2 * Helpers for controlling modem lines via GPIO
4 * Copyright (C) 2014 Paratronic S.A.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
17 #include <linux/err.h>
18 #include <linux/device.h>
19 #include <linux/irq.h>
20 #include <linux/gpio/consumer.h>
21 #include <linux/termios.h>
22 #include <linux/serial_core.h>
24 #include "serial_mctrl_gpio.h"
27 struct uart_port
*port
;
28 struct gpio_desc
*gpio
[UART_GPIO_MAX
];
29 int irq
[UART_GPIO_MAX
];
30 unsigned int mctrl_prev
;
38 } mctrl_gpios_desc
[UART_GPIO_MAX
] = {
39 { "cts", TIOCM_CTS
, false, },
40 { "dsr", TIOCM_DSR
, false, },
41 { "dcd", TIOCM_CD
, false, },
42 { "rng", TIOCM_RNG
, false, },
43 { "rts", TIOCM_RTS
, true, },
44 { "dtr", TIOCM_DTR
, true, },
45 { "out1", TIOCM_OUT1
, true, },
46 { "out2", TIOCM_OUT2
, true, },
49 void mctrl_gpio_set(struct mctrl_gpios
*gpios
, unsigned int mctrl
)
51 enum mctrl_gpio_idx i
;
52 struct gpio_desc
*desc_array
[UART_GPIO_MAX
];
53 int value_array
[UART_GPIO_MAX
];
54 unsigned int count
= 0;
56 for (i
= 0; i
< UART_GPIO_MAX
; i
++)
57 if (gpios
->gpio
[i
] && mctrl_gpios_desc
[i
].dir_out
) {
58 desc_array
[count
] = gpios
->gpio
[i
];
59 value_array
[count
] = !!(mctrl
& mctrl_gpios_desc
[i
].mctrl
);
62 gpiod_set_array_value(count
, desc_array
, value_array
);
64 EXPORT_SYMBOL_GPL(mctrl_gpio_set
);
66 struct gpio_desc
*mctrl_gpio_to_gpiod(struct mctrl_gpios
*gpios
,
67 enum mctrl_gpio_idx gidx
)
69 return gpios
->gpio
[gidx
];
71 EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod
);
73 unsigned int mctrl_gpio_get(struct mctrl_gpios
*gpios
, unsigned int *mctrl
)
75 enum mctrl_gpio_idx i
;
77 for (i
= 0; i
< UART_GPIO_MAX
; i
++) {
78 if (gpios
->gpio
[i
] && !mctrl_gpios_desc
[i
].dir_out
) {
79 if (gpiod_get_value(gpios
->gpio
[i
]))
80 *mctrl
|= mctrl_gpios_desc
[i
].mctrl
;
82 *mctrl
&= ~mctrl_gpios_desc
[i
].mctrl
;
88 EXPORT_SYMBOL_GPL(mctrl_gpio_get
);
90 struct mctrl_gpios
*mctrl_gpio_init_noauto(struct device
*dev
, unsigned int idx
)
92 struct mctrl_gpios
*gpios
;
93 enum mctrl_gpio_idx i
;
95 gpios
= devm_kzalloc(dev
, sizeof(*gpios
), GFP_KERNEL
);
97 return ERR_PTR(-ENOMEM
);
99 for (i
= 0; i
< UART_GPIO_MAX
; i
++) {
100 enum gpiod_flags flags
;
102 if (mctrl_gpios_desc
[i
].dir_out
)
103 flags
= GPIOD_OUT_LOW
;
108 devm_gpiod_get_index_optional(dev
,
109 mctrl_gpios_desc
[i
].name
,
112 if (IS_ERR(gpios
->gpio
[i
]))
113 return ERR_CAST(gpios
->gpio
[i
]);
118 EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto
);
120 #define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
121 static irqreturn_t
mctrl_gpio_irq_handle(int irq
, void *context
)
123 struct mctrl_gpios
*gpios
= context
;
124 struct uart_port
*port
= gpios
->port
;
125 u32 mctrl
= gpios
->mctrl_prev
;
128 mctrl_gpio_get(gpios
, &mctrl
);
130 mctrl_diff
= mctrl
^ gpios
->mctrl_prev
;
131 gpios
->mctrl_prev
= mctrl
;
133 if (mctrl_diff
& MCTRL_ANY_DELTA
&& port
->state
!= NULL
) {
134 if ((mctrl_diff
& mctrl
) & TIOCM_RI
)
137 if ((mctrl_diff
& mctrl
) & TIOCM_DSR
)
140 if (mctrl_diff
& TIOCM_CD
)
141 uart_handle_dcd_change(port
, mctrl
& TIOCM_CD
);
143 if (mctrl_diff
& TIOCM_CTS
)
144 uart_handle_cts_change(port
, mctrl
& TIOCM_CTS
);
146 wake_up_interruptible(&port
->state
->port
.delta_msr_wait
);
152 struct mctrl_gpios
*mctrl_gpio_init(struct uart_port
*port
, unsigned int idx
)
154 struct mctrl_gpios
*gpios
;
155 enum mctrl_gpio_idx i
;
157 gpios
= mctrl_gpio_init_noauto(port
->dev
, idx
);
163 for (i
= 0; i
< UART_GPIO_MAX
; ++i
) {
166 if (!gpios
->gpio
[i
] || mctrl_gpios_desc
[i
].dir_out
)
169 ret
= gpiod_to_irq(gpios
->gpio
[i
]);
172 "failed to find corresponding irq for %s (idx=%d, err=%d)\n",
173 mctrl_gpios_desc
[i
].name
, idx
, ret
);
178 /* irqs should only be enabled in .enable_ms */
179 irq_set_status_flags(gpios
->irq
[i
], IRQ_NOAUTOEN
);
181 ret
= devm_request_irq(port
->dev
, gpios
->irq
[i
],
182 mctrl_gpio_irq_handle
,
183 IRQ_TYPE_EDGE_BOTH
, dev_name(port
->dev
),
186 /* alternatively implement polling */
188 "failed to request irq for %s (idx=%d, err=%d)\n",
189 mctrl_gpios_desc
[i
].name
, idx
, ret
);
196 EXPORT_SYMBOL_GPL(mctrl_gpio_init
);
198 void mctrl_gpio_free(struct device
*dev
, struct mctrl_gpios
*gpios
)
200 enum mctrl_gpio_idx i
;
202 for (i
= 0; i
< UART_GPIO_MAX
; i
++) {
204 devm_free_irq(gpios
->port
->dev
, gpios
->irq
[i
], gpios
);
207 devm_gpiod_put(dev
, gpios
->gpio
[i
]);
209 devm_kfree(dev
, gpios
);
211 EXPORT_SYMBOL_GPL(mctrl_gpio_free
);
213 void mctrl_gpio_enable_ms(struct mctrl_gpios
*gpios
)
215 enum mctrl_gpio_idx i
;
217 /* .enable_ms may be called multiple times */
221 gpios
->mctrl_on
= true;
223 /* get initial status of modem lines GPIOs */
224 mctrl_gpio_get(gpios
, &gpios
->mctrl_prev
);
226 for (i
= 0; i
< UART_GPIO_MAX
; ++i
) {
230 enable_irq(gpios
->irq
[i
]);
233 EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms
);
235 void mctrl_gpio_disable_ms(struct mctrl_gpios
*gpios
)
237 enum mctrl_gpio_idx i
;
239 if (!gpios
->mctrl_on
)
242 gpios
->mctrl_on
= false;
244 for (i
= 0; i
< UART_GPIO_MAX
; ++i
) {
248 disable_irq(gpios
->irq
[i
]);
251 EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms
);
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