1 // SPDX-License-Identifier: GPL-2.0+
2 /* Realtek Simple Management Interface (SMI) driver
5  * The SMI protocol piggy-backs the MDIO MDC and MDIO signals levels
6  * but the protocol is not MDIO at all. Instead it is a Realtek
7  * pecularity that need to bit-bang the lines in a special way to
12  * RTL8366   - The original version, apparently
13  * RTL8369   - Similar enough to have the same datsheet as RTL8366
14  * RTL8366RB - Probably reads out "RTL8366 revision B", has a quite
16  * RTL8366S  - Is this "RTL8366 super"?
17  * RTL8367   - Has an OpenWRT driver as well
18  * RTL8368S  - Seems to be an alternative name for RTL8366RB
19  * RTL8370   - Also uses SMI
25  * Copyright (C) 2009-2010 Gabor Juhos <juhosg@openwrt.org>
41 #include "realtek.h"
42 #include "realtek-smi.h"
49 	ndelay(priv->variant->clk_delay);  in realtek_smi_clk_delay()
57 	gpiod_direction_output(priv->mdc, 0);  in realtek_smi_start()
58 	gpiod_direction_output(priv->mdio, 1);  in realtek_smi_start()
61 	/* CLK 1: 0 -> 1, 1 -> 0 */  in realtek_smi_start()
62 	gpiod_set_value(priv->mdc, 1);  in realtek_smi_start()
64 	gpiod_set_value(priv->mdc, 0);  in realtek_smi_start()
68 	gpiod_set_value(priv->mdc, 1);  in realtek_smi_start()
70 	gpiod_set_value(priv->mdio, 0);  in realtek_smi_start()
72 	gpiod_set_value(priv->mdc, 0);  in realtek_smi_start()
74 	gpiod_set_value(priv->mdio, 1);  in realtek_smi_start()
80 	gpiod_set_value(priv->mdio, 0);  in realtek_smi_stop()
81 	gpiod_set_value(priv->mdc, 1);  in realtek_smi_stop()
83 	gpiod_set_value(priv->mdio, 1);  in realtek_smi_stop()
85 	gpiod_set_value(priv->mdc, 1);  in realtek_smi_stop()
87 	gpiod_set_value(priv->mdc, 0);  in realtek_smi_stop()
89 	gpiod_set_value(priv->mdc, 1);  in realtek_smi_stop()
93 	gpiod_set_value(priv->mdc, 0);  in realtek_smi_stop()
95 	gpiod_set_value(priv->mdc, 1);  in realtek_smi_stop()
98 	gpiod_direction_input(priv->mdio);  in realtek_smi_stop()
99 	gpiod_direction_input(priv->mdc);  in realtek_smi_stop()
104 	for (; len > 0; len--) {  in realtek_smi_write_bits()
108 		gpiod_set_value(priv->mdio, !!(data & (1 << (len - 1))));  in realtek_smi_write_bits()
112 		gpiod_set_value(priv->mdc, 1);  in realtek_smi_write_bits()
114 		gpiod_set_value(priv->mdc, 0);  in realtek_smi_write_bits()
120 	gpiod_direction_input(priv->mdio);  in realtek_smi_read_bits()
122 	for (*data = 0; len > 0; len--) {  in realtek_smi_read_bits()
128 		gpiod_set_value(priv->mdc, 1);  in realtek_smi_read_bits()
130 		u = !!gpiod_get_value(priv->mdio);  in realtek_smi_read_bits()
131 		gpiod_set_value(priv->mdc, 0);  in realtek_smi_read_bits()
133 		*data |= (u << (len - 1));  in realtek_smi_read_bits()
136 	gpiod_direction_output(priv->mdio, 0);  in realtek_smi_read_bits()
152 			dev_err(priv->dev, "ACK timeout\n");  in realtek_smi_wait_for_ack()
153 			return -ETIMEDOUT;  in realtek_smi_wait_for_ack()
207 	spin_lock_irqsave(&priv->lock, flags);  in realtek_smi_read_reg()
212 	ret = realtek_smi_write_byte(priv, priv->variant->cmd_read);  in realtek_smi_read_reg()
237 	spin_unlock_irqrestore(&priv->lock, flags);  in realtek_smi_read_reg()
248 	spin_lock_irqsave(&priv->lock, flags);  in realtek_smi_write_reg()
253 	ret = realtek_smi_write_byte(priv, priv->variant->cmd_write);  in realtek_smi_write_reg()
284 	spin_unlock_irqrestore(&priv->lock, flags);  in realtek_smi_write_reg()
320  * realtek_smi_probe() - Probe a platform device for an SMI-connected switch
325  * values specific for SMI-connected devices. Finally, it calls a common
328  * Context: Can sleep. Takes and releases priv->map_lock.
333 	struct device *dev = &pdev->dev;  in realtek_smi_probe()
342 	priv->mdc = devm_gpiod_get_optional(dev, "mdc", GPIOD_OUT_LOW);  in realtek_smi_probe()
343 	if (IS_ERR(priv->mdc)) {  in realtek_smi_probe()
345 		return PTR_ERR(priv->mdc);  in realtek_smi_probe()
348 	priv->mdio = devm_gpiod_get_optional(dev, "mdio", GPIOD_OUT_LOW);  in realtek_smi_probe()
349 	if (IS_ERR(priv->mdio)) {  in realtek_smi_probe()
351 		return PTR_ERR(priv->mdio);  in realtek_smi_probe()
354 	priv->write_reg_noack = realtek_smi_write_reg_noack;  in realtek_smi_probe()
367  * realtek_smi_remove() - Remove the driver of a SMI-connected switch
390  * realtek_smi_shutdown() - Shutdown the driver of a SMI-connected switch