forked from ~ljy/RK356X_SDK_RELEASE
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hc
2023-12-08 01573e231f18eb2d99162747186f59511f56b64d 
 kernel/drivers/tty/serial/ar933x_uart.c
....@@ -13,6 +13,7 @@
1313 #include <linux/console.h>
1414 #include <linux/sysrq.h>
1515 #include <linux/delay.h>
16
+#include <linux/gpio/consumer.h>
1617 #include <linux/platform_device.h>
1718 #include <linux/of.h>
1819 #include <linux/of_platform.h>
....@@ -28,6 +29,8 @@
2829 #include <asm/div64.h>
2930 
3031 #include <asm/mach-ath79/ar933x_uart.h>
32
+
33
+#include "serial_mctrl_gpio.h"
3134 
3235 #define DRIVER_NAME "ar933x-uart"
3336 
....@@ -47,6 +50,8 @@
4750 	unsigned int		min_baud;
4851 	unsigned int		max_baud;
4952 	struct clk		*clk;
53
+	struct mctrl_gpios	*gpios;
54
+	struct gpio_desc	*rts_gpiod;
5055 };
5156 
5257 static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
....@@ -100,6 +105,18 @@
100105 	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
101106 }
102107 
108
+static inline void ar933x_uart_start_rx_interrupt(struct ar933x_uart_port *up)
109
+{
110
+	up->ier |= AR933X_UART_INT_RX_VALID;
111
+	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
112
+}
113
+
114
+static inline void ar933x_uart_stop_rx_interrupt(struct ar933x_uart_port *up)
115
+{
116
+	up->ier &= ~AR933X_UART_INT_RX_VALID;
117
+	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
118
+}
119
+
103120 static inline void ar933x_uart_putc(struct ar933x_uart_port *up, int ch)
104121 {
105122 	unsigned int rdata;
....@@ -125,11 +142,21 @@
125142 
126143 static unsigned int ar933x_uart_get_mctrl(struct uart_port *port)
127144 {
128
-	return TIOCM_CAR;
145
+	struct ar933x_uart_port *up =
146
+		container_of(port, struct ar933x_uart_port, port);
147
+	int ret = TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
148
+
149
+	mctrl_gpio_get(up->gpios, &ret);
150
+
151
+	return ret;
129152 }
130153 
131154 static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
132155 {
156
+	struct ar933x_uart_port *up =
157
+		container_of(port, struct ar933x_uart_port, port);
158
+
159
+	mctrl_gpio_set(up->gpios, mctrl);
133160 }
134161 
135162 static void ar933x_uart_start_tx(struct uart_port *port)
....@@ -138,6 +165,37 @@
138165 		container_of(port, struct ar933x_uart_port, port);
139166 
140167 	ar933x_uart_start_tx_interrupt(up);
168
+}
169
+
170
+static void ar933x_uart_wait_tx_complete(struct ar933x_uart_port *up)
171
+{
172
+	unsigned int status;
173
+	unsigned int timeout = 60000;
174
+
175
+	/* Wait up to 60ms for the character(s) to be sent. */
176
+	do {
177
+		status = ar933x_uart_read(up, AR933X_UART_CS_REG);
178
+		if (--timeout == 0)
179
+			break;
180
+		udelay(1);
181
+	} while (status & AR933X_UART_CS_TX_BUSY);
182
+
183
+	if (timeout == 0)
184
+		dev_err(up->port.dev, "waiting for TX timed out\n");
185
+}
186
+
187
+static void ar933x_uart_rx_flush(struct ar933x_uart_port *up)
188
+{
189
+	unsigned int status;
190
+
191
+	/* clear RX_VALID interrupt */
192
+	ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_RX_VALID);
193
+
194
+	/* remove characters from the RX FIFO */
195
+	do {
196
+		ar933x_uart_write(up, AR933X_UART_DATA_REG, AR933X_UART_DATA_RX_CSR);
197
+		status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
198
+	} while (status & AR933X_UART_DATA_RX_CSR);
141199 }
142200 
143201 static void ar933x_uart_stop_tx(struct uart_port *port)
....@@ -153,8 +211,7 @@
153211 	struct ar933x_uart_port *up =
154212 		container_of(port, struct ar933x_uart_port, port);
155213 
156
-	up->ier &= ~AR933X_UART_INT_RX_VALID;
157
-	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
214
+	ar933x_uart_stop_rx_interrupt(up);
158215 }
159216 
160217 static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)
....@@ -336,10 +393,19 @@
336393 static void ar933x_uart_tx_chars(struct ar933x_uart_port *up)
337394 {
338395 	struct circ_buf *xmit = &up->port.state->xmit;
396
+	struct serial_rs485 *rs485conf = &up->port.rs485;
339397 	int count;
398
+	bool half_duplex_send = false;
340399 
341400 	if (uart_tx_stopped(&up->port))
342401 		return;
402
+
403
+	if ((rs485conf->flags & SER_RS485_ENABLED) &&
404
+	    (up->port.x_char || !uart_circ_empty(xmit))) {
405
+		ar933x_uart_stop_rx_interrupt(up);
406
+		gpiod_set_value(up->rts_gpiod, !!(rs485conf->flags & SER_RS485_RTS_ON_SEND));
407
+		half_duplex_send = true;
408
+	}
343409 
344410 	count = up->port.fifosize;
345411 	do {
....@@ -368,8 +434,14 @@
368434 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
369435 		uart_write_wakeup(&up->port);
370436 
371
-	if (!uart_circ_empty(xmit))
437
+	if (!uart_circ_empty(xmit)) {
372438 		ar933x_uart_start_tx_interrupt(up);
439
+	} else if (half_duplex_send) {
440
+		ar933x_uart_wait_tx_complete(up);
441
+		ar933x_uart_rx_flush(up);
442
+		ar933x_uart_start_rx_interrupt(up);
443
+		gpiod_set_value(up->rts_gpiod, !!(rs485conf->flags & SER_RS485_RTS_AFTER_SEND));
444
+	}
373445 }
374446 
375447 static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
....@@ -427,8 +499,7 @@
427499 		AR933X_UART_CS_TX_READY_ORIDE | AR933X_UART_CS_RX_READY_ORIDE);
428500 
429501 	/* Enable RX interrupts */
430
-	up->ier = AR933X_UART_INT_RX_VALID;
431
-	ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
502
+	ar933x_uart_start_rx_interrupt(up);
432503 
433504 	spin_unlock_irqrestore(&up->port.lock, flags);
434505 
....@@ -510,6 +581,26 @@
510581 	.config_port	= ar933x_uart_config_port,
511582 	.verify_port	= ar933x_uart_verify_port,
512583 };
584
+
585
+static int ar933x_config_rs485(struct uart_port *port,
586
+				struct serial_rs485 *rs485conf)
587
+{
588
+	struct ar933x_uart_port *up =
589
+		container_of(port, struct ar933x_uart_port, port);
590
+
591
+	if ((rs485conf->flags & SER_RS485_ENABLED) &&
592
+	    !up->rts_gpiod) {
593
+		dev_err(port->dev, "RS485 needs rts-gpio\n");
594
+		return 1;
595
+	}
596
+
597
+	if (rs485conf->flags & SER_RS485_ENABLED)
598
+		gpiod_set_value(up->rts_gpiod,
599
+			!!(rs485conf->flags & SER_RS485_RTS_AFTER_SEND));
600
+
601
+	port->rs485 = *rs485conf;
602
+	return 0;
603
+}
513604 
514605 #ifdef CONFIG_SERIAL_AR933X_CONSOLE
515606 static struct ar933x_uart_port *
....@@ -690,6 +781,7 @@
690781 	port->regshift = 2;
691782 	port->fifosize = AR933X_UART_FIFO_SIZE;
692783 	port->ops = &ar933x_uart_ops;
784
+	port->rs485_config = ar933x_config_rs485;
693785 
694786 	baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);
695787 	up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);
....@@ -697,6 +789,24 @@
697789 	baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
698790 	up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
699791 
792
+	ret = uart_get_rs485_mode(port);
793
+	if (ret)
794
+		goto err_disable_clk;
795
+
796
+	up->gpios = mctrl_gpio_init(port, 0);
797
+	if (IS_ERR(up->gpios) && PTR_ERR(up->gpios) != -ENOSYS) {
798
+		ret = PTR_ERR(up->gpios);
799
+		goto err_disable_clk;
800
+	}
801
+
802
+	up->rts_gpiod = mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS);
803
+
804
+	if ((port->rs485.flags & SER_RS485_ENABLED) &&
805
+	    !up->rts_gpiod) {
806
+		dev_err(&pdev->dev, "lacking rts-gpio, disabling RS485\n");
807
+		port->rs485.flags &= ~SER_RS485_ENABLED;
808
+	}
809
+
700810 #ifdef CONFIG_SERIAL_AR933X_CONSOLE
701811 	ar933x_console_ports[up->port.line] = up;
702812 #endif