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Diffstat (limited to 'target/linux/generic-2.6/patches-2.6.28/920-spi-gpio.patch')
-rw-r--r--target/linux/generic-2.6/patches-2.6.28/920-spi-gpio.patch475
1 files changed, 475 insertions, 0 deletions
diff --git a/target/linux/generic-2.6/patches-2.6.28/920-spi-gpio.patch b/target/linux/generic-2.6/patches-2.6.28/920-spi-gpio.patch
new file mode 100644
index 000000000..963b2c806
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.28/920-spi-gpio.patch
@@ -0,0 +1,475 @@
+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
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-31 19:09:21 +0000