drivers/i2c/mvtwsi.c

1 // SPDX-License-Identifier: GPL-2.0+
87 	/* Number of the device (determined from cell-index property) */
99  * enum mvtwsi_ctrl_register_fields - Bit masks for flags in the control
107 	/* Stop bit */
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.
144 	/* Address + write bit transmitted, ACK received */
146 	/* Data transmitted, ACK received */
148 	/* Address + read bit transmitted, ACK received */
150 	/* Address + read bit transmitted, ACK not received */
152 	/* Data received, ACK transmitted */
154 	/* Data received, ACK not transmitted */
161  * enum mvstwsi_ack_flags - Determine whether a read byte should be
167 	/* Send ACK after received byte */
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
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.
293  * back-to-back transactions (repeated starts).
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.
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()
333 	/* Wait for controller to receive byte, and check ACK */  in twsi_send()
338  * twsi_recv() - Receive a byte on the I2C bus.
340  * The static variable mvtwsi_control_flags controls whether we ack or nak.
345  *			be acknowledged by the controller or not (sent ACK/NAK).
347  * @return Zero if status is as expected, or a non-zero code if either a time
355 	/* Compute expected status based on passed ACK flag */  in twsi_recv()
361 	writel(control | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control);  in twsi_recv()
362 	/* Wait for controller to receive byte, and assert ACK or NAK */  in twsi_recv()
366 		*byte = readl(&twsi->data);  in twsi_recv()
371  * twsi_stop() - Assert a STOP condition on the bus.
378  * @return Zero if the operation succeeded, or a non-zero code if a time out
387 	/* Assert STOP */  in twsi_stop()
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.
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.
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()
504 	/* Assert STOP, but don't care for the result */  in __twsi_i2c_init()
513  * i2c_begin() - Start a I2C transaction.
526  * @return Zero if the operation succeeded, or a non-zero code if a time out or
550  * __twsi_i2c_probe_chip() - Probe the given I2C chip address.
558  * @return Zero if the operation succeeded, or a non-zero code if a time out or
572 	/* Stop transaction */  in __twsi_i2c_probe_chip()
579  * __twsi_i2c_read() - Read data from a I2C chip.
584  * NOTE: Some devices want a stop right before the second start, while some
587  * will be a repeated start without a preceding stop.
597  * @return Zero if the operation succeeded, or a non-zero code if a time out or
612 		while ((status == 0) && alen--)  in __twsi_i2c_read()
623 	while ((status == 0) && length--)  in __twsi_i2c_read()
627 	/* Stop transaction */  in __twsi_i2c_read()
634  * __twsi_i2c_write() - Send data to a I2C chip.
646  * @return Zero if the operation succeeded, or a non-zero code if a time out or
659 	while ((status == 0) && (alen-- > 0))  in __twsi_i2c_write()
663 	while ((status == 0) && (length-- > 0))  in __twsi_i2c_write()
666 	/* Stop transaction */  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", },