[linux-block.git] / drivers / tty / serial / 8250 / 8250_lpc18xx.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Serial port driver for NXP LPC18xx/43xx UART
 *
 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
 *
 * Based on 8250_mtk.c:
 * Copyright (c) 2014 MundoReader S.L.
 * Matthias Brugger <matthias.bgg@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>

#include "8250.h"

/* Additional LPC18xx/43xx 8250 registers and bits */
#define LPC18XX_UART_RS485CTRL		(0x04c / sizeof(u32))
#define  LPC18XX_UART_RS485CTRL_NMMEN	BIT(0)
#define  LPC18XX_UART_RS485CTRL_DCTRL	BIT(4)
#define  LPC18XX_UART_RS485CTRL_OINV	BIT(5)
#define LPC18XX_UART_RS485DLY		(0x054 / sizeof(u32))
#define LPC18XX_UART_RS485DLY_MAX	255

struct lpc18xx_uart_data {
	struct uart_8250_dma dma;
	struct clk *clk_uart;
	struct clk *clk_reg;
	int line;
};

static int lpc18xx_rs485_config(struct uart_port *port,
				struct serial_rs485 *rs485)
{
	struct uart_8250_port *up = up_to_u8250p(port);
	u32 rs485_ctrl_reg = 0;
	u32 rs485_dly_reg = 0;
	unsigned baud_clk;

	if (rs485->flags & SER_RS485_ENABLED)
		memset(rs485->padding, 0, sizeof(rs485->padding));
	else
		memset(rs485, 0, sizeof(*rs485));

	rs485->flags &= SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND |
			SER_RS485_RTS_AFTER_SEND;

	if (rs485->flags & SER_RS485_ENABLED) {
		rs485_ctrl_reg |= LPC18XX_UART_RS485CTRL_NMMEN |
				  LPC18XX_UART_RS485CTRL_DCTRL;

		if (rs485->flags & SER_RS485_RTS_ON_SEND) {
			rs485_ctrl_reg |= LPC18XX_UART_RS485CTRL_OINV;
			rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
		} else {
			rs485->flags |= SER_RS485_RTS_AFTER_SEND;
		}
	}

	if (rs485->delay_rts_after_send) {
		baud_clk = port->uartclk / up->dl_read(up);
		rs485_dly_reg = DIV_ROUND_UP(rs485->delay_rts_after_send
						* baud_clk, MSEC_PER_SEC);

		if (rs485_dly_reg > LPC18XX_UART_RS485DLY_MAX)
			rs485_dly_reg = LPC18XX_UART_RS485DLY_MAX;

		/* Calculate the resulting delay in ms */
		rs485->delay_rts_after_send = (rs485_dly_reg * MSEC_PER_SEC)
						/ baud_clk;
	}

	/* Delay RTS before send not supported */
	rs485->delay_rts_before_send = 0;

	serial_out(up, LPC18XX_UART_RS485CTRL, rs485_ctrl_reg);
	serial_out(up, LPC18XX_UART_RS485DLY, rs485_dly_reg);

	port->rs485 = *rs485;

	return 0;
}

static void lpc18xx_uart_serial_out(struct uart_port *p, int offset, int value)
{
	/*
	 * For DMA mode one must ensure that the UART_FCR_DMA_SELECT
	 * bit is set when FIFO is enabled. Even if DMA is not used
	 * setting this bit doesn't seem to affect anything.
	 */
	if (offset == UART_FCR && (value & UART_FCR_ENABLE_FIFO))
		value |= UART_FCR_DMA_SELECT;

	offset = offset << p->regshift;
	writel(value, p->membase + offset);
}

static int lpc18xx_serial_probe(struct platform_device *pdev)
{
	struct lpc18xx_uart_data *data;
	struct uart_8250_port uart;
	struct resource *res;
	int irq, ret;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "irq not found");
		return irq;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(&pdev->dev, "memory resource not found");
		return -EINVAL;
	}

	memset(&uart, 0, sizeof(uart));

	uart.port.membase = devm_ioremap(&pdev->dev, res->start,
					 resource_size(res));
	if (!uart.port.membase)
		return -ENOMEM;

	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->clk_uart = devm_clk_get(&pdev->dev, "uartclk");
	if (IS_ERR(data->clk_uart)) {
		dev_err(&pdev->dev, "uart clock not found\n");
		return PTR_ERR(data->clk_uart);
	}

	data->clk_reg = devm_clk_get(&pdev->dev, "reg");
	if (IS_ERR(data->clk_reg)) {
		dev_err(&pdev->dev, "reg clock not found\n");
		return PTR_ERR(data->clk_reg);
	}

	ret = clk_prepare_enable(data->clk_reg);
	if (ret) {
		dev_err(&pdev->dev, "unable to enable reg clock\n");
		return ret;
	}

	ret = clk_prepare_enable(data->clk_uart);
	if (ret) {
		dev_err(&pdev->dev, "unable to enable uart clock\n");
		goto dis_clk_reg;
	}

	ret = of_alias_get_id(pdev->dev.of_node, "serial");
	if (ret >= 0)
		uart.port.line = ret;

	data->dma.rx_param = data;
	data->dma.tx_param = data;

	spin_lock_init(&uart.port.lock);
	uart.port.dev = &pdev->dev;
	uart.port.irq = irq;
	uart.port.iotype = UPIO_MEM32;
	uart.port.mapbase = res->start;
	uart.port.regshift = 2;
	uart.port.type = PORT_16550A;
	uart.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SKIP_TEST;
	uart.port.uartclk = clk_get_rate(data->clk_uart);
	uart.port.private_data = data;
	uart.port.rs485_config = lpc18xx_rs485_config;
	uart.port.serial_out = lpc18xx_uart_serial_out;

	uart.dma = &data->dma;
	uart.dma->rxconf.src_maxburst = 1;
	uart.dma->txconf.dst_maxburst = 1;

	ret = serial8250_register_8250_port(&uart);
	if (ret < 0) {
		dev_err(&pdev->dev, "unable to register 8250 port\n");
		goto dis_uart_clk;
	}

	data->line = ret;
	platform_set_drvdata(pdev, data);

	return 0;

dis_uart_clk:
	clk_disable_unprepare(data->clk_uart);
dis_clk_reg:
	clk_disable_unprepare(data->clk_reg);
	return ret;
}

static int lpc18xx_serial_remove(struct platform_device *pdev)
{
	struct lpc18xx_uart_data *data = platform_get_drvdata(pdev);

	serial8250_unregister_port(data->line);
	clk_disable_unprepare(data->clk_uart);
	clk_disable_unprepare(data->clk_reg);

	return 0;
}

static const struct of_device_id lpc18xx_serial_match[] = {
	{ .compatible = "nxp,lpc1850-uart" },
	{ },
};
MODULE_DEVICE_TABLE(of, lpc18xx_serial_match);

static struct platform_driver lpc18xx_serial_driver = {
	.probe  = lpc18xx_serial_probe,
	.remove = lpc18xx_serial_remove,
	.driver = {
		.name = "lpc18xx-uart",
		.of_match_table = lpc18xx_serial_match,
	},
};
module_platform_driver(lpc18xx_serial_driver);

MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
MODULE_DESCRIPTION("Serial port driver NXP LPC18xx/43xx devices");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
e3b3d0f5	1	// SPDX-License-Identifier: GPL-2.0
d2aef35a JE	2	/*
	3	* Serial port driver for NXP LPC18xx/43xx UART
	4	*
	5	* Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
	6	*
	7	* Based on 8250_mtk.c:
	8	* Copyright (c) 2014 MundoReader S.L.
	9	* Matthias Brugger <matthias.bgg@gmail.com>
	10	*
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License version 2 as
	13	* published by the Free Software Foundation.
	14	*
	15	*/
	16
	17	#include <linux/clk.h>
	18	#include <linux/io.h>
	19	#include <linux/module.h>
	20	#include <linux/of.h>
	21	#include <linux/platform_device.h>
	22
	23	#include "8250.h"
	24
	25	/* Additional LPC18xx/43xx 8250 registers and bits */
	26	#define LPC18XX_UART_RS485CTRL (0x04c / sizeof(u32))
	27	#define LPC18XX_UART_RS485CTRL_NMMEN BIT(0)
	28	#define LPC18XX_UART_RS485CTRL_DCTRL BIT(4)
	29	#define LPC18XX_UART_RS485CTRL_OINV BIT(5)
	30	#define LPC18XX_UART_RS485DLY (0x054 / sizeof(u32))
	31	#define LPC18XX_UART_RS485DLY_MAX 255
	32
	33	struct lpc18xx_uart_data {
	34	struct uart_8250_dma dma;
	35	struct clk *clk_uart;
	36	struct clk *clk_reg;
	37	int line;
	38	};
	39
	40	static int lpc18xx_rs485_config(struct uart_port *port,
	41	struct serial_rs485 *rs485)
	42	{
	43	struct uart_8250_port *up = up_to_u8250p(port);
	44	u32 rs485_ctrl_reg = 0;
	45	u32 rs485_dly_reg = 0;
	46	unsigned baud_clk;
	47
	48	if (rs485->flags & SER_RS485_ENABLED)
	49	memset(rs485->padding, 0, sizeof(rs485->padding));
	50	else
	51	memset(rs485, 0, sizeof(*rs485));
	52
	53	rs485->flags &= SER_RS485_ENABLED \| SER_RS485_RTS_ON_SEND \|
	54	SER_RS485_RTS_AFTER_SEND;
	55
	56	if (rs485->flags & SER_RS485_ENABLED) {
	57	rs485_ctrl_reg \|= LPC18XX_UART_RS485CTRL_NMMEN \|
	58	LPC18XX_UART_RS485CTRL_DCTRL;
	59
	60	if (rs485->flags & SER_RS485_RTS_ON_SEND) {
	61	rs485_ctrl_reg \|= LPC18XX_UART_RS485CTRL_OINV;
	62	rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
	63	} else {
	64	rs485->flags \|= SER_RS485_RTS_AFTER_SEND;
	65	}
66	}
67
68	if (rs485->delay_rts_after_send) {
69	baud_clk = port->uartclk / up->dl_read(up);
70	rs485_dly_reg = DIV_ROUND_UP(rs485->delay_rts_after_send
71	* baud_clk, MSEC_PER_SEC);
72
73	if (rs485_dly_reg > LPC18XX_UART_RS485DLY_MAX)
74	rs485_dly_reg = LPC18XX_UART_RS485DLY_MAX;
75
76	/* Calculate the resulting delay in ms */
77	rs485->delay_rts_after_send = (rs485_dly_reg * MSEC_PER_SEC)
78	/ baud_clk;
79	}
80
81	/* Delay RTS before send not supported */
82	rs485->delay_rts_before_send = 0;
83
84	serial_out(up, LPC18XX_UART_RS485CTRL, rs485_ctrl_reg);
85	serial_out(up, LPC18XX_UART_RS485DLY, rs485_dly_reg);
86
87	port->rs485 = *rs485;
88
89	return 0;
90	}
91
92	static void lpc18xx_uart_serial_out(struct uart_port *p, int offset, int value)
93	{
94	/*
95	* For DMA mode one must ensure that the UART_FCR_DMA_SELECT
96	* bit is set when FIFO is enabled. Even if DMA is not used
97	* setting this bit doesn't seem to affect anything.
98	*/
99	if (offset == UART_FCR && (value & UART_FCR_ENABLE_FIFO))
100	value \|= UART_FCR_DMA_SELECT;
101
102	offset = offset << p->regshift;
103	writel(value, p->membase + offset);
104	}
105
106	static int lpc18xx_serial_probe(struct platform_device *pdev)
107	{
108	struct lpc18xx_uart_data *data;
109	struct uart_8250_port uart;
110	struct resource *res;
111	int irq, ret;
112
113	irq = platform_get_irq(pdev, 0);
114	if (irq < 0) {
115	dev_err(&pdev->dev, "irq not found");
116	return irq;
117	}
118
119	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
120	if (!res) {
121	dev_err(&pdev->dev, "memory resource not found");
122	return -EINVAL;
123	}
124
125	memset(&uart, 0, sizeof(uart));
126
127	uart.port.membase = devm_ioremap(&pdev->dev, res->start,
128	resource_size(res));
129	if (!uart.port.membase)
130	return -ENOMEM;
131
132	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
133	if (!data)
134	return -ENOMEM;
135
136	data->clk_uart = devm_clk_get(&pdev->dev, "uartclk");
137	if (IS_ERR(data->clk_uart)) {
138	dev_err(&pdev->dev, "uart clock not found\n");
139	return PTR_ERR(data->clk_uart);
140	}
141
142	data->clk_reg = devm_clk_get(&pdev->dev, "reg");
143	if (IS_ERR(data->clk_reg)) {
144	dev_err(&pdev->dev, "reg clock not found\n");
145	return PTR_ERR(data->clk_reg);
146	}
147
148	ret = clk_prepare_enable(data->clk_reg);
149	if (ret) {
150	dev_err(&pdev->dev, "unable to enable reg clock\n");
151	return ret;
152	}
153
154	ret = clk_prepare_enable(data->clk_uart);
155	if (ret) {
156	dev_err(&pdev->dev, "unable to enable uart clock\n");
157	goto dis_clk_reg;
158	}
159
160	ret = of_alias_get_id(pdev->dev.of_node, "serial");
161	if (ret >= 0)
162	uart.port.line = ret;
163
164	data->dma.rx_param = data;
165	data->dma.tx_param = data;
166
167	spin_lock_init(&uart.port.lock);
168	uart.port.dev = &pdev->dev;
169	uart.port.irq = irq;
170	uart.port.iotype = UPIO_MEM32;
171	uart.port.mapbase = res->start;
172	uart.port.regshift = 2;
173	uart.port.type = PORT_16550A;
174	uart.port.flags = UPF_FIXED_PORT \| UPF_FIXED_TYPE \| UPF_SKIP_TEST;
175	uart.port.uartclk = clk_get_rate(data->clk_uart);
176	uart.port.private_data = data;
177	uart.port.rs485_config = lpc18xx_rs485_config;
178	uart.port.serial_out = lpc18xx_uart_serial_out;
179
180	uart.dma = &data->dma;
181	uart.dma->rxconf.src_maxburst = 1;
182	uart.dma->txconf.dst_maxburst = 1;
183
184	ret = serial8250_register_8250_port(&uart);
185	if (ret < 0) {
186	dev_err(&pdev->dev, "unable to register 8250 port\n");
187	goto dis_uart_clk;
188	}
189
190	data->line = ret;
191	platform_set_drvdata(pdev, data);
192
193	return 0;
194
195	dis_uart_clk:
196	clk_disable_unprepare(data->clk_uart);
197	dis_clk_reg:
198	clk_disable_unprepare(data->clk_reg);
199	return ret;
200	}
201
202	static int lpc18xx_serial_remove(struct platform_device *pdev)
203	{
204	struct lpc18xx_uart_data *data = platform_get_drvdata(pdev);
205
206	serial8250_unregister_port(data->line);
207	clk_disable_unprepare(data->clk_uart);
208	clk_disable_unprepare(data->clk_reg);
209
210	return 0;
211	}
212
213	static const struct of_device_id lpc18xx_serial_match[] = {
214	{ .compatible = "nxp,lpc1850-uart" },
215	{ },
216	};
217	MODULE_DEVICE_TABLE(of, lpc18xx_serial_match);
218
219	static struct platform_driver lpc18xx_serial_driver = {
220	.probe = lpc18xx_serial_probe,
221	.remove = lpc18xx_serial_remove,
222	.driver = {
223	.name = "lpc18xx-uart",
224	.of_match_table = lpc18xx_serial_match,
225	},
226	};
227	module_platform_driver(lpc18xx_serial_driver);
228
229	MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
230	MODULE_DESCRIPTION("Serial port driver NXP LPC18xx/43xx devices");
231	MODULE_LICENSE("GPL v2");