diff options
Diffstat (limited to 'target/linux/generic-2.6/patches-2.6.28/920-00-spi-gpio.patch')
| -rw-r--r-- | target/linux/generic-2.6/patches-2.6.28/920-00-spi-gpio.patch | 475 |
1 files changed, 475 insertions, 0 deletions
diff --git a/target/linux/generic-2.6/patches-2.6.28/920-00-spi-gpio.patch b/target/linux/generic-2.6/patches-2.6.28/920-00-spi-gpio.patch new file mode 100644 index 0000000..963b2c8 --- /dev/null +++ b/target/linux/generic-2.6/patches-2.6.28/920-00-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 |