Re: [PATCH v2 2/6] i2c: i2c-stm32f7: Add slave support

Pierre Yves MORDRET
2018-03-26T08:41:51Z

On 03/25/2018 08:16 PM, Wolfram Sang wrote:
> On Wed, Mar 21, 2018 at 05:48:56PM +0100, Pierre-Yves MORDRET wrote:
>> 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>
>
> Looks OK from a first look. What kind of tests did you do?

As mentioned for 10-bit, I'm using 2 I2C instances from the SoC.
Here are the tests I dit:
- Master/slave send in 7 and 10 bits
- master/slave recv in 7 and 10 bits
- E2PROM Read/Write

>
>
>> ---
>> Version history:
>> v1:
>> * Initial
>> v2:
>> ---
>> ---
>> 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 e2954fb..118b9be 100644
>> --- a/drivers/i2c/busses/Kconfig
>> +++ b/drivers/i2c/busses/Kconfig
>> @@ -964,6 +964,7 @@ 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 ae0d15c..9bf676e 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
>>