diff options
Diffstat (limited to 'drivers/spi/spi-pic32.c')
| -rw-r--r-- | drivers/spi/spi-pic32.c | 881 |
1 files changed, 881 insertions, 0 deletions
diff --git a/drivers/spi/spi-pic32.c b/drivers/spi/spi-pic32.c new file mode 100644 index 000000000..5eb7b61bb --- /dev/null +++ b/drivers/spi/spi-pic32.c @@ -0,0 +1,881 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Microchip PIC32 SPI controller driver. + * + * Purna Chandra Mandal <purna.mandal@microchip.com> + * Copyright (c) 2016, Microchip Technology Inc. + */ + +#include <linux/clk.h> +#include <linux/clkdev.h> +#include <linux/delay.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/highmem.h> +#include <linux/module.h> +#include <linux/io.h> +#include <linux/interrupt.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_gpio.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> +#include <linux/spi/spi.h> + +/* SPI controller registers */ +struct pic32_spi_regs { + u32 ctrl; + u32 ctrl_clr; + u32 ctrl_set; + u32 ctrl_inv; + u32 status; + u32 status_clr; + u32 status_set; + u32 status_inv; + u32 buf; + u32 dontuse[3]; + u32 baud; + u32 dontuse2[3]; + u32 ctrl2; + u32 ctrl2_clr; + u32 ctrl2_set; + u32 ctrl2_inv; +}; + +/* Bit fields of SPI Control Register */ +#define CTRL_RX_INT_SHIFT 0 /* Rx interrupt generation */ +#define RX_FIFO_EMPTY 0 +#define RX_FIFO_NOT_EMPTY 1 /* not empty */ +#define RX_FIFO_HALF_FULL 2 /* full by half or more */ +#define RX_FIFO_FULL 3 /* completely full */ + +#define CTRL_TX_INT_SHIFT 2 /* TX interrupt generation */ +#define TX_FIFO_ALL_EMPTY 0 /* completely empty */ +#define TX_FIFO_EMPTY 1 /* empty */ +#define TX_FIFO_HALF_EMPTY 2 /* empty by half or more */ +#define TX_FIFO_NOT_FULL 3 /* atleast one empty */ + +#define CTRL_MSTEN BIT(5) /* enable master mode */ +#define CTRL_CKP BIT(6) /* active low */ +#define CTRL_CKE BIT(8) /* Tx on falling edge */ +#define CTRL_SMP BIT(9) /* Rx at middle or end of tx */ +#define CTRL_BPW_MASK 0x03 /* bits per word/sample */ +#define CTRL_BPW_SHIFT 10 +#define PIC32_BPW_8 0 +#define PIC32_BPW_16 1 +#define PIC32_BPW_32 2 +#define CTRL_SIDL BIT(13) /* sleep when idle */ +#define CTRL_ON BIT(15) /* enable macro */ +#define CTRL_ENHBUF BIT(16) /* enable enhanced buffering */ +#define CTRL_MCLKSEL BIT(23) /* select clock source */ +#define CTRL_MSSEN BIT(28) /* macro driven /SS */ +#define CTRL_FRMEN BIT(31) /* enable framing mode */ + +/* Bit fields of SPI Status Register */ +#define STAT_RF_EMPTY BIT(5) /* RX Fifo empty */ +#define STAT_RX_OV BIT(6) /* err, s/w needs to clear */ +#define STAT_TX_UR BIT(8) /* UR in Framed SPI modes */ +#define STAT_FRM_ERR BIT(12) /* Multiple Frame Sync pulse */ +#define STAT_TF_LVL_MASK 0x1F +#define STAT_TF_LVL_SHIFT 16 +#define STAT_RF_LVL_MASK 0x1F +#define STAT_RF_LVL_SHIFT 24 + +/* Bit fields of SPI Baud Register */ +#define BAUD_MASK 0x1ff + +/* Bit fields of SPI Control2 Register */ +#define CTRL2_TX_UR_EN BIT(10) /* Enable int on Tx under-run */ +#define CTRL2_RX_OV_EN BIT(11) /* Enable int on Rx over-run */ +#define CTRL2_FRM_ERR_EN BIT(12) /* Enable frame err int */ + +/* Minimum DMA transfer size */ +#define PIC32_DMA_LEN_MIN 64 + +struct pic32_spi { + dma_addr_t dma_base; + struct pic32_spi_regs __iomem *regs; + int fault_irq; + int rx_irq; + int tx_irq; + u32 fifo_n_byte; /* FIFO depth in bytes */ + struct clk *clk; + struct spi_master *master; + /* Current controller setting */ + u32 speed_hz; /* spi-clk rate */ + u32 mode; + u32 bits_per_word; + u32 fifo_n_elm; /* FIFO depth in words */ +#define PIC32F_DMA_PREP 0 /* DMA chnls configured */ + unsigned long flags; + /* Current transfer state */ + struct completion xfer_done; + /* PIO transfer specific */ + const void *tx; + const void *tx_end; + const void *rx; + const void *rx_end; + int len; + void (*rx_fifo)(struct pic32_spi *); + void (*tx_fifo)(struct pic32_spi *); +}; + +static inline void pic32_spi_enable(struct pic32_spi *pic32s) +{ + writel(CTRL_ON | CTRL_SIDL, &pic32s->regs->ctrl_set); +} + +static inline void pic32_spi_disable(struct pic32_spi *pic32s) +{ + writel(CTRL_ON | CTRL_SIDL, &pic32s->regs->ctrl_clr); + + /* avoid SPI registers read/write at immediate next CPU clock */ + ndelay(20); +} + +static void pic32_spi_set_clk_rate(struct pic32_spi *pic32s, u32 spi_ck) +{ + u32 div; + + /* div = (clk_in / 2 * spi_ck) - 1 */ + div = DIV_ROUND_CLOSEST(clk_get_rate(pic32s->clk), 2 * spi_ck) - 1; + + writel(div & BAUD_MASK, &pic32s->regs->baud); +} + +static inline u32 pic32_rx_fifo_level(struct pic32_spi *pic32s) +{ + u32 sr = readl(&pic32s->regs->status); + + return (sr >> STAT_RF_LVL_SHIFT) & STAT_RF_LVL_MASK; +} + +static inline u32 pic32_tx_fifo_level(struct pic32_spi *pic32s) +{ + u32 sr = readl(&pic32s->regs->status); + + return (sr >> STAT_TF_LVL_SHIFT) & STAT_TF_LVL_MASK; +} + +/* Return the max entries we can fill into tx fifo */ +static u32 pic32_tx_max(struct pic32_spi *pic32s, int n_bytes) +{ + u32 tx_left, tx_room, rxtx_gap; + + tx_left = (pic32s->tx_end - pic32s->tx) / n_bytes; + tx_room = pic32s->fifo_n_elm - pic32_tx_fifo_level(pic32s); + + /* + * Another concern is about the tx/rx mismatch, we + * though to use (pic32s->fifo_n_byte - rxfl - txfl) as + * one maximum value for tx, but it doesn't cover the + * data which is out of tx/rx fifo and inside the + * shift registers. So a ctrl from sw point of + * view is taken. + */ + rxtx_gap = ((pic32s->rx_end - pic32s->rx) - + (pic32s->tx_end - pic32s->tx)) / n_bytes; + return min3(tx_left, tx_room, (u32)(pic32s->fifo_n_elm - rxtx_gap)); +} + +/* Return the max entries we should read out of rx fifo */ +static u32 pic32_rx_max(struct pic32_spi *pic32s, int n_bytes) +{ + u32 rx_left = (pic32s->rx_end - pic32s->rx) / n_bytes; + + return min_t(u32, rx_left, pic32_rx_fifo_level(pic32s)); +} + +#define BUILD_SPI_FIFO_RW(__name, __type, __bwl) \ +static void pic32_spi_rx_##__name(struct pic32_spi *pic32s) \ +{ \ + __type v; \ + u32 mx = pic32_rx_max(pic32s, sizeof(__type)); \ + for (; mx; mx--) { \ + v = read##__bwl(&pic32s->regs->buf); \ + if (pic32s->rx_end - pic32s->len) \ + *(__type *)(pic32s->rx) = v; \ + pic32s->rx += sizeof(__type); \ + } \ +} \ + \ +static void pic32_spi_tx_##__name(struct pic32_spi *pic32s) \ +{ \ + __type v; \ + u32 mx = pic32_tx_max(pic32s, sizeof(__type)); \ + for (; mx ; mx--) { \ + v = (__type)~0U; \ + if (pic32s->tx_end - pic32s->len) \ + v = *(__type *)(pic32s->tx); \ + write##__bwl(v, &pic32s->regs->buf); \ + pic32s->tx += sizeof(__type); \ + } \ +} + +BUILD_SPI_FIFO_RW(byte, u8, b); +BUILD_SPI_FIFO_RW(word, u16, w); +BUILD_SPI_FIFO_RW(dword, u32, l); + +static void pic32_err_stop(struct pic32_spi *pic32s, const char *msg) +{ + /* disable all interrupts */ + disable_irq_nosync(pic32s->fault_irq); + disable_irq_nosync(pic32s->rx_irq); + disable_irq_nosync(pic32s->tx_irq); + + /* Show err message and abort xfer with err */ + dev_err(&pic32s->master->dev, "%s\n", msg); + if (pic32s->master->cur_msg) + pic32s->master->cur_msg->status = -EIO; + complete(&pic32s->xfer_done); +} + +static irqreturn_t pic32_spi_fault_irq(int irq, void *dev_id) +{ + struct pic32_spi *pic32s = dev_id; + u32 status; + + status = readl(&pic32s->regs->status); + + /* Error handling */ + if (status & (STAT_RX_OV | STAT_TX_UR)) { + writel(STAT_RX_OV, &pic32s->regs->status_clr); + writel(STAT_TX_UR, &pic32s->regs->status_clr); + pic32_err_stop(pic32s, "err_irq: fifo ov/ur-run\n"); + return IRQ_HANDLED; + } + + if (status & STAT_FRM_ERR) { + pic32_err_stop(pic32s, "err_irq: frame error"); + return IRQ_HANDLED; + } + + if (!pic32s->master->cur_msg) { + pic32_err_stop(pic32s, "err_irq: no mesg"); + return IRQ_NONE; + } + + return IRQ_NONE; +} + +static irqreturn_t pic32_spi_rx_irq(int irq, void *dev_id) +{ + struct pic32_spi *pic32s = dev_id; + + pic32s->rx_fifo(pic32s); + + /* rx complete ? */ + if (pic32s->rx_end == pic32s->rx) { + /* disable all interrupts */ + disable_irq_nosync(pic32s->fault_irq); + disable_irq_nosync(pic32s->rx_irq); + + /* complete current xfer */ + complete(&pic32s->xfer_done); + } + + return IRQ_HANDLED; +} + +static irqreturn_t pic32_spi_tx_irq(int irq, void *dev_id) +{ + struct pic32_spi *pic32s = dev_id; + + pic32s->tx_fifo(pic32s); + + /* tx complete? disable tx interrupt */ + if (pic32s->tx_end == pic32s->tx) + disable_irq_nosync(pic32s->tx_irq); + + return IRQ_HANDLED; +} + +static void pic32_spi_dma_rx_notify(void *data) +{ + struct pic32_spi *pic32s = data; + + complete(&pic32s->xfer_done); +} + +static int pic32_spi_dma_transfer(struct pic32_spi *pic32s, + struct spi_transfer *xfer) +{ + struct spi_master *master = pic32s->master; + struct dma_async_tx_descriptor *desc_rx; + struct dma_async_tx_descriptor *desc_tx; + dma_cookie_t cookie; + int ret; + + if (!master->dma_rx || !master->dma_tx) + return -ENODEV; + + desc_rx = dmaengine_prep_slave_sg(master->dma_rx, + xfer->rx_sg.sgl, + xfer->rx_sg.nents, + DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc_rx) { + ret = -EINVAL; + goto err_dma; + } + + desc_tx = dmaengine_prep_slave_sg(master->dma_tx, + xfer->tx_sg.sgl, + xfer->tx_sg.nents, + DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc_tx) { + ret = -EINVAL; + goto err_dma; + } + + /* Put callback on the RX transfer, that should finish last */ + desc_rx->callback = pic32_spi_dma_rx_notify; + desc_rx->callback_param = pic32s; + + cookie = dmaengine_submit(desc_rx); + ret = dma_submit_error(cookie); + if (ret) + goto err_dma; + + cookie = dmaengine_submit(desc_tx); + ret = dma_submit_error(cookie); + if (ret) + goto err_dma_tx; + + dma_async_issue_pending(master->dma_rx); + dma_async_issue_pending(master->dma_tx); + + return 0; + +err_dma_tx: + dmaengine_terminate_all(master->dma_rx); +err_dma: + return ret; +} + +static int pic32_spi_dma_config(struct pic32_spi *pic32s, u32 dma_width) +{ + int buf_offset = offsetof(struct pic32_spi_regs, buf); + struct spi_master *master = pic32s->master; + struct dma_slave_config cfg; + int ret; + + memset(&cfg, 0, sizeof(cfg)); + cfg.device_fc = true; + cfg.src_addr = pic32s->dma_base + buf_offset; + cfg.dst_addr = pic32s->dma_base + buf_offset; + cfg.src_maxburst = pic32s->fifo_n_elm / 2; /* fill one-half */ + cfg.dst_maxburst = pic32s->fifo_n_elm / 2; /* drain one-half */ + cfg.src_addr_width = dma_width; + cfg.dst_addr_width = dma_width; + /* tx channel */ + cfg.slave_id = pic32s->tx_irq; + cfg.direction = DMA_MEM_TO_DEV; + ret = dmaengine_slave_config(master->dma_tx, &cfg); + if (ret) { + dev_err(&master->dev, "tx channel setup failed\n"); + return ret; + } + /* rx channel */ + cfg.slave_id = pic32s->rx_irq; + cfg.direction = DMA_DEV_TO_MEM; + ret = dmaengine_slave_config(master->dma_rx, &cfg); + if (ret) + dev_err(&master->dev, "rx channel setup failed\n"); + + return ret; +} + +static int pic32_spi_set_word_size(struct pic32_spi *pic32s, u8 bits_per_word) +{ + enum dma_slave_buswidth dmawidth; + u32 buswidth, v; + + switch (bits_per_word) { + case 8: + pic32s->rx_fifo = pic32_spi_rx_byte; + pic32s->tx_fifo = pic32_spi_tx_byte; + buswidth = PIC32_BPW_8; + dmawidth = DMA_SLAVE_BUSWIDTH_1_BYTE; + break; + case 16: + pic32s->rx_fifo = pic32_spi_rx_word; + pic32s->tx_fifo = pic32_spi_tx_word; + buswidth = PIC32_BPW_16; + dmawidth = DMA_SLAVE_BUSWIDTH_2_BYTES; + break; + case 32: + pic32s->rx_fifo = pic32_spi_rx_dword; + pic32s->tx_fifo = pic32_spi_tx_dword; + buswidth = PIC32_BPW_32; + dmawidth = DMA_SLAVE_BUSWIDTH_4_BYTES; + break; + default: + /* not supported */ + return -EINVAL; + } + + /* calculate maximum number of words fifos can hold */ + pic32s->fifo_n_elm = DIV_ROUND_UP(pic32s->fifo_n_byte, + bits_per_word / 8); + /* set word size */ + v = readl(&pic32s->regs->ctrl); + v &= ~(CTRL_BPW_MASK << CTRL_BPW_SHIFT); + v |= buswidth << CTRL_BPW_SHIFT; + writel(v, &pic32s->regs->ctrl); + + /* re-configure dma width, if required */ + if (test_bit(PIC32F_DMA_PREP, &pic32s->flags)) + pic32_spi_dma_config(pic32s, dmawidth); + + return 0; +} + +static int pic32_spi_prepare_hardware(struct spi_master *master) +{ + struct pic32_spi *pic32s = spi_master_get_devdata(master); + + pic32_spi_enable(pic32s); + + return 0; +} + +static int pic32_spi_prepare_message(struct spi_master *master, + struct spi_message *msg) +{ + struct pic32_spi *pic32s = spi_master_get_devdata(master); + struct spi_device *spi = msg->spi; + u32 val; + + /* set device specific bits_per_word */ + if (pic32s->bits_per_word != spi->bits_per_word) { + pic32_spi_set_word_size(pic32s, spi->bits_per_word); + pic32s->bits_per_word = spi->bits_per_word; + } + + /* device specific speed change */ + if (pic32s->speed_hz != spi->max_speed_hz) { + pic32_spi_set_clk_rate(pic32s, spi->max_speed_hz); + pic32s->speed_hz = spi->max_speed_hz; + } + + /* device specific mode change */ + if (pic32s->mode != spi->mode) { + val = readl(&pic32s->regs->ctrl); + /* active low */ + if (spi->mode & SPI_CPOL) + val |= CTRL_CKP; + else + val &= ~CTRL_CKP; + /* tx on rising edge */ + if (spi->mode & SPI_CPHA) + val &= ~CTRL_CKE; + else + val |= CTRL_CKE; + + /* rx at end of tx */ + val |= CTRL_SMP; + writel(val, &pic32s->regs->ctrl); + pic32s->mode = spi->mode; + } + + return 0; +} + +static bool pic32_spi_can_dma(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *xfer) +{ + struct pic32_spi *pic32s = spi_master_get_devdata(master); + + /* skip using DMA on small size transfer to avoid overhead.*/ + return (xfer->len >= PIC32_DMA_LEN_MIN) && + test_bit(PIC32F_DMA_PREP, &pic32s->flags); +} + +static int pic32_spi_one_transfer(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *transfer) +{ + struct pic32_spi *pic32s; + bool dma_issued = false; + unsigned long timeout; + int ret; + + pic32s = spi_master_get_devdata(master); + + /* handle transfer specific word size change */ + if (transfer->bits_per_word && + (transfer->bits_per_word != pic32s->bits_per_word)) { + ret = pic32_spi_set_word_size(pic32s, transfer->bits_per_word); + if (ret) + return ret; + pic32s->bits_per_word = transfer->bits_per_word; + } + + /* handle transfer specific speed change */ + if (transfer->speed_hz && (transfer->speed_hz != pic32s->speed_hz)) { + pic32_spi_set_clk_rate(pic32s, transfer->speed_hz); + pic32s->speed_hz = transfer->speed_hz; + } + + reinit_completion(&pic32s->xfer_done); + + /* transact by DMA mode */ + if (transfer->rx_sg.nents && transfer->tx_sg.nents) { + ret = pic32_spi_dma_transfer(pic32s, transfer); + if (ret) { + dev_err(&spi->dev, "dma submit error\n"); + return ret; + } + + /* DMA issued */ + dma_issued = true; + } else { + /* set current transfer information */ + pic32s->tx = (const void *)transfer->tx_buf; + pic32s->rx = (const void *)transfer->rx_buf; + pic32s->tx_end = pic32s->tx + transfer->len; + pic32s->rx_end = pic32s->rx + transfer->len; + pic32s->len = transfer->len; + + /* transact by interrupt driven PIO */ + enable_irq(pic32s->fault_irq); + enable_irq(pic32s->rx_irq); + enable_irq(pic32s->tx_irq); + } + + /* wait for completion */ + timeout = wait_for_completion_timeout(&pic32s->xfer_done, 2 * HZ); + if (timeout == 0) { + dev_err(&spi->dev, "wait error/timedout\n"); + if (dma_issued) { + dmaengine_terminate_all(master->dma_rx); + dmaengine_terminate_all(master->dma_tx); + } + ret = -ETIMEDOUT; + } else { + ret = 0; + } + + return ret; +} + +static int pic32_spi_unprepare_message(struct spi_master *master, + struct spi_message *msg) +{ + /* nothing to do */ + return 0; +} + +static int pic32_spi_unprepare_hardware(struct spi_master *master) +{ + struct pic32_spi *pic32s = spi_master_get_devdata(master); + + pic32_spi_disable(pic32s); + + return 0; +} + +/* This may be called multiple times by same spi dev */ +static int pic32_spi_setup(struct spi_device *spi) +{ + if (!spi->max_speed_hz) { + dev_err(&spi->dev, "No max speed HZ parameter\n"); + return -EINVAL; + } + + /* PIC32 spi controller can drive /CS during transfer depending + * on tx fifo fill-level. /CS will stay asserted as long as TX + * fifo is non-empty, else will be deasserted indicating + * completion of the ongoing transfer. This might result into + * unreliable/erroneous SPI transactions. + * To avoid that we will always handle /CS by toggling GPIO. + */ + if (!gpio_is_valid(spi->cs_gpio)) + return -EINVAL; + + gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH)); + + return 0; +} + +static void pic32_spi_cleanup(struct spi_device *spi) +{ + /* de-activate cs-gpio */ + gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH)); +} + +static int pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev) +{ + struct spi_master *master = pic32s->master; + int ret = 0; + + master->dma_rx = dma_request_chan(dev, "spi-rx"); + if (IS_ERR(master->dma_rx)) { + if (PTR_ERR(master->dma_rx) == -EPROBE_DEFER) + ret = -EPROBE_DEFER; + else + dev_warn(dev, "RX channel not found.\n"); + + master->dma_rx = NULL; + goto out_err; + } + + master->dma_tx = dma_request_chan(dev, "spi-tx"); + if (IS_ERR(master->dma_tx)) { + if (PTR_ERR(master->dma_tx) == -EPROBE_DEFER) + ret = -EPROBE_DEFER; + else + dev_warn(dev, "TX channel not found.\n"); + + master->dma_tx = NULL; + goto out_err; + } + + if (pic32_spi_dma_config(pic32s, DMA_SLAVE_BUSWIDTH_1_BYTE)) + goto out_err; + + /* DMA chnls allocated and prepared */ + set_bit(PIC32F_DMA_PREP, &pic32s->flags); + + return 0; + +out_err: + if (master->dma_rx) { + dma_release_channel(master->dma_rx); + master->dma_rx = NULL; + } + + if (master->dma_tx) { + dma_release_channel(master->dma_tx); + master->dma_tx = NULL; + } + + return ret; +} + +static void pic32_spi_dma_unprep(struct pic32_spi *pic32s) +{ + if (!test_bit(PIC32F_DMA_PREP, &pic32s->flags)) + return; + + clear_bit(PIC32F_DMA_PREP, &pic32s->flags); + if (pic32s->master->dma_rx) + dma_release_channel(pic32s->master->dma_rx); + + if (pic32s->master->dma_tx) + dma_release_channel(pic32s->master->dma_tx); +} + +static void pic32_spi_hw_init(struct pic32_spi *pic32s) +{ + u32 ctrl; + + /* disable hardware */ + pic32_spi_disable(pic32s); + + ctrl = readl(&pic32s->regs->ctrl); + /* enable enhanced fifo of 128bit deep */ + ctrl |= CTRL_ENHBUF; + pic32s->fifo_n_byte = 16; + + /* disable framing mode */ + ctrl &= ~CTRL_FRMEN; + + /* enable master mode while disabled */ + ctrl |= CTRL_MSTEN; + + /* set tx fifo threshold interrupt */ + ctrl &= ~(0x3 << CTRL_TX_INT_SHIFT); + ctrl |= (TX_FIFO_HALF_EMPTY << CTRL_TX_INT_SHIFT); + + /* set rx fifo threshold interrupt */ + ctrl &= ~(0x3 << CTRL_RX_INT_SHIFT); + ctrl |= (RX_FIFO_NOT_EMPTY << CTRL_RX_INT_SHIFT); + + /* select clk source */ + ctrl &= ~CTRL_MCLKSEL; + + /* set manual /CS mode */ + ctrl &= ~CTRL_MSSEN; + + writel(ctrl, &pic32s->regs->ctrl); + + /* enable error reporting */ + ctrl = CTRL2_TX_UR_EN | CTRL2_RX_OV_EN | CTRL2_FRM_ERR_EN; + writel(ctrl, &pic32s->regs->ctrl2_set); +} + +static int pic32_spi_hw_probe(struct platform_device *pdev, + struct pic32_spi *pic32s) +{ + struct resource *mem; + int ret; + + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + pic32s->regs = devm_ioremap_resource(&pdev->dev, mem); + if (IS_ERR(pic32s->regs)) + return PTR_ERR(pic32s->regs); + + pic32s->dma_base = mem->start; + + /* get irq resources: err-irq, rx-irq, tx-irq */ + pic32s->fault_irq = platform_get_irq_byname(pdev, "fault"); + if (pic32s->fault_irq < 0) + return pic32s->fault_irq; + + pic32s->rx_irq = platform_get_irq_byname(pdev, "rx"); + if (pic32s->rx_irq < 0) + return pic32s->rx_irq; + + pic32s->tx_irq = platform_get_irq_byname(pdev, "tx"); + if (pic32s->tx_irq < 0) + return pic32s->tx_irq; + + /* get clock */ + pic32s->clk = devm_clk_get(&pdev->dev, "mck0"); + if (IS_ERR(pic32s->clk)) { + dev_err(&pdev->dev, "clk not found\n"); + ret = PTR_ERR(pic32s->clk); + goto err_unmap_mem; + } + + ret = clk_prepare_enable(pic32s->clk); + if (ret) + goto err_unmap_mem; + + pic32_spi_hw_init(pic32s); + + return 0; + +err_unmap_mem: + dev_err(&pdev->dev, "%s failed, err %d\n", __func__, ret); + return ret; +} + +static int pic32_spi_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct pic32_spi *pic32s; + int ret; + + master = spi_alloc_master(&pdev->dev, sizeof(*pic32s)); + if (!master) + return -ENOMEM; + + pic32s = spi_master_get_devdata(master); + pic32s->master = master; + + ret = pic32_spi_hw_probe(pdev, pic32s); + if (ret) + goto err_master; + + master->dev.of_node = pdev->dev.of_node; + master->mode_bits = SPI_MODE_3 | SPI_MODE_0 | SPI_CS_HIGH; + master->num_chipselect = 1; /* single chip-select */ + master->max_speed_hz = clk_get_rate(pic32s->clk); + master->setup = pic32_spi_setup; + master->cleanup = pic32_spi_cleanup; + master->flags = SPI_MASTER_MUST_TX | SPI_MASTER_MUST_RX; + master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16) | + SPI_BPW_MASK(32); + master->transfer_one = pic32_spi_one_transfer; + master->prepare_message = pic32_spi_prepare_message; + master->unprepare_message = pic32_spi_unprepare_message; + master->prepare_transfer_hardware = pic32_spi_prepare_hardware; + master->unprepare_transfer_hardware = pic32_spi_unprepare_hardware; + + /* optional DMA support */ + ret = pic32_spi_dma_prep(pic32s, &pdev->dev); + if (ret) + goto err_bailout; + + if (test_bit(PIC32F_DMA_PREP, &pic32s->flags)) + master->can_dma = pic32_spi_can_dma; + + init_completion(&pic32s->xfer_done); + pic32s->mode = -1; + + /* install irq handlers (with irq-disabled) */ + irq_set_status_flags(pic32s->fault_irq, IRQ_NOAUTOEN); + ret = devm_request_irq(&pdev->dev, pic32s->fault_irq, + pic32_spi_fault_irq, IRQF_NO_THREAD, + dev_name(&pdev->dev), pic32s); + if (ret < 0) { + dev_err(&pdev->dev, "request fault-irq %d\n", pic32s->rx_irq); + goto err_bailout; + } + + /* receive interrupt handler */ + irq_set_status_flags(pic32s->rx_irq, IRQ_NOAUTOEN); + ret = devm_request_irq(&pdev->dev, pic32s->rx_irq, + pic32_spi_rx_irq, IRQF_NO_THREAD, + dev_name(&pdev->dev), pic32s); + if (ret < 0) { + dev_err(&pdev->dev, "request rx-irq %d\n", pic32s->rx_irq); + goto err_bailout; + } + + /* transmit interrupt handler */ + irq_set_status_flags(pic32s->tx_irq, IRQ_NOAUTOEN); + ret = devm_request_irq(&pdev->dev, pic32s->tx_irq, + pic32_spi_tx_irq, IRQF_NO_THREAD, + dev_name(&pdev->dev), pic32s); + if (ret < 0) { + dev_err(&pdev->dev, "request tx-irq %d\n", pic32s->tx_irq); + goto err_bailout; + } + + /* register master */ + ret = devm_spi_register_master(&pdev->dev, master); + if (ret) { + dev_err(&master->dev, "failed registering spi master\n"); + goto err_bailout; + } + + platform_set_drvdata(pdev, pic32s); + + return 0; + +err_bailout: + pic32_spi_dma_unprep(pic32s); + clk_disable_unprepare(pic32s->clk); +err_master: + spi_master_put(master); + return ret; +} + +static int pic32_spi_remove(struct platform_device *pdev) +{ + struct pic32_spi *pic32s; + + pic32s = platform_get_drvdata(pdev); + pic32_spi_disable(pic32s); + clk_disable_unprepare(pic32s->clk); + pic32_spi_dma_unprep(pic32s); + + return 0; +} + +static const struct of_device_id pic32_spi_of_match[] = { + {.compatible = "microchip,pic32mzda-spi",}, + {}, +}; +MODULE_DEVICE_TABLE(of, pic32_spi_of_match); + +static struct platform_driver pic32_spi_driver = { + .driver = { + .name = "spi-pic32", + .of_match_table = of_match_ptr(pic32_spi_of_match), + }, + .probe = pic32_spi_probe, + .remove = pic32_spi_remove, +}; + +module_platform_driver(pic32_spi_driver); + +MODULE_AUTHOR("Purna Chandra Mandal <purna.mandal@microchip.com>"); +MODULE_DESCRIPTION("Microchip SPI driver for PIC32 SPI controller."); +MODULE_LICENSE("GPL v2"); |