ARM: NUC900: Add spi driver support for nuc900

Signed-off-by: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

3 files changed, 512 insertions, 0 deletions

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 06e1c0c9d35e..b9908e9a9954 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -275,6 +275,13 @@ config SPI_XILINX_PLTFM
           This is the platform driver for the SPI controller IP
           from the Xilinx EDK.
 
+config SPI_NUC900
+        tristate "Nuvoton NUC900 series SPI"
+        depends on ARCH_W90X900 && EXPERIMENTAL
+        select SPI_BITBANG
+        help
+          SPI driver for Nuvoton NUC900 series ARM SoCs
+
 #
 # Add new SPI master controllers in alphabetical order above this line
 #
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 9c51e2526892..be6e8a50468e 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_SPI_XILINX_PLTFM)		+= xilinx_spi_pltfm.o
 obj-$(CONFIG_SPI_SH_SCI)                += spi_sh_sci.o
 obj-$(CONFIG_SPI_SH_MSIOF)              += spi_sh_msiof.o
 obj-$(CONFIG_SPI_STMP3XXX)              += spi_stmp.o
+obj-$(CONFIG_SPI_NUC900)                += spi_nuc900.o
 #       ... add above this line ...
 
 # SPI protocol drivers (device/link on bus)
diff --git a/drivers/spi/spi_nuc900.c b/drivers/spi/spi_nuc900.c
new file mode 100644
index 000000000000..b319f9bf9b9b
--- /dev/null
+++ b/drivers/spi/spi_nuc900.c
@@ -0,0 +1,504 @@
+/* linux/drivers/spi/spi_nuc900.c
+ *
+ * Copyright (c) 2009 Nuvoton technology.
+ * Wan ZongShun <mcuos.com@gmail.com>
+ *
+ * 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/init.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/io.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+
+#include <mach/nuc900_spi.h>
+
+/* usi registers offset */
+#define USI_CNT         0x00
+#define USI_DIV         0x04
+#define USI_SSR         0x08
+#define USI_RX0         0x10
+#define USI_TX0         0x10
+
+/* usi register bit */
+#define ENINT           (0x01 << 17)
+#define ENFLG           (0x01 << 16)
+#define TXNUM           (0x03 << 8)
+#define TXNEG           (0x01 << 2)
+#define RXNEG           (0x01 << 1)
+#define LSB             (0x01 << 10)
+#define SELECTLEV       (0x01 << 2)
+#define SELECTPOL       (0x01 << 31)
+#define SELECTSLAVE     0x01
+#define GOBUSY          0x01
+
+struct nuc900_spi {
+        struct spi_bitbang       bitbang;
+        struct completion        done;
+        void __iomem            *regs;
+        int                      irq;
+        int                      len;
+        int                      count;
+        const unsigned char     *tx;
+        unsigned char           *rx;
+        struct clk              *clk;
+        struct resource         *ioarea;
+        struct spi_master       *master;
+        struct spi_device       *curdev;
+        struct device           *dev;
+        struct nuc900_spi_info *pdata;
+        spinlock_t              lock;
+        struct resource         *res;
+};
+
+static inline struct nuc900_spi *to_hw(struct spi_device *sdev)
+{
+        return spi_master_get_devdata(sdev->master);
+}
+
+static void nuc900_slave_select(struct spi_device *spi, unsigned int ssr)
+{
+        struct nuc900_spi *hw = to_hw(spi);
+        unsigned int val;
+        unsigned int cs = spi->mode & SPI_CS_HIGH ? 1 : 0;
+        unsigned int cpol = spi->mode & SPI_CPOL ? 1 : 0;
+        unsigned long flags;
+
+        spin_lock_irqsave(&hw->lock, flags);
+
+        val = __raw_readl(hw->regs + USI_SSR);
+
+        if (!cs)
+                val &= ~SELECTLEV;
+        else
+                val |= SELECTLEV;
+
+        if (!ssr)
+                val &= ~SELECTSLAVE;
+        else
+                val |= SELECTSLAVE;
+
+        __raw_writel(val, hw->regs + USI_SSR);
+
+        val = __raw_readl(hw->regs + USI_CNT);
+
+        if (!cpol)
+                val &= ~SELECTPOL;
+        else
+                val |= SELECTPOL;
+
+        __raw_writel(val, hw->regs + USI_CNT);
+
+        spin_unlock_irqrestore(&hw->lock, flags);
+}
+
+static void nuc900_spi_chipsel(struct spi_device *spi, int value)
+{
+        switch (value) {
+        case BITBANG_CS_INACTIVE:
+                nuc900_slave_select(spi, 0);
+                break;
+
+        case BITBANG_CS_ACTIVE:
+                nuc900_slave_select(spi, 1);
+                break;
+        }
+}
+
+static void nuc900_spi_setup_txnum(struct nuc900_spi *hw,
+                                                        unsigned int txnum)
+{
+        unsigned int val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&hw->lock, flags);
+
+        val = __raw_readl(hw->regs + USI_CNT);
+
+        if (!txnum)
+                val &= ~TXNUM;
+        else
+                val |= txnum << 0x08;
+
+        __raw_writel(val, hw->regs + USI_CNT);
+
+        spin_unlock_irqrestore(&hw->lock, flags);
+
+}
+
+static void nuc900_spi_setup_txbitlen(struct nuc900_spi *hw,
+                                                        unsigned int txbitlen)
+{
+        unsigned int val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&hw->lock, flags);
+
+        val = __raw_readl(hw->regs + USI_CNT);
+
+        val |= (txbitlen << 0x03);
+
+        __raw_writel(val, hw->regs + USI_CNT);
+
+        spin_unlock_irqrestore(&hw->lock, flags);
+}
+
+static void nuc900_spi_gobusy(struct nuc900_spi *hw)
+{
+        unsigned int val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&hw->lock, flags);
+
+        val = __raw_readl(hw->regs + USI_CNT);
+
+        val |= GOBUSY;
+
+        __raw_writel(val, hw->regs + USI_CNT);
+
+        spin_unlock_irqrestore(&hw->lock, flags);
+}
+
+static int nuc900_spi_setupxfer(struct spi_device *spi,
+                                 struct spi_transfer *t)
+{
+        return 0;
+}
+
+static int nuc900_spi_setup(struct spi_device *spi)
+{
+        return 0;
+}
+
+static inline unsigned int hw_txbyte(struct nuc900_spi *hw, int count)
+{
+        return hw->tx ? hw->tx[count] : 0;
+}
+
+static int nuc900_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
+{
+        struct nuc900_spi *hw = to_hw(spi);
+
+        hw->tx = t->tx_buf;
+        hw->rx = t->rx_buf;
+        hw->len = t->len;
+        hw->count = 0;
+
+        __raw_writel(hw_txbyte(hw, 0x0), hw->regs + USI_TX0);
+
+        nuc900_spi_gobusy(hw);
+
+        wait_for_completion(&hw->done);
+
+        return hw->count;
+}
+
+static irqreturn_t nuc900_spi_irq(int irq, void *dev)
+{
+        struct nuc900_spi *hw = dev;
+        unsigned int status;
+        unsigned int count = hw->count;
+
+        status = __raw_readl(hw->regs + USI_CNT);
+        __raw_writel(status, hw->regs + USI_CNT);
+
+        if (status & ENFLG) {
+                hw->count++;
+
+                if (hw->rx)
+                        hw->rx[count] = __raw_readl(hw->regs + USI_RX0);
+                count++;
+
+                if (count < hw->len) {
+                        __raw_writel(hw_txbyte(hw, count), hw->regs + USI_TX0);
+                        nuc900_spi_gobusy(hw);
+                } else {
+                        complete(&hw->done);
+                }
+
+                return IRQ_HANDLED;
+        }
+
+        complete(&hw->done);
+        return IRQ_HANDLED;
+}
+
+static void nuc900_tx_edge(struct nuc900_spi *hw, unsigned int edge)
+{
+        unsigned int val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&hw->lock, flags);
+
+        val = __raw_readl(hw->regs + USI_CNT);
+
+        if (edge)
+                val |= TXNEG;
+        else
+                val &= ~TXNEG;
+        __raw_writel(val, hw->regs + USI_CNT);
+
+        spin_unlock_irqrestore(&hw->lock, flags);
+}
+
+static void nuc900_rx_edge(struct nuc900_spi *hw, unsigned int edge)
+{
+        unsigned int val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&hw->lock, flags);
+
+        val = __raw_readl(hw->regs + USI_CNT);
+
+        if (edge)
+                val |= RXNEG;
+        else
+                val &= ~RXNEG;
+        __raw_writel(val, hw->regs + USI_CNT);
+
+        spin_unlock_irqrestore(&hw->lock, flags);
+}
+
+static void nuc900_send_first(struct nuc900_spi *hw, unsigned int lsb)
+{
+        unsigned int val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&hw->lock, flags);
+
+        val = __raw_readl(hw->regs + USI_CNT);
+
+        if (lsb)
+                val |= LSB;
+        else
+                val &= ~LSB;
+        __raw_writel(val, hw->regs + USI_CNT);
+
+        spin_unlock_irqrestore(&hw->lock, flags);
+}
+
+static void nuc900_set_sleep(struct nuc900_spi *hw, unsigned int sleep)
+{
+        unsigned int val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&hw->lock, flags);
+
+        val = __raw_readl(hw->regs + USI_CNT);
+
+        if (sleep)
+                val |= (sleep << 12);
+        else
+                val &= ~(0x0f << 12);
+        __raw_writel(val, hw->regs + USI_CNT);
+
+        spin_unlock_irqrestore(&hw->lock, flags);
+}
+
+static void nuc900_enable_int(struct nuc900_spi *hw)
+{
+        unsigned int val;
+        unsigned long flags;
+
+        spin_lock_irqsave(&hw->lock, flags);
+
+        val = __raw_readl(hw->regs + USI_CNT);
+
+        val |= ENINT;
+
+        __raw_writel(val, hw->regs + USI_CNT);
+
+        spin_unlock_irqrestore(&hw->lock, flags);
+}
+
+static void nuc900_set_divider(struct nuc900_spi *hw)
+{
+        __raw_writel(hw->pdata->divider, hw->regs + USI_DIV);
+}
+
+static void nuc900_init_spi(struct nuc900_spi *hw)
+{
+        clk_enable(hw->clk);
+        spin_lock_init(&hw->lock);
+
+        nuc900_tx_edge(hw, hw->pdata->txneg);
+        nuc900_rx_edge(hw, hw->pdata->rxneg);
+        nuc900_send_first(hw, hw->pdata->lsb);
+        nuc900_set_sleep(hw, hw->pdata->sleep);
+        nuc900_spi_setup_txbitlen(hw, hw->pdata->txbitlen);
+        nuc900_spi_setup_txnum(hw, hw->pdata->txnum);
+        nuc900_set_divider(hw);
+        nuc900_enable_int(hw);
+}
+
+static int __devinit nuc900_spi_probe(struct platform_device *pdev)
+{
+        struct nuc900_spi *hw;
+        struct spi_master *master;
+        int err = 0;
+
+        master = spi_alloc_master(&pdev->dev, sizeof(struct nuc900_spi));
+        if (master == NULL) {
+                dev_err(&pdev->dev, "No memory for spi_master\n");
+                err = -ENOMEM;
+                goto err_nomem;
+        }
+
+        hw = spi_master_get_devdata(master);
+        memset(hw, 0, sizeof(struct nuc900_spi));
+
+        hw->master = spi_master_get(master);
+        hw->pdata  = pdev->dev.platform_data;
+        hw->dev = &pdev->dev;
+
+        if (hw->pdata == NULL) {
+                dev_err(&pdev->dev, "No platform data supplied\n");
+                err = -ENOENT;
+                goto err_pdata;
+        }
+
+        platform_set_drvdata(pdev, hw);
+        init_completion(&hw->done);
+
+        master->mode_bits          = SPI_MODE_0;
+        master->num_chipselect     = hw->pdata->num_cs;
+        master->bus_num            = hw->pdata->bus_num;
+        hw->bitbang.master         = hw->master;
+        hw->bitbang.setup_transfer = nuc900_spi_setupxfer;
+        hw->bitbang.chipselect     = nuc900_spi_chipsel;
+        hw->bitbang.txrx_bufs      = nuc900_spi_txrx;
+        hw->bitbang.master->setup  = nuc900_spi_setup;
+
+        hw->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (hw->res == NULL) {
+                dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
+                err = -ENOENT;
+                goto err_pdata;
+        }
+
+        hw->ioarea = request_mem_region(hw->res->start,
+                                        resource_size(hw->res), pdev->name);
+
+        if (hw->ioarea == NULL) {
+                dev_err(&pdev->dev, "Cannot reserve region\n");
+                err = -ENXIO;
+                goto err_pdata;
+        }
+
+        hw->regs = ioremap(hw->res->start, resource_size(hw->res));
+        if (hw->regs == NULL) {
+                dev_err(&pdev->dev, "Cannot map IO\n");
+                err = -ENXIO;
+                goto err_iomap;
+        }
+
+        hw->irq = platform_get_irq(pdev, 0);
+        if (hw->irq < 0) {
+                dev_err(&pdev->dev, "No IRQ specified\n");
+                err = -ENOENT;
+                goto err_irq;
+        }
+
+        err = request_irq(hw->irq, nuc900_spi_irq, 0, pdev->name, hw);
+        if (err) {
+                dev_err(&pdev->dev, "Cannot claim IRQ\n");
+                goto err_irq;
+        }
+
+        hw->clk = clk_get(&pdev->dev, "spi");
+        if (IS_ERR(hw->clk)) {
+                dev_err(&pdev->dev, "No clock for device\n");
+                err = PTR_ERR(hw->clk);
+                goto err_clk;
+        }
+
+        mfp_set_groupg(&pdev->dev);
+        nuc900_init_spi(hw);
+
+        err = spi_bitbang_start(&hw->bitbang);
+        if (err) {
+                dev_err(&pdev->dev, "Failed to register SPI master\n");
+                goto err_register;
+        }
+
+        return 0;
+
+err_register:
+        clk_disable(hw->clk);
+        clk_put(hw->clk);
+err_clk:
+        free_irq(hw->irq, hw);
+err_irq:
+        iounmap(hw->regs);
+err_iomap:
+        release_mem_region(hw->res->start, resource_size(hw->res));
+        kfree(hw->ioarea);
+err_pdata:
+        spi_master_put(hw->master);;
+
+err_nomem:
+        return err;
+}
+
+static int __devexit nuc900_spi_remove(struct platform_device *dev)
+{
+        struct nuc900_spi *hw = platform_get_drvdata(dev);
+
+        free_irq(hw->irq, hw);
+
+        platform_set_drvdata(dev, NULL);
+
+        spi_unregister_master(hw->master);
+
+        clk_disable(hw->clk);
+        clk_put(hw->clk);
+
+        iounmap(hw->regs);
+
+        release_mem_region(hw->res->start, resource_size(hw->res));
+        kfree(hw->ioarea);
+
+        spi_master_put(hw->master);
+        return 0;
+}
+
+static struct platform_driver nuc900_spi_driver = {
+        .probe          = nuc900_spi_probe,
+        .remove         = __devexit_p(nuc900_spi_remove),
+        .driver         = {
+                .name   = "nuc900-spi",
+                .owner  = THIS_MODULE,
+        },
+};
+
+static int __init nuc900_spi_init(void)
+{
+        return platform_driver_register(&nuc900_spi_driver);
+}
+
+static void __exit nuc900_spi_exit(void)
+{
+        platform_driver_unregister(&nuc900_spi_driver);
+}
+
+module_init(nuc900_spi_init);
+module_exit(nuc900_spi_exit);
+
+MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
+MODULE_DESCRIPTION("nuc900 spi driver!");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:nuc900-spi");