Enabling SPI1 on Linux (Diva)

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Diva-am335x-overview.png Applies to Diva
Tux.png Applies to Linux

Introduction[edit | edit source]

This article shows how to enable the SPI1 interface (with CS0 and CS1 chip selects) which can be used in a standard Linux application.

Pin Mux Option[edit | edit source]

SPI1 signals are available at different Diva pins. The following configurations can be used:

Option 1[edit | edit source]

Signal Diva Connector Phisical Pin CPU Ball
SPI1_SCLK J1.109 C18
SPI1_D0 J1.31 E18
SPI1_D1 J1.29 E17
SPI1_CS0 J1.144 C12
SPI1_CS1 J1.69 A15

Option 2[edit | edit source]

200px-Emblem-important.svg.png This configuration can be implemented on the DivaEVB-Lite using the on-board expansion connectors. 200px-Emblem-important.svg.png
Signal Diva Connector Phisical Pin CPU Ball DivaEVB-Lite signal
SPI1_SCLK J1.150 A13 J10.7
SPI1_D0 J1.140 B13 J9.15
SPI1_D1 J1.142 D12 J9.17
SPI1_CS0 J1.144 C12 J9.19
SPI1_CS1 J1.69 A15 J11.19

Linux kernel patches[edit | edit source]

200px-Emblem-important.svg.png The patches below applies to DIVELK 1.0.0 Linux source tree. 200px-Emblem-important.svg.png

Option 1[edit | edit source]

The files arch/arm/mach-omap2/board-diva.c and arch/arm/mach-omap2/diva_pinmux_table.h must be modified according to the following patches:

diff --git a/arch/arm/mach-omap2/board-diva.c b/arch/arm/mach-omap2/board-diva.c
index f6b77fc..a8b3996 100644
--- a/arch/arm/mach-omap2/board-diva.c
+++ b/arch/arm/mach-omap2/board-diva.c
@@ -356,6 +356,30 @@ static void spi0_init(int evm_id, int profile)
 			ARRAY_SIZE(diva_spi0_slave_info));
 }
 
+/* -------------- SPI 1 Platform Data -----------------------------*/
+struct spi_board_info __initdata diva_spi1_slave_info[] = {
+	{
+		.modalias = "spidev",
+		.max_speed_hz = 2000000,     /* max spi clock (SCK) speed in HZ */
+		.bus_num = 2,
+		.chip_select = 0,
+	},
+	{
+		.modalias = "spidev",
+		.max_speed_hz = 2000000,     /* max spi clock (SCK) speed in HZ */
+		.bus_num = 2,
+		.chip_select = 1,
+	},
+};
+
+/* setup spi0 */
+
+static void spi1_init(int evm_id, int profile)
+{
+	setup_pin_mux(spi1_pin_mux);
+	spi_register_board_info(diva_spi1_slave_info,
+			ARRAY_SIZE(diva_spi1_slave_info));
+}
 
 /* ----------- NAND Init ---------------------------------------*/
 
@@ -878,6 +902,7 @@ static struct evm_dev_cfg diva_dev_cfg[] = {
 	{mmc0_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
 	{rmii1_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
 	{spi0_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
+	{spi1_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
 	{usb0_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
 	{usb1_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
diff --git a/arch/arm/mach-omap2/diva_pinmux_table.h b/arch/arm/mach-omap2/diva_pinmux_table.h
index 5a2646a..9509b46 100644
--- a/arch/arm/mach-omap2/diva_pinmux_table.h
+++ b/arch/arm/mach-omap2/diva_pinmux_table.h
@@ -180,6 +180,21 @@ static struct pinmux_config w1_gpio_pin_mux[] = {
 	{NULL, 0},
 };
 
+/* Module pin mux for SPI fash */
+static struct pinmux_config spi1_pin_mux[] = {
+	{"ecap0_in_pwm0_out.spi1_sclk", OMAP_MUX_MODE0 | AM33XX_PULL_ENBL
+							| AM33XX_INPUT_EN},
+	{"uart0_ctsn.spi1_d0", OMAP_MUX_MODE0 | AM33XX_PULL_ENBL | AM33XX_PULL_UP
+							| AM33XX_INPUT_EN},
+	{"uart0_rtsn.spi1_d1", OMAP_MUX_MODE0 | AM33XX_PULL_ENBL
+							| AM33XX_INPUT_EN},
+	{"mcasp0_ahclkr.spi1_cs0", OMAP_MUX_MODE0 | AM33XX_PULL_ENBL | AM33XX_PULL_UP
+							| AM33XX_INPUT_EN},
+	{"xdma_event_intr0.spi1_cs1", OMAP_MUX_MODE0 | AM33XX_PULL_ENBL | AM33XX_PULL_UP
+							| AM33XX_INPUT_EN},
+	{NULL, 0},
+};
+
 /*
  * the following mux configurations are un-tested but are left here for
  * reference. They are all comment-out to avoid "defined but not used" warning

The kernel must be rebuilt to make these modifications effective.


Option 2[edit | edit source]

The files arch/arm/mach-omap2/board-diva.c and arch/arm/mach-omap2/diva_pinmux_table.h must be modified according to the following patches:

diff --git a/arch/arm/mach-omap2/board-diva.c b/arch/arm/mach-omap2/board-diva.c
index 42898e9..8f7810d 100644
--- a/arch/arm/mach-omap2/board-diva.c
+++ b/arch/arm/mach-omap2/board-diva.c
@@ -356,6 +356,30 @@ static void spi0_init(int evm_id, int profile)
 			ARRAY_SIZE(diva_spi0_slave_info));
 }
 
+/* -------------- SPI 1 Platform Data -----------------------------*/
+struct spi_board_info __initdata diva_spi1_slave_info[] = {
+	{
+		.modalias = "spidev",
+		.max_speed_hz = 2000000,     /* max spi clock (SCK) speed in HZ */
+		.bus_num = 2,
+		.chip_select = 0,
+	},
+	{
+		.modalias = "spidev",
+		.max_speed_hz = 2000000,     /* max spi clock (SCK) speed in HZ */
+		.bus_num = 2,
+		.chip_select = 1,
+	},
+};
+
+/* setup spi1 */
+
+static void spi1_init(int evm_id, int profile)
+{
+	setup_pin_mux(spi1_pin_mux);
+	spi_register_board_info(diva_spi1_slave_info,
+			ARRAY_SIZE(diva_spi1_slave_info));
+}
 
 /* ----------- NAND Init ---------------------------------------*/
 
@@ -872,11 +896,12 @@ static struct evm_dev_cfg diva_dev_cfg[] = {
 	{mmc0_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
 	{rmii1_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
 	{spi0_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
+	{spi1_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
 	{usb0_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
 	{usb1_init,	DEV_ON_BASEBOARD, PROFILE_NONE},
 	
 	{mfd_tscadc_init,	DEV_ON_BASEBOARD, PROFILE_NONE},	
-	{mcasp0_init,   DEV_ON_BASEBOARD, PROFILE_NONE},
+	//{mcasp0_init,   DEV_ON_BASEBOARD, PROFILE_NONE},
 	
 	{w1_init, DEV_ON_BASEBOARD, PROFILE_NONE},


200px-Emblem-important.svg.png With this pinmux configuration, the SPI1 signals are shared with the McASP0 signals. Thus, for a proper setup, the MCASP0 interface initialization must be disabled in evm_dev_cfg diva_dev_cfg[] (please see the patch above). 200px-Emblem-important.svg.png
diff --git a/arch/arm/mach-omap2/diva_pinmux_table.h b/arch/arm/mach-omap2/diva_pinmux_table.h
index f6647b0..d2722a3 100644
--- a/arch/arm/mach-omap2/diva_pinmux_table.h
+++ b/arch/arm/mach-omap2/diva_pinmux_table.h
@@ -179,6 +179,19 @@ static struct pinmux_config w1_gpio_pin_mux[] = {
 	{NULL, 0},
 };
 
+/* Module pin mux for SPI1 */
+
+
+static struct pinmux_config spi1_pin_mux[] = {
+	{"mcasp0_aclkx.spi1_sclk", OMAP_MUX_MODE3 | AM33XX_PULL_ENBL | AM33XX_INPUT_EN}, // clock
+	{"mcasp0_fsx.spi1_d0", OMAP_MUX_MODE3 | AM33XX_PULL_ENBL | AM33XX_PULL_UP | AM33XX_INPUT_EN}, // d0
+	{"mcasp0_axr0.spi1_d1", OMAP_MUX_MODE3 | AM33XX_PULL_ENBL | AM33XX_INPUT_EN}, // d1
+	{"mcasp0_ahclkr.spi1_cs0", OMAP_MUX_MODE3 | AM33XX_PULL_ENBL | AM33XX_PULL_UP | AM33XX_INPUT_EN}, // cs0
+	{"xdma_event_intr0.spi1_cs1", OMAP_MUX_MODE4 | AM33XX_PULL_ENBL | AM33XX_PULL_UP | AM33XX_INPUT_EN}, // cs1
+	{NULL, 0},
+};
+
+
 /*
  * the following mux configurations are un-tested but are left here for
  * reference. They are all comment-out to avoid "defined but not used" warning
@@ -187,7 +200,7 @@ static struct pinmux_config w1_gpio_pin_mux[] = {
 #ifdef UNUSED_DIVA_PINMUX
 
 /* Module pin mux for SPI flash */
-static struct pinmux_config spi1_pin_mux[] = {
+/*static struct pinmux_config spi1_pin_mux[] = {
 	{"mcasp0_aclkx.spi1_sclk", OMAP_MUX_MODE3 | AM33XX_PULL_ENBL
 		| AM33XX_INPUT_EN},
 	{"mcasp0_fsx.spi1_d0", OMAP_MUX_MODE3 | AM33XX_PULL_ENBL
@@ -197,7 +210,7 @@ static struct pinmux_config spi1_pin_mux[] = {
 	{"mcasp0_ahclkr.spi1_cs0", OMAP_MUX_MODE3 | AM33XX_PULL_ENBL
 		| AM33XX_PULL_UP | AM33XX_INPUT_EN},
 	{NULL, 0},
-};
+};*/
 
 /* Module pin mux for rgmii1 */
 static struct pinmux_config rgmii1_pin_mux[] = {

The kernel must be rebuilt to make these modifications effective.

Using the interface[edit | edit source]

Users can access the peripherals connected to the SP1 bus through the spidev interface. For further information, please refer to

Patch download[edit | edit source]