From: Purna Chandra Mandal <purna.mandal@xxxxxxxxxxxxx>
The PIC32 SPI driver is capable of performing SPI transfers either using
polling or based on interrupt-trigger. GPIO based CS support (necessary
for correct SPI operation) is available. It is dependent on availability
of "cs-gpios" property of spi node in board dts file.
Signed-off-by: Purna Chandra Mandal <purna.mandal@xxxxxxxxxxxxx>
Signed-off-by: Joshua Henderson <joshua.henderson@xxxxxxxxxxxxx>
---
drivers/spi/Kconfig | 7 +
drivers/spi/Makefile | 1 +
drivers/spi/spi-pic32.c | 1212 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 1220 insertions(+)
create mode 100644 drivers/spi/spi-pic32.c
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 7706416..cda8b7a 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -654,6 +654,13 @@ config SPI_NUC900
help
SPI driver for Nuvoton NUC900 series ARM SoCs
+config SPI_PIC32
+ tristate "Microchip PIC32 series SPI"
+ depends on MACH_PIC32
+ help
+ SPI driver for PIC32 SPI master controller.
+
+
#
# Add new SPI master controllers in alphabetical order above this line
#
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 8991ffc..bb37fed 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -94,3 +94,4 @@ obj-$(CONFIG_SPI_XILINX) += spi-xilinx.o
obj-$(CONFIG_SPI_XLP) += spi-xlp.o
obj-$(CONFIG_SPI_XTENSA_XTFPGA) += spi-xtensa-xtfpga.o
obj-$(CONFIG_SPI_ZYNQMP_GQSPI) += spi-zynqmp-gqspi.o
+obj-$(CONFIG_SPI_PIC32) += spi-pic32.o
diff --git a/drivers/spi/spi-pic32.c b/drivers/spi/spi-pic32.c
new file mode 100644
index 0000000..6658efb
--- /dev/null
+++ b/drivers/spi/spi-pic32.c
@@ -0,0 +1,1212 @@
+/*
+ * PIC32 SPI core controller driver (refer dw_spi.c)
+ *
+ * Purna Chandra Mandal <purna.mandal@xxxxxxxxxxxxx>
+ * Copyright (c) 2016, Microchip Technology Inc.
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/highmem.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/clk-provider.h>
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/of_address.h>
+#include <linux/dmaengine.h>
+#include <linux/sizes.h>
+
+/* SPI Register offsets */
+#define SPICON 0x00
+#define SPICON_CLR 0x04
+#define SPICON_SET 0x08
+#define SPISTAT 0x10
+#define SPISTAT_CLR 0x14
+#define SPIBUF 0x20
+#define SPIBRG 0x30
+#define SPICON2 0x40
+#define SPICON2_CLR 0x44
+#define SPICON2_SET 0x48
+
+/* Bit fields in SPICON Register */
+/* Rx interrupt generation condition */
+#define SPICON_RXI_SHIFT 0
+/* TX interrupt generation condition */
+#define SPICON_TXI_SHIFT 2
+/* Enable SPI Master */
+#define SPICON_MSTEN BIT(5)
+/* active low */
+#define SPICON_CKP BIT(6)
+/* Tx on falling edge */
+#define SPICON_CKE BIT(8)
+/* Rx at middle or end of tx */
+#define SPICON_SMP BIT(9)
+/* Bits per word/audio-sample */
+#define SPICON_BPW 0x03
+#define SPICON_BPW_SHIFT 10
+/* STOP on idle */
+#define SPICON_SIDL BIT(13)
+/* Macro enable */
+#define SPICON_ON BIT(15)
+/* Enable enhanced buffering */
+#define SPICON_ENHBUF BIT(16)
+/* Select SPI Clock src */
+#define SPICON_MCLKSEL BIT(23)
+/* SPI macro will drive SS */
+#define SPICON_MSSEN BIT(28)
+/* SPI SS polarity */
+#define SPICON_FRMPOL BIT(29)
+/* Enable framing mode */
+#define SPICON_FRMEN BIT(31)
+
+/* Bit fields in SPISTAT Register */
+/* RX fifo full */
+#define STAT_RF_FULL BIT(0)
+/* TX fifo full */
+#define STAT_TF_FULL BIT(1)
+/* standard buffer mode */
+#define STAT_TX_EMPTY BIT(3)
+/* RX Fifo empty */
+#define STAT_RF_EMPTY BIT(5)
+/* err, s/w needs to clear */
+#define STAT_RX_OV BIT(6)
+/* Internal shift-reg empty */
+#define STAT_SHIFT_REG_EMPTY BIT(7)
+/* UR in Framed SPI modes */
+#define STAT_TX_UR BIT(8)
+/* Macro is processing tx or rx */
+#define STAT_BUSY BIT(11)
+/* Multiple Frame Sync pulse */
+#define STAT_FRM_ERR BIT(12)
+#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 in SPIBRG Register */
+#define SPIBRG_MASK 0x1ff
+#define SPIBRG_SHIFT 0x0
+
+/* Bit fields in SPICON2 Register */
+/* Enable int on Tx under-run */
+#define SPI_INT_TX_UR_EN BIT(10)
+/* Enable int on Rx over-run */
+#define SPI_INT_RX_OV_EN BIT(11)
+/* Enable frame err int */
+#define SPI_INT_FRM_ERR_EN BIT(12)
+
+/* Rx-fifo state for RX interrupt generation */
+#define SPI_RX_FIFO_EMTPY 0x0
+/* not empty */
+#define SPI_RX_FIFO_NOT_EMPTY 0x1
+/* full by one-half or more */
+#define SPI_RX_FIFO_HALF_FULL 0x2
+/* completely full */
+#define SPI_RX_FIFO_FULL 0x3
+
+/* TX-fifo state for TX interrupt generation */
+/* completely empty */
+#define SPI_TX_FIFO_ALL_EMPTY 0x0
+/* empty */
+#define SPI_TX_FIFO_EMTPY 0x1
+/* empty by half or more */
+#define SPI_TX_FIFO_HALF_EMPTY 0x2
+/* atleast one empty */
+#define SPI_TX_FIFO_NOT_FULL 0x3
+
+/* Transfer bits-per-word */
+#define SPI_BPW_8 0x0
+#define SPI_BPW_16 0x1
+#define SPI_BPW_32 0x2
+
+/* SPI clock sources */
+#define SPI_CLKSRC_PBCLK 0x0
+#define SPI_CLKSRC_MCLK 0x1
+
+/* Minimum DMA transfer size */
+#define SPI_DMA_LEN_MIN SZ_64
+
+/* struct pic32_spi::flags */
+/* PIO Transfer based on polling */
+#define SPI_XFER_POLL BIT(1)
+/* SPI master controlled SS */
+#define SPI_SS_MASTER BIT(2)
+/* DMA is supported */
+#define SPI_DMA_CAP BIT(3)
+/* DMA channels allocated */
+#define SPI_DMA_PREP BIT(4)
+/* buffer mapped and ready for DMA */
+#define SPI_DMA_READY BIT(5)
+
+struct pic32_spi {
+ void __iomem *regs;
+ dma_addr_t phys_base;
+ int fault_irq;
+ int rx_irq;
+ int tx_irq;
+ u32 fifo_n_byte;
+ struct clk *clk;
+ spinlock_t lock;
+ struct spi_master *master;
+
+ /* Current SPI device specific */
+ struct spi_device *spi_dev;
+ u32 speed_hz;
+ u32 mode;
+ u32 flags;
+ u8 fifo_n_elm;
+ enum dma_slave_buswidth dma_width;
+
+ /* Current message/transfer state */
+ struct spi_message *mesg;
+ const void *tx;
+ const void *tx_end;
+ const void *rx;
+ const void *rx_end;
+ int len;
+ struct completion xfer_done;
+
+ void (*rx_fifo)(struct pic32_spi *);
+ void (*tx_fifo)(struct pic32_spi *);
+};
+
+static inline u32 spi_rx_fifo_level(struct pic32_spi *pic32s)
+{
+ u32 sr = readl(pic32s->regs + SPISTAT);
+
+ return (sr >> STAT_RF_LVL_SHIFT) & STAT_RF_LVL_MASK;
+}
+
+static inline u32 spi_tx_fifo_level(struct pic32_spi *pic32s)
+{
+ u32 sr = readl(pic32s->regs + SPISTAT);
+
+ return (sr >> STAT_TF_LVL_SHIFT) & STAT_TF_LVL_MASK;
+}
+
+static inline void spi_enable_chip(struct pic32_spi *pic32s)
+{
+ writel(SPICON_ON, pic32s->regs + SPICON_SET);
+}
+
+static inline void spi_disable_chip(struct pic32_spi *pic32s)
+{
+ writel(SPICON_ON, pic32s->regs + SPICON_CLR);
+ cpu_relax();
+}
+
+static inline void spi_set_clk_mode(struct pic32_spi *pic32s, int mode)
+{
+ u32 conset = 0, conclr = 0;
+
+ /* active low */
+ if (mode & SPI_CPOL)
+ conset |= SPICON_CKP;
+ else
+ conclr |= SPICON_CKP;
+
+ /* tx on rising edge of clk */
+ if (mode & SPI_CPHA)
+ conclr |= SPICON_CKE;
+ else
+ conset |= SPICON_CKE;
+
+ /* rx at end of tx */
+ conset |= SPICON_SMP;
+
+ writel(conclr, pic32s->regs + SPICON_CLR);
+ writel(conset, pic32s->regs + SPICON_SET);
+}
+
+static inline void spi_set_ws(struct pic32_spi *pic32s, int ws)
+{
+ writel(SPICON_BPW << SPICON_BPW_SHIFT, pic32s->regs + SPICON_CLR);
+ writel(ws << SPICON_BPW_SHIFT, pic32s->regs + SPICON_SET);
+}
+
+static inline void spi_drain_rx_buf(struct pic32_spi *pic32s)
+{
+ u32 sr;
+
+ /* drain rx bytes until empty */
+ for (;;) {
+ sr = readl(pic32s->regs + SPISTAT);
+ if (sr & STAT_RF_EMPTY)
+ break;
+
+ (void)readl(pic32s->regs + SPIBUF);
+ }
+
+ /* clear rx overflow */
+ writel(STAT_RX_OV, pic32s->regs + SPISTAT_CLR);
+}
+
+static inline void spi_set_clk_rate(struct pic32_spi *pic32s, u32 sck)
+{
+ u16 clk_div;
+
+ /* sck = clk_in / [2 * (clk_div + 1)]
+ * ie. clk_div = [clk_in / (2 * sck)] - 1
+ */
+ clk_div = (clk_get_rate(pic32s->clk) / (2 * sck)) - 1;
+ clk_div &= SPIBRG_MASK;
+
+ writel(clk_div, pic32s->regs + SPIBRG);
+}
+
+static inline void spi_set_clk(struct pic32_spi *pic32s, int clk_id)
+{
+ switch (clk_id) {
+ case SPI_CLKSRC_PBCLK:
+ writel(SPICON_MCLKSEL, pic32s->regs + SPICON_CLR);
+ break;
+ case SPI_CLKSRC_MCLK:
+ writel(SPICON_MCLKSEL, pic32s->regs + SPICON_SET);
+ break;
+ }
+}
+
+static inline void spi_set_ss_auto(struct pic32_spi *pic32s, u8 mst, u32 mode)
+{
+ u32 v;
+
+ /* spi controller can drive CS/SS during transfer depending on fifo
+ * fill-level. SS will stay asserted as long as TX fifo has something
+ * to transfer, else will be deasserted confirming completion of
+ * the ongoing transfer.
+ */
+
+ v = readl(pic32s->regs + SPICON);
+ v &= ~SPICON_MSSEN;
+ if (mst) {
+ v |= SPICON_MSSEN;
+ if (mode & SPI_CS_HIGH)
+ v |= SPICON_FRMPOL;
+ else
+ v &= ~SPICON_FRMPOL;
+ }
+
+ writel(v, pic32s->regs + SPICON);
+}
+
+static inline void spi_set_err_int(struct pic32_spi *pic32s)
+{
+ u32 mask;
+
+ mask = SPI_INT_TX_UR_EN | SPI_INT_RX_OV_EN | SPI_INT_FRM_ERR_EN;
+ writel(mask, pic32s->regs + SPICON2_SET);
+}
+
+/* Return the max entries we can fill into tx fifo */
+static inline 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 - spi_tx_fifo_level(pic32s);
+
+ /* Another concern is about the tx/rx mismatch, we
+ * thought 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 control 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 inline 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, spi_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 + SPIBUF); \
+ 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 + SPIBUF); \
+ 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)
+{
+ spi_disable_chip(pic32s);
+
+ /* Show err message and abort xfer with err */
+ dev_err(&pic32s->master->dev, "%s\n", msg);
+ pic32s->mesg->state = (void *)-1;
+ complete(&pic32s->xfer_done);
+
+ disable_irq_nosync(pic32s->fault_irq);
+ disable_irq_nosync(pic32s->rx_irq);
+ disable_irq_nosync(pic32s->tx_irq);
+ dev_err(&pic32s->master->dev, "irq: disable all\n");
+}
+
+static irqreturn_t pic32_spi_fault_irq(int irq, void *dev_id)
+{
+ u32 status;
+ struct pic32_spi *pic32s = dev_id;
+
+ spin_lock(&pic32s->lock);
+
+ status = readl(pic32s->regs + SPISTAT);
+
+ if (status & (STAT_RX_OV | STAT_FRM_ERR | STAT_TX_UR)) {
+ writel(STAT_RX_OV, pic32s->regs + SPISTAT_CLR);
+ writel(STAT_TX_UR, pic32s->regs + SPISTAT_CLR);
+ pic32_err_stop(pic32s, "err_irq: fifo ov/ur-run\n");
+ goto irq_handled;
+ }
+
+ if (status & STAT_FRM_ERR) {
+ pic32_err_stop(pic32s, "err_irq: frame error");
+ goto irq_handled;
+ }
+
+ if (!pic32s->mesg) {
+ pic32_err_stop(pic32s, "err_irq: mesg error");
+ goto irq_handled;
+ }
+
+irq_handled:
+ spin_unlock(&pic32s->lock);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t pic32_spi_rx_irq(int irq, void *dev_id)
+{
+ struct pic32_spi *pic32s = dev_id;
+
+ spin_lock(&pic32s->lock);
+
+ pic32s->rx_fifo(pic32s);
+
+ /* rx complete? */
+ if (pic32s->rx_end == pic32s->rx) {
+ disable_irq_nosync(pic32s->fault_irq);
+ disable_irq_nosync(pic32s->rx_irq);
+
+ complete(&pic32s->xfer_done);
+ }
+
+ spin_unlock(&pic32s->lock);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t pic32_spi_tx_irq(int irq, void *dev_id)
+{
+ struct pic32_spi *pic32s = dev_id;
+
+ spin_lock(&pic32s->lock);
+
+ pic32s->tx_fifo(pic32s);
+
+ /* tx complete? mask and disable tx interrupt */
+ if (pic32s->tx_end == pic32s->tx)
+ disable_irq_nosync(pic32s->tx_irq);
+
+ spin_unlock(&pic32s->lock);
+
+ return IRQ_HANDLED;
+}
+
+static inline void pic32_spi_cs_assert(struct pic32_spi *pic32s)
+{
+ int cs_high;
+ struct spi_device *spi_dev = pic32s->spi_dev;
+
+ if (pic32s->flags & SPI_SS_MASTER)
+ return;
+
+ cs_high = pic32s->mode & SPI_CS_HIGH;
+ gpio_set_value(spi_dev->cs_gpio, cs_high);
+}
+
+static inline void pic32_spi_cs_deassert(struct pic32_spi *pic32s)
+{
+ int cs_high;
+ struct spi_device *spi_dev = pic32s->spi_dev;
+
+ if (pic32s->flags & SPI_SS_MASTER)
+ return;
+
+ cs_high = pic32s->mode & SPI_CS_HIGH;
+ gpio_set_value(spi_dev->cs_gpio, !cs_high);
+}
+
+static int pic32_spi_poll_transfer(struct pic32_spi *pic32s,
+ unsigned long timeout)
+{
+ unsigned long deadline;
+
+ deadline = timeout + jiffies;
+ for (;;) {
+ pic32s->tx_fifo(pic32s);
+ cpu_relax();
+
+ pic32s->rx_fifo(pic32s);
+ cpu_relax();
+
+ /* received sufficient data */
+ if (pic32s->rx >= pic32s->rx_end)
+ break;
+
+ if (time_after_eq(jiffies, deadline))
+ return -EIO;
+ }
+
+ 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);
+
+ return (xfer->len >= SPI_DMA_LEN_MIN) && (pic32s->flags & SPI_DMA_PREP);
+}
+
+static inline bool pic32_spi_dma_is_ready(struct pic32_spi *pic32s)
+{
+ int ret;
+
+ ret = (pic32s->flags & SPI_DMA_PREP) &&
+ (pic32s->len >= SPI_DMA_LEN_MIN) && (pic32s->tx && pic32s->rx);
+
+ if (ret)
+ pic32s->flags |= SPI_DMA_READY;
+
+ return ret;
+}
+
+static inline void pic32_spi_dma_unmap(struct pic32_spi *pic32s)
+{
+ pic32s->flags &= ~SPI_DMA_READY;
+}
+
+static void pic32_spi_dma_rx_notify(void *data)
+{
+ struct pic32_spi *pic32s = data;
+
+ spin_lock(&pic32s->lock);
+ complete(&pic32s->xfer_done);
+ spin_unlock(&pic32s->lock);
+}
+
+static inline void pic32_spi_dma_abort(struct pic32_spi *pic32s)
+{
+ if (!(pic32s->flags & SPI_DMA_READY))
+ return;
+
+ if (pic32s->master->dma_rx)
+ dmaengine_terminate_all(pic32s->master->dma_rx);
+
+ if (pic32s->master->dma_tx)
+ dmaengine_terminate_all(pic32s->master->dma_tx);
+
+ dev_err(&pic32s->master->dev, "%s, aborted\n", __func__);
+}
+
+static int pic32_spi_dma_transfer(struct pic32_spi *pic32s,
+ struct spi_transfer *xfer)
+{
+ dma_cookie_t cookie;
+ struct spi_master *master = pic32s->master;
+ struct dma_async_tx_descriptor *desc_rx;
+ struct dma_async_tx_descriptor *desc_tx;
+
+ 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_FROM_DEVICE,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!desc_rx)
+ goto err_dma;
+
+ desc_tx = dmaengine_prep_slave_sg(master->dma_tx,
+ xfer->tx_sg.sgl,
+ xfer->tx_sg.nents,
+ DMA_TO_DEVICE,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!desc_tx)
+ goto err_dma;
+
+ dev_vdbg(&master->dev, "dma_xfer %p: len %u, tx %p(%p), rx %p(%p)\n",
+ xfer, xfer->len,
+ xfer->tx_buf, (void *)xfer->tx_dma,
+ xfer->rx_buf, (void *)xfer->rx_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);
+ if (dma_submit_error(cookie))
+ goto err_dma;
+
+ cookie = dmaengine_submit(desc_tx);
+ if (dma_submit_error(cookie))
+ goto err_dma;
+
+ dma_async_issue_pending(master->dma_rx);
+ dma_async_issue_pending(master->dma_tx);
+
+ return 0;
+
+err_dma:
+ pic32_spi_dma_abort(pic32s);
+ return -ENOMEM;
+}
+
+static int pic32_spi_dma_config(struct pic32_spi *pic32s, u32 dma_width)
+{
+ int err;
+ struct dma_slave_config cfg;
+ struct spi_master *master = pic32s->master;
+
+ cfg.device_fc = true;
+ cfg.dst_addr = pic32s->phys_base + SPIBUF;
+ cfg.src_addr = pic32s->phys_base + SPIBUF;
+ cfg.dst_addr_width = dma_width;
+ cfg.src_addr_width = dma_width;
+ cfg.src_maxburst = pic32s->fifo_n_elm >> 1; /* fill one-half */
+ cfg.dst_maxburst = pic32s->fifo_n_elm >> 1; /* drain one-half */
+
+ cfg.slave_id = pic32s->tx_irq;
+ cfg.direction = DMA_MEM_TO_DEV;
+ err = dmaengine_slave_config(master->dma_tx, &cfg);
+ if (err) {
+ dev_err(&master->dev, "configure tx dma channel failed\n");
+ goto out;
+ }
+
+ cfg.slave_id = pic32s->rx_irq;
+ cfg.direction = DMA_DEV_TO_MEM;
+ err = dmaengine_slave_config(master->dma_rx, &cfg);
+ if (err)
+ dev_err(&master->dev, "configure rx dma channel failed\n");
+out:
+ return err;
+}
+
+static void pic32_spi_set_word_size(struct pic32_spi *pic32s, u8 bpw)
+{
+ u8 spi_bpw;
+ enum dma_slave_buswidth busw;
+
+ switch (bpw) {
+ default:
+ case 8:
+ pic32s->rx_fifo = pic32_spi_rx_byte;
+ pic32s->tx_fifo = pic32_spi_tx_byte;
+ spi_bpw = SPI_BPW_8;
+ busw = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ break;
+ case 16:
+ pic32s->rx_fifo = pic32_spi_rx_word;
+ pic32s->tx_fifo = pic32_spi_tx_word;
+ spi_bpw = SPI_BPW_16;
+ busw = DMA_SLAVE_BUSWIDTH_2_BYTES;
+ break;
+ case 32:
+ pic32s->rx_fifo = pic32_spi_rx_dword;
+ pic32s->tx_fifo = pic32_spi_tx_dword;
+ spi_bpw = SPI_BPW_32;
+ busw = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ break;
+ }
+ spi_set_ws(pic32s, spi_bpw);
+
+ /* calculate maximum elements fifo can hold */
+ pic32s->fifo_n_elm = DIV_ROUND_UP(pic32s->fifo_n_byte, bpw >> 3);
+
+ /* re-configure dma width, if required */
+ if ((pic32s->flags & SPI_DMA_PREP) && (busw != pic32s->dma_width)) {
+ pic32_spi_dma_config(pic32s, busw);
+ pic32s->dma_width = busw;
+ }
+}
+
+static int pic32_spi_one_transfer(struct pic32_spi *pic32s,
+ struct spi_message *message,
+ struct spi_transfer *transfer)
+{
+ int ret = 0;
+ unsigned long flags;
+ struct spi_master *master = pic32s->master;
+
+ /* 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;
+
+ if (transfer->speed_hz && (transfer->speed_hz != pic32s->speed_hz)) {
+ spi_set_clk_rate(pic32s, transfer->speed_hz);
+ pic32s->speed_hz = transfer->speed_hz;
+ }
+
+ if (transfer->bits_per_word)
+ pic32_spi_set_word_size(pic32s, transfer->bits_per_word);
+
+ spin_lock_irqsave(&pic32s->lock, flags);
+
+ spi_enable_chip(pic32s);
+
+ /* polling mode? */
+ if (pic32s->flags & SPI_XFER_POLL) {
+ ret = pic32_spi_poll_transfer(pic32s, 2 * HZ);
+ spin_unlock_irqrestore(&pic32s->lock, flags);
+
+ if (ret) {
+ dev_err(&master->dev, "poll-xfer timedout\n");
+ message->status = ret;
+ goto err_xfer_done;
+ }
+ goto out_xfer_done;
+ }
+
+ reinit_completion(&pic32s->xfer_done);
+
+ /* DMA mode ? */
+ if (pic32_spi_dma_is_ready(pic32s)) {
+ spin_unlock_irqrestore(&pic32s->lock, flags);
+
+ ret = pic32_spi_dma_transfer(pic32s, transfer);
+ if (ret) {
+ dev_err(&master->dev, "dma xfer error\n");
+ message->status = ret;
+ spin_lock_irqsave(&pic32s->lock, flags);
+ } else {
+ goto out_wait_for_xfer;
+ }
+ }
+
+ /* enable interrupt */
+ enable_irq(pic32s->fault_irq);
+ enable_irq(pic32s->tx_irq);
+ enable_irq(pic32s->rx_irq);
+
+ spin_unlock_irqrestore(&pic32s->lock, flags);
+
+out_wait_for_xfer:
+
+ /* wait for completion */
+ ret = wait_for_completion_timeout(&pic32s->xfer_done, 2 * HZ);
+ if (ret <= 0) {
+ dev_err(&master->dev, "wait timedout/interrupted\n");
+ ret = -EIO;
+ message->status = ret;
+ pic32_spi_dma_abort(pic32s);
+ goto err_xfer_done;
+ }
+
+out_xfer_done:
+ /* Update total byte transferred */
+ message->actual_length += transfer->len;
+ ret = 0;
+
+err_xfer_done:
+ pic32_spi_dma_unmap(pic32s);
+ return ret;
+}
+
+static int pic32_spi_one_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ int ret = 0;
+ int cs_active = 0;
+ struct pic32_spi *pic32s;
+ struct spi_transfer *xfer;
+ struct spi_device *spi = msg->spi;
+
+ dev_vdbg(&spi->dev, "new message %p submitted for %s\n",
+ msg, dev_name(&spi->dev));
+
+ pic32s = spi_master_get_devdata(master);
+
+ msg->status = 0;
+ msg->state = (void *)-2; /* running */
+ msg->actual_length = 0;
+
+ pic32s->mesg = msg;
+
+ spi_disable_chip(pic32s);
+
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ if (!cs_active) {
+ pic32_spi_cs_assert(pic32s);
+ cs_active = 1;
+ }
+
+ ret = pic32_spi_one_transfer(pic32s, msg, xfer);
+ if (ret) {
+ dev_err(&spi->dev, "xfer %p err\n", xfer);
+ goto xfer_done;
+ }
+
+ /* handle delay, if asked */
+ if (xfer->delay_usecs)
+ udelay(xfer->delay_usecs);
+
+ /* handle cs-change
+ * - for terminal transfer of the list skips CS deassertion.
+ * - for others deassert CS temporarily, before starting next
+ * transfer CS will be asserted as usual.
+ */
+ if (!xfer->cs_change)
+ continue;
+
+ cs_active = 0;
+ if (!list_is_last(&xfer->transfer_list, &msg->transfers)) {
+ pic32_spi_cs_deassert(pic32s);
+ continue;
+ }
+ }
+
+ msg->state = NULL;
+ msg->status = 0;
+
+xfer_done:
+ /* deassert cs */
+ if (cs_active)
+ pic32_spi_cs_deassert(pic32s);
+
+ spi_disable_chip(pic32s);
+
+ spi_finalize_current_message(spi->master);
+
+ return ret;
+}
+
+static void pic32_spi_cleanup(struct spi_device *spi)
+{
+ int cs_high;
+ struct pic32_spi *pic32s;
+
+ pic32s = spi_master_get_devdata(spi->master);
+
+ /* diasable chip */
+ spi_disable_chip(pic32s);
+
+ /* release cs-gpio */
+ if (!(pic32s->flags & SPI_SS_MASTER)) {
+ cs_high = pic32s->mode & SPI_CS_HIGH;
+ gpio_direction_output(spi->cs_gpio, !cs_high);
+ gpio_free(spi->cs_gpio);
+ }
+
+ /* reset reference */
+ pic32s->spi_dev = NULL;
+ pic32s->speed_hz = 0;
+}
+
+/* This may be called multiple times by same spi dev */
+static int pic32_spi_setup(struct spi_device *spi)
+{
+ struct pic32_spi *pic32s;
+ int cs_high;
+ int ret;
+
+ pic32s = spi_master_get_devdata(spi->master);
+
+ /* SPI master supports only one spi-device at a time.
+ * So multiple spi_setup() to different devices is not allowed.
+ */
+ if (unlikely(pic32s->spi_dev && (pic32s->spi_dev != spi))) {
+ dev_err(&spi->dev, "spi-master already associated with %s\n",
+ dev_name(&pic32s->spi_dev->dev));
+ return -EPERM;
+ }
+
+ if (pic32s->spi_dev == spi)
+ pic32_spi_cleanup(spi);
+
+ pic32s->spi_dev = spi;
+
+ /* set POLL mode, if invalid irq is provided */
+ if ((pic32s->fault_irq <= 0) || (pic32s->rx_irq <= 0) ||
+ (pic32s->tx_irq <= 0))
+ pic32s->flags |= SPI_XFER_POLL;
+
+ if (!spi->bits_per_word) {
+ dev_err(&spi->dev, "No bits_per_word defined\n");
+ return -EINVAL;
+ }
+
+ if (!spi->max_speed_hz) {
+ dev_err(&spi->dev, "No max speed HZ parameter\n");
+ return -EINVAL;
+ }
+
+ spi_disable_chip(pic32s);
+
+ pic32_spi_set_word_size(pic32s, spi->bits_per_word);
+
+ pic32s->speed_hz = spi->max_speed_hz;
+ spi_set_clk_rate(pic32s, spi->max_speed_hz);
+
+ /* set spi mode */
+ spi_set_clk_mode(pic32s, spi->mode);
+ pic32s->mode = spi->mode;
+
+ /* configure master-ctl CS assert/deassert, if cs_gpio is invalid */
+ pic32s->flags |= SPI_SS_MASTER;
+
+ cs_high = pic32s->mode & SPI_CS_HIGH;
+ if (gpio_is_valid(spi->cs_gpio)) {
+ ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev));
+ if (!ret) {
+ gpio_direction_output(spi->cs_gpio, !cs_high);
+ pic32s->flags &= ~SPI_SS_MASTER;
+ dev_vdbg(&spi->dev,
+ "gpio-%d configured for spics (%s)\n",
+ spi->cs_gpio, cs_high ? "cs_high" : "cs_low");
+ }
+ }
+ spi_set_ss_auto(pic32s, pic32s->flags & SPI_SS_MASTER, spi->mode);
+
+ dev_vdbg(&spi->master->dev,
+ "successfully registered spi-device %s\n",
+ dev_name(&spi->dev));
+ return 0;
+}
+
+static int pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev)
+{
+ int err;
+ struct spi_master *master = pic32s->master;
+ dma_cap_mask_t mask;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+
+ master->dma_rx = dma_request_slave_channel_compat(mask, NULL, NULL,
+ dev, "spi-rx");
+ if (!master->dma_rx) {
+ dev_err(dev, "RX channel not found, SPI unable to use DMA\n");
+ err = -EBUSY;
+ goto out_err;
+ }
+
+ master->dma_tx = dma_request_slave_channel_compat(mask, NULL, NULL,
+ dev, "spi-tx");
+ if (!master->dma_tx) {
+ dev_err(dev, "TX channel not found, SPI unable to use DMA\n");
+ err = -EBUSY;
+ goto out_err;
+ }
+
+ pic32s->dma_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ err = pic32_spi_dma_config(pic32s, pic32s->dma_width);
+ if (err)
+ goto out_err;
+
+ /* DMA chnls allocated & prepared */
+ pic32s->flags |= SPI_DMA_PREP;
+
+ dev_dbg(dev, "Using %s (tx) and %s (rx) for DMA transfers\n",
+ dma_chan_name(master->dma_tx),
+ dma_chan_name(master->dma_rx));
+ return 0;
+
+out_err:
+ if (master->dma_rx)
+ dma_release_channel(master->dma_rx);
+
+ if (master->dma_tx)
+ dma_release_channel(master->dma_tx);
+
+ return err;
+}
+
+static void pic32_spi_dma_unprep(struct pic32_spi *pic32s)
+{
+ if (!(pic32s->flags & SPI_DMA_PREP))
+ return;
+
+ pic32s->flags &= ~SPI_DMA_PREP;
+ 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 v;
+
+ /* disable module */
+ spi_disable_chip(pic32s);
+
+ /* drain rx buf */
+ spi_drain_rx_buf(pic32s);
+
+ v = readl(pic32s->regs + SPICON);
+
+ /* enable fifo: fifo-depth is fixed to 128bit(= 16B) */
+ v |= SPICON_ENHBUF;
+ pic32s->fifo_n_byte = 16;
+
+ /* disable framing mode */
+ v &= ~SPICON_FRMEN;
+
+ /* enable master mode while disabled */
+ v |= SPICON_MSTEN;
+
+ /* set tx fifo threshold interrupt */
+ v &= ~(0x3 << SPICON_TXI_SHIFT);
+ v |= (SPI_TX_FIFO_HALF_EMPTY << SPICON_TXI_SHIFT);
+
+ /* set rx fifo threshold interrupt */
+ v &= ~(0x3 << SPICON_RXI_SHIFT);
+ v |= (SPI_RX_FIFO_NOT_EMPTY << SPICON_RXI_SHIFT);
+
+ writel(v, pic32s->regs + SPICON);
+
+ spi_set_err_int(pic32s);
+}
+
+static int pic32_spi_hw_probe(struct platform_device *pdev,
+ struct pic32_spi *pic32s)
+{
+ int ret, clk_id = SPI_CLKSRC_PBCLK;
+ struct resource *mem;
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ pic32s->regs = devm_ioremap_resource(&pdev->dev, mem);
+ if (!pic32s->regs) {
+ dev_err(&pdev->dev, "mem map failed\n");
+ return -ENOMEM;
+ }
+ pic32s->phys_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)
+ dev_warn(&pdev->dev, "no fault-irq supplied\n");
+
+ pic32s->rx_irq = platform_get_irq_byname(pdev, "rx");
+ if (pic32s->rx_irq < 0)
+ dev_warn(&pdev->dev, "no rx-irq supplied\n");
+
+ pic32s->tx_irq = platform_get_irq_byname(pdev, "tx");
+ if (pic32s->tx_irq < 0)
+ dev_warn(&pdev->dev, "no tx-irq supplied\n");
+
+ pic32_spi_hw_init(pic32s);
+
+ /* any one of the two clk sources is mandatory; pbxclk:0, m_clk:1 */
+ pic32s->clk = devm_clk_get(&pdev->dev, "mck0");
+ if (IS_ERR(pic32s->clk)) {
+ pic32s->clk = devm_clk_get(&pdev->dev, "mck1");
+ if (IS_ERR(pic32s->clk)) {
+ ret = PTR_ERR(pic32s->clk);
+ dev_err(&pdev->dev, "no clk supplied\n");
+ goto err_unmap_mem;
+ }
+ clk_id = SPI_CLKSRC_MCLK;
+ }
+
+ clk_prepare_enable(pic32s->clk);
+
+ /* Select clk src */
+ spi_set_clk(pic32s, clk_id);
+
+ return 0;
+
+err_unmap_mem:
+ dev_err(&pdev->dev, "hw_probe failed, ret %d\n", ret);
+ return ret;
+}
+
+static int pic32_spi_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct spi_master *master;
+ struct pic32_spi *pic32s;
+ struct device *dev = &pdev->dev;
+ u32 max_spi_rate = 50000000;
+
+ master = spi_alloc_master(dev, sizeof(*pic32s));
+ if (!master)
+ return -ENOMEM;
+
+ pic32s = spi_master_get_devdata(master);
+ pic32s->master = master;
+ pic32s->flags = SPI_DMA_CAP;
+
+ ret = pic32_spi_hw_probe(pdev, pic32s);
+ if (ret) {
+ dev_err(&pdev->dev, "hw probe failed\n");
+ goto err_free_master;
+ }
+
+ if (dev->of_node) {
+ of_property_read_u32(dev->of_node,
+ "max-clock-frequency", &max_spi_rate);
+
+ if (of_find_property(dev->of_node, "use-no-dma", NULL)) {
+ dev_warn(dev, "DMA support not requested\n");
+ pic32s->flags &= ~SPI_DMA_CAP;
+ }
+ }
+
+ if (pic32s->flags & SPI_DMA_CAP) {
+ ret = pic32_spi_dma_prep(pic32s, dev);
+ if (ret)
+ dev_warn(dev, "DMA support kept disabled\n");
+ }
+
+ master->dev.of_node = of_node_get(pdev->dev.of_node);
+ master->mode_bits = SPI_MODE_3 | SPI_MODE_0 | SPI_CS_HIGH;
+ master->num_chipselect = 1;
+ master->max_speed_hz = max_spi_rate;
+ 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_RANGE_MASK(8, 32);
+ master->transfer_one_message = pic32_spi_one_message;
+ if (pic32s->flags & SPI_DMA_PREP)
+ master->can_dma = pic32_spi_can_dma;
+
+ init_completion(&pic32s->xfer_done);
+ spin_lock_init(&pic32s->lock);
+
+ irq_set_status_flags(pic32s->fault_irq, IRQ_NOAUTOEN);
+ ret = devm_request_irq(dev, pic32s->fault_irq,
+ pic32_spi_fault_irq, IRQF_NO_THREAD,
+ dev_name(dev), pic32s);
+ if (ret < 0) {
+ dev_warn(dev, "request fault-irq %d\n", pic32s->rx_irq);
+ pic32s->flags |= SPI_XFER_POLL;
+ goto irq_request_done;
+ }
+
+ irq_set_status_flags(pic32s->rx_irq, IRQ_NOAUTOEN);
+ ret = devm_request_irq(dev, pic32s->rx_irq,
+ pic32_spi_rx_irq, IRQF_NO_THREAD, dev_name(dev),
+ pic32s);
+ if (ret < 0) {
+ dev_warn(dev, "request rx-irq %d\n", pic32s->rx_irq);
+ pic32s->flags |= SPI_XFER_POLL;
+ goto irq_request_done;
+ }
+
+ irq_set_status_flags(pic32s->tx_irq, IRQ_NOAUTOEN);
+ ret = devm_request_irq(dev, pic32s->tx_irq,
+ pic32_spi_tx_irq, IRQF_NO_THREAD, dev_name(dev),
+ pic32s);
+ if (ret < 0) {
+ dev_warn(dev, "request tx-irq %d\n", pic32s->tx_irq);
+ pic32s->flags |= SPI_XFER_POLL;
+ goto irq_request_done;
+ }
+
+irq_request_done:
+ ret = devm_spi_register_master(dev, master);
+ if (ret) {
+ dev_err(&master->dev, "failed registering spi master\n");
+ goto err_hw_remove;
+ }
+
+ platform_set_drvdata(pdev, pic32s);
+
+ return 0;
+
+err_hw_remove:
+ spi_disable_chip(pic32s);
+
+ if (!IS_ERR_OR_NULL(pic32s->clk))
+ clk_disable_unprepare(pic32s->clk);
+err_free_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);
+
+ spi_disable_chip(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",
+ .owner = THIS_MODULE,
+ .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@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Microchip PIC32 SPI Driver");
+MODULE_LICENSE("GPL");
--
1.7.9.5
