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>
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@ -875,6 +875,7 @@ config I2C_PXA_PCI
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config I2C_PXA_SLAVE
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bool "Intel PXA2XX I2C Slave comms support"
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depends on I2C_PXA && !X86_32
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select I2C_SLAVE
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help
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Support I2C slave mode communications on the PXA I2C bus. This
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is necessary for systems where the PXA may be a target on the
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@ -180,7 +180,7 @@ struct pxa_i2c {
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struct i2c_adapter adap;
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struct clk *clk;
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#ifdef CONFIG_I2C_PXA_SLAVE
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struct i2c_slave_client *slave;
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struct i2c_client *slave;
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#endif
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unsigned int irqlogidx;
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@ -544,22 +544,23 @@ static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
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if (isr & ISR_BED) {
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/* what should we do here? */
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} else {
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int ret = 0;
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u8 byte = 0;
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if (i2c->slave != NULL)
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ret = i2c->slave->read(i2c->slave->data);
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i2c_slave_event(i2c->slave, I2C_SLAVE_READ_PROCESSED,
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&byte);
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writel(ret, _IDBR(i2c));
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writel(byte, _IDBR(i2c));
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writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c)); /* allow next byte */
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}
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}
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static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
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{
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unsigned int byte = readl(_IDBR(i2c));
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u8 byte = readl(_IDBR(i2c));
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if (i2c->slave != NULL)
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i2c->slave->write(i2c->slave->data, byte);
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i2c_slave_event(i2c->slave, I2C_SLAVE_WRITE_RECEIVED, &byte);
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writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c));
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}
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@ -572,9 +573,18 @@ static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
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dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n",
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(isr & ISR_RWM) ? 'r' : 't');
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if (i2c->slave != NULL)
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i2c->slave->event(i2c->slave->data,
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(isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE);
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if (i2c->slave != NULL) {
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if (isr & ISR_RWM) {
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u8 byte = 0;
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i2c_slave_event(i2c->slave, I2C_SLAVE_READ_REQUESTED,
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&byte);
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writel(byte, _IDBR(i2c));
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} else {
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i2c_slave_event(i2c->slave, I2C_SLAVE_WRITE_REQUESTED,
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NULL);
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}
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}
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/*
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* slave could interrupt in the middle of us generating a
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@ -607,7 +617,7 @@ static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
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dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n");
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if (i2c->slave != NULL)
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i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP);
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i2c_slave_event(i2c->slave, I2C_SLAVE_STOP, NULL);
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if (i2c_debug > 2)
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dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n");
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@ -619,6 +629,38 @@ static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
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if (i2c->msg)
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i2c_pxa_master_complete(i2c, I2C_RETRY);
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}
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static int i2c_pxa_slave_reg(struct i2c_client *slave)
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{
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struct pxa_i2c *i2c = slave->adapter->algo_data;
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if (i2c->slave)
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return -EBUSY;
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if (!i2c->reg_isar)
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return -EAFNOSUPPORT;
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i2c->slave = slave;
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i2c->slave_addr = slave->addr;
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writel(i2c->slave_addr, _ISAR(i2c));
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return 0;
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}
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static int i2c_pxa_slave_unreg(struct i2c_client *slave)
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{
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struct pxa_i2c *i2c = slave->adapter->algo_data;
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WARN_ON(!i2c->slave);
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i2c->slave_addr = I2C_PXA_SLAVE_ADDR;
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writel(i2c->slave_addr, _ISAR(i2c));
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i2c->slave = NULL;
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return 0;
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}
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#else
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static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
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{
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@ -1141,11 +1183,19 @@ static u32 i2c_pxa_functionality(struct i2c_adapter *adap)
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static const struct i2c_algorithm i2c_pxa_algorithm = {
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.master_xfer = i2c_pxa_xfer,
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.functionality = i2c_pxa_functionality,
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#ifdef CONFIG_I2C_PXA_SLAVE
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.reg_slave = i2c_pxa_slave_reg,
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.unreg_slave = i2c_pxa_slave_unreg,
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#endif
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};
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static const struct i2c_algorithm i2c_pxa_pio_algorithm = {
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.master_xfer = i2c_pxa_pio_xfer,
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.functionality = i2c_pxa_functionality,
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#ifdef CONFIG_I2C_PXA_SLAVE
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.reg_slave = i2c_pxa_slave_reg,
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.unreg_slave = i2c_pxa_slave_unreg,
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#endif
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};
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static const struct of_device_id i2c_pxa_dt_ids[] = {
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@ -1270,10 +1320,6 @@ static int i2c_pxa_probe(struct platform_device *dev)
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i2c->highmode_enter = false;
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if (plat) {
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#ifdef CONFIG_I2C_PXA_SLAVE
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i2c->slave_addr = plat->slave_addr;
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i2c->slave = plat->slave;
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#endif
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i2c->adap.class = plat->class;
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}
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