diff options
Diffstat (limited to 'drivers/gpio/max7301.c')
| -rw-r--r-- | drivers/gpio/max7301.c | 293 |
1 files changed, 34 insertions, 259 deletions
diff --git a/drivers/gpio/max7301.c b/drivers/gpio/max7301.c index 480956f1ca5..965d9b1ea13 100644 --- a/drivers/gpio/max7301.c +++ b/drivers/gpio/max7301.c @@ -1,98 +1,41 @@ -/** +/* * drivers/gpio/max7301.c * * Copyright (C) 2006 Juergen Beisert, Pengutronix * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix + * Copyright (C) 2009 Wolfram Sang, Pengutronix * * 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. * - * The Maxim's MAX7301 device is an SPI driven GPIO expander. There are - * 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more - * details - * Note: - * - DIN must be stable at the rising edge of clock. - * - when writing: - * - always clock in 16 clocks at once - * - at DIN: D15 first, D0 last - * - D0..D7 = databyte, D8..D14 = commandbyte - * - D15 = low -> write command - * - when reading - * - always clock in 16 clocks at once - * - at DIN: D15 first, D0 last - * - D0..D7 = dummy, D8..D14 = register address - * - D15 = high -> read command - * - raise CS and assert it again - * - always clock in 16 clocks at once - * - at DOUT: D15 first, D0 last - * - D0..D7 contains the data from the first cycle - * - * The driver exports a standard gpiochip interface + * Check max730x.c for further details. */ +#include <linux/module.h> #include <linux/init.h> #include <linux/platform_device.h> #include <linux/mutex.h> #include <linux/spi/spi.h> #include <linux/spi/max7301.h> -#include <linux/gpio.h> - -#define DRIVER_NAME "max7301" - -/* - * Pin configurations, see MAX7301 datasheet page 6 - */ -#define PIN_CONFIG_MASK 0x03 -#define PIN_CONFIG_IN_PULLUP 0x03 -#define PIN_CONFIG_IN_WO_PULLUP 0x02 -#define PIN_CONFIG_OUT 0x01 - -#define PIN_NUMBER 28 - - -/* - * Some registers must be read back to modify. - * To save time we cache them here in memory - */ -struct max7301 { - struct mutex lock; - u8 port_config[8]; /* field 0 is unused */ - u32 out_level; /* cached output levels */ - struct gpio_chip chip; - struct spi_device *spi; -}; -/** - * max7301_write - Write a new register content - * @spi: The SPI device - * @reg: Register offset - * @val: Value to write - * - * A write to the MAX7301 means one message with one transfer - * - * Returns 0 if successful or a negative value on error - */ -static int max7301_write(struct spi_device *spi, unsigned int reg, unsigned int val) +/* A write to the MAX7301 means one message with one transfer */ +static int max7301_spi_write(struct device *dev, unsigned int reg, + unsigned int val) { + struct spi_device *spi = to_spi_device(dev); u16 word = ((reg & 0x7F) << 8) | (val & 0xFF); + return spi_write(spi, (const u8 *)&word, sizeof(word)); } -/** - * max7301_read - Read back register content - * @spi: The SPI device - * @reg: Register offset - * - * A read from the MAX7301 means two transfers; here, one message each - * - * Returns positive 8 bit value from device if successful or a - * negative value on error - */ -static int max7301_read(struct spi_device *spi, unsigned int reg) +/* A read from the MAX7301 means two transfers; here, one message each */ + +static int max7301_spi_read(struct device *dev, unsigned int reg) { int ret; u16 word; + struct spi_device *spi = to_spi_device(dev); word = 0x8000 | (reg << 8); ret = spi_write(spi, (const u8 *)&word, sizeof(word)); @@ -108,125 +51,13 @@ static int max7301_read(struct spi_device *spi, unsigned int reg) return word & 0xff; } -static int max7301_direction_input(struct gpio_chip *chip, unsigned offset) -{ - struct max7301 *ts = container_of(chip, struct max7301, chip); - u8 *config; - int ret; - - /* First 4 pins are unused in the controller */ - offset += 4; - - config = &ts->port_config[offset >> 2]; - - mutex_lock(&ts->lock); - - /* Standard GPIO API doesn't support pull-ups, has to be extended. - * Hard-coding no pollup for now. */ - *config = (*config & ~(3 << (offset & 3))) | (1 << (offset & 3)); - - ret = max7301_write(ts->spi, 0x08 + (offset >> 2), *config); - - mutex_unlock(&ts->lock); - - return ret; -} - -static int __max7301_set(struct max7301 *ts, unsigned offset, int value) -{ - if (value) { - ts->out_level |= 1 << offset; - return max7301_write(ts->spi, 0x20 + offset, 0x01); - } else { - ts->out_level &= ~(1 << offset); - return max7301_write(ts->spi, 0x20 + offset, 0x00); - } -} - -static int max7301_direction_output(struct gpio_chip *chip, unsigned offset, - int value) -{ - struct max7301 *ts = container_of(chip, struct max7301, chip); - u8 *config; - int ret; - - /* First 4 pins are unused in the controller */ - offset += 4; - - config = &ts->port_config[offset >> 2]; - - mutex_lock(&ts->lock); - - *config = (*config & ~(3 << (offset & 3))) | (1 << (offset & 3)); - - ret = __max7301_set(ts, offset, value); - - if (!ret) - ret = max7301_write(ts->spi, 0x08 + (offset >> 2), *config); - - mutex_unlock(&ts->lock); - - return ret; -} - -static int max7301_get(struct gpio_chip *chip, unsigned offset) -{ - struct max7301 *ts = container_of(chip, struct max7301, chip); - int config, level = -EINVAL; - - /* First 4 pins are unused in the controller */ - offset += 4; - - mutex_lock(&ts->lock); - - config = (ts->port_config[offset >> 2] >> ((offset & 3) * 2)) & 3; - - switch (config) { - case 1: - /* Output: return cached level */ - level = !!(ts->out_level & (1 << offset)); - break; - case 2: - case 3: - /* Input: read out */ - level = max7301_read(ts->spi, 0x20 + offset) & 0x01; - } - mutex_unlock(&ts->lock); - - return level; -} - -static void max7301_set(struct gpio_chip *chip, unsigned offset, int value) -{ - struct max7301 *ts = container_of(chip, struct max7301, chip); - - /* First 4 pins are unused in the controller */ - offset += 4; - - mutex_lock(&ts->lock); - - __max7301_set(ts, offset, value); - - mutex_unlock(&ts->lock); -} - static int __devinit max7301_probe(struct spi_device *spi) { struct max7301 *ts; - struct max7301_platform_data *pdata; - int i, ret; - - pdata = spi->dev.platform_data; - if (!pdata || !pdata->base) { - dev_dbg(&spi->dev, "incorrect or missing platform data\n"); - return -EINVAL; - } + int ret; - /* - * bits_per_word cannot be configured in platform data - */ + /* bits_per_word cannot be configured in platform data */ spi->bits_per_word = 16; - ret = spi_setup(spi); if (ret < 0) return ret; @@ -235,90 +66,35 @@ static int __devinit max7301_probe(struct spi_device *spi) if (!ts) return -ENOMEM; - mutex_init(&ts->lock); - - dev_set_drvdata(&spi->dev, ts); + ts->read = max7301_spi_read; + ts->write = max7301_spi_write; + ts->dev = &spi->dev; - /* Power up the chip and disable IRQ output */ - max7301_write(spi, 0x04, 0x01); - - ts->spi = spi; - - ts->chip.label = DRIVER_NAME, - - ts->chip.direction_input = max7301_direction_input; - ts->chip.get = max7301_get; - ts->chip.direction_output = max7301_direction_output; - ts->chip.set = max7301_set; - - ts->chip.base = pdata->base; - ts->chip.ngpio = PIN_NUMBER; - ts->chip.can_sleep = 1; - ts->chip.dev = &spi->dev; - ts->chip.owner = THIS_MODULE; - - /* - * tristate all pins in hardware and cache the - * register values for later use. - */ - for (i = 1; i < 8; i++) { - int j; - /* 0xAA means input with internal pullup disabled */ - max7301_write(spi, 0x08 + i, 0xAA); - ts->port_config[i] = 0xAA; - for (j = 0; j < 4; j++) { - int offset = (i - 1) * 4 + j; - ret = max7301_direction_input(&ts->chip, offset); - if (ret) - goto exit_destroy; - } - } - - ret = gpiochip_add(&ts->chip); + ret = __max730x_probe(ts); if (ret) - goto exit_destroy; - - return ret; - -exit_destroy: - dev_set_drvdata(&spi->dev, NULL); - mutex_destroy(&ts->lock); - kfree(ts); + kfree(ts); return ret; } static int __devexit max7301_remove(struct spi_device *spi) { - struct max7301 *ts; - int ret; - - ts = dev_get_drvdata(&spi->dev); - if (ts == NULL) - return -ENODEV; - - dev_set_drvdata(&spi->dev, NULL); - - /* Power down the chip and disable IRQ output */ - max7301_write(spi, 0x04, 0x00); - - ret = gpiochip_remove(&ts->chip); - if (!ret) { - mutex_destroy(&ts->lock); - kfree(ts); - } else - dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n", - ret); - - return ret; + return __max730x_remove(&spi->dev); } +static const struct spi_device_id max7301_id[] = { + { "max7301", 0 }, + { } +}; +MODULE_DEVICE_TABLE(spi, max7301_id); + static struct spi_driver max7301_driver = { .driver = { - .name = DRIVER_NAME, - .owner = THIS_MODULE, + .name = "max7301", + .owner = THIS_MODULE, }, - .probe = max7301_probe, - .remove = __devexit_p(max7301_remove), + .probe = max7301_probe, + .remove = __devexit_p(max7301_remove), + .id_table = max7301_id, }; static int __init max7301_init(void) @@ -336,7 +112,6 @@ static void __exit max7301_exit(void) } module_exit(max7301_exit); -MODULE_AUTHOR("Juergen Beisert"); +MODULE_AUTHOR("Juergen Beisert, Wolfram Sang"); MODULE_LICENSE("GPL v2"); -MODULE_DESCRIPTION("MAX7301 SPI based GPIO-Expander"); -MODULE_ALIAS("spi:" DRIVER_NAME); +MODULE_DESCRIPTION("MAX7301 GPIO-Expander"); |