2 * MC33880 high-side/low-side switch GPIO driver
3 * Copyright (c) 2009 Intel Corporation
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 * Freescale MC33880 high-side/low-side switch
23 #include <linux/init.h>
24 #include <linux/mutex.h>
25 #include <linux/spi/spi.h>
26 #include <linux/spi/mc33880.h>
27 #include <linux/gpio.h>
28 #include <linux/slab.h>
29 #include <linux/module.h>
31 #define DRIVER_NAME "mc33880"
34 * Pin configurations, see MAX7301 datasheet page 6
36 #define PIN_CONFIG_MASK 0x03
37 #define PIN_CONFIG_IN_PULLUP 0x03
38 #define PIN_CONFIG_IN_WO_PULLUP 0x02
39 #define PIN_CONFIG_OUT 0x01
45 * Some registers must be read back to modify.
46 * To save time we cache them here in memory
49 struct mutex lock
; /* protect from simultaneous accesses */
51 struct gpio_chip chip
;
52 struct spi_device
*spi
;
55 static int mc33880_write_config(struct mc33880
*mc
)
57 return spi_write(mc
->spi
, &mc
->port_config
, sizeof(mc
->port_config
));
61 static int __mc33880_set(struct mc33880
*mc
, unsigned offset
, int value
)
64 mc
->port_config
|= 1 << offset
;
66 mc
->port_config
&= ~(1 << offset
);
68 return mc33880_write_config(mc
);
72 static void mc33880_set(struct gpio_chip
*chip
, unsigned offset
, int value
)
74 struct mc33880
*mc
= container_of(chip
, struct mc33880
, chip
);
76 mutex_lock(&mc
->lock
);
78 __mc33880_set(mc
, offset
, value
);
80 mutex_unlock(&mc
->lock
);
83 static int mc33880_probe(struct spi_device
*spi
)
86 struct mc33880_platform_data
*pdata
;
89 pdata
= dev_get_platdata(&spi
->dev
);
90 if (!pdata
|| !pdata
->base
) {
91 dev_dbg(&spi
->dev
, "incorrect or missing platform data\n");
96 * bits_per_word cannot be configured in platform data
98 spi
->bits_per_word
= 8;
100 ret
= spi_setup(spi
);
104 mc
= devm_kzalloc(&spi
->dev
, sizeof(struct mc33880
), GFP_KERNEL
);
108 mutex_init(&mc
->lock
);
110 spi_set_drvdata(spi
, mc
);
114 mc
->chip
.label
= DRIVER_NAME
,
115 mc
->chip
.set
= mc33880_set
;
116 mc
->chip
.base
= pdata
->base
;
117 mc
->chip
.ngpio
= PIN_NUMBER
;
118 mc
->chip
.can_sleep
= 1;
119 mc
->chip
.dev
= &spi
->dev
;
120 mc
->chip
.owner
= THIS_MODULE
;
122 mc
->port_config
= 0x00;
123 /* write twice, because during initialisation the first setting
124 * is just for testing SPI communication, and the second is the
125 * "real" configuration
127 ret
= mc33880_write_config(mc
);
128 mc
->port_config
= 0x00;
130 ret
= mc33880_write_config(mc
);
133 dev_err(&spi
->dev
, "Failed writing to " DRIVER_NAME
": %d\n",
138 ret
= gpiochip_add(&mc
->chip
);
145 spi_set_drvdata(spi
, NULL
);
146 mutex_destroy(&mc
->lock
);
150 static int mc33880_remove(struct spi_device
*spi
)
155 mc
= spi_get_drvdata(spi
);
159 spi_set_drvdata(spi
, NULL
);
161 ret
= gpiochip_remove(&mc
->chip
);
163 mutex_destroy(&mc
->lock
);
165 dev_err(&spi
->dev
, "Failed to remove the GPIO controller: %d\n",
171 static struct spi_driver mc33880_driver
= {
174 .owner
= THIS_MODULE
,
176 .probe
= mc33880_probe
,
177 .remove
= mc33880_remove
,
180 static int __init
mc33880_init(void)
182 return spi_register_driver(&mc33880_driver
);
184 /* register after spi postcore initcall and before
185 * subsys initcalls that may rely on these GPIOs
187 subsys_initcall(mc33880_init
);
189 static void __exit
mc33880_exit(void)
191 spi_unregister_driver(&mc33880_driver
);
193 module_exit(mc33880_exit
);
195 MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
196 MODULE_LICENSE("GPL v2");