[PATCH v10 3/3] i2c: npcm7xx: Add support for slave mode for Nuvoton
Tali Perry
tali.perry1 at gmail.com
Sun May 10 20:23:30 AEST 2020
Add support for slave mode for Nuvoton
NPCM BMC I2C controller driver.
Signed-off-by: Tali Perry <tali.perry1 at gmail.com>
---
drivers/i2c/busses/i2c-npcm7xx.c | 614 +++++++++++++++++++++++++++++++
1 file changed, 614 insertions(+)
diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index e732c40f0cf3..54af253249d5 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -73,6 +73,24 @@ enum i2c_state {
I2C_STOP_PENDING,
};
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+// Module supports setting multiple own slave addresses
+enum i2c_addr {
+ I2C_SLAVE_ADDR1 = 0,
+ I2C_SLAVE_ADDR2,
+ I2C_SLAVE_ADDR3,
+ I2C_SLAVE_ADDR4,
+ I2C_SLAVE_ADDR5,
+ I2C_SLAVE_ADDR6,
+ I2C_SLAVE_ADDR7,
+ I2C_SLAVE_ADDR8,
+ I2C_SLAVE_ADDR9,
+ I2C_SLAVE_ADDR10,
+ I2C_GC_ADDR,
+ I2C_ARP_ADDR,
+};
+#endif
+
// init register and default value required to enable module
#define NPCM_I2CSEGCTL 0xE4
#define NPCM_I2CSEGCTL_INIT_VAL 0x0333F000
@@ -100,6 +118,14 @@ enum i2c_state {
#define NPCM_I2CADDR6 0x16
#define NPCM_I2CADDR10 0x17
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+// I2CADDR array: because the addr regs are sprinkled all over the address space
+const int npcm_i2caddr[10] = {NPCM_I2CADDR1, NPCM_I2CADDR2, NPCM_I2CADDR3,
+ NPCM_I2CADDR4, NPCM_I2CADDR5, NPCM_I2CADDR6,
+ NPCM_I2CADDR7, NPCM_I2CADDR8, NPCM_I2CADDR9,
+ NPCM_I2CADDR10};
+#endif
+
#define NPCM_I2CCTL4 0x1A
#define NPCM_I2CCTL5 0x1B
#define NPCM_I2CSCLLT 0x1C // SCL Low Time
@@ -273,6 +299,16 @@ struct npcm_i2c {
unsigned long int_time_stamp;
unsigned long bus_freq; // in kHz
u32 xmits;
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ u8 own_slave_addr;
+ struct i2c_client *slave;
+ int slv_rd_size;
+ int slv_rd_ind;
+ int slv_wr_size;
+ int slv_wr_ind;
+ u8 slv_rd_buf[I2C_HW_FIFO_SIZE];
+ u8 slv_wr_buf[I2C_HW_FIFO_SIZE];
+#endif
#if IS_ENABLED(CONFIG_DEBUG_FS)
struct dentry *debugfs;/* debugfs device directory */
uint64_t ber_count;
@@ -316,6 +352,10 @@ static void npcm_i2c_init_params(struct npcm_i2c *bus)
bus->int_time_stamp = 0;
bus->PEC_use = false;
bus->PEC_mask = 0;
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ if (bus->slave)
+ bus->master_or_slave = I2C_SLAVE;
+#endif
}
static inline void npcm_i2c_wr_byte(struct npcm_i2c *bus, u8 data)
@@ -363,6 +403,18 @@ static void npcm_i2c_disable(struct npcm_i2c *bus)
{
u8 i2cctl2;
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ int i;
+
+ // select bank 0 for I2C addresses
+ npcm_i2c_select_bank(bus, I2C_BANK_0);
+
+ // Slave addresses removal
+ for (i = I2C_SLAVE_ADDR1; i < I2C_NUM_OF_ADDR; i++)
+ iowrite8(0, bus->reg + npcm_i2caddr[i]);
+
+ npcm_i2c_select_bank(bus, I2C_BANK_1);
+#endif
// Disable module.
i2cctl2 = ioread8(bus->reg + NPCM_I2CCTL2);
i2cctl2 = i2cctl2 & ~I2CCTL2_ENABLE;
@@ -529,6 +581,63 @@ static inline void npcm_i2c_nack(struct npcm_i2c *bus)
iowrite8(val, bus->reg + NPCM_I2CCTL1);
}
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+static void npcm_i2c_slave_int_enable(struct npcm_i2c *bus, bool enable)
+{
+ u8 i2cctl1;
+
+ // enable interrupt on slave match:
+ i2cctl1 = ioread8(bus->reg + NPCM_I2CCTL1);
+ i2cctl1 &= ~NPCM_I2CCTL1_RWS;
+ if (enable)
+ i2cctl1 |= NPCM_I2CCTL1_NMINTE;
+ else
+ i2cctl1 &= ~NPCM_I2CCTL1_NMINTE;
+ iowrite8(i2cctl1, bus->reg + NPCM_I2CCTL1);
+}
+
+static int npcm_i2c_slave_enable_l(struct npcm_i2c *bus,
+ enum i2c_addr addr_type, u8 addr,
+ bool enable)
+{
+ u8 i2cctl1;
+ u8 i2cctl3;
+ u8 sa_reg;
+
+ // npcm_i2c_slave_int_enable(bus, false);
+ sa_reg = (addr & 0x7F) | FIELD_PREP(NPCM_I2CADDR_SAEN, enable);
+ if (addr_type == I2C_GC_ADDR) {
+ i2cctl1 = ioread8(bus->reg + NPCM_I2CCTL1);
+ if (enable)
+ i2cctl1 |= NPCM_I2CCTL1_GCMEN;
+ else
+ i2cctl1 &= ~NPCM_I2CCTL1_GCMEN;
+ iowrite8(i2cctl1, bus->reg + NPCM_I2CCTL1);
+ return 0;
+ }
+ if (addr_type == I2C_ARP_ADDR) {
+ i2cctl3 = ioread8(bus->reg + NPCM_I2CCTL3);
+ if (enable)
+ i2cctl3 |= I2CCTL3_ARPMEN;
+ else
+ i2cctl3 &= ~I2CCTL3_ARPMEN;
+ iowrite8(i2cctl3, bus->reg + NPCM_I2CCTL3);
+ return 0;
+ }
+ if (addr_type >= I2C_ARP_ADDR)
+ return -EFAULT;
+ // select bank 0 for address 3 to 10
+ if (addr_type > I2C_SLAVE_ADDR2)
+ npcm_i2c_select_bank(bus, I2C_BANK_0);
+ // Set and enable the address
+ iowrite8(sa_reg, bus->reg + npcm_i2caddr[(int)addr_type]);
+ npcm_i2c_slave_int_enable(bus, enable);
+ if (addr_type > I2C_SLAVE_ADDR2)
+ npcm_i2c_select_bank(bus, I2C_BANK_1);
+ return 0;
+}
+#endif
+
static void npcm_i2c_reset(struct npcm_i2c *bus)
{
// Save I2CCTL1 relevant bits. It is being cleared when the module
@@ -556,6 +665,12 @@ static void npcm_i2c_reset(struct npcm_i2c *bus)
// Clear all fifo bits:
iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, bus->reg + NPCM_I2CFIF_CTS);
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ if (bus->slave)
+ npcm_i2c_slave_enable_l(bus, I2C_SLAVE_ADDR1, bus->slave->addr,
+ true);
+#endif
+
bus->state = I2C_IDLE;
}
@@ -620,6 +735,10 @@ static void npcm_i2c_callback(struct npcm_i2c *bus,
}
bus->operation = I2C_NO_OPER;
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ if (bus->slave)
+ bus->master_or_slave = I2C_SLAVE;
+#endif
}
static u32 npcm_i2c_fifo_usage(struct npcm_i2c *bus)
@@ -647,6 +766,33 @@ static void npcm_i2c_write_to_fifo_master(struct npcm_i2c *bus,
}
}
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+static void npcm_i2c_write_to_fifo_slave(struct npcm_i2c *bus,
+ u16 max_bytes_to_send)
+{
+ // Fill the FIFO, while the FIFO is not full and there are more bytes to
+ // write
+ npcm_i2c_clear_fifo_int(bus);
+ npcm_i2c_clear_tx_fifo(bus);
+ iowrite8(0, bus->reg + NPCM_I2CTXF_CTL);
+
+ while ((max_bytes_to_send--) &&
+ (I2C_HW_FIFO_SIZE - npcm_i2c_fifo_usage(bus))) {
+
+ if (bus->slv_wr_size > 0) {
+ bus->slv_wr_ind = bus->slv_wr_ind % I2C_HW_FIFO_SIZE;
+ npcm_i2c_wr_byte(bus,
+ bus->slv_wr_buf[bus->slv_wr_ind]);
+ bus->slv_wr_ind++;
+ bus->slv_wr_ind = bus->slv_wr_ind % I2C_HW_FIFO_SIZE;
+ bus->slv_wr_size--; // size indicates the # of bytes in
+ // the SW buffer, not HW fifo.
+ } else {
+ break;
+ }
+ }
+}
+#endif
/*
* configure the FIFO before using it. If nread is -1 RX FIFO will not be
* configured. same for nwrite
@@ -705,6 +851,21 @@ static void npcm_i2c_read_from_fifo(struct npcm_i2c *bus, u8 bytes_in_fifo)
if (bus->rd_ind < bus->rd_size)
bus->rd_buf[bus->rd_ind++] = data;
}
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ else {
+ if (bus->slave) {
+ bus->slv_rd_ind = bus->slv_rd_ind %
+ I2C_HW_FIFO_SIZE;
+ bus->slv_rd_buf[bus->slv_rd_ind] = data;
+ bus->slv_rd_ind++;
+ if (bus->slv_rd_ind == 1 && bus->read_block_use)
+ // 1st byte is length in block protocol
+ bus->slv_rd_size = data +
+ (u8)bus->PEC_use +
+ (u8)bus->read_block_use;
+ }
+ }
+#endif
}
}
@@ -727,6 +888,433 @@ static void npcm_i2c_master_abort(struct npcm_i2c *bus)
}
}
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+static u8 npcm_i2c_get_slave_addr(struct npcm_i2c *bus,
+ enum i2c_addr addr_type)
+{
+ u8 slave_add;
+
+ // select bank 0 for address 3 to 10
+ if (addr_type > I2C_SLAVE_ADDR2)
+ npcm_i2c_select_bank(bus, I2C_BANK_0);
+
+ slave_add = ioread8(bus->reg + npcm_i2caddr[(int)addr_type]);
+
+ if (addr_type > I2C_SLAVE_ADDR2)
+ npcm_i2c_select_bank(bus, I2C_BANK_1);
+
+ return slave_add;
+}
+
+static int npcm_i2c_remove_slave_addr(struct npcm_i2c *bus, u8 slave_add)
+{
+ int i;
+
+ // Set the enable bit
+ slave_add |= 0x80;
+ npcm_i2c_select_bank(bus, I2C_BANK_0);
+ for (i = I2C_SLAVE_ADDR1; i < I2C_NUM_OF_ADDR; i++) {
+ if (ioread8(bus->reg + npcm_i2caddr[i]) == slave_add)
+ iowrite8(0, bus->reg + npcm_i2caddr[i]);
+ }
+ npcm_i2c_select_bank(bus, I2C_BANK_1);
+ return 0;
+}
+
+static int npcm_i2c_slave_get_wr_buf(struct npcm_i2c *bus)
+{
+ int i;
+ u8 value = 0;
+ int ret = bus->slv_wr_ind;
+
+ // fill a cyclic buffer
+ for (i = 0; i < I2C_HW_FIFO_SIZE; i++) {
+ if (bus->slv_wr_size >= I2C_HW_FIFO_SIZE)
+ break;
+ i2c_slave_event(bus->slave, I2C_SLAVE_READ_REQUESTED, &value);
+ bus->slv_wr_buf[(bus->slv_wr_ind + bus->slv_wr_size) %
+ I2C_HW_FIFO_SIZE] = value;
+ bus->slv_wr_size++;
+ i2c_slave_event(bus->slave, I2C_SLAVE_READ_PROCESSED, &value);
+ }
+ return I2C_HW_FIFO_SIZE - ret;
+}
+
+static void npcm_i2c_slave_send_rd_buf(struct npcm_i2c *bus)
+{
+ int i;
+
+ for (i = 0; i < bus->slv_rd_ind; i++)
+ i2c_slave_event(bus->slave, I2C_SLAVE_WRITE_RECEIVED,
+ &bus->slv_rd_buf[i]);
+
+ // once we send bytes up, need to reset the counter of the wr buf
+ // got data from master (new offset in device), ignore wr fifo:
+ if (bus->slv_rd_ind) {
+ bus->slv_wr_size = 0;
+ bus->slv_wr_ind = 0;
+ }
+
+ bus->slv_rd_ind = 0;
+ bus->slv_rd_size = bus->adap.quirks->max_read_len;
+
+ npcm_i2c_clear_fifo_int(bus);
+ npcm_i2c_clear_rx_fifo(bus);
+}
+
+static bool npcm_i2c_slave_receive(struct npcm_i2c *bus, u16 nread,
+ u8 *read_data)
+{
+ bus->state = I2C_OPER_STARTED;
+ bus->operation = I2C_READ_OPER;
+ bus->slv_rd_size = nread;
+ bus->slv_rd_ind = 0;
+
+ iowrite8(0, bus->reg + NPCM_I2CTXF_CTL);
+ iowrite8(I2C_HW_FIFO_SIZE, bus->reg + NPCM_I2CRXF_CTL);
+
+ npcm_i2c_clear_tx_fifo(bus);
+ npcm_i2c_clear_rx_fifo(bus);
+
+ return true;
+}
+
+static bool npcm_i2c_slave_xmit(struct npcm_i2c *bus, u16 nwrite,
+ u8 *write_data)
+{
+ if (nwrite == 0)
+ return false;
+
+ bus->state = I2C_OPER_STARTED;
+ bus->operation = I2C_WRITE_OPER;
+
+ // get the next buffer
+ npcm_i2c_slave_get_wr_buf(bus);
+
+ if (nwrite > 0)
+ npcm_i2c_write_to_fifo_slave(bus, nwrite);
+
+ return true;
+}
+
+/*
+ * currently slave IF only supports single byte operations.
+ * in order to utilyze the npcm HW FIFO, the driver will ask for 16 bytes
+ * at a time, pack them in buffer, and then transmit them all together
+ * to the FIFO and onward to the bus.
+ * NACK on read will be once reached to bus->adap->quirks->max_read_len.
+ * sending a NACK wherever the backend requests for it is not supported.
+ * the next two functions allow reading to local buffer before writing it all
+ * to the HW FIFO.
+ * ret val: number of bytes read from the IF:
+ */
+static int npcm_i2c_slave_wr_buf_sync(struct npcm_i2c *bus)
+{
+ int left_in_fifo;
+
+ left_in_fifo = FIELD_GET(NPCM_I2CTXF_STS_TX_BYTES,
+ ioread8(bus->reg + NPCM_I2CTXF_STS));
+ if (left_in_fifo >= I2C_HW_FIFO_SIZE)
+ return left_in_fifo;
+
+ // fifo already full:
+ if (bus->slv_wr_size >= I2C_HW_FIFO_SIZE)
+ return left_in_fifo;
+
+ // update the wr fifo ind, back to the untransmitted bytes:
+ bus->slv_wr_ind = bus->slv_wr_ind - left_in_fifo;
+ bus->slv_wr_size = bus->slv_wr_size + left_in_fifo;
+
+ if (bus->slv_wr_ind < 0)
+ bus->slv_wr_ind += I2C_HW_FIFO_SIZE;
+
+ return left_in_fifo;
+}
+
+static void npcm_i2c_slave_rd_wr(struct npcm_i2c *bus)
+{
+ if (FIELD_GET(NPCM_I2CST_XMIT, ioread8(bus->reg + NPCM_I2CST))) {
+ /*
+ * Slave got an address match with direction bit 1 so
+ * it should transmit data
+ * Write till the master will NACK
+ */
+ bus->operation = I2C_WRITE_OPER;
+ npcm_i2c_slave_xmit(bus,
+ bus->adap.quirks->max_write_len,
+ bus->slv_wr_buf);
+ } else {
+ /*
+ * Slave got an address match with direction bit 0
+ * so it should receive data.
+ * this module does not support saying no to bytes.
+ * it will always ACK.
+ */
+ bus->operation = I2C_READ_OPER;
+ npcm_i2c_read_from_fifo(bus, npcm_i2c_fifo_usage(bus));
+ bus->stop_ind = I2C_SLAVE_RCV_IND;
+ npcm_i2c_slave_send_rd_buf(bus);
+ npcm_i2c_slave_receive(bus,
+ bus->adap.quirks->max_read_len,
+ bus->slv_rd_buf);
+ }
+}
+
+static irqreturn_t npcm_i2c_int_slave_handler(struct npcm_i2c *bus)
+{
+ u8 val;
+ irqreturn_t ret = IRQ_NONE;
+ u8 i2cst = ioread8(bus->reg + NPCM_I2CST);
+
+ // Slave: A NACK has occurred
+ if (FIELD_GET(NPCM_I2CST_NEGACK, i2cst)) {
+ bus->stop_ind = I2C_NACK_IND;
+ npcm_i2c_slave_wr_buf_sync(bus);
+ if (bus->fifo_use)
+ // clear the FIFO
+ iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO,
+ bus->reg + NPCM_I2CFIF_CTS);
+
+ // In slave write, NACK is OK, otherwise it is a problem
+ bus->stop_ind = I2C_NO_STATUS_IND;
+ bus->operation = I2C_NO_OPER;
+ bus->own_slave_addr = 0xFF;
+
+ /*
+ * Slave has to wait for I2C_STOP to decide this is the end
+ * of the transaction.
+ * Therefore transaction is not yet considered as done
+ */
+ iowrite8(NPCM_I2CST_NEGACK, bus->reg + NPCM_I2CST);
+
+ ret = IRQ_HANDLED;
+ }
+
+ // Slave mode: a Bus Error (BER) has been identified
+ if (FIELD_GET(NPCM_I2CST_BER, i2cst)) {
+ // Check whether bus arbitration or Start or Stop during data
+ // xfer bus arbitration problem should not result in recovery
+ bus->stop_ind = I2C_BUS_ERR_IND;
+
+ // wait for bus busy before clear fifo
+ iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, bus->reg + NPCM_I2CFIF_CTS);
+
+ bus->state = I2C_IDLE;
+
+ // in BER case we might get 2 interrupts: one for slave one for
+ // master ( for a channel which is master\slave switching)
+ if (completion_done(&bus->cmd_complete) == false) {
+ bus->cmd_err = -EIO;
+ complete(&bus->cmd_complete);
+ }
+ bus->own_slave_addr = 0xFF;
+ iowrite8(NPCM_I2CST_BER, bus->reg + NPCM_I2CST);
+ ret = IRQ_HANDLED;
+ }
+
+ // A Slave Stop Condition has been identified
+ if (FIELD_GET(NPCM_I2CST_SLVSTP, i2cst)) {
+ int bytes_in_fifo = npcm_i2c_fifo_usage(bus);
+
+ bus->stop_ind = I2C_SLAVE_DONE_IND;
+
+ if (bus->operation == I2C_READ_OPER) {
+ npcm_i2c_read_from_fifo(bus, bytes_in_fifo);
+
+ // Slave done transmitting or receiving
+ // if the buffer is empty nothing will be sent
+ }
+
+ // Slave done transmitting or receiving
+ // if the buffer is empty nothing will be sent
+ npcm_i2c_slave_send_rd_buf(bus);
+
+ bus->stop_ind = I2C_NO_STATUS_IND;
+
+ /*
+ * Note, just because we got here, it doesn't mean we through
+ * away the wr buffer.
+ * we keep it until the next received offset.
+ */
+ bus->operation = I2C_NO_OPER;
+ bus->int_cnt = 0;
+ bus->own_slave_addr = 0xFF;
+ i2c_slave_event(bus->slave, I2C_SLAVE_STOP, 0);
+ iowrite8(NPCM_I2CST_SLVSTP, bus->reg + NPCM_I2CST);
+ if (bus->fifo_use) {
+ npcm_i2c_clear_fifo_int(bus);
+ npcm_i2c_clear_rx_fifo(bus);
+ npcm_i2c_clear_tx_fifo(bus);
+
+ iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO,
+ bus->reg + NPCM_I2CFIF_CTS);
+ }
+ bus->state = I2C_IDLE;
+ ret = IRQ_HANDLED;
+ }
+
+ // restart condition occurred and Rx-FIFO was not empty
+ if (bus->fifo_use && FIELD_GET(NPCM_I2CFIF_CTS_SLVRSTR,
+ ioread8(bus->reg + NPCM_I2CFIF_CTS))) {
+ bus->stop_ind = I2C_SLAVE_RESTART_IND;
+ bus->master_or_slave = I2C_SLAVE;
+ if (bus->operation == I2C_READ_OPER)
+ npcm_i2c_read_from_fifo(bus, npcm_i2c_fifo_usage(bus));
+ bus->operation = I2C_WRITE_OPER;
+ iowrite8(0, bus->reg + NPCM_I2CRXF_CTL);
+ val = NPCM_I2CFIF_CTS_CLR_FIFO | NPCM_I2CFIF_CTS_SLVRSTR |
+ NPCM_I2CFIF_CTS_RXF_TXE;
+ iowrite8(val, bus->reg + NPCM_I2CFIF_CTS);
+ npcm_i2c_slave_rd_wr(bus);
+ ret = IRQ_HANDLED;
+ }
+
+ // A Slave Address Match has been identified
+ if (FIELD_GET(NPCM_I2CST_NMATCH, i2cst)) {
+ u8 info = 0;
+
+ // Address match automatically implies slave mode
+ bus->master_or_slave = I2C_SLAVE;
+ npcm_i2c_clear_fifo_int(bus);
+ npcm_i2c_clear_rx_fifo(bus);
+ npcm_i2c_clear_tx_fifo(bus);
+ iowrite8(0, bus->reg + NPCM_I2CTXF_CTL);
+ iowrite8(I2C_HW_FIFO_SIZE, bus->reg + NPCM_I2CRXF_CTL);
+ if (FIELD_GET(NPCM_I2CST_XMIT, i2cst)) {
+ bus->operation = I2C_WRITE_OPER;
+ } else {
+ i2c_slave_event(bus->slave, I2C_SLAVE_WRITE_REQUESTED,
+ &info);
+ bus->operation = I2C_READ_OPER;
+ }
+ if (bus->own_slave_addr == 0xFF) { // unknown address
+ // Check which type of address match
+ val = ioread8(bus->reg + NPCM_I2CCST);
+ if (!!(NPCM_I2CCST_MATCH & val)) {
+ u16 addr;
+ enum i2c_addr eaddr;
+ u8 i2ccst2;
+ u8 i2ccst3;
+
+ i2ccst3 = ioread8(bus->reg + NPCM_I2CCST3);
+ i2ccst2 = ioread8(bus->reg + NPCM_I2CCST2);
+
+ // the i2c module can response to 10 own SA.
+ // check which one was addressed by the master.
+ // repond to the first one.
+ addr = ((i2ccst3 & 0x07) << 7) |
+ (i2ccst2 & 0x7F);
+ info = ffs(addr);
+ eaddr = (enum i2c_addr)info;
+ addr = npcm_i2c_get_slave_addr(bus, eaddr);
+ addr &= 0x7F;
+ bus->own_slave_addr = addr;
+ if (bus->PEC_mask & BIT(info))
+ bus->PEC_use = true;
+ else
+ bus->PEC_use = false;
+ } else {
+ val = ioread8(bus->reg + NPCM_I2CCST);
+ if (!!(NPCM_I2CCST_GCMATCH & val))
+ bus->own_slave_addr = 0;
+ if (!!(NPCM_I2CCST_ARPMATCH & val))
+ bus->own_slave_addr = 0x61;
+ }
+ } else {
+ /*
+ * Slave match can happen in two options:
+ * 1. Start, SA, read (slave read without further ado)
+ * 2. Start, SA, read, data, restart, SA, read, ...
+ * (slave read in fragmented mode)
+ * 3. Start, SA, write, data, restart, SA, read, ..
+ * (regular write-read mode)
+ */
+ if ((bus->state == I2C_OPER_STARTED &&
+ bus->operation == I2C_READ_OPER &&
+ bus->stop_ind == I2C_SLAVE_XMIT_IND) ||
+ bus->stop_ind == I2C_SLAVE_RCV_IND) {
+ // slave transmit after slave receive w/o Slave
+ // Stop implies repeated start
+ bus->stop_ind = I2C_SLAVE_RESTART_IND;
+ }
+ }
+
+ if (FIELD_GET(NPCM_I2CST_XMIT, i2cst))
+ bus->stop_ind = I2C_SLAVE_XMIT_IND;
+ else
+ bus->stop_ind = I2C_SLAVE_RCV_IND;
+ bus->state = I2C_SLAVE_MATCH;
+ npcm_i2c_slave_rd_wr(bus);
+ iowrite8(NPCM_I2CST_NMATCH, bus->reg + NPCM_I2CST);
+ ret = IRQ_HANDLED;
+ }
+
+ // Slave SDA status is set - transmit or receive, slave
+ if (FIELD_GET(NPCM_I2CST_SDAST, i2cst) ||
+ (bus->fifo_use &&
+ (npcm_i2c_tx_fifo_empty(bus) || npcm_i2c_rx_fifo_full(bus)))) {
+ npcm_i2c_slave_rd_wr(bus);
+ iowrite8(NPCM_I2CST_SDAST, bus->reg + NPCM_I2CST);
+ ret = IRQ_HANDLED;
+ } //SDAST
+
+ return ret;
+}
+
+static int npcm_i2c_reg_slave(struct i2c_client *client)
+{
+ unsigned long lock_flags;
+ struct npcm_i2c *bus = i2c_get_adapdata(client->adapter);
+
+ bus->slave = client;
+
+ if (!bus->slave)
+ return -EINVAL;
+
+ if (client->flags & I2C_CLIENT_TEN)
+ return -EAFNOSUPPORT;
+
+ spin_lock_irqsave(&bus->lock, lock_flags);
+
+ npcm_i2c_init_params(bus);
+ bus->slv_rd_size = 0;
+ bus->slv_wr_size = 0;
+ bus->slv_rd_ind = 0;
+ bus->slv_wr_ind = 0;
+ if (client->flags & I2C_CLIENT_PEC)
+ bus->PEC_use = true;
+
+ dev_info(bus->dev, "i2c%d register slave SA=0x%x, PEC=%d\n", bus->num,
+ client->addr, bus->PEC_use);
+
+ npcm_i2c_slave_enable_l(bus, I2C_SLAVE_ADDR1, client->addr, true);
+ npcm_i2c_clear_fifo_int(bus);
+ npcm_i2c_clear_rx_fifo(bus);
+ npcm_i2c_clear_tx_fifo(bus);
+ npcm_i2c_slave_int_enable(bus, true);
+
+ spin_unlock_irqrestore(&bus->lock, lock_flags);
+ return 0;
+}
+
+static int npcm_i2c_unreg_slave(struct i2c_client *client)
+{
+ struct npcm_i2c *bus = client->adapter->algo_data;
+ unsigned long lock_flags;
+
+ spin_lock_irqsave(&bus->lock, lock_flags);
+ if (!bus->slave) {
+ spin_unlock_irqrestore(&bus->lock, lock_flags);
+ return -EINVAL;
+ }
+ npcm_i2c_slave_int_enable(bus, false);
+ npcm_i2c_remove_slave_addr(bus, client->addr);
+ bus->slave = NULL;
+ spin_unlock_irqrestore(&bus->lock, lock_flags);
+ return 0;
+}
+#endif // CONFIG_I2C_SLAVE
+
static void npcm_i2c_master_fifo_read(struct npcm_i2c *bus)
{
int rcount;
@@ -1393,6 +1981,9 @@ static int __npcm_i2c_init(struct npcm_i2c *bus, struct platform_device *pdev)
bus->state = I2C_DISABLE;
bus->master_or_slave = I2C_SLAVE;
bus->int_time_stamp = 0;
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ bus->slave = NULL;
+#endif
bus->xmits = 0;
ret = device_property_read_u32(&pdev->dev, "bus-frequency", &clk_freq);
@@ -1426,6 +2017,14 @@ static irqreturn_t npcm_i2c_bus_irq(int irq, void *dev_id)
if (ret == IRQ_HANDLED)
return ret;
}
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ if (bus->slave) {
+ bus->master_or_slave = I2C_SLAVE;
+ ret = npcm_i2c_int_slave_handler(bus);
+ if (ret == IRQ_HANDLED)
+ return ret;
+ }
+#endif
return IRQ_HANDLED;
}
@@ -1568,6 +2167,11 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
*/
spin_lock_irqsave(&bus->lock, flags);
bus_busy = ioread8(bus->reg + NPCM_I2CCST) & NPCM_I2CCST_BB;
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ if (!bus_busy && bus->slave)
+ iowrite8((bus->slave->addr & 0x7F),
+ bus->reg + NPCM_I2CADDR1);
+#endif
spin_unlock_irqrestore(&bus->lock, flags);
} while (time_is_after_jiffies(time_left) && bus_busy);
@@ -1620,6 +2224,12 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
if (bus->cmd_err == -EAGAIN)
ret = i2c_recover_bus(adap);
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ // reenable slave if it was enabled
+ if (bus->slave)
+ iowrite8((bus->slave->addr & 0x7F) | NPCM_I2CADDR_SAEN,
+ bus->reg + NPCM_I2CADDR1);
+#endif
return bus->cmd_err;
}
@@ -1642,6 +2252,10 @@ static const struct i2c_adapter_quirks npcm_i2c_quirks = {
static const struct i2c_algorithm npcm_i2c_algo = {
.master_xfer = npcm_i2c_master_xfer,
.functionality = npcm_i2c_functionality,
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ .reg_slave = npcm_i2c_reg_slave,
+ .unreg_slave = npcm_i2c_unreg_slave,
+#endif
};
#if IS_ENABLED(CONFIG_DEBUG_FS)
--
2.22.0
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