3 files changed, 184 insertions, 0 deletions

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index ba9310bc9acb..c87475db0f79 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -520,6 +520,19 @@ config SPI_XILINX
 
           Or for the DS570, see "XPS Serial Peripheral Interface (SPI) (v2.00b)"
 
+config SPI_XTENSA_XTFPGA
+        tristate "Xtensa SPI controller for xtfpga"
+        depends on XTENSA && XTENSA_PLATFORM_XTFPGA
+        select SPI_BITBANG
+        help
+          SPI driver for xtfpga SPI master controller.
+
+          This simple SPI master controller is built into xtfpga bitstreams
+          and is used to control daughterboard audio codec. It always transfers
+          16 bit words in SPI mode 0, automatically asserting CS on transfer
+          start and deasserting on end.
+
+
 config SPI_NUC900
         tristate "Nuvoton NUC900 series SPI"
         depends on ARCH_W90X900
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 95af48d2d360..5379adee0a77 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -79,3 +79,4 @@ obj-$(CONFIG_SPI_TOPCLIFF_PCH)		+= spi-topcliff-pch.o
 obj-$(CONFIG_SPI_TXX9)                  += spi-txx9.o
 obj-$(CONFIG_SPI_XCOMM)         += spi-xcomm.o
 obj-$(CONFIG_SPI_XILINX)                += spi-xilinx.o
+obj-$(CONFIG_SPI_XTENSA_XTFPGA)         += spi-xtensa-xtfpga.o
diff --git a/drivers/spi/spi-xtensa-xtfpga.c b/drivers/spi/spi-xtensa-xtfpga.c
new file mode 100644
index 000000000000..41e158187f9d
--- /dev/null
+++ b/drivers/spi/spi-xtensa-xtfpga.c
@@ -0,0 +1,170 @@
+/*
+ * Xtensa xtfpga SPI controller driver
+ *
+ * Copyright (c) 2014 Cadence Design Systems Inc.
+ *
+ * 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 <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+
+#define XTFPGA_SPI_NAME "xtfpga_spi"
+
+#define XTFPGA_SPI_START        0x0
+#define XTFPGA_SPI_BUSY         0x4
+#define XTFPGA_SPI_DATA         0x8
+
+#define BUSY_WAIT_US            100
+
+struct xtfpga_spi {
+        struct spi_bitbang bitbang;
+        void __iomem *regs;
+        u32 data;
+        unsigned data_sz;
+};
+
+static inline void xtfpga_spi_write32(const struct xtfpga_spi *spi,
+                                      unsigned addr, u32 val)
+{
+        iowrite32(val, spi->regs + addr);
+}
+
+static inline unsigned int xtfpga_spi_read32(const struct xtfpga_spi *spi,
+                                             unsigned addr)
+{
+        return ioread32(spi->regs + addr);
+}
+
+static inline void xtfpga_spi_wait_busy(struct xtfpga_spi *xspi)
+{
+        unsigned i;
+        for (i = 0; xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY) &&
+             i < BUSY_WAIT_US; ++i)
+                udelay(1);
+        WARN_ON_ONCE(i == BUSY_WAIT_US);
+}
+
+static u32 xtfpga_spi_txrx_word(struct spi_device *spi, unsigned nsecs,
+                                u32 v, u8 bits)
+{
+        struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master);
+
+        xspi->data = (xspi->data << bits) | (v & GENMASK(bits - 1, 0));
+        xspi->data_sz += bits;
+        if (xspi->data_sz >= 16) {
+                xtfpga_spi_write32(xspi, XTFPGA_SPI_DATA,
+                                   xspi->data >> (xspi->data_sz - 16));
+                xspi->data_sz -= 16;
+                xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 1);
+                xtfpga_spi_wait_busy(xspi);
+                xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
+        }
+
+        return 0;
+}
+
+static void xtfpga_spi_chipselect(struct spi_device *spi, int is_on)
+{
+        struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master);
+
+        WARN_ON(xspi->data_sz != 0);
+        xspi->data_sz = 0;
+}
+
+static int xtfpga_spi_probe(struct platform_device *pdev)
+{
+        struct xtfpga_spi *xspi;
+        struct resource *mem;
+        int ret;
+        struct spi_master *master;
+
+        master = spi_alloc_master(&pdev->dev, sizeof(struct xtfpga_spi));
+        if (!master)
+                return -ENOMEM;
+
+        master->flags = SPI_MASTER_NO_RX;
+        master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
+        master->bus_num = pdev->dev.id;
+        master->dev.of_node = pdev->dev.of_node;
+
+        xspi = spi_master_get_devdata(master);
+        xspi->bitbang.master = master;
+        xspi->bitbang.chipselect = xtfpga_spi_chipselect;
+        xspi->bitbang.txrx_word[SPI_MODE_0] = xtfpga_spi_txrx_word;
+
+        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!mem) {
+                dev_err(&pdev->dev, "No memory resource\n");
+                ret = -ENODEV;
+                goto err;
+        }
+        xspi->regs = devm_ioremap_resource(&pdev->dev, mem);
+        if (IS_ERR(xspi->regs)) {
+                ret = PTR_ERR(xspi->regs);
+                goto err;
+        }
+
+        xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
+        usleep_range(1000, 2000);
+        if (xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY)) {
+                dev_err(&pdev->dev, "Device stuck in busy state\n");
+                ret = -EBUSY;
+                goto err;
+        }
+
+        ret = spi_bitbang_start(&xspi->bitbang);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "spi_bitbang_start failed\n");
+                goto err;
+        }
+
+        platform_set_drvdata(pdev, master);
+        return 0;
+err:
+        spi_master_put(master);
+        return ret;
+}
+
+static int xtfpga_spi_remove(struct platform_device *pdev)
+{
+        struct spi_master *master = platform_get_drvdata(pdev);
+        struct xtfpga_spi *xspi = spi_master_get_devdata(master);
+
+        spi_bitbang_stop(&xspi->bitbang);
+        spi_master_put(master);
+
+        return 0;
+}
+
+MODULE_ALIAS("platform:" XTFPGA_SPI_NAME);
+
+#ifdef CONFIG_OF
+static const struct of_device_id xtfpga_spi_of_match[] = {
+        { .compatible = "cdns,xtfpga-spi", },
+        {}
+};
+MODULE_DEVICE_TABLE(of, xtfpga_spi_of_match);
+#endif
+
+static struct platform_driver xtfpga_spi_driver = {
+        .probe = xtfpga_spi_probe,
+        .remove = xtfpga_spi_remove,
+        .driver = {
+                .name = XTFPGA_SPI_NAME,
+                .owner = THIS_MODULE,
+                .of_match_table = of_match_ptr(xtfpga_spi_of_match),
+        },
+};
+module_platform_driver(xtfpga_spi_driver);
+
+MODULE_AUTHOR("Max Filippov <jcmvbkbc@gmail.com>");
+MODULE_DESCRIPTION("xtensa xtfpga SPI driver");
+MODULE_LICENSE("GPL");