spi: New driver for Altera SPI
Thomas Chou [Mon, 14 Feb 2011 02:10:43 +0000 (10:10 +0800)]
This patch adds a new SPI driver to support the Altera SOPC Builder
SPI component. It uses the bitbanging library.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

Documentation/devicetree/bindings/spi/spi_altera.txt [new file with mode: 0644]
drivers/spi/Kconfig
drivers/spi/Makefile
drivers/spi/spi_altera.c [new file with mode: 0644]

diff --git a/Documentation/devicetree/bindings/spi/spi_altera.txt b/Documentation/devicetree/bindings/spi/spi_altera.txt
new file mode 100644 (file)
index 0000000..dda3759
--- /dev/null
@@ -0,0 +1,4 @@
+Altera SPI
+
+Required properties:
+- compatible : should be "ALTR,spi-1.0".
index 8faa57a..e85b248 100644 (file)
@@ -53,6 +53,12 @@ if SPI_MASTER
 
 comment "SPI Master Controller Drivers"
 
+config SPI_ALTERA
+       tristate "Altera SPI Controller"
+       select SPI_BITBANG
+       help
+         This is the driver for the Altera SPI Controller.
+
 config SPI_ATH79
        tristate "Atheros AR71XX/AR724X/AR913X SPI controller driver"
        depends on ATH79 && GENERIC_GPIO
index c7e4c23..e111a0f 100644 (file)
@@ -9,6 +9,7 @@ ccflags-$(CONFIG_SPI_DEBUG) := -DDEBUG
 obj-$(CONFIG_SPI_MASTER)               += spi.o
 
 # SPI master controller drivers (bus)
+obj-$(CONFIG_SPI_ALTERA)               += spi_altera.o
 obj-$(CONFIG_SPI_ATMEL)                        += atmel_spi.o
 obj-$(CONFIG_SPI_ATH79)                        += ath79_spi.o
 obj-$(CONFIG_SPI_BFIN)                 += spi_bfin5xx.o
diff --git a/drivers/spi/spi_altera.c b/drivers/spi/spi_altera.c
new file mode 100644 (file)
index 0000000..4813a63
--- /dev/null
@@ -0,0 +1,339 @@
+/*
+ * Altera SPI driver
+ *
+ * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * Based on spi_s3c24xx.c, which is:
+ * Copyright (c) 2006 Ben Dooks
+ * Copyright (c) 2006 Simtec Electronics
+ *     Ben Dooks <ben@simtec.co.uk>
+ *
+ * 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/interrupt.h>
+#include <linux/errno.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/io.h>
+#include <linux/of.h>
+
+#define DRV_NAME "spi_altera"
+
+#define ALTERA_SPI_RXDATA      0
+#define ALTERA_SPI_TXDATA      4
+#define ALTERA_SPI_STATUS      8
+#define ALTERA_SPI_CONTROL     12
+#define ALTERA_SPI_SLAVE_SEL   20
+
+#define ALTERA_SPI_STATUS_ROE_MSK      0x8
+#define ALTERA_SPI_STATUS_TOE_MSK      0x10
+#define ALTERA_SPI_STATUS_TMT_MSK      0x20
+#define ALTERA_SPI_STATUS_TRDY_MSK     0x40
+#define ALTERA_SPI_STATUS_RRDY_MSK     0x80
+#define ALTERA_SPI_STATUS_E_MSK                0x100
+
+#define ALTERA_SPI_CONTROL_IROE_MSK    0x8
+#define ALTERA_SPI_CONTROL_ITOE_MSK    0x10
+#define ALTERA_SPI_CONTROL_ITRDY_MSK   0x40
+#define ALTERA_SPI_CONTROL_IRRDY_MSK   0x80
+#define ALTERA_SPI_CONTROL_IE_MSK      0x100
+#define ALTERA_SPI_CONTROL_SSO_MSK     0x400
+
+struct altera_spi {
+       /* bitbang has to be first */
+       struct spi_bitbang bitbang;
+       struct completion done;
+
+       void __iomem *base;
+       int irq;
+       int len;
+       int count;
+       int bytes_per_word;
+       unsigned long imr;
+
+       /* data buffers */
+       const unsigned char *tx;
+       unsigned char *rx;
+};
+
+static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
+{
+       return spi_master_get_devdata(sdev->master);
+}
+
+static void altera_spi_chipsel(struct spi_device *spi, int value)
+{
+       struct altera_spi *hw = altera_spi_to_hw(spi);
+
+       if (spi->mode & SPI_CS_HIGH) {
+               switch (value) {
+               case BITBANG_CS_INACTIVE:
+                       writel(1 << spi->chip_select,
+                              hw->base + ALTERA_SPI_SLAVE_SEL);
+                       hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
+                       writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
+                       break;
+
+               case BITBANG_CS_ACTIVE:
+                       hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
+                       writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
+                       writel(0, hw->base + ALTERA_SPI_SLAVE_SEL);
+                       break;
+               }
+       } else {
+               switch (value) {
+               case BITBANG_CS_INACTIVE:
+                       hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
+                       writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
+                       break;
+
+               case BITBANG_CS_ACTIVE:
+                       writel(1 << spi->chip_select,
+                              hw->base + ALTERA_SPI_SLAVE_SEL);
+                       hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
+                       writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
+                       break;
+               }
+       }
+}
+
+static int altera_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
+{
+       return 0;
+}
+
+static int altera_spi_setup(struct spi_device *spi)
+{
+       return 0;
+}
+
+static inline unsigned int hw_txbyte(struct altera_spi *hw, int count)
+{
+       if (hw->tx) {
+               switch (hw->bytes_per_word) {
+               case 1:
+                       return hw->tx[count];
+               case 2:
+                       return (hw->tx[count * 2]
+                               | (hw->tx[count * 2 + 1] << 8));
+               }
+       }
+       return 0;
+}
+
+static int altera_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
+{
+       struct altera_spi *hw = altera_spi_to_hw(spi);
+
+       hw->tx = t->tx_buf;
+       hw->rx = t->rx_buf;
+       hw->count = 0;
+       hw->bytes_per_word = (t->bits_per_word ? : spi->bits_per_word) / 8;
+       hw->len = t->len / hw->bytes_per_word;
+
+       if (hw->irq >= 0) {
+               /* enable receive interrupt */
+               hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK;
+               writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
+
+               /* send the first byte */
+               writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
+
+               wait_for_completion(&hw->done);
+               /* disable receive interrupt */
+               hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
+               writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
+       } else {
+               /* send the first byte */
+               writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
+
+               while (1) {
+                       unsigned int rxd;
+
+                       while (!(readl(hw->base + ALTERA_SPI_STATUS) &
+                                ALTERA_SPI_STATUS_RRDY_MSK))
+                               cpu_relax();
+
+                       rxd = readl(hw->base + ALTERA_SPI_RXDATA);
+                       if (hw->rx) {
+                               switch (hw->bytes_per_word) {
+                               case 1:
+                                       hw->rx[hw->count] = rxd;
+                                       break;
+                               case 2:
+                                       hw->rx[hw->count * 2] = rxd;
+                                       hw->rx[hw->count * 2 + 1] = rxd >> 8;
+                                       break;
+                               }
+                       }
+
+                       hw->count++;
+
+                       if (hw->count < hw->len)
+                               writel(hw_txbyte(hw, hw->count),
+                                      hw->base + ALTERA_SPI_TXDATA);
+                       else
+                               break;
+               }
+
+       }
+
+       return hw->count * hw->bytes_per_word;
+}
+
+static irqreturn_t altera_spi_irq(int irq, void *dev)
+{
+       struct altera_spi *hw = dev;
+       unsigned int rxd;
+
+       rxd = readl(hw->base + ALTERA_SPI_RXDATA);
+       if (hw->rx) {
+               switch (hw->bytes_per_word) {
+               case 1:
+                       hw->rx[hw->count] = rxd;
+                       break;
+               case 2:
+                       hw->rx[hw->count * 2] = rxd;
+                       hw->rx[hw->count * 2 + 1] = rxd >> 8;
+                       break;
+               }
+       }
+
+       hw->count++;
+
+       if (hw->count < hw->len)
+               writel(hw_txbyte(hw, hw->count), hw->base + ALTERA_SPI_TXDATA);
+       else
+               complete(&hw->done);
+
+       return IRQ_HANDLED;
+}
+
+static int __devinit altera_spi_probe(struct platform_device *pdev)
+{
+       struct altera_spi_platform_data *platp = pdev->dev.platform_data;
+       struct altera_spi *hw;
+       struct spi_master *master;
+       struct resource *res;
+       int err = -ENODEV;
+
+       master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
+       if (!master)
+               return err;
+
+       /* setup the master state. */
+       master->bus_num = pdev->id;
+       master->num_chipselect = 16;
+       master->mode_bits = SPI_CS_HIGH;
+       master->setup = altera_spi_setup;
+
+       hw = spi_master_get_devdata(master);
+       platform_set_drvdata(pdev, hw);
+
+       /* setup the state for the bitbang driver */
+       hw->bitbang.master = spi_master_get(master);
+       if (!hw->bitbang.master)
+               return err;
+       hw->bitbang.setup_transfer = altera_spi_setupxfer;
+       hw->bitbang.chipselect = altera_spi_chipsel;
+       hw->bitbang.txrx_bufs = altera_spi_txrx;
+
+       /* find and map our resources */
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res)
+               goto exit_busy;
+       if (!devm_request_mem_region(&pdev->dev, res->start, resource_size(res),
+                                    pdev->name))
+               goto exit_busy;
+       hw->base = devm_ioremap_nocache(&pdev->dev, res->start,
+                                       resource_size(res));
+       if (!hw->base)
+               goto exit_busy;
+       /* program defaults into the registers */
+       hw->imr = 0;            /* disable spi interrupts */
+       writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
+       writel(0, hw->base + ALTERA_SPI_STATUS);        /* clear status reg */
+       if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)
+               readl(hw->base + ALTERA_SPI_RXDATA);    /* flush rxdata */
+       /* irq is optional */
+       hw->irq = platform_get_irq(pdev, 0);
+       if (hw->irq >= 0) {
+               init_completion(&hw->done);
+               err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0,
+                                      pdev->name, hw);
+               if (err)
+                       goto exit;
+       }
+       /* find platform data */
+       if (!platp)
+               hw->bitbang.master->dev.of_node = pdev->dev.of_node;
+
+       /* register our spi controller */
+       err = spi_bitbang_start(&hw->bitbang);
+       if (err)
+               goto exit;
+       dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
+
+       return 0;
+
+exit_busy:
+       err = -EBUSY;
+exit:
+       platform_set_drvdata(pdev, NULL);
+       spi_master_put(master);
+       return err;
+}
+
+static int __devexit altera_spi_remove(struct platform_device *dev)
+{
+       struct altera_spi *hw = platform_get_drvdata(dev);
+       struct spi_master *master = hw->bitbang.master;
+
+       spi_bitbang_stop(&hw->bitbang);
+       platform_set_drvdata(dev, NULL);
+       spi_master_put(master);
+       return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id altera_spi_match[] = {
+       { .compatible = "ALTR,spi-1.0", },
+       {},
+};
+MODULE_DEVICE_TABLE(of, altera_spi_match);
+#else /* CONFIG_OF */
+#define altera_spi_match NULL
+#endif /* CONFIG_OF */
+
+static struct platform_driver altera_spi_driver = {
+       .probe = altera_spi_probe,
+       .remove = __devexit_p(altera_spi_remove),
+       .driver = {
+               .name = DRV_NAME,
+               .owner = THIS_MODULE,
+               .pm = NULL,
+               .of_match_table = altera_spi_match,
+       },
+};
+
+static int __init altera_spi_init(void)
+{
+       return platform_driver_register(&altera_spi_driver);
+}
+module_init(altera_spi_init);
+
+static void __exit altera_spi_exit(void)
+{
+       platform_driver_unregister(&altera_spi_driver);
+}
+module_exit(altera_spi_exit);
+
+MODULE_DESCRIPTION("Altera SPI driver");
+MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);