498 lines
11 KiB
C
498 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/* Realtek Simple Management Interface (SMI) driver
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* It can be discussed how "simple" this interface is.
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*
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* The SMI protocol piggy-backs the MDIO MDC and MDIO signals levels
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* but the protocol is not MDIO at all. Instead it is a Realtek
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* pecularity that need to bit-bang the lines in a special way to
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* communicate with the switch.
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*
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* ASICs we intend to support with this driver:
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*
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* RTL8366 - The original version, apparently
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* RTL8369 - Similar enough to have the same datsheet as RTL8366
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* RTL8366RB - Probably reads out "RTL8366 revision B", has a quite
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* different register layout from the other two
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* RTL8366S - Is this "RTL8366 super"?
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* RTL8367 - Has an OpenWRT driver as well
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* RTL8368S - Seems to be an alternative name for RTL8366RB
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* RTL8370 - Also uses SMI
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*
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* Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
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* Copyright (C) 2010 Antti Seppälä <a.seppala@gmail.com>
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* Copyright (C) 2010 Roman Yeryomin <roman@advem.lv>
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* Copyright (C) 2011 Colin Leitner <colin.leitner@googlemail.com>
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* Copyright (C) 2009-2010 Gabor Juhos <juhosg@openwrt.org>
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/spinlock.h>
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#include <linux/skbuff.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/of_mdio.h>
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#include <linux/delay.h>
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#include <linux/gpio/consumer.h>
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#include <linux/platform_device.h>
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#include <linux/regmap.h>
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#include <linux/bitops.h>
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#include <linux/if_bridge.h>
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#include "realtek-smi-core.h"
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#define REALTEK_SMI_ACK_RETRY_COUNT 5
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#define REALTEK_SMI_HW_STOP_DELAY 25 /* msecs */
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#define REALTEK_SMI_HW_START_DELAY 100 /* msecs */
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static inline void realtek_smi_clk_delay(struct realtek_smi *smi)
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{
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ndelay(smi->clk_delay);
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}
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static void realtek_smi_start(struct realtek_smi *smi)
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{
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/* Set GPIO pins to output mode, with initial state:
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* SCK = 0, SDA = 1
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*/
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gpiod_direction_output(smi->mdc, 0);
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gpiod_direction_output(smi->mdio, 1);
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realtek_smi_clk_delay(smi);
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/* CLK 1: 0 -> 1, 1 -> 0 */
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gpiod_set_value(smi->mdc, 1);
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdc, 0);
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realtek_smi_clk_delay(smi);
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/* CLK 2: */
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gpiod_set_value(smi->mdc, 1);
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdio, 0);
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdc, 0);
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdio, 1);
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}
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static void realtek_smi_stop(struct realtek_smi *smi)
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{
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdio, 0);
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gpiod_set_value(smi->mdc, 1);
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdio, 1);
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdc, 1);
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdc, 0);
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdc, 1);
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/* Add a click */
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdc, 0);
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdc, 1);
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/* Set GPIO pins to input mode */
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gpiod_direction_input(smi->mdio);
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gpiod_direction_input(smi->mdc);
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}
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static void realtek_smi_write_bits(struct realtek_smi *smi, u32 data, u32 len)
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{
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for (; len > 0; len--) {
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realtek_smi_clk_delay(smi);
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/* Prepare data */
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gpiod_set_value(smi->mdio, !!(data & (1 << (len - 1))));
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realtek_smi_clk_delay(smi);
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/* Clocking */
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gpiod_set_value(smi->mdc, 1);
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realtek_smi_clk_delay(smi);
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gpiod_set_value(smi->mdc, 0);
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}
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}
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static void realtek_smi_read_bits(struct realtek_smi *smi, u32 len, u32 *data)
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{
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gpiod_direction_input(smi->mdio);
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for (*data = 0; len > 0; len--) {
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u32 u;
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realtek_smi_clk_delay(smi);
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/* Clocking */
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gpiod_set_value(smi->mdc, 1);
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realtek_smi_clk_delay(smi);
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u = !!gpiod_get_value(smi->mdio);
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gpiod_set_value(smi->mdc, 0);
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*data |= (u << (len - 1));
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}
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gpiod_direction_output(smi->mdio, 0);
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}
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static int realtek_smi_wait_for_ack(struct realtek_smi *smi)
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{
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int retry_cnt;
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retry_cnt = 0;
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do {
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u32 ack;
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realtek_smi_read_bits(smi, 1, &ack);
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if (ack == 0)
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break;
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if (++retry_cnt > REALTEK_SMI_ACK_RETRY_COUNT) {
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dev_err(smi->dev, "ACK timeout\n");
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return -ETIMEDOUT;
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}
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} while (1);
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return 0;
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}
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static int realtek_smi_write_byte(struct realtek_smi *smi, u8 data)
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{
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realtek_smi_write_bits(smi, data, 8);
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return realtek_smi_wait_for_ack(smi);
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}
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static int realtek_smi_write_byte_noack(struct realtek_smi *smi, u8 data)
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{
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realtek_smi_write_bits(smi, data, 8);
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return 0;
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}
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static int realtek_smi_read_byte0(struct realtek_smi *smi, u8 *data)
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{
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u32 t;
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/* Read data */
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realtek_smi_read_bits(smi, 8, &t);
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*data = (t & 0xff);
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/* Send an ACK */
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realtek_smi_write_bits(smi, 0x00, 1);
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return 0;
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}
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static int realtek_smi_read_byte1(struct realtek_smi *smi, u8 *data)
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{
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u32 t;
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/* Read data */
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realtek_smi_read_bits(smi, 8, &t);
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*data = (t & 0xff);
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/* Send an ACK */
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realtek_smi_write_bits(smi, 0x01, 1);
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return 0;
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}
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static int realtek_smi_read_reg(struct realtek_smi *smi, u32 addr, u32 *data)
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{
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unsigned long flags;
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u8 lo = 0;
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u8 hi = 0;
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int ret;
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spin_lock_irqsave(&smi->lock, flags);
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realtek_smi_start(smi);
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/* Send READ command */
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ret = realtek_smi_write_byte(smi, smi->cmd_read);
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if (ret)
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goto out;
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/* Set ADDR[7:0] */
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ret = realtek_smi_write_byte(smi, addr & 0xff);
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if (ret)
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goto out;
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/* Set ADDR[15:8] */
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ret = realtek_smi_write_byte(smi, addr >> 8);
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if (ret)
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goto out;
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/* Read DATA[7:0] */
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realtek_smi_read_byte0(smi, &lo);
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/* Read DATA[15:8] */
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realtek_smi_read_byte1(smi, &hi);
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*data = ((u32)lo) | (((u32)hi) << 8);
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ret = 0;
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out:
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realtek_smi_stop(smi);
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spin_unlock_irqrestore(&smi->lock, flags);
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return ret;
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}
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static int realtek_smi_write_reg(struct realtek_smi *smi,
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u32 addr, u32 data, bool ack)
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{
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unsigned long flags;
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int ret;
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spin_lock_irqsave(&smi->lock, flags);
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realtek_smi_start(smi);
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/* Send WRITE command */
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ret = realtek_smi_write_byte(smi, smi->cmd_write);
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if (ret)
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goto out;
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/* Set ADDR[7:0] */
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ret = realtek_smi_write_byte(smi, addr & 0xff);
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if (ret)
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goto out;
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/* Set ADDR[15:8] */
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ret = realtek_smi_write_byte(smi, addr >> 8);
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if (ret)
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goto out;
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/* Write DATA[7:0] */
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ret = realtek_smi_write_byte(smi, data & 0xff);
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if (ret)
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goto out;
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/* Write DATA[15:8] */
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if (ack)
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ret = realtek_smi_write_byte(smi, data >> 8);
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else
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ret = realtek_smi_write_byte_noack(smi, data >> 8);
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if (ret)
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goto out;
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ret = 0;
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out:
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realtek_smi_stop(smi);
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spin_unlock_irqrestore(&smi->lock, flags);
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return ret;
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}
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/* There is one single case when we need to use this accessor and that
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* is when issueing soft reset. Since the device reset as soon as we write
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* that bit, no ACK will come back for natural reasons.
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*/
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int realtek_smi_write_reg_noack(struct realtek_smi *smi, u32 addr,
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u32 data)
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{
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return realtek_smi_write_reg(smi, addr, data, false);
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}
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EXPORT_SYMBOL_GPL(realtek_smi_write_reg_noack);
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/* Regmap accessors */
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static int realtek_smi_write(void *ctx, u32 reg, u32 val)
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{
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struct realtek_smi *smi = ctx;
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return realtek_smi_write_reg(smi, reg, val, true);
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}
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static int realtek_smi_read(void *ctx, u32 reg, u32 *val)
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{
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struct realtek_smi *smi = ctx;
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return realtek_smi_read_reg(smi, reg, val);
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}
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static const struct regmap_config realtek_smi_mdio_regmap_config = {
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.reg_bits = 10, /* A4..A0 R4..R0 */
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.val_bits = 16,
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.reg_stride = 1,
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/* PHY regs are at 0x8000 */
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.max_register = 0xffff,
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.reg_format_endian = REGMAP_ENDIAN_BIG,
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.reg_read = realtek_smi_read,
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.reg_write = realtek_smi_write,
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.cache_type = REGCACHE_NONE,
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};
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static int realtek_smi_mdio_read(struct mii_bus *bus, int addr, int regnum)
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{
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struct realtek_smi *smi = bus->priv;
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return smi->ops->phy_read(smi, addr, regnum);
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}
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static int realtek_smi_mdio_write(struct mii_bus *bus, int addr, int regnum,
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u16 val)
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{
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struct realtek_smi *smi = bus->priv;
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return smi->ops->phy_write(smi, addr, regnum, val);
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}
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int realtek_smi_setup_mdio(struct realtek_smi *smi)
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{
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struct device_node *mdio_np;
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int ret;
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mdio_np = of_get_compatible_child(smi->dev->of_node, "realtek,smi-mdio");
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if (!mdio_np) {
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dev_err(smi->dev, "no MDIO bus node\n");
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return -ENODEV;
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}
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smi->slave_mii_bus = devm_mdiobus_alloc(smi->dev);
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if (!smi->slave_mii_bus) {
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ret = -ENOMEM;
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goto err_put_node;
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}
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smi->slave_mii_bus->priv = smi;
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smi->slave_mii_bus->name = "SMI slave MII";
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smi->slave_mii_bus->read = realtek_smi_mdio_read;
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smi->slave_mii_bus->write = realtek_smi_mdio_write;
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snprintf(smi->slave_mii_bus->id, MII_BUS_ID_SIZE, "SMI-%d",
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smi->ds->index);
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smi->slave_mii_bus->dev.of_node = mdio_np;
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smi->slave_mii_bus->parent = smi->dev;
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smi->ds->slave_mii_bus = smi->slave_mii_bus;
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ret = of_mdiobus_register(smi->slave_mii_bus, mdio_np);
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if (ret) {
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dev_err(smi->dev, "unable to register MDIO bus %s\n",
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smi->slave_mii_bus->id);
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goto err_put_node;
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}
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return 0;
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err_put_node:
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of_node_put(mdio_np);
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return ret;
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}
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static int realtek_smi_probe(struct platform_device *pdev)
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{
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const struct realtek_smi_variant *var;
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struct device *dev = &pdev->dev;
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struct realtek_smi *smi;
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struct device_node *np;
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int ret;
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var = of_device_get_match_data(dev);
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np = dev->of_node;
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smi = devm_kzalloc(dev, sizeof(*smi), GFP_KERNEL);
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if (!smi)
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return -ENOMEM;
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smi->map = devm_regmap_init(dev, NULL, smi,
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&realtek_smi_mdio_regmap_config);
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if (IS_ERR(smi->map)) {
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ret = PTR_ERR(smi->map);
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dev_err(dev, "regmap init failed: %d\n", ret);
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return ret;
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}
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/* Link forward and backward */
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smi->dev = dev;
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smi->clk_delay = var->clk_delay;
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smi->cmd_read = var->cmd_read;
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smi->cmd_write = var->cmd_write;
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smi->ops = var->ops;
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dev_set_drvdata(dev, smi);
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spin_lock_init(&smi->lock);
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/* TODO: if power is software controlled, set up any regulators here */
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/* Assert then deassert RESET */
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smi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
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if (IS_ERR(smi->reset)) {
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dev_err(dev, "failed to get RESET GPIO\n");
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return PTR_ERR(smi->reset);
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}
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msleep(REALTEK_SMI_HW_STOP_DELAY);
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gpiod_set_value(smi->reset, 0);
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msleep(REALTEK_SMI_HW_START_DELAY);
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dev_info(dev, "deasserted RESET\n");
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/* Fetch MDIO pins */
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smi->mdc = devm_gpiod_get_optional(dev, "mdc", GPIOD_OUT_LOW);
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if (IS_ERR(smi->mdc))
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return PTR_ERR(smi->mdc);
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smi->mdio = devm_gpiod_get_optional(dev, "mdio", GPIOD_OUT_LOW);
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if (IS_ERR(smi->mdio))
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return PTR_ERR(smi->mdio);
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smi->leds_disabled = of_property_read_bool(np, "realtek,disable-leds");
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ret = smi->ops->detect(smi);
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if (ret) {
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dev_err(dev, "unable to detect switch\n");
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return ret;
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}
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smi->ds = dsa_switch_alloc(dev, smi->num_ports);
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if (!smi->ds)
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return -ENOMEM;
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smi->ds->priv = smi;
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smi->ds->ops = var->ds_ops;
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ret = dsa_register_switch(smi->ds);
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if (ret) {
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dev_err(dev, "unable to register switch ret = %d\n", ret);
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return ret;
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}
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return 0;
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}
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static int realtek_smi_remove(struct platform_device *pdev)
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{
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struct realtek_smi *smi = dev_get_drvdata(&pdev->dev);
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dsa_unregister_switch(smi->ds);
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if (smi->slave_mii_bus)
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of_node_put(smi->slave_mii_bus->dev.of_node);
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gpiod_set_value(smi->reset, 1);
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return 0;
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}
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static const struct of_device_id realtek_smi_of_match[] = {
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{
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.compatible = "realtek,rtl8366rb",
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.data = &rtl8366rb_variant,
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},
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{
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/* FIXME: add support for RTL8366S and more */
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.compatible = "realtek,rtl8366s",
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.data = NULL,
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},
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{ /* sentinel */ },
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};
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MODULE_DEVICE_TABLE(of, realtek_smi_of_match);
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static struct platform_driver realtek_smi_driver = {
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.driver = {
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.name = "realtek-smi",
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.of_match_table = of_match_ptr(realtek_smi_of_match),
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},
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.probe = realtek_smi_probe,
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.remove = realtek_smi_remove,
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};
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module_platform_driver(realtek_smi_driver);
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MODULE_LICENSE("GPL");
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