Commit 4d51b4ce authored by Patrick Williams's avatar Patrick Williams Committed by Wolfram Sang
Browse files

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: default avatarPatrick Williams <alpawi@amazon.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 9af1563a

drivers/i2c/busses/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/i2c/busses/i2c-pxa.c

+60 −14
Original line number Diff line number Diff line
@@ -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;

	}

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