1 // SPDX-License-Identifier: GPL-2.0+
3  * Driver for the TWSI (i2c) controller found on the Marvell
11 #include <i2c.h>
33 #include <asm/arch/i2c.h>
44 #include <asm/arch/i2c.h>
87 	/* Number of the device (determined from cell-index property) */
89 	/* The I2C slave address for the device */
91 	/* The configured I2C speed in Hz */
99  * enum mvtwsi_ctrl_register_fields - Bit masks for flags in the control
111 	/* I2C enable */
118  * On sun6i and newer, IFLG is a write-clear bit, which is cleared by writing 1;
129  * enum mvstwsi_status_values - Possible values of I2C controller's status
133  * non-10-bit-address devices are specified.
161  * enum mvstwsi_ack_flags - Determine whether a read byte should be
172  * calc_tick() - Calculate the duration of a clock cycle from the I2C speed
187  * twsi_get_base() - Get controller register base for specified adapter
194 	switch (adap->hwadapnr) {  in twsi_get_base()
220 		printf("Missing mvtwsi controller %d base\n", adap->hwadapnr);  in twsi_get_base()
229  * enum mvtwsi_error_class - types of I2C errors
239  * mvtwsi_error() - Build I2C return code from error information
242  * error into a return code. These error codes are returned from I2C API
260  * twsi_wait() - Wait for I2C bus interrupt flag and check status, or time out.
262  * @return Zero if status is as expected, or a non-zero code if either a time
272 		control = readl(&twsi->control);  in twsi_wait()
274 			status = readl(&twsi->status);  in twsi_wait()
283 	} while (timeout--);  in twsi_wait()
284 	status = readl(&twsi->status);  in twsi_wait()
290  * twsi_start() - Assert a START condition on the bus.
292  * This function is used in both single I2C transactions and inside
293  * back-to-back transactions (repeated starts).
296  * @expected_status:	The I2C bus status expected to be asserted after the
298  * @tick:		The duration of a clock cycle at the current I2C speed.
299  * @return Zero if status is as expected, or a non-zero code if either a time
307 	       MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control);  in twsi_start()
313  * twsi_send() - Send a byte on the I2C bus.
319  * @expected_status:	The I2C bus status expected to be asserted after the
321  * @tick:		The duration of a clock cycle at the current I2C speed.
322  * @return Zero if status is as expected, or a non-zero code if either a time
329 	writel(byte, &twsi->data);  in twsi_send()
330 	/* Clear any pending interrupt -- that will cause sending */  in twsi_send()
332 	       &twsi->control);  in twsi_send()
338  * twsi_recv() - Receive a byte on the I2C bus.
346  * @tick:		The duration of a clock cycle at the current I2C speed.
347  * @return Zero if status is as expected, or a non-zero code if either a time
361 	writel(control | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control);  in twsi_recv()
366 		*byte = readl(&twsi->data);  in twsi_recv()
371  * twsi_stop() - Assert a STOP condition on the bus.
377  * @tick:	The duration of a clock cycle at the current I2C speed.
378  * @return Zero if the operation succeeded, or a non-zero code if a time out
389 	writel(control | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control);  in twsi_stop()
392 		stop_status = readl(&twsi->status);  in twsi_stop()
396 	} while (timeout--);  in twsi_stop()
397 	control = readl(&twsi->control);  in twsi_stop()
405  * twsi_calc_freq() - Compute I2C frequency depending on m and n parameters.
409  * @return The I2C frequency corresponding to the passed m and n parameters.
421  * twsi_reset() - Reset the I2C controller.
424  * they must be re-established after the reset.
431 	writel(0, &twsi->soft_reset);  in twsi_reset()
432 	/* Wait 2 ms -- this is what the Marvell LSP does */  in twsi_reset()
437  * __twsi_i2c_set_bus_speed() - Set the speed of the I2C controller.
467 	writel(baud, &twsi->baudrate);  in __twsi_i2c_set_bus_speed()
479  * __twsi_i2c_init() - Initialize the I2C controller.
484  * @slaveadd:		The I2C address to be set for the I2C master.
487  * @return Zero if the operation succeeded, or a non-zero code if a time out
502 	writel(slaveadd, &twsi->slave_address);  in __twsi_i2c_init()
503 	writel(0, &twsi->xtnd_slave_addr);  in __twsi_i2c_init()
513  * i2c_begin() - Start a I2C transaction.
515  * Begin a I2C transaction with a given expected start status and chip address.
516  * A START is asserted, and the address byte is sent to the I2C controller. The
521  * @expected_start_status:	The I2C status the controller is expected to
525  *				I2C speed.
526  * @return Zero if the operation succeeded, or a non-zero code if a time out or
527  *	   unexpected I2C status occurred.
550  * __twsi_i2c_probe_chip() - Probe the given I2C chip address.
552  * This function begins a I2C read transaction, does a dummy read and NAKs; if
557  * @tick:	The duration of a clock cycle at the current I2C speed.
558  * @return Zero if the operation succeeded, or a non-zero code if a time out or
559  *	   unexpected I2C status occurred.
567 	/* Begin i2c read */  in __twsi_i2c_probe_chip()
579  * __twsi_i2c_read() - Read data from a I2C chip.
581  * This function begins a I2C write transaction, and transmits the address
582  * bytes; then begins a I2C read transaction, and receives the data bytes.
596  * @tick:	The duration of a clock cycle at the current I2C speed.
597  * @return Zero if the operation succeeded, or a non-zero code if a time out or
598  *	   unexpected I2C status occurred.
609 		/* Begin i2c write to send the address bytes */  in __twsi_i2c_read()
612 		while ((status == 0) && alen--)  in __twsi_i2c_read()
618 	/* Begin i2c read to receive data bytes */  in __twsi_i2c_read()
623 	while ((status == 0) && length--)  in __twsi_i2c_read()
634  * __twsi_i2c_write() - Send data to a I2C chip.
636  * This function begins a I2C write transaction, and transmits the address
637  * bytes; then begins a new I2C write transaction, and sends the data bytes.
645  * @tick:	The duration of a clock cycle at the current I2C speed.
646  * @return Zero if the operation succeeded, or a non-zero code if a time out or
647  *	   unexpected I2C status occurred.
655 	/* Begin i2c write to send first the address bytes, then the  in __twsi_i2c_write()
659 	while ((status == 0) && (alen-- > 0))  in __twsi_i2c_write()
663 	while ((status == 0) && (length-- > 0))  in __twsi_i2c_write()
771 	return __twsi_i2c_probe_chip(dev->base, chip_addr, dev->tick);
778 	dev->speed = __twsi_i2c_set_bus_speed(dev->base, speed);
779 	dev->tick = calc_tick(dev->speed);
788 	dev->base = devfdt_get_addr_ptr(bus);
790 	if (!dev->base)
791 		return -ENOMEM;
793 	dev->index = fdtdec_get_int(gd->fdt_blob, dev_of_offset(bus),
794 				    "cell-index", -1);
795 	dev->slaveadd = fdtdec_get_int(gd->fdt_blob, dev_of_offset(bus),
796 				       "u-boot,i2c-slave-addr", 0x0);
797 	dev->speed = fdtdec_get_int(gd->fdt_blob, dev_of_offset(bus),
798 				    "clock-frequency", 100000);
804 	clrbits_le32(&twsi->debug, BIT(18));
813 			&& bus->req_seq == 0)
824 	__twsi_i2c_init(dev->base, dev->speed, dev->slaveadd, &actual_speed);
825 	dev->speed = actual_speed;
826 	dev->tick = calc_tick(dev->speed);
841 		return -1;
847 	if (dmsg->flags & I2C_M_RD)
848 		return __twsi_i2c_read(dev->base, dmsg->addr, omsg->buf,
849 				       omsg->len, dmsg->buf, dmsg->len,
850 				       dev->tick);
852 		return __twsi_i2c_write(dev->base, dmsg->addr, omsg->buf,
853 					omsg->len, dmsg->buf, dmsg->len,
854 					dev->tick);
864 	{ .compatible = "marvell,mv64xxx-i2c", },
865 	{ .compatible = "marvell,mv78230-i2c", },
866 	{ .compatible = "allwinner,sun6i-a31-i2c", },