[PATCH v2] spi: add OpenCores tiny SPI driver
Thomas Chou
thomas at wytron.com.tw
Wed Jan 12 13:41:49 EST 2011
This patch adds support of OpenCores tiny SPI master driver.
http://opencores.org/project,tiny_spi
Signed-off-by: Thomas Chou <thomas at wytron.com.tw>
---
v2 add devicetree support
drivers/spi/Kconfig | 6 +
drivers/spi/Makefile | 1 +
drivers/spi/oc_tiny_spi.c | 428 +++++++++++++++++++++++++++++++++++++++
include/linux/spi/oc_tiny_spi.h | 16 ++
4 files changed, 451 insertions(+), 0 deletions(-)
create mode 100644 drivers/spi/oc_tiny_spi.c
create mode 100644 include/linux/spi/oc_tiny_spi.h
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index c58d81b..46a2ddc 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -227,6 +227,12 @@ config SPI_FSL_ESPI
From MPC8536, 85xx platform uses the controller, and all P10xx,
P20xx, P30xx,P40xx, P50xx uses this controller.
+config SPI_OC_TINY_SPI
+ tristate "OpenCores tiny SPI"
+ select SPI_BITBANG
+ help
+ This is the driver for OpenCores tiny SPI master controller.
+
config SPI_OMAP_UWIRE
tristate "OMAP1 MicroWire"
depends on ARCH_OMAP1
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 10e516a..6a2ae28 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -25,6 +25,7 @@ obj-$(CONFIG_SPI_GPIO) += spi_gpio.o
obj-$(CONFIG_SPI_IMX) += spi_imx.o
obj-$(CONFIG_SPI_LM70_LLP) += spi_lm70llp.o
obj-$(CONFIG_SPI_PXA2XX) += pxa2xx_spi.o
+obj-$(CONFIG_SPI_OC_TINY_SPI) += oc_tiny_spi.o
obj-$(CONFIG_SPI_OMAP_UWIRE) += omap_uwire.o
obj-$(CONFIG_SPI_OMAP24XX) += omap2_mcspi.o
obj-$(CONFIG_SPI_OMAP_100K) += omap_spi_100k.o
diff --git a/drivers/spi/oc_tiny_spi.c b/drivers/spi/oc_tiny_spi.c
new file mode 100644
index 0000000..c575dba
--- /dev/null
+++ b/drivers/spi/oc_tiny_spi.c
@@ -0,0 +1,428 @@
+/*
+ * OpenCores tiny SPI master driver
+ *
+ * http://opencores.org/project,tiny_spi
+ *
+ * Copyright (C) 2011 Thomas Chou <thomas at wytron.com.tw>
+ *
+ * Based on spi_s3c24xx.c, which is:
+ * Copyright (c) 2006 Ben Dooks
+ * Copyright (c) 2006 Simtec Electronics
+ * Ben Dooks <ben at 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/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/spi/oc_tiny_spi.h>
+#include <linux/io.h>
+#include <linux/gpio.h>
+#include <linux/of.h>
+
+#define DRV_NAME "oc_tiny_spi"
+
+#define TINY_SPI_RXDATA 0
+#define TINY_SPI_TXDATA 4
+#define TINY_SPI_STATUS 8
+#define TINY_SPI_CONTROL 12
+#define TINY_SPI_BAUD 16
+
+#define TINY_SPI_STATUS_TXE 0x1
+#define TINY_SPI_STATUS_TXR 0x2
+
+struct tiny_spi {
+ /* bitbang has to be first */
+ struct spi_bitbang bitbang;
+ struct completion done;
+
+ void __iomem *base;
+ int irq;
+ unsigned int freq;
+ unsigned int baudwidth;
+ int interrupt; /* use interrupt driven data transfer, slow */
+ unsigned int baud;
+ unsigned int speed_hz;
+ unsigned int mode;
+ unsigned int len;
+ unsigned int txc, rxc;
+ const u8 *txp;
+ u8 *rxp;
+};
+
+static inline struct tiny_spi *to_hw(struct spi_device *sdev)
+{
+ return spi_master_get_devdata(sdev->master);
+}
+
+static unsigned int tiny_spi_baud(struct spi_device *spi, unsigned int hz)
+{
+ struct tiny_spi *hw = to_hw(spi);
+
+ return min(DIV_ROUND_UP(hw->freq, hz * 2), (1U << hw->baudwidth)) - 1;
+}
+
+static void tiny_spi_chipselect(struct spi_device *spi, int is_active)
+{
+ gpio_set_value(spi->chip_select,
+ (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
+}
+
+static int tiny_spi_setup_transfer(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct tiny_spi *hw = to_hw(spi);
+ unsigned int baud = hw->baud;
+
+ if (t) {
+ if (t->speed_hz && t->speed_hz != hw->speed_hz)
+ baud = tiny_spi_baud(spi, t->speed_hz);
+ }
+ writel(baud, hw->base + TINY_SPI_BAUD);
+ writel(hw->mode, hw->base + TINY_SPI_CONTROL);
+ return 0;
+}
+
+static int tiny_spi_setup(struct spi_device *spi)
+{
+ struct tiny_spi *hw = to_hw(spi);
+
+ if (spi->max_speed_hz != hw->speed_hz) {
+ hw->speed_hz = spi->max_speed_hz;
+ hw->baud = tiny_spi_baud(spi, hw->speed_hz);
+ }
+ hw->mode = spi->mode & (SPI_CPOL | SPI_CPHA);
+ return 0;
+}
+
+#ifndef CONFIG_TINY_SPI_IDLE_VAL
+# define CONFIG_TINY_SPI_IDLE_VAL 0x00
+#endif
+
+static int tiny_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct tiny_spi *hw = to_hw(spi);
+ const u8 *txp = t->tx_buf;
+ u8 *rxp = t->rx_buf;
+ unsigned int i;
+
+ if (hw->irq >= 0 && hw->interrupt) {
+ /* use intrrupt driven data transfer */
+ hw->len = t->len;
+ hw->txp = t->tx_buf;
+ hw->rxp = t->rx_buf;
+ hw->txc = 0;
+ hw->rxc = 0;
+ init_completion(&hw->done);
+
+ /* send the first byte */
+ if (t->len > 1) {
+ writeb(hw->txp ? *hw->txp++ : CONFIG_TINY_SPI_IDLE_VAL,
+ hw->base + TINY_SPI_TXDATA);
+ hw->txc++;
+ writeb(hw->txp ? *hw->txp++ : CONFIG_TINY_SPI_IDLE_VAL,
+ hw->base + TINY_SPI_TXDATA);
+ hw->txc++;
+ writeb(TINY_SPI_STATUS_TXR, hw->base + TINY_SPI_STATUS);
+ } else {
+ writeb(hw->txp ? *hw->txp++ : CONFIG_TINY_SPI_IDLE_VAL,
+ hw->base + TINY_SPI_TXDATA);
+ hw->txc++;
+ writeb(TINY_SPI_STATUS_TXE, hw->base + TINY_SPI_STATUS);
+ }
+
+ wait_for_completion(&hw->done);
+ } else if (txp && rxp) {
+ /* we need to tighten the transfer loop */
+ writeb(*txp++, hw->base + TINY_SPI_TXDATA);
+ if (t->len > 1) {
+ writeb(*txp++, hw->base + TINY_SPI_TXDATA);
+ for (i = 2; i < t->len; i++) {
+ u8 rx, tx = *txp++;
+ while (!(readb(hw->base + TINY_SPI_STATUS) &
+ TINY_SPI_STATUS_TXR))
+ cpu_relax();
+ rx = readb(hw->base + TINY_SPI_TXDATA);
+ writeb(tx, hw->base + TINY_SPI_TXDATA);
+ *rxp++ = rx;
+ }
+ while (!(readb(hw->base + TINY_SPI_STATUS) &
+ TINY_SPI_STATUS_TXR))
+ cpu_relax();
+ *rxp++ = readb(hw->base + TINY_SPI_TXDATA);
+ }
+ while (!(readb(hw->base + TINY_SPI_STATUS) &
+ TINY_SPI_STATUS_TXE))
+ cpu_relax();
+ *rxp++ = readb(hw->base + TINY_SPI_RXDATA);
+ } else if (rxp) {
+ writeb(CONFIG_TINY_SPI_IDLE_VAL, hw->base + TINY_SPI_TXDATA);
+ if (t->len > 1) {
+ writeb(CONFIG_TINY_SPI_IDLE_VAL,
+ hw->base + TINY_SPI_TXDATA);
+ for (i = 2; i < t->len; i++) {
+ u8 rx;
+ while (!(readb(hw->base + TINY_SPI_STATUS) &
+ TINY_SPI_STATUS_TXR))
+ cpu_relax();
+ rx = readb(hw->base + TINY_SPI_TXDATA);
+ writeb(CONFIG_TINY_SPI_IDLE_VAL,
+ hw->base + TINY_SPI_TXDATA);
+ *rxp++ = rx;
+ }
+ while (!(readb(hw->base + TINY_SPI_STATUS) &
+ TINY_SPI_STATUS_TXR))
+ cpu_relax();
+ *rxp++ = readb(hw->base + TINY_SPI_TXDATA);
+ }
+ while (!(readb(hw->base + TINY_SPI_STATUS) &
+ TINY_SPI_STATUS_TXE))
+ cpu_relax();
+ *rxp++ = readb(hw->base + TINY_SPI_RXDATA);
+ } else if (txp) {
+ writeb(*txp++, hw->base + TINY_SPI_TXDATA);
+ if (t->len > 1) {
+ writeb(*txp++, hw->base + TINY_SPI_TXDATA);
+ for (i = 2; i < t->len; i++) {
+ u8 tx = *txp++;
+ while (!(readb(hw->base + TINY_SPI_STATUS) &
+ TINY_SPI_STATUS_TXR))
+ cpu_relax();
+ writeb(tx, hw->base + TINY_SPI_TXDATA);
+ }
+ }
+ while (!(readb(hw->base + TINY_SPI_STATUS) &
+ TINY_SPI_STATUS_TXE))
+ cpu_relax();
+ } else {
+ writeb(CONFIG_TINY_SPI_IDLE_VAL, hw->base + TINY_SPI_TXDATA);
+ if (t->len > 1) {
+ writeb(CONFIG_TINY_SPI_IDLE_VAL,
+ hw->base + TINY_SPI_TXDATA);
+ for (i = 2; i < t->len; i++) {
+ while (!(readb(hw->base + TINY_SPI_STATUS) &
+ TINY_SPI_STATUS_TXR))
+ cpu_relax();
+ writeb(CONFIG_TINY_SPI_IDLE_VAL,
+ hw->base + TINY_SPI_TXDATA);
+ }
+ }
+ while (!(readb(hw->base + TINY_SPI_STATUS) &
+ TINY_SPI_STATUS_TXE))
+ cpu_relax();
+ }
+ return t->len;
+}
+
+static irqreturn_t tiny_spi_irq(int irq, void *dev)
+{
+ struct tiny_spi *hw = dev;
+
+ writeb(0, hw->base + TINY_SPI_STATUS);
+ if (hw->rxc + 1 == hw->len) {
+ if (hw->rxp)
+ *hw->rxp++ = readb(hw->base + TINY_SPI_RXDATA);
+ hw->rxc++;
+ complete(&hw->done);
+ } else {
+ if (hw->rxp)
+ *hw->rxp++ = readb(hw->base + TINY_SPI_TXDATA);
+ hw->rxc++;
+ if (hw->txc < hw->len) {
+ writeb(hw->txp ? *hw->txp++ : CONFIG_TINY_SPI_IDLE_VAL,
+ hw->base + TINY_SPI_TXDATA);
+ hw->txc++;
+ writeb(TINY_SPI_STATUS_TXR,
+ hw->base + TINY_SPI_STATUS);
+ } else {
+ writeb(TINY_SPI_STATUS_TXE,
+ hw->base + TINY_SPI_STATUS);
+ }
+ }
+ return IRQ_HANDLED;
+}
+
+#ifdef CONFIG_OF
+static int __devinit tiny_spi_of_probe(struct platform_device *pdev,
+ struct tiny_spi *hw)
+{
+ const __be32 *val;
+
+ hw->bitbang.master->dev.of_node = pdev->dev.of_node;
+ val = of_get_property(pdev->dev.of_node, "baud-width", NULL);
+ if (val)
+ hw->baudwidth = be32_to_cpup(val);
+ val = of_get_property(pdev->dev.of_node, "clock-frequency", NULL);
+ if (val)
+ hw->freq = be32_to_cpup(val);
+ val = of_get_property(pdev->dev.of_node, "interrupt-driven", NULL);
+ if (val)
+ hw->interrupt = be32_to_cpup(val);
+ return 0;
+}
+#else
+static int __devinit tiny_spi_of_probe(struct platform_device *pdev,
+ struct tiny_spi *hw)
+{
+ return 0;
+}
+#endif
+
+static int __devinit tiny_spi_probe(struct platform_device *pdev)
+{
+ struct tiny_spi_platform_data *platp = pdev->dev.platform_data;
+ struct tiny_spi *hw;
+ struct spi_master *master;
+ struct resource *res;
+ int err = 0;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(struct tiny_spi));
+ if (master == NULL) {
+ dev_err(&pdev->dev, "No memory for spi_master\n");
+ err = -ENOMEM;
+ goto err_no_mem;
+ }
+
+ /* setup the master state. */
+ master->bus_num = pdev->id;
+ master->num_chipselect = 255;
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+ master->setup = tiny_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 == NULL) {
+ dev_err(&pdev->dev, "Cannot get device\n");
+ err = -ENODEV;
+ goto err_no_dev;
+ }
+ hw->bitbang.setup_transfer = tiny_spi_setup_transfer;
+ hw->bitbang.chipselect = tiny_spi_chipselect;
+ hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs;
+
+ /* find and map our resources */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (res == NULL) {
+ dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
+ err = -ENOENT;
+ goto err_no_iores;
+ }
+ hw->base = ioremap(res->start, (res->end - res->start) + 1);
+ if (hw->base == 0) {
+ dev_err(&pdev->dev, "Cannot map IO\n");
+ err = -ENXIO;
+ goto err_no_iomap;
+ }
+ /* irq is optional */
+ hw->irq = platform_get_irq(pdev, 0);
+ if (hw->irq >= 0) {
+ init_completion(&hw->done);
+ err = request_irq(hw->irq, tiny_spi_irq, 0, pdev->name, hw);
+ if (err) {
+ dev_err(&pdev->dev, "Cannot claim IRQ\n");
+ goto err_no_irq;
+ }
+ }
+ /* find platform data */
+ if (platp) {
+ hw->freq = platp->freq;
+ hw->baudwidth = platp->baudwidth;
+ hw->interrupt = platp->interrupt;
+ } else {
+ err = tiny_spi_of_probe(pdev, hw);
+ if (err)
+ goto err_no_of;
+ }
+
+ /* register our spi controller */
+ err = spi_bitbang_start(&hw->bitbang);
+ if (err) {
+ dev_err(&pdev->dev, "Failed to register SPI master\n");
+ goto err_register;
+ }
+ dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
+
+ return 0;
+
+err_register:
+ if (hw->irq >= 0)
+ free_irq(hw->irq, hw);
+err_no_irq:
+ iounmap((void *)hw->base);
+err_no_iomap:
+err_no_iores:
+ spi_master_put(master);
+err_no_mem:
+err_no_of:
+err_no_dev:
+ return err;
+}
+
+static int __devexit tiny_spi_remove(struct platform_device *dev)
+{
+ struct tiny_spi *hw = platform_get_drvdata(dev);
+ struct spi_master *master = hw->bitbang.master;
+
+ spi_bitbang_stop(&hw->bitbang);
+
+ if (hw->irq >= 0)
+ free_irq(hw->irq, hw);
+ iounmap((void *)hw->base);
+
+ platform_set_drvdata(dev, NULL);
+ spi_master_put(master);
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static struct of_device_id oc_tiny_spi_match[] = {
+ {
+ .compatible = "opencores,oc_tiny_spi",
+ },
+ {},
+}
+MODULE_DEVICE_TABLE(of, oc_tiny_spi_match);
+#endif
+
+static struct platform_driver tiny_spidrv = {
+ .remove = __devexit_p(tiny_spi_remove),
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ .pm = NULL,
+#ifdef CONFIG_OF
+ .of_match_table = oc_tiny_spi_match,
+#endif
+ },
+};
+
+static int __init tiny_spi_init(void)
+{
+ return platform_driver_probe(&tiny_spidrv, tiny_spi_probe);
+}
+
+static void __exit tiny_spi_exit(void)
+{
+ platform_driver_unregister(&tiny_spidrv);
+}
+
+module_init(tiny_spi_init);
+module_exit(tiny_spi_exit);
+
+MODULE_DESCRIPTION("OpenCores tiny SPI driver");
+MODULE_AUTHOR("Thomas Chou <thomas at wytron.com.tw>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/include/linux/spi/oc_tiny_spi.h b/include/linux/spi/oc_tiny_spi.h
new file mode 100644
index 0000000..9dedd59
--- /dev/null
+++ b/include/linux/spi/oc_tiny_spi.h
@@ -0,0 +1,16 @@
+#ifndef _LINUX_SPI_OC_TINY_SPI_H
+#define _LINUX_SPI_OC_TINY_SPI_H
+
+/**
+ * struct tiny_spi_platform_data - platform data of the OpenCores tiny SPI
+ * @freq: input clock freq to the core.
+ * @baudwidth: baud rate divider width of the core.
+ * @interrupt: use intrrupt driven data transfer.
+ */
+struct tiny_spi_platform_data {
+ uint freq;
+ uint baudwidth;
+ int interrupt;
+};
+
+#endif /* _LINUX_SPI_OC_TINY_SPI_H */
--
1.7.3.4
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