i2c: imx: support slave mode for imx I2C driver (f7414cd6) · Commits · git / linux-net

drivers/i2c/busses/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -675,6 +675,7 @@ config I2C_IMG
		config I2C_IMX
		tristate "IMX I2C interface"
		depends on ARCH_MXC \|\| ARCH_LAYERSCAPE \|\| COLDFIRE
		select I2C_SLAVE
		help
		Say Y here if you want to use the IIC bus controller on
		the Freescale i.MX/MXC, Layerscape or ColdFire processors.

drivers/i2c/busses/i2c-imx.c

+195 −24

Original line number	Diff line number	Diff line
		@@ -17,6 +17,7 @@
		* Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt>
		*
		* Copyright 2013 Freescale Semiconductor, Inc.
		* Copyright 2020 NXP
		*
		*/

		@@ -73,6 +74,11 @@
		#define IMX_I2C_I2SR 0x03 /* i2c status */
		#define IMX_I2C_I2DR 0x04 /* i2c transfer data */

		/*
		* All of the layerscape series SoCs support IBIC register.
		*/
		#define IMX_I2C_IBIC 0x05 /* i2c bus interrupt config */

		#define IMX_I2C_REGSHIFT 2
		#define VF610_I2C_REGSHIFT 0

		@@ -91,6 +97,7 @@
		#define I2CR_MSTA 0x20
		#define I2CR_IIEN 0x40
		#define I2CR_IEN 0x80
		#define IBIC_BIIE 0x80 /* Bus idle interrupt enable */

		/* register bits different operating codes definition:
		* 1) I2SR: Interrupt flags clear operation differ between SoCs:
		@@ -201,6 +208,7 @@ struct imx_i2c_struct {
		struct pinctrl_state *pinctrl_pins_gpio;

		struct imx_i2c_dma *dma;
		struct i2c_client *slave;
		};

		static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
		@@ -252,6 +260,11 @@ static inline int is_imx1_i2c(struct imx_i2c_struct *i2c_imx)
		return i2c_imx->hwdata->devtype == IMX1_I2C;
		}

		static inline int is_vf610_i2c(struct imx_i2c_struct *i2c_imx)
		{
		return i2c_imx->hwdata->devtype == VF610_I2C;
		}

		static inline void imx_i2c_write_reg(unsigned int val,
		struct imx_i2c_struct *i2c_imx, unsigned int reg)
		{
		@@ -264,6 +277,27 @@ static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx,
		return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
		}

		static void i2c_imx_clear_irq(struct imx_i2c_struct *i2c_imx, unsigned int bits)
		{
		unsigned int temp;

		/*
		* i2sr_clr_opcode is the value to clear all interrupts. Here we want to
		* clear only <bits>, so we write ~i2sr_clr_opcode with just <bits>
		* toggled. This is required because i.MX needs W0C and Vybrid uses W1C.
		*/
		temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ bits;
		imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
		}

		/* Set up i2c controller register and i2c status register to default value. */
		static void i2c_imx_reset_regs(struct imx_i2c_struct *i2c_imx)
		{
		imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
		i2c_imx, IMX_I2C_I2CR);
		i2c_imx_clear_irq(i2c_imx, I2SR_IIF \| I2SR_IAL);
		}

		/* Functions for DMA support */
		static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
		dma_addr_t phy_addr)
		@@ -399,19 +433,6 @@ static void i2c_imx_dma_free(struct imx_i2c_struct *i2c_imx)
		dma->chan_using = NULL;
		}

		static void i2c_imx_clear_irq(struct imx_i2c_struct *i2c_imx, unsigned int bits)
		{
		unsigned int temp;

		/*
		* i2sr_clr_opcode is the value to clear all interrupts. Here we want to
		* clear only <bits>, so we write ~i2sr_clr_opcode with just <bits>
		* toggled. This is required because i.MX needs W0C and Vybrid uses W1C.
		*/
		temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ bits;
		imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
		}

		static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy, bool atomic)
		{
		unsigned long orig_jiffies = jiffies;
		@@ -625,20 +646,167 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx, bool atomic)
		imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
		}

		static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
		/*
		* Enable bus idle interrupts
		* Note: IBIC register will be cleared after disabled i2c module.
		* All of layerscape series SoCs support IBIC register.
		*/
		static void i2c_imx_enable_bus_idle(struct imx_i2c_struct *i2c_imx)
		{
		struct imx_i2c_struct *i2c_imx = dev_id;
		if (is_vf610_i2c(i2c_imx)) {
		unsigned int temp;

		temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
		if (temp & I2SR_IIF) {
		temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_IBIC);
		temp \|= IBIC_BIIE;
		imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_IBIC);
		}
		}

		static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx,
		unsigned int status, unsigned int ctl)
		{
		u8 value;

		if (status & I2SR_IAL) { /* Arbitration lost */
		i2c_imx_clear_irq(i2c_imx, I2SR_IAL);
		if (!(status & I2SR_IAAS))
		return IRQ_HANDLED;
		}

		if (status & I2SR_IAAS) { /* Addressed as a slave */
		if (status & I2SR_SRW) { /* Master wants to read from us*/
		dev_dbg(&i2c_imx->adapter.dev, "read requested");
		i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_REQUESTED, &value);

		/* Slave transmit */
		ctl \|= I2CR_MTX;
		imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);

		/* Send data */
		imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR);
		} else { /* Master wants to write to us */
		dev_dbg(&i2c_imx->adapter.dev, "write requested");
		i2c_slave_event(i2c_imx->slave, I2C_SLAVE_WRITE_REQUESTED, &value);

		/* Slave receive */
		ctl &= ~I2CR_MTX;
		imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
		/* Dummy read */
		imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
		}
		} else if (!(ctl & I2CR_MTX)) { /* Receive mode */
		if (status & I2SR_IBB) { /* No STOP signal detected */
		value = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
		i2c_slave_event(i2c_imx->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
		} else { /* STOP signal is detected */
		dev_dbg(&i2c_imx->adapter.dev,
		"STOP signal detected");
		i2c_slave_event(i2c_imx->slave, I2C_SLAVE_STOP, &value);
		}
		} else if (!(status & I2SR_RXAK)) { /* Transmit mode received ACK */
		ctl \|= I2CR_MTX;
		imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);

		i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_PROCESSED, &value);

		imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR);
		} else { /* Transmit mode received NAK */
		ctl &= ~I2CR_MTX;
		imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
		imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
		}

		return IRQ_HANDLED;
		}

		static void i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx)
		{
		int temp;

		/* Set slave addr. */
		imx_i2c_write_reg((i2c_imx->slave->addr << 1), i2c_imx, IMX_I2C_IADR);

		i2c_imx_reset_regs(i2c_imx);

		/* Enable module */
		temp = i2c_imx->hwdata->i2cr_ien_opcode;
		imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);

		/* Enable interrupt from i2c module */
		temp \|= I2CR_IIEN;
		imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);

		i2c_imx_enable_bus_idle(i2c_imx);
		}

		static int i2c_imx_reg_slave(struct i2c_client *client)
		{
		struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter);
		int ret;

		if (i2c_imx->slave)
		return -EBUSY;

		i2c_imx->slave = client;

		/* Resume */
		ret = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
		if (ret < 0) {
		dev_err(&i2c_imx->adapter.dev, "failed to resume i2c controller");
		return ret;
		}

		i2c_imx_slave_init(i2c_imx);

		return 0;
		}

		static int i2c_imx_unreg_slave(struct i2c_client *client)
		{
		struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter);
		int ret;

		if (!i2c_imx->slave)
		return -EINVAL;

		/* Reset slave address. */
		imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR);

		i2c_imx_reset_regs(i2c_imx);

		i2c_imx->slave = NULL;

		/* Suspend */
		ret = pm_runtime_put_sync(i2c_imx->adapter.dev.parent);
		if (ret < 0)
		dev_err(&i2c_imx->adapter.dev, "failed to suspend i2c controller");

		return ret;
		}

		static irqreturn_t i2c_imx_master_isr(struct imx_i2c_struct *i2c_imx, unsigned int status)
		{
		/* save status register */
		i2c_imx->i2csr = temp;
		i2c_imx_clear_irq(i2c_imx, I2SR_IIF);
		i2c_imx->i2csr = status;
		wake_up(&i2c_imx->queue);

		return IRQ_HANDLED;
		}

		static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
		{
		struct imx_i2c_struct *i2c_imx = dev_id;
		unsigned int ctl, status;

		status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
		ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
		if (status & I2SR_IIF) {
		i2c_imx_clear_irq(i2c_imx, I2SR_IIF);
		if (i2c_imx->slave && !(ctl & I2CR_MSTA))
		return i2c_imx_slave_isr(i2c_imx, status, ctl);
		return i2c_imx_master_isr(i2c_imx, status);
		}

		return IRQ_NONE;
		}

		@@ -1014,6 +1182,10 @@ static int i2c_imx_xfer_common(struct i2c_adapter *adapter,
		dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
		(result < 0) ? "error" : "success msg",
		(result < 0) ? result : num);
		/* After data is transferred, switch to slave mode(as a receiver) */
		if (i2c_imx->slave)
		i2c_imx_slave_init(i2c_imx);

		return (result < 0) ? result : num;
		}

		@@ -1127,6 +1299,8 @@ static const struct i2c_algorithm i2c_imx_algo = {
		.master_xfer = i2c_imx_xfer,
		.master_xfer_atomic = i2c_imx_xfer_atomic,
		.functionality = i2c_imx_func,
		.reg_slave = i2c_imx_reg_slave,
		.unreg_slave = i2c_imx_unreg_slave,
		};

		static int i2c_imx_probe(struct platform_device *pdev)
		@@ -1216,10 +1390,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
		clk_notifier_register(i2c_imx->clk, &i2c_imx->clk_change_nb);
		i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));

		/* Set up chip registers to defaults */
		imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
		i2c_imx, IMX_I2C_I2CR);
		imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
		i2c_imx_reset_regs(i2c_imx);

		/* Init optional bus recovery function */
		ret = i2c_imx_init_recovery_info(i2c_imx, pdev);