From 716ca530e1c4515d8683c9d5be3d56b301758b66 Mon Sep 17 00:00:00 2001
From: James <>
Date: Wed, 4 Nov 2015 11:49:21 +0000
Subject: trunk-47381

---
 .../861-04_spi_gpio_implement_spi_delay.patch      | 58 ++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 target/linux/generic/patches-4.3/861-04_spi_gpio_implement_spi_delay.patch

(limited to 'target/linux/generic/patches-4.3/861-04_spi_gpio_implement_spi_delay.patch')

diff --git a/target/linux/generic/patches-4.3/861-04_spi_gpio_implement_spi_delay.patch b/target/linux/generic/patches-4.3/861-04_spi_gpio_implement_spi_delay.patch
new file mode 100644
index 0000000..fc1b40c
--- /dev/null
+++ b/target/linux/generic/patches-4.3/861-04_spi_gpio_implement_spi_delay.patch
@@ -0,0 +1,58 @@
+Implement the SPI-GPIO delay function for busses that need speed limitation.
+
+--mb
+
+
+
+--- a/drivers/spi/spi-gpio.c
++++ b/drivers/spi/spi-gpio.c
+@@ -17,6 +17,7 @@
+ #include <linux/module.h>
+ #include <linux/platform_device.h>
+ #include <linux/gpio.h>
++#include <linux/delay.h>
+ #include <linux/of.h>
+ #include <linux/of_device.h>
+ #include <linux/of_gpio.h>
+@@ -69,6 +70,7 @@ struct spi_gpio {
+  *		#define	SPI_MOSI_GPIO	120
+  *		#define	SPI_SCK_GPIO	121
+  *		#define	SPI_N_CHIPSEL	4
++ *		#undef NEED_SPIDELAY
+  *		#include "spi-gpio.c"
+  */
+ 
+@@ -76,6 +78,7 @@ struct spi_gpio {
+ #define DRIVER_NAME	"spi_gpio"
+ 
+ #define GENERIC_BITBANG	/* vs tight inlines */
++#define NEED_SPIDELAY	1
+ 
+ /* all functions referencing these symbols must define pdata */
+ #define SPI_MISO_GPIO	((pdata)->miso)
+@@ -126,12 +129,20 @@ static inline int getmiso(const struct s
+ #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.
++ * NOTE:  to clock "as fast as we can", set spi_device.max_speed_hz
++ * and spi_transfer.speed_hz to 0.
++ * Otherwise this is 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 on small
++ * embedded devices with fast SPI slaves you usually don't need a delay.
+  */
+-#define spidelay(nsecs)	do {} while (0)
++static inline void spidelay(unsigned nsecs)
++{
++#ifdef NEED_SPIDELAY
++	if (unlikely(nsecs))
++		ndelay(nsecs);
++#endif /* NEED_SPIDELAY */
++}
+ 
+ #include "spi-bitbang-txrx.h"
+ 
-- 
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