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Subject[PATCH 2/6] i2c: i2c-stm32f7: Add slave support
Date
This patch adds slave support for I2C controller embedded in STM32F7 SoC

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
---
Version history:
v1:
* Initial
---
---
drivers/i2c/busses/Kconfig | 1 +
drivers/i2c/busses/i2c-stm32f7.c | 434 ++++++++++++++++++++++++++++++++++++++-
2 files changed, 429 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index a9805c7..08f1490 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -962,6 +962,7 @@ config I2C_STM32F4
config I2C_STM32F7
tristate "STMicroelectronics STM32F7 I2C support"
depends on ARCH_STM32 || COMPILE_TEST
+ select I2C_SLAVE
help
Enable this option to add support for STM32 I2C controller embedded
in STM32F7 SoCs.
diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 31bfa00..aff1750 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -35,6 +35,8 @@
/* STM32F7 I2C registers */
#define STM32F7_I2C_CR1 0x00
#define STM32F7_I2C_CR2 0x04
+#define STM32F7_I2C_OAR1 0x08
+#define STM32F7_I2C_OAR2 0x0C
#define STM32F7_I2C_TIMINGR 0x10
#define STM32F7_I2C_ISR 0x18
#define STM32F7_I2C_ICR 0x1C
@@ -42,6 +44,7 @@
#define STM32F7_I2C_TXDR 0x28

/* STM32F7 I2C control 1 */
+#define STM32F7_I2C_CR1_SBC BIT(16)
#define STM32F7_I2C_CR1_ANFOFF BIT(12)
#define STM32F7_I2C_CR1_ERRIE BIT(7)
#define STM32F7_I2C_CR1_TCIE BIT(6)
@@ -57,6 +60,11 @@
| STM32F7_I2C_CR1_NACKIE \
| STM32F7_I2C_CR1_RXIE \
| STM32F7_I2C_CR1_TXIE)
+#define STM32F7_I2C_XFER_IRQ_MASK (STM32F7_I2C_CR1_TCIE \
+ | STM32F7_I2C_CR1_STOPIE \
+ | STM32F7_I2C_CR1_NACKIE \
+ | STM32F7_I2C_CR1_RXIE \
+ | STM32F7_I2C_CR1_TXIE)

/* STM32F7 I2C control 2 */
#define STM32F7_I2C_CR2_RELOAD BIT(24)
@@ -74,7 +82,34 @@
#define STM32F7_I2C_CR2_SADD7_MASK GENMASK(7, 1)
#define STM32F7_I2C_CR2_SADD7(n) (((n) & 0x7f) << 1)

+/* STM32F7 I2C Own Address 1 */
+#define STM32F7_I2C_OAR1_OA1EN BIT(15)
+#define STM32F7_I2C_OAR1_OA1MODE BIT(10)
+#define STM32F7_I2C_OAR1_OA1_10_MASK GENMASK(9, 0)
+#define STM32F7_I2C_OAR1_OA1_10(n) (((n) & \
+ STM32F7_I2C_OAR1_OA1_10_MASK))
+#define STM32F7_I2C_OAR1_OA1_7_MASK GENMASK(7, 1)
+#define STM32F7_I2C_OAR1_OA1_7(n) (((n) & 0x7f) << 1)
+#define STM32F7_I2C_OAR1_MASK (STM32F7_I2C_OAR1_OA1_7_MASK \
+ | STM32F7_I2C_OAR1_OA1_10_MASK \
+ | STM32F7_I2C_OAR1_OA1EN \
+ | STM32F7_I2C_OAR1_OA1MODE)
+
+/* STM32F7 I2C Own Address 2 */
+#define STM32F7_I2C_OAR2_OA2EN BIT(15)
+#define STM32F7_I2C_OAR2_OA2MSK_MASK GENMASK(10, 8)
+#define STM32F7_I2C_OAR2_OA2MSK(n) (((n) & 0x7) << 8)
+#define STM32F7_I2C_OAR2_OA2_7_MASK GENMASK(7, 1)
+#define STM32F7_I2C_OAR2_OA2_7(n) (((n) & 0x7f) << 1)
+#define STM32F7_I2C_OAR2_MASK (STM32F7_I2C_OAR2_OA2MSK_MASK \
+ | STM32F7_I2C_OAR2_OA2_7_MASK \
+ | STM32F7_I2C_OAR2_OA2EN)
+
/* STM32F7 I2C Interrupt Status */
+#define STM32F7_I2C_ISR_ADDCODE_MASK GENMASK(23, 17)
+#define STM32F7_I2C_ISR_ADDCODE_GET(n) \
+ (((n) & STM32F7_I2C_ISR_ADDCODE_MASK) >> 17)
+#define STM32F7_I2C_ISR_DIR BIT(16)
#define STM32F7_I2C_ISR_BUSY BIT(15)
#define STM32F7_I2C_ISR_ARLO BIT(9)
#define STM32F7_I2C_ISR_BERR BIT(8)
@@ -82,14 +117,17 @@
#define STM32F7_I2C_ISR_TC BIT(6)
#define STM32F7_I2C_ISR_STOPF BIT(5)
#define STM32F7_I2C_ISR_NACKF BIT(4)
+#define STM32F7_I2C_ISR_ADDR BIT(3)
#define STM32F7_I2C_ISR_RXNE BIT(2)
#define STM32F7_I2C_ISR_TXIS BIT(1)
+#define STM32F7_I2C_ISR_TXE BIT(0)

/* STM32F7 I2C Interrupt Clear */
#define STM32F7_I2C_ICR_ARLOCF BIT(9)
#define STM32F7_I2C_ICR_BERRCF BIT(8)
#define STM32F7_I2C_ICR_STOPCF BIT(5)
#define STM32F7_I2C_ICR_NACKCF BIT(4)
+#define STM32F7_I2C_ICR_ADDRCF BIT(3)

/* STM32F7 I2C Timing */
#define STM32F7_I2C_TIMINGR_PRESC(n) (((n) & 0xf) << 28)
@@ -99,6 +137,7 @@
#define STM32F7_I2C_TIMINGR_SCLL(n) ((n) & 0xff)

#define STM32F7_I2C_MAX_LEN 0xff
+#define STM32F7_I2C_MAX_SLAVE 0x2

#define STM32F7_I2C_DNF_DEFAULT 0
#define STM32F7_I2C_DNF_MAX 16
@@ -209,6 +248,11 @@ struct stm32f7_i2c_msg {
* @f7_msg: customized i2c msg for driver usage
* @setup: I2C timing input setup
* @timing: I2C computed timings
+ * @slave: list of slave devices registered on the I2C bus
+ * @slave_running: slave device currently used
+ * @slave_dir: transfer direction for the current slave device
+ * @master_mode: boolean to know in which mode the I2C is running (master or
+ * slave)
*/
struct stm32f7_i2c_dev {
struct i2c_adapter adap;
@@ -223,6 +267,10 @@ struct stm32f7_i2c_dev {
struct stm32f7_i2c_msg f7_msg;
struct stm32f7_i2c_setup setup;
struct stm32f7_i2c_timings timing;
+ struct i2c_client *slave[STM32F7_I2C_MAX_SLAVE];
+ struct i2c_client *slave_running;
+ u32 slave_dir;
+ bool master_mode;
};

/**
@@ -288,6 +336,11 @@ static inline void stm32f7_i2c_clr_bits(void __iomem *reg, u32 mask)
writel_relaxed(readl_relaxed(reg) & ~mask, reg);
}

+static void stm32f7_i2c_disable_irq(struct stm32f7_i2c_dev *i2c_dev, u32 mask)
+{
+ stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1, mask);
+}
+
static int stm32f7_i2c_compute_timing(struct stm32f7_i2c_dev *i2c_dev,
struct stm32f7_i2c_setup *setup,
struct stm32f7_i2c_timings *output)
@@ -572,6 +625,9 @@ static void stm32f7_i2c_read_rx_data(struct stm32f7_i2c_dev *i2c_dev)
if (f7_msg->count) {
*f7_msg->buf++ = readb_relaxed(base + STM32F7_I2C_RXDR);
f7_msg->count--;
+ } else {
+ /* Flush RX buffer has no data is expected */
+ readb_relaxed(base + STM32F7_I2C_RXDR);
}
}

@@ -669,14 +725,250 @@ static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,
/* Configure Start/Repeated Start */
cr2 |= STM32F7_I2C_CR2_START;

+ i2c_dev->master_mode = true;
+
/* Write configurations registers */
writel_relaxed(cr1, base + STM32F7_I2C_CR1);
writel_relaxed(cr2, base + STM32F7_I2C_CR2);
}

-static void stm32f7_i2c_disable_irq(struct stm32f7_i2c_dev *i2c_dev, u32 mask)
+static bool stm32f7_i2c_is_addr_match(struct i2c_client *slave, u32 addcode)
{
- stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1, mask);
+ u32 addr;
+
+ if (!slave)
+ return false;
+
+ if (slave->flags & I2C_CLIENT_TEN) {
+ /*
+ * For 10-bit addr, addcode = 11110XY with
+ * X = Bit 9 of slave address
+ * Y = Bit 8 of slave address
+ */
+ addr = slave->addr >> 8;
+ addr |= 0x78;
+ if (addr == addcode)
+ return true;
+ } else {
+ addr = slave->addr & 0x7f;
+ if (addr == addcode)
+ return true;
+ }
+
+ return false;
+}
+
+static void stm32f7_i2c_slave_start(struct stm32f7_i2c_dev *i2c_dev)
+{
+ struct i2c_client *slave = i2c_dev->slave_running;
+ void __iomem *base = i2c_dev->base;
+ u32 mask;
+ u8 value = 0;
+
+ if (i2c_dev->slave_dir) {
+ /* Notify i2c slave that new read transfer is starting */
+ i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value);
+
+ /*
+ * Disable slave TX config in case of I2C combined message
+ * (I2C Write followed by I2C Read)
+ */
+ mask = STM32F7_I2C_CR2_RELOAD;
+ stm32f7_i2c_clr_bits(base + STM32F7_I2C_CR2, mask);
+ mask = STM32F7_I2C_CR1_SBC | STM32F7_I2C_CR1_RXIE |
+ STM32F7_I2C_CR1_TCIE;
+ stm32f7_i2c_clr_bits(base + STM32F7_I2C_CR1, mask);
+
+ /* Enable TX empty, STOP, NACK interrupts */
+ mask = STM32F7_I2C_CR1_STOPIE | STM32F7_I2C_CR1_NACKIE |
+ STM32F7_I2C_CR1_TXIE;
+ stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, mask);
+
+ } else {
+ /* Notify i2c slave that new write transfer is starting */
+ i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+
+ /* Set reload mode to be able to ACK/NACK each received byte */
+ mask = STM32F7_I2C_CR2_RELOAD;
+ stm32f7_i2c_set_bits(base + STM32F7_I2C_CR2, mask);
+
+ /*
+ * Set STOP, NACK, RX empty and transfer complete interrupts.*
+ * Set Slave Byte Control to be able to ACK/NACK each data
+ * byte received
+ */
+ mask = STM32F7_I2C_CR1_STOPIE | STM32F7_I2C_CR1_NACKIE |
+ STM32F7_I2C_CR1_SBC | STM32F7_I2C_CR1_RXIE |
+ STM32F7_I2C_CR1_TCIE;
+ stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, mask);
+ }
+}
+
+static void stm32f7_i2c_slave_addr(struct stm32f7_i2c_dev *i2c_dev)
+{
+ void __iomem *base = i2c_dev->base;
+ u32 isr, addcode, dir, mask;
+ int i;
+
+ isr = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);
+ addcode = STM32F7_I2C_ISR_ADDCODE_GET(isr);
+ dir = isr & STM32F7_I2C_ISR_DIR;
+
+ for (i = 0; i < STM32F7_I2C_MAX_SLAVE; i++) {
+ if (stm32f7_i2c_is_addr_match(i2c_dev->slave[i], addcode)) {
+ i2c_dev->slave_running = i2c_dev->slave[i];
+ i2c_dev->slave_dir = dir;
+
+ /* Start I2C slave processing */
+ stm32f7_i2c_slave_start(i2c_dev);
+
+ /* Clear ADDR flag */
+ mask = STM32F7_I2C_ICR_ADDRCF;
+ writel_relaxed(mask, base + STM32F7_I2C_ICR);
+ break;
+ }
+ }
+}
+
+static int stm32f7_i2c_get_slave_id(struct stm32f7_i2c_dev *i2c_dev,
+ struct i2c_client *slave, int *id)
+{
+ int i;
+
+ for (i = 0; i < STM32F7_I2C_MAX_SLAVE; i++) {
+ if (i2c_dev->slave[i] == slave) {
+ *id = i;
+ return 0;
+ }
+ }
+
+ dev_err(i2c_dev->dev, "Slave 0x%x not registered\n", slave->addr);
+
+ return -ENODEV;
+}
+
+static int stm32f7_i2c_get_free_slave_id(struct stm32f7_i2c_dev *i2c_dev,
+ struct i2c_client *slave, int *id)
+{
+ struct device *dev = i2c_dev->dev;
+ int i;
+
+ /*
+ * slave[0] supports 7-bit and 10-bit slave address
+ * slave[1] supports 7-bit slave address only
+ */
+ for (i = 0; i < STM32F7_I2C_MAX_SLAVE; i++) {
+ if (i == 1 && (slave->flags & I2C_CLIENT_PEC))
+ continue;
+ if (!i2c_dev->slave[i]) {
+ *id = i;
+ return 0;
+ }
+ }
+
+ dev_err(dev, "Slave 0x%x could not be registered\n", slave->addr);
+
+ return -EINVAL;
+}
+
+static bool stm32f7_i2c_is_slave_registered(struct stm32f7_i2c_dev *i2c_dev)
+{
+ int i;
+
+ for (i = 0; i < STM32F7_I2C_MAX_SLAVE; i++) {
+ if (i2c_dev->slave[i])
+ return true;
+ }
+
+ return false;
+}
+
+static bool stm32f7_i2c_is_slave_busy(struct stm32f7_i2c_dev *i2c_dev)
+{
+ int i, busy;
+
+ busy = 0;
+ for (i = 0; i < STM32F7_I2C_MAX_SLAVE; i++) {
+ if (i2c_dev->slave[i])
+ busy++;
+ }
+
+ return i == busy;
+}
+
+static irqreturn_t stm32f7_i2c_slave_isr_event(struct stm32f7_i2c_dev *i2c_dev)
+{
+ void __iomem *base = i2c_dev->base;
+ u32 cr2, status, mask;
+ u8 val;
+ int ret;
+
+ status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);
+
+ /* Slave transmitter mode */
+ if (status & STM32F7_I2C_ISR_TXIS) {
+ i2c_slave_event(i2c_dev->slave_running,
+ I2C_SLAVE_READ_PROCESSED,
+ &val);
+
+ /* Write data byte */
+ writel_relaxed(val, base + STM32F7_I2C_TXDR);
+ }
+
+ /* Transfer Complete Reload for Slave receiver mode */
+ if (status & STM32F7_I2C_ISR_TCR || status & STM32F7_I2C_ISR_RXNE) {
+ /*
+ * Read data byte then set NBYTES to receive next byte or NACK
+ * the current received byte
+ */
+ val = readb_relaxed(i2c_dev->base + STM32F7_I2C_RXDR);
+ ret = i2c_slave_event(i2c_dev->slave_running,
+ I2C_SLAVE_WRITE_RECEIVED,
+ &val);
+ if (!ret) {
+ cr2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR2);
+ cr2 |= STM32F7_I2C_CR2_NBYTES(1);
+ writel_relaxed(cr2, i2c_dev->base + STM32F7_I2C_CR2);
+ } else {
+ mask = STM32F7_I2C_CR2_NACK;
+ stm32f7_i2c_set_bits(base + STM32F7_I2C_CR2, mask);
+ }
+ }
+
+ /* NACK received */
+ if (status & STM32F7_I2C_ISR_NACKF) {
+ dev_dbg(i2c_dev->dev, "<%s>: Receive NACK\n", __func__);
+ writel_relaxed(STM32F7_I2C_ICR_NACKCF, base + STM32F7_I2C_ICR);
+ }
+
+ /* STOP received */
+ if (status & STM32F7_I2C_ISR_STOPF) {
+ /* Disable interrupts */
+ stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_XFER_IRQ_MASK);
+
+ if (i2c_dev->slave_dir) {
+ /*
+ * Flush TX buffer in order to not used the byte in
+ * TXDR for the next transfer
+ */
+ mask = STM32F7_I2C_ISR_TXE;
+ stm32f7_i2c_set_bits(base + STM32F7_I2C_ISR, mask);
+ }
+
+ /* Clear STOP flag */
+ writel_relaxed(STM32F7_I2C_ICR_STOPCF, base + STM32F7_I2C_ICR);
+
+ /* Notify i2c slave that a STOP flag has been detected */
+ i2c_slave_event(i2c_dev->slave_running, I2C_SLAVE_STOP, &val);
+
+ i2c_dev->slave_running = NULL;
+ }
+
+ /* Address match received */
+ if (status & STM32F7_I2C_ISR_ADDR)
+ stm32f7_i2c_slave_addr(i2c_dev);
+
+ return IRQ_HANDLED;
}

static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data)
@@ -685,6 +977,13 @@ static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data)
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
void __iomem *base = i2c_dev->base;
u32 status, mask;
+ int ret;
+
+ /* Check if the interrupt if for a slave device */
+ if (!i2c_dev->master_mode) {
+ ret = stm32f7_i2c_slave_isr_event(i2c_dev);
+ return ret;
+ }

status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);

@@ -706,11 +1005,16 @@ static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data)
/* STOP detection flag */
if (status & STM32F7_I2C_ISR_STOPF) {
/* Disable interrupts */
- stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK);
+ if (stm32f7_i2c_is_slave_registered(i2c_dev))
+ mask = STM32F7_I2C_XFER_IRQ_MASK;
+ else
+ mask = STM32F7_I2C_ALL_IRQ_MASK;
+ stm32f7_i2c_disable_irq(i2c_dev, mask);

/* Clear STOP flag */
writel_relaxed(STM32F7_I2C_ICR_STOPCF, base + STM32F7_I2C_ICR);

+ i2c_dev->master_mode = false;
complete(&i2c_dev->complete);
}

@@ -743,7 +1047,7 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data)
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
void __iomem *base = i2c_dev->base;
struct device *dev = i2c_dev->dev;
- u32 status;
+ u32 mask, status;

status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);

@@ -761,8 +1065,14 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data)
f7_msg->result = -EAGAIN;
}

- stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK);
+ /* Disable interrupts */
+ if (stm32f7_i2c_is_slave_registered(i2c_dev))
+ mask = STM32F7_I2C_XFER_IRQ_MASK;
+ else
+ mask = STM32F7_I2C_ALL_IRQ_MASK;
+ stm32f7_i2c_disable_irq(i2c_dev, mask);

+ i2c_dev->master_mode = false;
complete(&i2c_dev->complete);

return IRQ_HANDLED;
@@ -808,14 +1118,126 @@ static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
return (ret < 0) ? ret : num;
}

+static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
+{
+ struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(slave->adapter);
+ void __iomem *base = i2c_dev->base;
+ struct device *dev = i2c_dev->dev;
+ u32 oar1, oar2, mask;
+ int id, ret;
+
+ if (slave->flags & I2C_CLIENT_PEC) {
+ dev_err(dev, "SMBus PEC not supported in slave mode\n");
+ return -EINVAL;
+ }
+
+ if (stm32f7_i2c_is_slave_busy(i2c_dev)) {
+ dev_err(dev, "Too much slave registered\n");
+ return -EBUSY;
+ }
+
+ ret = stm32f7_i2c_get_free_slave_id(i2c_dev, slave, &id);
+ if (ret)
+ return ret;
+
+ if (!(stm32f7_i2c_is_slave_registered(i2c_dev))) {
+ ret = clk_enable(i2c_dev->clk);
+ if (ret) {
+ dev_err(dev, "Failed to enable clock\n");
+ return ret;
+ }
+ }
+
+ if (id == 0) {
+ /* Configure Own Address 1 */
+ oar1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_OAR1);
+ oar1 &= ~STM32F7_I2C_OAR1_MASK;
+ if (slave->flags & I2C_CLIENT_TEN) {
+ oar1 |= STM32F7_I2C_OAR1_OA1_10(slave->addr);
+ oar1 |= STM32F7_I2C_OAR1_OA1MODE;
+ } else {
+ oar1 |= STM32F7_I2C_OAR1_OA1_7(slave->addr);
+ }
+ oar1 |= STM32F7_I2C_OAR1_OA1EN;
+ i2c_dev->slave[id] = slave;
+ writel_relaxed(oar1, i2c_dev->base + STM32F7_I2C_OAR1);
+ } else if (id == 1) {
+ /* Configure Own Address 2 */
+ oar2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_OAR2);
+ oar2 &= ~STM32F7_I2C_OAR2_MASK;
+ if (slave->flags & I2C_CLIENT_TEN) {
+ ret = -EOPNOTSUPP;
+ goto exit;
+ }
+
+ oar2 |= STM32F7_I2C_OAR2_OA2_7(slave->addr);
+ oar2 |= STM32F7_I2C_OAR2_OA2EN;
+ i2c_dev->slave[id] = slave;
+ writel_relaxed(oar2, i2c_dev->base + STM32F7_I2C_OAR2);
+ } else {
+ ret = -ENODEV;
+ goto exit;
+ }
+
+ /* Enable ACK */
+ stm32f7_i2c_clr_bits(base + STM32F7_I2C_CR2, STM32F7_I2C_CR2_NACK);
+
+ /* Enable Address match interrupt, error interrupt and enable I2C */
+ mask = STM32F7_I2C_CR1_ADDRIE | STM32F7_I2C_CR1_ERRIE |
+ STM32F7_I2C_CR1_PE;
+ stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, mask);
+
+ return 0;
+
+exit:
+ if (!(stm32f7_i2c_is_slave_registered(i2c_dev)))
+ clk_disable(i2c_dev->clk);
+
+ return ret;
+}
+
+static int stm32f7_i2c_unreg_slave(struct i2c_client *slave)
+{
+ struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(slave->adapter);
+ void __iomem *base = i2c_dev->base;
+ u32 mask;
+ int id, ret;
+
+ ret = stm32f7_i2c_get_slave_id(i2c_dev, slave, &id);
+ if (ret)
+ return ret;
+
+ WARN_ON(!i2c_dev->slave[id]);
+
+ if (id == 0) {
+ mask = STM32F7_I2C_OAR1_OA1EN;
+ stm32f7_i2c_clr_bits(base + STM32F7_I2C_OAR1, mask);
+ } else {
+ mask = STM32F7_I2C_OAR2_OA2EN;
+ stm32f7_i2c_clr_bits(base + STM32F7_I2C_OAR2, mask);
+ }
+
+ i2c_dev->slave[id] = NULL;
+
+ if (!(stm32f7_i2c_is_slave_registered(i2c_dev))) {
+ stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK);
+ clk_disable(i2c_dev->clk);
+ }
+
+ return 0;
+}
+
static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
{
- return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
+ I2C_FUNC_SLAVE;
}

static struct i2c_algorithm stm32f7_i2c_algo = {
.master_xfer = stm32f7_i2c_xfer,
.functionality = stm32f7_i2c_func,
+ .reg_slave = stm32f7_i2c_reg_slave,
+ .unreg_slave = stm32f7_i2c_unreg_slave,
};

static int stm32f7_i2c_probe(struct platform_device *pdev)
--
2.7.4
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