Hi, all!
I use the following patch on my AT91SAM9260-based custom board to
configure bit-banged I2C:
diff --git a/board/atmel/at91sam9260ek/at91sam9260ek.c
b/board/atmel/at91sam9260ek/at91sam9260ek.c
index b30aad8..99fc2bd 100644
--- a/board/atmel/at91sam9260ek/at91sam9260ek.c
+++ b/board/atmel/at91sam9260ek/at91sam9260ek.c
@ -234,3 +234,46 @@ void reset_phy(void)
#endif
}
#endif
+
+#define GPIO_I2C_SCL AT91_PIN_PA24
+#define GPIO_I2C_SDA AT91_PIN_PA23
+
+void at91sam9260_i2c_init(void)
+{
+ __raw_writel(pin_to_mask(GPIO_I2C_SCL), pin_to_controller(GPIO_I2C_SCL)
+ PIO_IDR);
+ __raw_writel(pin_to_mask(GPIO_I2C_SCL), pin_to_controller(GPIO_I2C_SCL)
+ PIO_PUER);
+ __raw_writel(pin_to_mask(GPIO_I2C_SCL), pin_to_controller(GPIO_I2C_SCL)
+ PIO_PER);
+ __raw_writel(pin_to_mask(GPIO_I2C_SCL), pin_to_controller(GPIO_I2C_SCL)
+ PIO_MDER);
+ __raw_writel(pin_to_mask(GPIO_I2C_SCL), pin_to_controller(GPIO_I2C_SCL)
+ PIO_SODR);
+ __raw_writel(pin_to_mask(GPIO_I2C_SCL), pin_to_controller(GPIO_I2C_SCL)
+ PIO_OER);
+
+ __raw_writel(pin_to_mask(GPIO_I2C_SDA), pin_to_controller(GPIO_I2C_SDA)
+ PIO_IDR);
+ __raw_writel(pin_to_mask(GPIO_I2C_SDA), pin_to_controller(GPIO_I2C_SDA)
+ PIO_PUER);
+ __raw_writel(pin_to_mask(GPIO_I2C_SDA), pin_to_controller(GPIO_I2C_SDA)
+ PIO_PER);
+ __raw_writel(pin_to_mask(GPIO_I2C_SDA), pin_to_controller(GPIO_I2C_SDA)
+ PIO_MDER);
+ __raw_writel(pin_to_mask(GPIO_I2C_SDA), pin_to_controller(GPIO_I2C_SDA)
+ PIO_SODR);
+ __raw_writel(pin_to_mask(GPIO_I2C_SDA), pin_to_controller(GPIO_I2C_SDA)
+ PIO_OER);
+}
+void at91sam9260_i2c_scl(unsigned long bit)
+{
+ if(bit)
+ __raw_writel(pin_to_mask(GPIO_I2C_SCL),
pin_to_controller(GPIO_I2C_SCL) + PIO_SODR);
+ else
+ __raw_writel(pin_to_mask(GPIO_I2C_SCL),
pin_to_controller(GPIO_I2C_SCL) + PIO_CODR);
+}
+
+void at91sam9260_i2c_sda(unsigned long bit)
+{
+ printf("Setting %u\n", bit);
+ if(bit)
+ __raw_writel(pin_to_mask(GPIO_I2C_SDA),
pin_to_controller(GPIO_I2C_SDA) + PIO_SODR);
+ else
+ __raw_writel(pin_to_mask(GPIO_I2C_SDA),
pin_to_controller(GPIO_I2C_SDA) + PIO_CODR);
+}
+
+int at91sam9260_i2c_read(void)
+{
+ int c = (__raw_readl(pin_to_controller(GPIO_I2C_SDA) + PIO_PDSR) &
pin_to_mask(GPIO_I2C_SDA)) ? 1 : 0;
+ printf("Reading %d\n", c);
+ return c;
+}
diff --git a/include/configs/at91sam9260ek.h b/include/configs/at91sam9260ek.h
index fd9932f..5e66c9e 100644
--- a/include/configs/at91sam9260ek.h
+++ b/include/configs/at91sam9260ek.h
@@ -85,6 +85,8 @@
#define CONFIG_CMD_NAND 1
#define CONFIG_CMD_USB 1
+#define CONFIG_CMD_I2C 1
+#define CONFIG_I2C_CMD_TREE 1
/* SDRAM */
#define CONFIG_NR_DRAM_BANKS 1
@ -192,4 +194,20 @@
#error CONFIG_USE_IRQ not supported
#endif
+/*
+ * Software (bit-bang) I2C driver configuration
+ */
+#define CONFIG_SOFT_I2C 1
+#define CFG_I2C_SPEED 1000000
+#define I2C_INIT at91sam9260_i2c_init()
+
+#define I2C_ACTIVE
+#define I2C_TRISTATE
+#define I2C_SCL(bit) at91sam9260_i2c_scl(bit)
+#define I2C_SDA(bit) at91sam9260_i2c_sda(bit)
+#define I2C_DELAY udelay(2)
+#define I2C_READ at91sam9260_i2c_read()
+#define CFG_I2C_SLAVE 0
+#define DEBUG_I2C
#endif
+
But I'm unable to read proper values from lines - they always
return 0s. Any ideas on fixing?
Linux i2c-gpio driver works perfectly.
Thanks a lot,
S.
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