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i2c: pxa: migrate to new i2c_slave APIs 

The i2c subsystem was enhanced circa 2015 to support operating as
an i2c-slave device.  Prior to that, the i2c-pxa driver supported
an i2c-slave but had its own APIs.  There are no existing in-kernel
drivers or platforms that utilize the i2c-pxa APIs.

Migrate the i2c-pxa driver to the general i2c-slave APIs so that
existing drivers, such as the i2c-slave-eeprom, can be used.

This has been tested with a Marvell EspressoBin, using i2c-pxa and
i2c-slave-eeprom, acting as a slave, and a RaspeberryPi 3, using the
at24 driver, acting as a master.

Signed-off-by: Patrick Williams <alpawi@amazon.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Patrick Williams 2019-10-01 10:59:59 -05:00 committed by Wolfram Sang
parent 9af1563a54
commit 4d51b4cea2
2 changed files with 61 additions and 14 deletions
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1
drivers/i2c/busses/Kconfig
View File

@ -875,6 +875,7 @@ config I2C_PXA_PCI
config I2C_PXA_SLAVE
bool "Intel PXA2XX I2C Slave comms support"
depends on I2C_PXA && !X86_32
select I2C_SLAVE
help
Support I2C slave mode communications on the PXA I2C bus. This
is necessary for systems where the PXA may be a target on the

74
drivers/i2c/busses/i2c-pxa.c
View File

@ -180,7 +180,7 @@ struct pxa_i2c {
struct i2c_adapter adap;
struct clk *clk;
#ifdef CONFIG_I2C_PXA_SLAVE
struct i2c_slave_client *slave;
struct i2c_client *slave;
#endif
unsigned int irqlogidx;
@ -544,22 +544,23 @@ static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
if (isr & ISR_BED) {
/* what should we do here? */
} else {
int ret = 0;
u8 byte = 0;
if (i2c->slave != NULL)
ret = i2c->slave->read(i2c->slave->data);
i2c_slave_event(i2c->slave, I2C_SLAVE_READ_PROCESSED,
&byte);
writel(ret, _IDBR(i2c));
writel(byte, _IDBR(i2c));
writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c)); /* allow next byte */
}
}
static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
{
unsigned int byte = readl(_IDBR(i2c));
u8 byte = readl(_IDBR(i2c));
if (i2c->slave != NULL)
i2c->slave->write(i2c->slave->data, byte);
i2c_slave_event(i2c->slave, I2C_SLAVE_WRITE_RECEIVED, &byte);
writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
}
@ -572,9 +573,18 @@ static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n",
(isr & ISR_RWM) ? 'r' : 't');
if (i2c->slave != NULL)
i2c->slave->event(i2c->slave->data,
(isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE);
if (i2c->slave != NULL) {
if (isr & ISR_RWM) {
u8 byte = 0;
i2c_slave_event(i2c->slave, I2C_SLAVE_READ_REQUESTED,
&byte);
writel(byte, _IDBR(i2c));
} else {
i2c_slave_event(i2c->slave, I2C_SLAVE_WRITE_REQUESTED,
NULL);
}
}
/*
* slave could interrupt in the middle of us generating a
@ -607,7 +617,7 @@ static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n");
if (i2c->slave != NULL)
i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP);
i2c_slave_event(i2c->slave, I2C_SLAVE_STOP, NULL);
if (i2c_debug > 2)
dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n");
@ -619,6 +629,38 @@ static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
if (i2c->msg)
i2c_pxa_master_complete(i2c, I2C_RETRY);
}
static int i2c_pxa_slave_reg(struct i2c_client *slave)
{
struct pxa_i2c *i2c = slave->adapter->algo_data;
if (i2c->slave)
return -EBUSY;
if (!i2c->reg_isar)
return -EAFNOSUPPORT;
i2c->slave = slave;
i2c->slave_addr = slave->addr;
writel(i2c->slave_addr, _ISAR(i2c));
return 0;
}
static int i2c_pxa_slave_unreg(struct i2c_client *slave)
{
struct pxa_i2c *i2c = slave->adapter->algo_data;
WARN_ON(!i2c->slave);
i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
writel(i2c->slave_addr, _ISAR(i2c));
i2c->slave = NULL;
return 0;
}
#else
static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
{
@ -1141,11 +1183,19 @@ static u32 i2c_pxa_functionality(struct i2c_adapter *adap)
static const struct i2c_algorithm i2c_pxa_algorithm = {
.master_xfer = i2c_pxa_xfer,
.functionality = i2c_pxa_functionality,
#ifdef CONFIG_I2C_PXA_SLAVE
.reg_slave = i2c_pxa_slave_reg,
.unreg_slave = i2c_pxa_slave_unreg,
#endif
};
static const struct i2c_algorithm i2c_pxa_pio_algorithm = {
.master_xfer = i2c_pxa_pio_xfer,
.functionality = i2c_pxa_functionality,
#ifdef CONFIG_I2C_PXA_SLAVE
.reg_slave = i2c_pxa_slave_reg,
.unreg_slave = i2c_pxa_slave_unreg,
#endif
};
static const struct of_device_id i2c_pxa_dt_ids[] = {
@ -1270,10 +1320,6 @@ static int i2c_pxa_probe(struct platform_device *dev)
i2c->highmode_enter = false;
if (plat) {
#ifdef CONFIG_I2C_PXA_SLAVE
i2c->slave_addr = plat->slave_addr;
i2c->slave = plat->slave;
#endif
i2c->adap.class = plat->class;
}