->device->device_control(as->dma.chan_tx, DMA_TERMINATE_ALL, 0); } static void atmel_spi_release_dma(struct atmel_spi *as) { if (as->dma.chan_rx) dma_release_channel(as->dma.chan_rx); if (as->dma.chan_tx) dma_release_channel(as->dma.chan_tx); } /* This function is called by the DMA driver from tasklet context */ static void dma_callback(void *data) { struct spi_master *master = data; struct atmel_spi *as = spi_master_get_devdata(master); /* trigger SPI tasklet */ tasklet_schedule(&as->tasklet); } /* * Next transfer using PIO. * lock is held, spi tasklet is blocked */ static void atmel_spi_next_xfer_pio(struct spi_master *master, struct spi_transfer *xfer) { struct atmel_spi *as = spi_master_get_devdata(master); dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_pio\n"); as->current_remaining_bytes = xfer->len; /* Make sure data is not remaining in RDR */ spi_readl(as, RDR); while (spi_readl(as, SR) & SPI_BIT(RDRF)) { spi_readl(as, RDR); cpu_relax(); } if (xfer->tx_buf) if (xfer->bits_per_word > 8) spi_writel(as, TDR, *(u16 *)(xfer->tx_buf)); else spi_writel(as, TDR, *(u8 *)(xfer->tx_buf)); else spi_writel(as, TDR, 0); dev_dbg(master->dev.parent, " start pio xfer %p: len %u tx %p rx %p bitpw %d\n", xfer, xfer->len, xfer->tx_buf, xfer->rx_buf, xfer->bits_per_word); /* Enable relevant interrupts */ spi_writel(as, IER, SPI_BIT(RDRF) | SPI_BIT(OVRES)); } /* * Submit next transfer for DMA. * lock is held, spi tasklet is blocked */ static int atmel_spi_next_xfer_dma_submit(struct spi_master *master, struct spi_transfer *xfer, u32 *plen) { struct atmel_spi *as = spi_master_get_devdata(master); struct dma_chan *rxchan = as->dma.chan_rx; struct dma_chan *txchan = as->dma.chan_tx; struct dma_async_tx_descriptor *rxdesc; struct dma_async_tx_descriptor *txdesc; struct dma_slave_config slave_config; dma_cookie_t cookie; u32 len = *plen; dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_dma_submit\n"); /* Check that the channels are available */ if (!rxchan || !txchan) return -ENODEV; /* release lock for DMA operations */ atmel_spi_unlock(as); /* prepare the RX dma transfer */ sg_init_table(&as->dma.sgrx, 1); if (xfer->rx_buf) { as->dma.sgrx.dma_address = xfer->rx_dma + xfer->len - *plen; } else { as->dma.sgrx.dma_address = as->buffer_dma; if (len > BUFFER_SIZE) len = BUFFER_SIZE; } /* prepare the TX dma transfer */ sg_init_table(&as->dma.sgtx, 1); if (xfer->tx_buf) { as->dma.sgtx.dma_address = xfer->tx_dma + xfer->len - *plen; } else { as->dma.sgtx.dma_address = as->buffer_dma; if (len > BUFFER_SIZE) len = BUFFER_SIZE; memset(as->buffer, 0, len); } sg_dma_len(&as->dma.sgtx) = len; sg_dma_len(&as->dma.sgrx) = len; *plen = len; if (atmel_spi_dma_slave_config(as, &slave_config, 8)) goto err_exit; /* Send both scatterlists */ rxdesc = rxchan->device->device_prep_slave_sg(rxchan, &as->dma.sgrx, 1, DMA_FROM_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK, NULL); if (!rxdesc) goto err_dma; txdesc = txchan->device->device_prep_slave_sg(txchan, &as->dma.sgtx, 1, DMA_TO_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK, NULL); if (!txdesc) goto err_dma; dev_dbg(master->dev.parent, " start dma xfer %p: len %u tx %p/%08llx rx %p/%08llx\n", xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma, xfer->rx_buf, (unsigned long long)xfer->rx_dma); /* Enable relevant interrupts */ spi_writel(as, IER, SPI_BIT(OVRES)); /* Put the callback on the RX transfer only, that should finish last */ rxdesc->callback = dma_callback; rxdesc->callback_param = master; /* Submit and fire RX and TX with TX last so we're ready to read! */ cookie = rxdesc->tx_submit(rxdesc); if (dma_submit_error(cookie)) goto err_dma; cookie = txdesc->tx_submit(txdesc); if (dma_submit_error(cookie)) goto err_dma; rxchan->device->device_issue_pending(rxchan); txchan->device->device_issue_pending(txchan); /* take back lock */ atmel_spi_lock(as); return 0; err_dma: spi_writel(as, IDR, SPI_BIT(OVRES)); atmel_spi_stop_dma(as); err_exit: atmel_spi_lock(as); return -ENOMEM; } static void atmel_spi_next_xfer_data(struct spi_master *master, struct spi_transfer *xfer, dma_addr_t *tx_dma, dma_addr_t *rx_dma, u32 *plen) { struct atmel_spi *as = spi_master_get_devdata(master); u32 len = *plen; /* use scratch buffer only when rx or tx data is unspecified */ if (xfer->rx_buf) *rx_dma = xfer->rx_dma + xfer->len - *plen; else { *rx_dma = as->buffer_dma; if (len > BUFFER_SIZE) len = BUFFER_SIZE; } if (xfer->tx_buf) *tx_dma = xfer->tx_dma + xfer->len - *plen; else { *tx_dma = as->buffer_dma; if (len > BUFFER_SIZE) len = BUFFER_SIZE; memset(as->buffer, 0, len); dma_sync_single_for_device(&as->pdev->dev, as->buffer_dma, len, DMA_TO_DEVICE); } *plen = len; } /* * Submit next transfer for PDC. * lock is held, spi irq is blocked */ static void atmel_spi_pdc_next_xfer(struct spi_master *master, struct spi_message *msg) { struct atmel_spi *as = spi_master_get_devdata(master); struct spi_transfer *xfer; u32 len, remaining; u32 ieval; dma_addr_t tx_dma, rx_dma; if (!as->current_transfer) xfer = list_entry(msg->transfers.next, struct spi_transfer, transfer_list); else if (!as->next_transfer) xfer = list_entry(as->current_transfer->transfer_list.next, struct spi_transfer, transfer_list); else xfer = NULL; if (xfer) { spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); len = xfer->len; atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len); remaining = xfer->len - len; spi_writel(as, RPR, rx_dma); spi_writel(as, TPR, tx_dma); if (msg->spi->bits_per_word > 8) len >>= 1; spi_writel(as, RCR, len); spi_writel(as, TCR, len); dev_dbg(&msg->spi->dev, " start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n", xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma, xfer->rx_buf, (unsigned long long)xfer->rx_dma); } else { xfer = as->next_transfer; remaining = as->next_remaining_bytes; } as->current_transfer = xfer; as->current_remaining_bytes = remaining; if (remaining > 0) len = remaining; else if (!atmel_spi_xfer_is_last(msg, xfer) && atmel_spi_xfer_can_be_chained(xfer)) { xfer = list_entry(xfer->transfer_list.next, struct spi_transfer, transfer_list); len = xfer->len; } else xfer = NULL; as->next_transfer = xfer; if (xfer) { u32 total; total = len; atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len); as->next_remaining_bytes = total - len; spi_writel(as, RNPR, rx_dma); spi_writel(as, TNPR, tx_dma); if (msg->spi->bits_per_word > 8) len >>= 1; spi_writel(as, RNCR, len); spi_writel(as, TNCR, len); dev_dbg(&msg->spi->dev, " next xfer %p: len %u tx %p/%08llx rx %p/%08llx\n", xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma, xfer->rx_buf, (unsigned long long)xfer->rx_dma); ieval = SPI_BIT(ENDRX) | SPI_BIT(OVRES); } else { spi_writel(as, RNCR, 0); spi_writel(as, TNCR, 0); ieval = SPI_BIT(RXBUFF) | SPI_BIT(ENDRX) | SPI_BIT(OVRES); } /* REVISIT: We're waiting for ENDRX before we start the next * transfer because we need to handle some difficult timing * issues otherwise. If we wait for ENDTX in one transfer and * then starts waiting for ENDRX in the next, it's difficult * to tell the difference between the ENDRX interrupt we're * actually waiting for and the ENDRX interrupt of the * previous transfer. * * It should be doable, though. Just not now... */ spi_writel(as, IER, ieval); spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN)); } /* * Choose way to submit next transfer and start it. * lock is held, spi tasklet is blocked */ static void atmel_spi_dma_next_xfer(struct spi_master *master, struct spi_message *msg) { struct atmel_spi *as = spi_master_get_devdata(master); struct spi_transfer *xfer; u32 remaining, len; remaining = as->current_remaining_bytes; if (remaining) { xfer = as->current_transfer; len = remaining; } else { if (!as->current_transfer) xfer = list_entry(msg->transfers.next, struct spi_transfer, transfer_list); else xfer = list_entry( as->current_transfer->transfer_list.next, struct spi_transfer, transfer_list); as->current_transfer = xfer; len = xfer->len; } if (atmel_spi_use_dma(as, xfer)) { u32 total = len; if (!atmel_spi_next_xfer_dma_submit(master, xfer, &len)) { as->current_remaining_bytes = total - len; return; } else { dev_err(&msg->spi->dev, "unable to use DMA, fallback to PIO\n"); } } /* use PIO if error appened using DMA */ atmel_spi_next_xfer_pio(master, xfer); } static void atmel_spi_next_message(struct spi_master *master) { struct atmel_spi *as = spi_master_get_devdata(master); struct spi_message *msg; struct spi_device *spi; BUG_ON(as->current_transfer); msg = list_entry(as->queue.next, struct spi_message, queue); spi = msg->spi; dev_dbg(master->dev.parent, "start message %p for %s\n", msg, dev_name(&spi->dev)); /* select chip if it's not still active */ if (as->stay) { if (as->stay != spi) { cs_deactivate(as, as->stay); cs_activate(as, spi); } as->stay = NULL; } else cs_activate(as, spi); if (as->use_pdc) atmel_spi_pdc_next_xfer(master, msg); else atmel_spi_dma_next_xfer(master, msg); } /* * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma: * - The buffer is either valid for CPU access, else NULL * - If the buffer is valid, so is its DMA address * * This driver manages the dma address unless message->is_dma_mapped. */ static int atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer) { struct device *dev = &as->pdev->dev; xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS; if (xfer->tx_buf) { /* tx_buf is a const void* where we need a void * for the dma * mapping */ void *nonconst_tx = (void *)xfer->tx_buf; xfer->tx_dma = dma_map_single(dev, nonconst_tx, xfer->len, DMA_TO_DEVICE); if (dma_mapping_error(dev, xfer->tx_dma)) return -ENOMEM; } if (xfer->rx_buf) { xfer->rx_dma = dma_map_single(dev, xfer->rx_buf, xfer->len, DMA_FROM_DEVICE); if (dma_mapping_error(dev, xfer->rx_dma)) { if (xfer->tx_buf) dma_unmap_single(dev, xfer->tx_dma, xfer->len, DMA_TO_DEVICE); return -ENOMEM; } } return 0; } static void atmel_spi_dma_unmap_xfer(struct spi_master *master, struct spi_transfer *xfer) { if (xfer->tx_dma != INVALID_DMA_ADDRESS) dma_unmap_single(master->dev.parent, xfer->tx_dma, xfer->len, DMA_TO_DEVICE); if (xfer->rx_dma != INVALID_DMA_ADDRESS) dma_unmap_single(master->dev.parent, xfer->rx_dma, xfer->len, DMA_FROM_DEVICE); } static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as) { spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); } static void atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as, struct spi_message *msg, int stay) { if (!stay || as->done_status < 0) cs_deactivate(as, msg->spi); else as->stay = msg->spi; list_del(&msg->queue); msg->status = as->done_status; dev_dbg(master->dev.parent, "xfer complete: %u bytes transferred\n", msg->actual_length); atmel_spi_unlock(as); msg->complete(msg->context); atmel_spi_lock(as); as->current_transfer = NULL; as->next_transfer = NULL; as->done_status = 0; /* continue if needed */ if (list_empty(&as->queue) || as->stopping) { if (as->use_pdc) atmel_spi_disable_pdc_transfer(as); } else { atmel_spi_next_message(master); } } /* Called from IRQ * lock is held * * Must update "current_remaining_bytes" to keep track of data * to transfer. */ static void atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer) { u8 *txp; u8 *rxp; u16 *txp16; u16 *rxp16; unsigned long xfer_pos = xfer->len - as->current_remaining_bytes; if (xfer->rx_buf) { if (xfer->bits_per_word > 8) { rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos); *rxp16 = spi_readl(as, RDR); } else { rxp = ((u8 *)xfer->rx_buf) + xfer_pos; *rxp = spi_readl(as, RDR); } } else { spi_readl(as, RDR); } if (xfer->bits_per_word > 8) { as->current_remaining_bytes -= 2; if (as->current_remaining_bytes < 0) as->current_remaining_bytes = 0; } else { as->current_remaining_bytes--; } if (as->current_remaining_bytes) { if (xfer->tx_buf) { if (xfer->bits_per_word > 8) { txp16 = (u16 *)(((u8 *)xfer->tx_buf) + xfer_pos + 2); spi_writel(as, TDR, *txp16); } else { txp = ((u8 *)xfer->tx_buf) + xfer_pos + 1; spi_writel(as, TDR, *txp); } } else { spi_writel(as, TDR, 0); } } } /* Tasklet * Called from DMA callback + pio transfer and overrun IRQ. */ static void atmel_spi_tasklet_func(unsigned long data) { struct spi_master *master = (struct spi_master *)data; struct atmel_spi *as = spi_master_get_devdata(master); struct spi_message *msg; struct spi_transfer *xfer; dev_vdbg(master->dev.parent, "atmel_spi_tasklet_func\n"); atmel_spi_lock(as); xfer = as->current_transfer; if (xfer == NULL) /* already been there */ goto tasklet_out; msg = list_entry(as->queue.next, struct spi_message, queue); if (as->current_remaining_bytes == 0) { if (as->done_status < 0) { /* error happened (overrun) */ if (atmel_spi_use_dma(as, xfer)) atmel_spi_stop_dma(as); } else { /* only update length if no error */ msg->actual_length += xfer->len; } if (atmel_spi_use_dma(as, xfer)) if (!msg->is_dma_mapped) atmel_spi_dma_unmap_xfer(master, xfer); if (xfer->delay_usecs) udelay(xfer->delay_usecs); if (atmel_spi_xfer_is_last(msg, xfer) || as->done_status < 0) { /* report completed (or erroneous) message */ atmel_spi_msg_done(master, as, msg, xfer->cs_change); } else { if (xfer->cs_change) { cs_deactivate(as, msg->spi); udelay(1); cs_activate(as, msg->spi); } /* * Not done yet. Submit the next transfer. * * FIXME handle protocol options for xfer */ atmel_spi_dma_next_xfer(master, msg); } } else { /* * Keep going, we still have data to send in * the current transfer. */ atmel_spi_dma_next_xfer(master, msg); } tasklet_out: atmel_spi_unlock(as); } /* Interrupt * * No need for locking in this Interrupt handler: done_status is the * only information modified. What we need is the update of this field * before tasklet runs. This is ensured by using barrier. */ static irqreturn_t atmel_spi_pio_interrupt(int irq, void *dev_id) { struct spi_master *master = dev_id; struct atmel_spi *as = spi_master_get_devdata(master); u32 status, pending, imr; struct spi_transfer *xfer; int ret = IRQ_NONE; imr = spi_readl(as, IMR); status = spi_readl(as, SR); pending = status & imr; if (pending & SPI_BIT(OVRES)) { ret = IRQ_HANDLED; spi_writel(as, IDR, SPI_BIT(OVRES)); dev_warn(master->dev.parent, "overrun\n"); /* * When we get an overrun, we disregard the current * transfer. Data will not be copied back from any * bounce buffer and msg->actual_len will not be * updated with the last xfer. * * We will also not process any remaning transfers in * the message. * * All actions are done in tasklet with done_status indication */ as->done_status = -EIO; smp_wmb(); /* Clear any overrun happening while cleaning up */ spi_readl(as, SR); tasklet_schedule(&as->tasklet); } else if (pending & SPI_BIT(RDRF)) { atmel_spi_lock(as); if (as->current_remaining_bytes) { ret = IRQ_HANDLED; xfer = as->current_transfer; atmel_spi_pump_pio_data(as, xfer); if (!as->current_remaining_bytes) { /* no more data to xfer, kick tasklet */ spi_writel(as, IDR, pending); tasklet_schedule(&as->tasklet); } } atmel_spi_unlock(as); } else { WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending); ret = IRQ_HANDLED; spi_writel(as, IDR, pending); } return ret; } static irqreturn_t atmel_spi_pdc_interrupt(int irq, void *dev_id) { struct spi_master *master = dev_id; struct atmel_spi *as = spi_master_get_devdata(master); struct spi_message *msg; struct spi_transfer *xfer; u32 status, pending, imr; int ret = IRQ_NONE; atmel_spi_lock(as); xfer = as->current_transfer; msg = list_entry(as->queue.next, struct spi_message, queue); imr = spi_readl(as, IMR); status = spi_readl(as, SR); pending = status & imr; if (pending & SPI_BIT(OVRES)) { int timeout; ret = IRQ_HANDLED; spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX) | SPI_BIT(OVRES))); /* * When we get an overrun, we disregard the current * transfer. Data will not be copied back from any * bounce buffer and msg->actual_len will not be * updated with the last xfer. * * We will also not process any remaning transfers in * the message. * * First, stop the transfer and unmap the DMA buffers. */ spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); if (!msg->is_dma_mapped) atmel_spi_dma_unmap_xfer(master, xfer); /* REVISIT: udelay in irq is unfriendly */ if (xfer->delay_usecs) udelay(xfer->delay_usecs); dev_warn(master->dev.parent, "overrun (%u/%u remaining)\n", spi_readl(as, TCR), spi_readl(as, RCR)); /* * Clean up DMA registers and make sure the data * registers are empty. */ spi_writel(as, RNCR, 0); spi_writel(as, TNCR, 0); spi_writel(as, RCR, 0); spi_writel(as, TCR, 0); for (timeout = 1000; timeout; timeout--) if (spi_readl(as, SR) & SPI_BIT(TXEMPTY)) break; if (!timeout) dev_warn(master->dev.parent, "timeout waiting for TXEMPTY"); while (spi_readl(as, SR) & SPI_BIT(RDRF)) spi_readl(as, RDR); /* Clear any overrun happening while cleaning up */ spi_readl(as, SR); as->done_status = -EIO; atmel_spi_msg_done(master, as, msg, 0); } else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) { ret = IRQ_HANDLED; spi_writel(as, IDR, pending); if (as->current_remaining_bytes == 0) { msg->actual_length += xfer->len; if (!msg->is_dma_mapped) atmel_spi_dma_unmap_xfer(master, xfer); /* REVISIT: udelay in irq is unfriendly */ if (xfer->delay_usecs) udelay(xfer->delay_usecs); if (atmel_spi_xfer_is_last(msg, xfer)) { /* report completed message */ atmel_spi_msg_done(master, as, msg, xfer->cs_change); } else { if (xfer->cs_change) { cs_deactivate(as, msg->spi); udelay(1); cs_activate(as, msg->spi); } /* * Not done yet. Submit the next transfer. * * FIXME handle protocol options for xfer */ atmel_spi_pdc_next_xfer(master, msg); } } else { /* * Keep going, we still have data to send in * the current transfer. */ atmel_spi_pdc_next_xfer(master, msg); } } atmel_spi_unlock(as); return ret; } static int atmel_spi_setup(struct spi_device *spi) { struct atmel_spi *as; struct atmel_spi_device *asd; u32 scbr, csr; unsigned int bits = spi->bits_per_word; unsigned long bus_hz; unsigned int npcs_pin; int ret; as = spi_master_get_devdata(spi->master); if (as->stopping) return -ESHUTDOWN; if (spi->chip_select > spi->master->num_chipselect) { dev_dbg(&spi->dev, "setup: invalid chipselect %u (%u defined)\n", spi->chip_select, spi->master->num_chipselect); return -EINVAL; } /* see notes above re chipselect */ if (!atmel_spi_is_v2(as) && spi->chip_select == 0 && (spi->mode & SPI_CS_HIGH)) { dev_dbg(&spi->dev, "setup: can't be active-high\n"); return -EINVAL; } /* v1 chips start out at half the peripheral bus speed. */ bus_hz = clk_get_rate(as->clk); if (!atmel_spi_is_v2(as)) bus_hz /= 2; if (spi->max_speed_hz) { /* * Calculate the lowest divider that satisfies the * constraint, assuming div32/fdiv/mbz == 0. */ scbr = DIV_ROUND_UP(bus_hz, spi->max_speed_hz); /* * If the resulting divider doesn't fit into the * register bitfield, we can't satisfy the constraint. */ if (scbr >= (1 << SPI_SCBR_SIZE)) { dev_dbg(&spi->dev, "setup: %d Hz too slow, scbr %u; min %ld Hz\n", spi->max_speed_hz, scbr, bus_hz/255); return -EINVAL; } } else /* speed zero means "as slow as possible" */ scbr = 0xff; csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8); if (spi->mode & SPI_CPOL) csr |= SPI_BIT(CPOL); if (!(spi->mode & SPI_CPHA)) csr |= SPI_BIT(NCPHA); /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs. * * DLYBCT would add delays between words, slowing down transfers. * It could potentially be useful to cope with DMA bottlenecks, but * in those cases it's probably best to just use a lower bitrate. */ csr |= SPI_BF(DLYBS, 0); csr |= SPI_BF(DLYBCT, 0); /* chipselect must have been muxed as GPIO (e.g. in board setup) */ npcs_pin = (unsigned int)spi->controller_data; if (gpio_is_valid(spi->cs_gpio)) npcs_pin = spi->cs_gpio; asd = spi->controller_state; if (!asd) { asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL); if (!asd) return -ENOMEM; ret = gpio_request(npcs_pin, dev_name(&spi->dev)); if (ret) { kfree(asd); return ret; } asd->npcs_pin = npcs_pin; spi->controller_state = asd; gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH)); } else { atmel_spi_lock(as); if (as->stay == spi) as->stay = NULL; cs_deactivate(as, spi); atmel_spi_unlock(as); } asd->csr = csr; dev_dbg(&spi->dev, "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n", bus_hz / scbr, bits, spi->mode, spi->chip_select, csr); if (!atmel_spi_is_v2(as)) spi_writel(as, CSR0 + 4 * spi->chip_select, csr); return 0; } static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg) { struct atmel_spi *as; struct spi_transfer *xfer; struct device *controller = spi->master->dev.parent; u8 bits; struct atmel_spi_device *asd; as = spi_master_get_devdata(spi->master); dev_dbg(controller, "new message %p submitted for %s\n", msg, dev_name(&spi->dev)); if (unlikely(list_empty(&msg->transfers))) return -EINVAL; if (as->stopping) return -ESHUTDOWN; list_for_each_entry(xfer, &msg->transfers, transfer_list) { if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) { dev_dbg(&spi->dev, "missing rx or tx buf\n"); return -EINVAL; } if (xfer->bits_per_word) { asd = spi->controller_state; bits = (asd->csr >> 4) & 0xf; if (bits != xfer->bits_per_word - 8) { dev_dbg(&spi->dev, "you can't yet change bits_per_word in transfers\n"); return -ENOPROTOOPT; } } if (xfer->bits_per_word > 8) { if (xfer->len % 2) { dev_dbg(&spi->dev, "buffer len should be 16 bits aligned\n"); return -EINVAL; } } /* FIXME implement these protocol options!! */ if (xfer->speed_hz < spi->max_speed_hz) { dev_dbg(&spi->dev, "can't change speed in transfer\n"); return -ENOPROTOOPT; } /* * DMA map early, for performance (empties dcache ASAP) and * better fault reporting. */ if ((!msg->is_dma_mapped) && (atmel_spi_use_dma(as, xfer) || as->use_pdc)) { if (atmel_spi_dma_map_xfer(as, xfer) < 0) return -ENOMEM; } } #ifdef VERBOSE list_for_each_entry(xfer, &msg->transfers, transfer_list) { dev_dbg(controller, " xfer %p: len %u tx %p/%08x rx %p/%08x\n", xfer, xfer->len, xfer->tx_buf, xfer->tx_dma, xfer->rx_buf, xfer->rx_dma); } #endif msg->status = -EINPROGRESS; msg->actual_length = 0; atmel_spi_lock(as); list_add_tail(&msg->queue, &as->queue); if (!as->current_transfer) atmel_spi_next_message(spi->master); atmel_spi_unlock(as); return 0; } static void atmel_spi_cleanup(struct spi_device *spi) { struct atmel_spi *as = spi_master_get_devdata(spi->master); struct atmel_spi_device *asd = spi->controller_state; unsigned gpio = (unsigned) spi->controller_data; if (!asd) return; atmel_spi_lock(as); if (as->stay == spi) { as->stay = NULL; cs_deactivate(as, spi); } atmel_spi_unlock(as); spi->controller_state = NULL; gpio_free(gpio); kfree(asd); } static inline unsigned int atmel_get_version(struct atmel_spi *as) { return spi_readl(as, VERSION) & 0x00000fff; } static void atmel_get_caps(struct atmel_spi *as) { unsigned int version; version = atmel_get_version(as); dev_info(&as->pdev->dev, "version: 0x%x\n", version); as->caps.is_spi2 = version > 0x121; as->caps.has_wdrbt = version >= 0x210; as->caps.has_dma_support = version >= 0x212; } /*-------------------------------------------------------------------------*/ static int atmel_spi_probe(struct platform_device *pdev) { struct resource *regs; int irq; struct clk *clk; int ret; struct spi_master *master; struct atmel_spi *as; regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!regs) return -ENXIO; irq = platform_get_irq(pdev, 0); if (irq < 0) return irq; clk = devm_clk_get(&pdev->dev, "spi_clk"); if (IS_ERR(clk)) return PTR_ERR(clk); /* setup spi core then atmel-specific driver state */ ret = -ENOMEM; master = spi_alloc_master(&pdev->dev, sizeof(*as)); if (!master) goto out_free; /* the spi->mode bits understood by this driver: */ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16); master->dev.of_node = pdev->dev.of_node; master->bus_num = pdev->id; master->num_chipselect = master->dev.of_node ? 0 : 4; master->setup = atmel_spi_setup; master->transfer = atmel_spi_transfer; master->cleanup = atmel_spi_cleanup; platform_set_drvdata(pdev, master); as = spi_master_get_devdata(master); /* * Scratch buffer is used for throwaway rx and tx data. * It's coherent to minimize dcache pollution. */ as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE, &as->buffer_dma, GFP_KERNEL); if (!as->buffer) goto out_free; spin_lock_init(&as->lock); INIT_LIST_HEAD(&as->queue); as->pdev = pdev; as->regs = devm_ioremap_resource(&pdev->dev, regs); if (IS_ERR(as->regs)) { ret = PTR_ERR(as->regs); goto out_free_buffer; } as->phybase = regs->start; as->irq = irq; as->clk = clk; atmel_get_caps(as); as->use_dma = false; as->use_pdc = false; if (as->caps.has_dma_support) { if (atmel_spi_configure_dma(as) == 0) as->use_dma = true; } else { as->use_pdc = true; } if (as->caps.has_dma_support && !as->use_dma) dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n"); if (as->use_pdc) { ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt, 0, dev_name(&pdev->dev), master); } else { tasklet_init(&as->tasklet, atmel_spi_tasklet_func, (unsigned long)master); ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt, 0, dev_name(&pdev->dev), master); } if (ret) goto out_unmap_regs; /* Initialize the hardware */ ret = clk_prepare_enable(clk); if (ret) goto out_free_irq; spi_writel(as, CR, SPI_BIT(SWRST)); spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */ if (as->caps.has_wdrbt) { spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS) | SPI_BIT(MSTR)); } else { spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS)); } if (as->use_pdc) spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); spi_writel(as, CR, SPI_BIT(SPIEN)); /* go! */ dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n", (unsigned long)regs->start, irq); ret = devm_spi_register_master(&pdev->dev, master); if (ret) goto out_free_dma; return 0; out_free_dma: if (as->use_dma) atmel_spi_release_dma(as); spi_writel(as, CR, SPI_BIT(SWRST)); spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */ clk_disable_unprepare(clk); out_free_irq: out_unmap_regs: out_free_buffer: if (!as->use_pdc) tasklet_kill(&as->tasklet); dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer, as->buffer_dma); out_free: spi_master_put(master); return ret; } static int atmel_spi_remove(struct platform_device *pdev) { struct spi_master *master = platform_get_drvdata(pdev); struct atmel_spi *as = spi_master_get_devdata(master); struct spi_message *msg; struct spi_transfer *xfer; /* reset the hardware and block queue progress */ spin_lock_irq(&as->lock); as->stopping = 1; if (as->use_dma) { atmel_spi_stop_dma(as); atmel_spi_release_dma(as); } spi_writel(as, CR, SPI_BIT(SWRST)); spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */ spi_readl(as, SR); spin_unlock_irq(&as->lock); /* Terminate remaining queued transfers */ list_for_each_entry(msg, &as->queue, queue) { list_for_each_entry(xfer, &msg->transfers, transfer_list) { if (!msg->is_dma_mapped && (atmel_spi_use_dma(as, xfer) || as->use_pdc)) atmel_spi_dma_unmap_xfer(master, xfer); } msg->status = -ESHUTDOWN; msg->complete(msg->context); } if (!as->use_pdc) tasklet_kill(&as->tasklet); dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer, as->buffer_dma); clk_disable_unprepare(as->clk); return 0; } #ifdef CONFIG_PM_SLEEP static int atmel_spi_suspend(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct atmel_spi *as = spi_master_get_devdata(master); clk_disable_unprepare(as->clk); return 0; } static int atmel_spi_resume(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct atmel_spi *as = spi_master_get_devdata(master); clk_prepare_enable(as->clk); return 0; } static SIMPLE_DEV_PM_OPS(atmel_spi_pm_ops, atmel_spi_suspend, atmel_spi_resume); #define ATMEL_SPI_PM_OPS (&atmel_spi_pm_ops) #else #define ATMEL_SPI_PM_OPS NULL #endif #if defined(CONFIG_OF) static const struct of_device_id atmel_spi_dt_ids[] = { { .compatible = "atmel,at91rm9200-spi" }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids); #endif static struct platform_driver atmel_spi_driver = { .driver = { .name = "atmel_spi", .owner = THIS_MODULE, .pm = ATMEL_SPI_PM_OPS, .of_match_table = of_match_ptr(atmel_spi_dt_ids), }, .probe = atmel_spi_probe, .remove = atmel_spi_remove, }; module_platform_driver(atmel_spi_driver); MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver"); MODULE_AUTHOR("Haavard Skinnemoen (Atmel)"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:atmel_spi");