+++ /dev/null
-Port of the SPI-GPIO driver from 2.6.29-rc4.
-
---mb
-
-
-
-Index: linux-2.6.28.2/drivers/spi/spi_gpio.c
-===================================================================
---- /dev/null 1970-01-01 00:00:00.000000000 +0000
-+++ linux-2.6.28.2/drivers/spi/spi_gpio.c 2009-02-10 17:56:59.000000000 +0100
-@@ -0,0 +1,360 @@
-+/*
-+ * spi_gpio.c - SPI master driver using generic bitbanged GPIO
-+ *
-+ * Copyright (C) 2006,2008 David Brownell
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License as published by
-+ * the Free Software Foundation; either version 2 of the License, or
-+ * (at your option) any later version.
-+ *
-+ * This program is distributed in the hope that 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.
-+ *
-+ * You should have received a copy of the GNU General Public License
-+ * along with this program; if not, write to the Free Software
-+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-+ */
-+#include <linux/kernel.h>
-+#include <linux/init.h>
-+#include <linux/platform_device.h>
-+#include <linux/gpio.h>
-+
-+#include <linux/spi/spi.h>
-+#include <linux/spi/spi_bitbang.h>
-+#include <linux/spi/spi_gpio.h>
-+
-+
-+/*
-+ * This bitbanging SPI master driver should help make systems usable
-+ * when a native hardware SPI engine is not available, perhaps because
-+ * its driver isn't yet working or because the I/O pins it requires
-+ * are used for other purposes.
-+ *
-+ * platform_device->driver_data ... points to spi_gpio
-+ *
-+ * spi->controller_state ... reserved for bitbang framework code
-+ * spi->controller_data ... holds chipselect GPIO
-+ *
-+ * spi->master->dev.driver_data ... points to spi_gpio->bitbang
-+ */
-+
-+struct spi_gpio {
-+ struct spi_bitbang bitbang;
-+ struct spi_gpio_platform_data pdata;
-+ struct platform_device *pdev;
-+};
-+
-+/*----------------------------------------------------------------------*/
-+
-+/*
-+ * Because the overhead of going through four GPIO procedure calls
-+ * per transferred bit can make performance a problem, this code
-+ * is set up so that you can use it in either of two ways:
-+ *
-+ * - The slow generic way: set up platform_data to hold the GPIO
-+ * numbers used for MISO/MOSI/SCK, and issue procedure calls for
-+ * each of them. This driver can handle several such busses.
-+ *
-+ * - The quicker inlined way: only helps with platform GPIO code
-+ * that inlines operations for constant GPIOs. This can give
-+ * you tight (fast!) inner loops, but each such bus needs a
-+ * new driver. You'll define a new C file, with Makefile and
-+ * Kconfig support; the C code can be a total of six lines:
-+ *
-+ * #define DRIVER_NAME "myboard_spi2"
-+ * #define SPI_MISO_GPIO 119
-+ * #define SPI_MOSI_GPIO 120
-+ * #define SPI_SCK_GPIO 121
-+ * #define SPI_N_CHIPSEL 4
-+ * #include "spi_gpio.c"
-+ */
-+
-+#ifndef DRIVER_NAME
-+#define DRIVER_NAME "spi_gpio"
-+
-+#define GENERIC_BITBANG /* vs tight inlines */
-+
-+/* all functions referencing these symbols must define pdata */
-+#define SPI_MISO_GPIO ((pdata)->miso)
-+#define SPI_MOSI_GPIO ((pdata)->mosi)
-+#define SPI_SCK_GPIO ((pdata)->sck)
-+
-+#define SPI_N_CHIPSEL ((pdata)->num_chipselect)
-+
-+#endif
-+
-+/*----------------------------------------------------------------------*/
-+
-+static inline const struct spi_gpio_platform_data * __pure
-+spi_to_pdata(const struct spi_device *spi)
-+{
-+ const struct spi_bitbang *bang;
-+ const struct spi_gpio *spi_gpio;
-+
-+ bang = spi_master_get_devdata(spi->master);
-+ spi_gpio = container_of(bang, struct spi_gpio, bitbang);
-+ return &spi_gpio->pdata;
-+}
-+
-+/* this is #defined to avoid unused-variable warnings when inlining */
-+#define pdata spi_to_pdata(spi)
-+
-+static inline void setsck(const struct spi_device *spi, int is_on)
-+{
-+ gpio_set_value(SPI_SCK_GPIO, is_on);
-+}
-+
-+static inline void setmosi(const struct spi_device *spi, int is_on)
-+{
-+ gpio_set_value(SPI_MOSI_GPIO, is_on);
-+}
-+
-+static inline int getmiso(const struct spi_device *spi)
-+{
-+ return gpio_get_value(SPI_MISO_GPIO);
-+}
-+
-+#undef pdata
-+
-+/*
-+ * NOTE: this clocks "as fast as we can". It "should" be a function of the
-+ * requested device clock. Software overhead means we usually have trouble
-+ * reaching even one Mbit/sec (except when we can inline bitops), so for now
-+ * we'll just assume we never need additional per-bit slowdowns.
-+ */
-+#define spidelay(nsecs) do {} while (0)
-+
-+#define EXPAND_BITBANG_TXRX
-+#include <linux/spi/spi_bitbang.h>
-+
-+/*
-+ * These functions can leverage inline expansion of GPIO calls to shrink
-+ * costs for a txrx bit, often by factors of around ten (by instruction
-+ * count). That is particularly visible for larger word sizes, but helps
-+ * even with default 8-bit words.
-+ *
-+ * REVISIT overheads calling these functions for each word also have
-+ * significant performance costs. Having txrx_bufs() calls that inline
-+ * the txrx_word() logic would help performance, e.g. on larger blocks
-+ * used with flash storage or MMC/SD. There should also be ways to make
-+ * GCC be less stupid about reloading registers inside the I/O loops,
-+ * even without inlined GPIO calls; __attribute__((hot)) on GCC 4.3?
-+ */
-+
-+static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi,
-+ unsigned nsecs, u32 word, u8 bits)
-+{
-+ return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
-+}
-+
-+static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi,
-+ unsigned nsecs, u32 word, u8 bits)
-+{
-+ return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
-+}
-+
-+static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi,
-+ unsigned nsecs, u32 word, u8 bits)
-+{
-+ return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
-+}
-+
-+static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi,
-+ unsigned nsecs, u32 word, u8 bits)
-+{
-+ return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
-+}
-+
-+/*----------------------------------------------------------------------*/
-+
-+static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
-+{
-+ unsigned long cs = (unsigned long) spi->controller_data;
-+
-+ /* set initial clock polarity */
-+ if (is_active)
-+ setsck(spi, spi->mode & SPI_CPOL);
-+
-+ /* SPI is normally active-low */
-+ gpio_set_value(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active);
-+}
-+
-+static int spi_gpio_setup(struct spi_device *spi)
-+{
-+ unsigned long cs = (unsigned long) spi->controller_data;
-+ int status = 0;
-+
-+ if (spi->bits_per_word > 32)
-+ return -EINVAL;
-+
-+ if (!spi->controller_state) {
-+ status = gpio_request(cs, spi->dev.bus_id);
-+ if (status)
-+ return status;
-+ status = gpio_direction_output(cs, spi->mode & SPI_CS_HIGH);
-+ }
-+ if (!status)
-+ status = spi_bitbang_setup(spi);
-+ if (status) {
-+ if (!spi->controller_state)
-+ gpio_free(cs);
-+ }
-+ return status;
-+}
-+
-+static void spi_gpio_cleanup(struct spi_device *spi)
-+{
-+ unsigned long cs = (unsigned long) spi->controller_data;
-+
-+ gpio_free(cs);
-+ spi_bitbang_cleanup(spi);
-+}
-+
-+static int __init spi_gpio_alloc(unsigned pin, const char *label, bool is_in)
-+{
-+ int value;
-+
-+ value = gpio_request(pin, label);
-+ if (value == 0) {
-+ if (is_in)
-+ value = gpio_direction_input(pin);
-+ else
-+ value = gpio_direction_output(pin, 0);
-+ }
-+ return value;
-+}
-+
-+static int __init
-+spi_gpio_request(struct spi_gpio_platform_data *pdata, const char *label)
-+{
-+ int value;
-+
-+ /* NOTE: SPI_*_GPIO symbols may reference "pdata" */
-+
-+ value = spi_gpio_alloc(SPI_MOSI_GPIO, label, false);
-+ if (value)
-+ goto done;
-+
-+ value = spi_gpio_alloc(SPI_MISO_GPIO, label, true);
-+ if (value)
-+ goto free_mosi;
-+
-+ value = spi_gpio_alloc(SPI_SCK_GPIO, label, false);
-+ if (value)
-+ goto free_miso;
-+
-+ goto done;
-+
-+free_miso:
-+ gpio_free(SPI_MISO_GPIO);
-+free_mosi:
-+ gpio_free(SPI_MOSI_GPIO);
-+done:
-+ return value;
-+}
-+
-+static int __init spi_gpio_probe(struct platform_device *pdev)
-+{
-+ int status;
-+ struct spi_master *master;
-+ struct spi_gpio *spi_gpio;
-+ struct spi_gpio_platform_data *pdata;
-+
-+ pdata = pdev->dev.platform_data;
-+#ifdef GENERIC_BITBANG
-+ if (!pdata || !pdata->num_chipselect)
-+ return -ENODEV;
-+#endif
-+
-+ status = spi_gpio_request(pdata, dev_name(&pdev->dev));
-+ if (status < 0)
-+ return status;
-+
-+ master = spi_alloc_master(&pdev->dev, sizeof *spi_gpio);
-+ if (!master) {
-+ status = -ENOMEM;
-+ goto gpio_free;
-+ }
-+ spi_gpio = spi_master_get_devdata(master);
-+ platform_set_drvdata(pdev, spi_gpio);
-+
-+ spi_gpio->pdev = pdev;
-+ if (pdata)
-+ spi_gpio->pdata = *pdata;
-+
-+ master->bus_num = pdev->id;
-+ master->num_chipselect = SPI_N_CHIPSEL;
-+ master->setup = spi_gpio_setup;
-+ master->cleanup = spi_gpio_cleanup;
-+
-+ spi_gpio->bitbang.master = spi_master_get(master);
-+ spi_gpio->bitbang.chipselect = spi_gpio_chipselect;
-+ spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;
-+ spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1;
-+ spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2;
-+ spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3;
-+ spi_gpio->bitbang.setup_transfer = spi_bitbang_setup_transfer;
-+ spi_gpio->bitbang.flags = SPI_CS_HIGH;
-+
-+ status = spi_bitbang_start(&spi_gpio->bitbang);
-+ if (status < 0) {
-+ spi_master_put(spi_gpio->bitbang.master);
-+gpio_free:
-+ gpio_free(SPI_MISO_GPIO);
-+ gpio_free(SPI_MOSI_GPIO);
-+ gpio_free(SPI_SCK_GPIO);
-+ spi_master_put(master);
-+ }
-+
-+ return status;
-+}
-+
-+static int __exit spi_gpio_remove(struct platform_device *pdev)
-+{
-+ struct spi_gpio *spi_gpio;
-+ struct spi_gpio_platform_data *pdata;
-+ int status;
-+
-+ spi_gpio = platform_get_drvdata(pdev);
-+ pdata = pdev->dev.platform_data;
-+
-+ /* stop() unregisters child devices too */
-+ status = spi_bitbang_stop(&spi_gpio->bitbang);
-+ spi_master_put(spi_gpio->bitbang.master);
-+
-+ platform_set_drvdata(pdev, NULL);
-+
-+ gpio_free(SPI_MISO_GPIO);
-+ gpio_free(SPI_MOSI_GPIO);
-+ gpio_free(SPI_SCK_GPIO);
-+
-+ return status;
-+}
-+
-+MODULE_ALIAS("platform:" DRIVER_NAME);
-+
-+static struct platform_driver spi_gpio_driver = {
-+ .driver.name = DRIVER_NAME,
-+ .driver.owner = THIS_MODULE,
-+ .remove = __exit_p(spi_gpio_remove),
-+};
-+
-+static int __init spi_gpio_init(void)
-+{
-+ return platform_driver_probe(&spi_gpio_driver, spi_gpio_probe);
-+}
-+module_init(spi_gpio_init);
-+
-+static void __exit spi_gpio_exit(void)
-+{
-+ platform_driver_unregister(&spi_gpio_driver);
-+}
-+module_exit(spi_gpio_exit);
-+
-+
-+MODULE_DESCRIPTION("SPI master driver using generic bitbanged GPIO ");
-+MODULE_AUTHOR("David Brownell");
-+MODULE_LICENSE("GPL");
-Index: linux-2.6.28.2/include/linux/spi/spi_gpio.h
-===================================================================
---- /dev/null 1970-01-01 00:00:00.000000000 +0000
-+++ linux-2.6.28.2/include/linux/spi/spi_gpio.h 2009-02-10 17:56:49.000000000 +0100
-@@ -0,0 +1,60 @@
-+#ifndef __LINUX_SPI_GPIO_H
-+#define __LINUX_SPI_GPIO_H
-+
-+/*
-+ * For each bitbanged SPI bus, set up a platform_device node with:
-+ * - name "spi_gpio"
-+ * - id the same as the SPI bus number it implements
-+ * - dev.platform data pointing to a struct spi_gpio_platform_data
-+ *
-+ * Or, see the driver code for information about speedups that are
-+ * possible on platforms that support inlined access for GPIOs (no
-+ * spi_gpio_platform_data is used).
-+ *
-+ * Use spi_board_info with these busses in the usual way, being sure
-+ * that the controller_data being the GPIO used for each device's
-+ * chipselect:
-+ *
-+ * static struct spi_board_info ... [] = {
-+ * ...
-+ * // this slave uses GPIO 42 for its chipselect
-+ * .controller_data = (void *) 42,
-+ * ...
-+ * // this one uses GPIO 86 for its chipselect
-+ * .controller_data = (void *) 86,
-+ * ...
-+ * };
-+ *
-+ * If the bitbanged bus is later switched to a "native" controller,
-+ * that platform_device and controller_data should be removed.
-+ */
-+
-+/**
-+ * struct spi_gpio_platform_data - parameter for bitbanged SPI master
-+ * @sck: number of the GPIO used for clock output
-+ * @mosi: number of the GPIO used for Master Output, Slave In (MOSI) data
-+ * @miso: number of the GPIO used for Master Input, Slave Output (MISO) data
-+ * @num_chipselect: how many slaves to allow
-+ *
-+ * All GPIO signals used with the SPI bus managed through this driver
-+ * (chipselects, MOSI, MISO, SCK) must be configured as GPIOs, instead
-+ * of some alternate function.
-+ *
-+ * It can be convenient to use this driver with pins that have alternate
-+ * functions associated with a "native" SPI controller if a driver for that
-+ * controller is not available, or is missing important functionality.
-+ *
-+ * On platforms which can do so, configure MISO with a weak pullup unless
-+ * there's an external pullup on that signal. That saves power by avoiding
-+ * floating signals. (A weak pulldown would save power too, but many
-+ * drivers expect to see all-ones data as the no slave "response".)
-+ */
-+struct spi_gpio_platform_data {
-+ unsigned sck;
-+ unsigned mosi;
-+ unsigned miso;
-+
-+ u16 num_chipselect;
-+};
-+
-+#endif /* __LINUX_SPI_GPIO_H */
-Index: linux-2.6.28.2/drivers/spi/Kconfig
-===================================================================
---- linux-2.6.28.2.orig/drivers/spi/Kconfig 2009-02-10 17:57:10.000000000 +0100
-+++ linux-2.6.28.2/drivers/spi/Kconfig 2009-02-10 18:08:31.000000000 +0100
-@@ -100,6 +100,22 @@ config SPI_BUTTERFLY
- inexpensive battery powered microcontroller evaluation board.
- This same cable can be used to flash new firmware.
-
-+config SPI_GPIO
-+ tristate "GPIO-based bitbanging SPI Master"
-+ depends on GENERIC_GPIO
-+ select SPI_BITBANG
-+ help
-+ This simple GPIO bitbanging SPI master uses the arch-neutral GPIO
-+ interface to manage MOSI, MISO, SCK, and chipselect signals. SPI
-+ slaves connected to a bus using this driver are configured as usual,
-+ except that the spi_board_info.controller_data holds the GPIO number
-+ for the chipselect used by this controller driver.
-+
-+ Note that this driver often won't achieve even 1 Mbit/sec speeds,
-+ making it unusually slow for SPI. If your platform can inline
-+ GPIO operations, you should be able to leverage that for better
-+ speed with a custom version of this driver; see the source code.
-+
- config SPI_IMX
- tristate "Freescale iMX SPI controller"
- depends on ARCH_IMX && EXPERIMENTAL
-Index: linux-2.6.28.2/drivers/spi/Makefile
-===================================================================
---- linux-2.6.28.2.orig/drivers/spi/Makefile 2009-02-10 17:58:46.000000000 +0100
-+++ linux-2.6.28.2/drivers/spi/Makefile 2009-02-10 18:08:31.000000000 +0100
-@@ -16,6 +16,7 @@ obj-$(CONFIG_SPI_BFIN) += spi_bfin5xx.
- obj-$(CONFIG_SPI_BITBANG) += spi_bitbang.o
- obj-$(CONFIG_SPI_AU1550) += au1550_spi.o
- obj-$(CONFIG_SPI_BUTTERFLY) += spi_butterfly.o
-+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
projects / openwrt / svn-archive / archive.git / blobdiff