From: Juergen Fitschen
Slave mode driver is based on the concept of i2c-designware driver.
Signed-off-by: Juergen Fitschen
[ludovic.desroc...@microchip.com: rework Kconfig]
Signed-off-by: Ludovic Desroches
---
drivers/i2c/busses/Kconfig | 13 +++
drivers/i2c/busses/Makefile | 3 +
drivers/i2c/busses/i2c-at91-core.c | 13 ++-
drivers/i2c/busses/i2c-at91-slave.c | 147
drivers/i2c/busses/i2c-at91.h | 30 +-
5 files changed, 202 insertions(+), 4 deletions(-)
create mode 100644 drivers/i2c/busses/i2c-at91-slave.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index f2c681971201..6b1f6dcdf533 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -387,6 +387,19 @@ config I2C_AT91
the latency to fill the transmission register is too long. If you
are facing this situation, use the i2c-gpio driver.
+config I2C_AT91_SLAVE_EXPERIMENTAL
+ tristate "Microchip AT91 I2C experimental slave mode"
+ depends on I2C_AT91
+ select I2C_SLAVE
+ help
+ If you say yes to this option, support for the slave mode will be
+ added. Caution: do not use it for production. This feature has not
+ been tested in a heavy way, help wanted.
+ There are known bugs:
+ - It can hang, on a SAMA5D4, after several transfers.
+ - There are some mismtaches with a SAMA5D4 as slave and a SAMA5D2 as
+ master.
+
config I2C_AU1550
tristate "Au1550/Au1200/Au1300 SMBus interface"
depends on MIPS_ALCHEMY
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index ea75a777940e..59b22fbef90a 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -36,6 +36,9 @@ obj-$(CONFIG_I2C_ALTERA) += i2c-altera.o
obj-$(CONFIG_I2C_ASPEED) += i2c-aspeed.o
obj-$(CONFIG_I2C_AT91) += i2c-at91.o
i2c-at91-objs := i2c-at91-core.o i2c-at91-master.o
+ifeq ($(CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL),y)
+ i2c-at91-objs += i2c-at91-slave.o
+endif
obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o
obj-$(CONFIG_I2C_AXXIA)+= i2c-axxia.o
obj-$(CONFIG_I2C_BCM2835) += i2c-bcm2835.o
diff --git a/drivers/i2c/busses/i2c-at91-core.c
b/drivers/i2c/busses/i2c-at91-core.c
index 5d9c6c81e6ab..c74283fa567f 100644
--- a/drivers/i2c/busses/i2c-at91-core.c
+++ b/drivers/i2c/busses/i2c-at91-core.c
@@ -60,8 +60,10 @@ void at91_init_twi_bus(struct at91_twi_dev *dev)
{
at91_disable_twi_interrupts(dev);
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
-
- at91_init_twi_bus_master(dev);
+ if (dev->slave_detected)
+ at91_init_twi_bus_slave(dev);
+ else
+ at91_init_twi_bus_master(dev);
}
static struct at91_twi_pdata at91rm9200_config = {
@@ -243,7 +245,12 @@ static int at91_twi_probe(struct platform_device *pdev)
dev->adapter.timeout = AT91_I2C_TIMEOUT;
dev->adapter.dev.of_node = pdev->dev.of_node;
- rc = at91_twi_probe_master(pdev, phy_addr, dev);
+ dev->slave_detected = i2c_detect_slave_mode(>dev);
+
+ if (dev->slave_detected)
+ rc = at91_twi_probe_slave(pdev, phy_addr, dev);
+ else
+ rc = at91_twi_probe_master(pdev, phy_addr, dev);
if (rc)
return rc;
diff --git a/drivers/i2c/busses/i2c-at91-slave.c
b/drivers/i2c/busses/i2c-at91-slave.c
new file mode 100644
index ..4b4808e0c8f7
--- /dev/null
+++ b/drivers/i2c/busses/i2c-at91-slave.c
@@ -0,0 +1,147 @@
+/*
+ * i2c slave support for Atmel's AT91 Two-Wire Interface (TWI)
+ *
+ * Copyright (C) 2017 Juergen Fitschen
+ *
+ * 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.
+ */
+
+#include
+#include
+#include
+#include
+
+#include "i2c-at91.h"
+
+static irqreturn_t atmel_twi_interrupt_slave(int irq, void *dev_id)
+{
+ struct at91_twi_dev *dev = dev_id;
+ const unsigned status = at91_twi_read(dev, AT91_TWI_SR);
+ const unsigned irqstatus = status & at91_twi_read(dev, AT91_TWI_IMR);
+ u8 value;
+
+ if (!irqstatus)
+ return IRQ_NONE;
+
+ /* slave address has been detected on I2C bus */
+ if (irqstatus & AT91_TWI_SVACC) {
+ if (status & AT91_TWI_SVREAD) {
+ i2c_slave_event(dev->slave,
+ I2C_SLAVE_READ_REQUESTED, );
+ writeb_relaxed(value, dev->base + AT91_TWI_THR);
+ at91_twi_write(dev, AT91_TWI_IER,
+ AT91_TWI_TXRDY | AT91_TWI_EOSACC);
+ } else {
+ i2c_slave_event(dev->slave,
+
