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

Wolfram Sang
2018-03-25T18:16:00Z

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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?

> ---
> 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
>

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