[kernel] backport SPI master with no RXTX support (from 2.6.36)

Signed-off-by: Miguel Gaio <miguel.gaio@efixo.com>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@23498 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 217 insertions, 0 deletions

diff --git a/target/linux/brcm63xx/patches-2.6.35/121-spi-gpio-norxtx-support.patch b/target/linux/brcm63xx/patches-2.6.35/121-spi-gpio-norxtx-support.patch
new file mode 100644
index 0000000000..7ecf39fb04
--- /dev/null
+++ b/target/linux/brcm63xx/patches-2.6.35/121-spi-gpio-norxtx-support.patch
@@ -0,0 +1,217 @@
+From 3c8e1a84fd6b984a7bce8816db2e3defc57bbfe4 Mon Sep 17 00:00:00 2001
+From: Marek Szyprowski <m.szyprowski@samsung.com>
+Date: Wed, 30 Jun 2010 14:27:37 -0600
+Subject: [PATCH] spi/spi-gpio: add support for controllers without MISO or MOSI pin
+
+There are some boards that do not strictly follow SPI standard and use
+only 3 wires (SCLK, MOSI or MISO, SS) for connecting some simple auxiliary
+chips and controls them with GPIO based 'spi controller'. In this
+configuration the MISO or MOSI line is missing (it is not required if the
+chip does not transfer any data back to host or host only reads data from
+chip).
+
+This patch adds support for such non-standard configuration in GPIO-based
+SPI controller. It has been tested in configuration without MISO pin.
+
+Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
+Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
+Acked-by: David Brownell <dbrownell@users.sourceforge.net>
+Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
+---
+ drivers/spi/spi_gpio.c       |  101 ++++++++++++++++++++++++++++++++++-------
+ include/linux/spi/spi_gpio.h |    5 ++
+ 2 files changed, 88 insertions(+), 18 deletions(-)
+
+--- a/drivers/spi/spi_gpio.c
++++ b/drivers/spi/spi_gpio.c
+@@ -178,6 +178,44 @@ static u32 spi_gpio_txrx_word_mode3(stru
+ 	return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
+ }
+ 
++/*
++ * These functions do not call setmosi or getmiso if respective flag
++ * (SPI_MASTER_NO_RX or SPI_MASTER_NO_TX) is set, so they are safe to
++ * call when such pin is not present or defined in the controller.
++ * A separate set of callbacks is defined to get highest possible
++ * speed in the generic case (when both MISO and MOSI lines are
++ * available), as optimiser will remove the checks when argument is
++ * constant.
++ */
++
++static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi,
++		unsigned nsecs, u32 word, u8 bits)
++{
++	unsigned flags = spi->master->flags;
++	return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
++}
++
++static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi,
++		unsigned nsecs, u32 word, u8 bits)
++{
++	unsigned flags = spi->master->flags;
++	return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
++}
++
++static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi,
++		unsigned nsecs, u32 word, u8 bits)
++{
++	unsigned flags = spi->master->flags;
++	return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
++}
++
++static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi,
++		unsigned nsecs, u32 word, u8 bits)
++{
++	unsigned flags = spi->master->flags;
++	return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
++}
++
+ /*----------------------------------------------------------------------*/
+ 
+ static void spi_gpio_chipselect(struct spi_device *spi, int is_active)
+@@ -243,19 +281,30 @@ static int __devinit spi_gpio_alloc(unsi
+ }
+ 
+ static int __devinit
+-spi_gpio_request(struct spi_gpio_platform_data *pdata, const char *label)
++spi_gpio_request(struct spi_gpio_platform_data *pdata, const char *label,
++	u16 *res_flags)
+ {
+ 	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;
++	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI) {
++		value = spi_gpio_alloc(SPI_MOSI_GPIO, label, false);
++		if (value)
++			goto done;
++	} else {
++		/* HW configuration without MOSI pin */
++		*res_flags |= SPI_MASTER_NO_TX;
++	}
++
++	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO) {
++		value = spi_gpio_alloc(SPI_MISO_GPIO, label, true);
++		if (value)
++			goto free_mosi;
++	} else {
++		/* HW configuration without MISO pin */
++		*res_flags |= SPI_MASTER_NO_RX;
++	}
+ 
+ 	value = spi_gpio_alloc(SPI_SCK_GPIO, label, false);
+ 	if (value)
+@@ -264,9 +313,11 @@ spi_gpio_request(struct spi_gpio_platfor
+ 	goto done;
+ 
+ free_miso:
+-	gpio_free(SPI_MISO_GPIO);
++	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
++		gpio_free(SPI_MISO_GPIO);
+ free_mosi:
+-	gpio_free(SPI_MOSI_GPIO);
++	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
++		gpio_free(SPI_MOSI_GPIO);
+ done:
+ 	return value;
+ }
+@@ -277,6 +328,7 @@ static int __devinit spi_gpio_probe(stru
+ 	struct spi_master		*master;
+ 	struct spi_gpio			*spi_gpio;
+ 	struct spi_gpio_platform_data	*pdata;
++	u16 master_flags = 0;
+ 
+ 	pdata = pdev->dev.platform_data;
+ #ifdef GENERIC_BITBANG
+@@ -284,7 +336,7 @@ static int __devinit spi_gpio_probe(stru
+ 		return -ENODEV;
+ #endif
+ 
+-	status = spi_gpio_request(pdata, dev_name(&pdev->dev));
++	status = spi_gpio_request(pdata, dev_name(&pdev->dev), &master_flags);
+ 	if (status < 0)
+ 		return status;
+ 
+@@ -300,6 +352,7 @@ static int __devinit spi_gpio_probe(stru
+ 	if (pdata)
+ 		spi_gpio->pdata = *pdata;
+ 
++	master->flags = master_flags;
+ 	master->bus_num = pdev->id;
+ 	master->num_chipselect = SPI_N_CHIPSEL;
+ 	master->setup = spi_gpio_setup;
+@@ -307,10 +360,18 @@ static int __devinit spi_gpio_probe(stru
+ 
+ 	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;
++
++	if ((master_flags & (SPI_MASTER_NO_RX | SPI_MASTER_NO_RX)) == 0) {
++		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;
++	} else {
++		spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0;
++		spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1;
++		spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2;
++		spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3;
++	}
+ 	spi_gpio->bitbang.setup_transfer = spi_bitbang_setup_transfer;
+ 	spi_gpio->bitbang.flags = SPI_CS_HIGH;
+ 
+@@ -318,8 +379,10 @@ static int __devinit spi_gpio_probe(stru
+ 	if (status < 0) {
+ 		spi_master_put(spi_gpio->bitbang.master);
+ gpio_free:
+-		gpio_free(SPI_MISO_GPIO);
+-		gpio_free(SPI_MOSI_GPIO);
++		if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
++			gpio_free(SPI_MISO_GPIO);
++		if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
++			gpio_free(SPI_MOSI_GPIO);
+ 		gpio_free(SPI_SCK_GPIO);
+ 		spi_master_put(master);
+ 	}
+@@ -342,8 +405,10 @@ static int __devexit spi_gpio_remove(str
+ 
+ 	platform_set_drvdata(pdev, NULL);
+ 
+-	gpio_free(SPI_MISO_GPIO);
+-	gpio_free(SPI_MOSI_GPIO);
++	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
++		gpio_free(SPI_MISO_GPIO);
++	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
++		gpio_free(SPI_MOSI_GPIO);
+ 	gpio_free(SPI_SCK_GPIO);
+ 
+ 	return status;
+--- a/include/linux/spi/spi_gpio.h
++++ b/include/linux/spi/spi_gpio.h
+@@ -29,11 +29,16 @@
+  * SPI_GPIO_NO_CHIPSELECT to the controller_data:
+  *		.controller_data = (void *) SPI_GPIO_NO_CHIPSELECT;
+  *
++ * If the MISO or MOSI pin is not available then it should be set to
++ * SPI_GPIO_NO_MISO or SPI_GPIO_NO_MOSI.
++ *
+  * If the bitbanged bus is later switched to a "native" controller,
+  * that platform_device and controller_data should be removed.
+  */
+ 
+ #define SPI_GPIO_NO_CHIPSELECT		((unsigned long)-1l)
++#define SPI_GPIO_NO_MISO		((unsigned long)-1l)
++#define SPI_GPIO_NO_MOSI		((unsigned long)-1l)
+ 
+ /**
+  * struct spi_gpio_platform_data - parameter for bitbanged SPI master