diff options
author | Anton Vorontsov <cbouatmailru@gmail.com> | 2010-10-27 15:33:15 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-27 18:03:06 -0700 |
commit | aeec56e331c6d2750de02ef34b305338305ca690 (patch) | |
tree | 1a9df159e4408cf1f4d9ab8451ae803de6007126 /drivers | |
parent | d0f744c8cbd19a8d07eccb15bb08e6a29c4d5192 (diff) | |
download | op-kernel-dev-aeec56e331c6d2750de02ef34b305338305ca690.zip op-kernel-dev-aeec56e331c6d2750de02ef34b305338305ca690.tar.gz |
gpio: add driver for basic memory-mapped GPIO controllers
The basic GPIO controllers may be found in various on-board FPGA and ASIC
solutions that are used to control board's switches, LEDs, chip-selects,
Ethernet/USB PHY power, etc.
These controllers may not provide any means of pin setup
(in/out/open drain).
The driver supports:
- 8/16/32/64 bits registers;
- GPIO controllers with clear/set registers;
- GPIO controllers with a single "data" register;
- Big endian bits/GPIOs ordering (mostly used on PowerPC).
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Samuel Ortiz <sameo@linux.intel.com>,
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/gpio/Kconfig | 5 | ||||
-rw-r--r-- | drivers/gpio/Makefile | 1 | ||||
-rw-r--r-- | drivers/gpio/basic_mmio_gpio.c | 297 |
3 files changed, 303 insertions, 0 deletions
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 510aa20..e47ef94 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -70,6 +70,11 @@ config GPIO_MAX730X comment "Memory mapped GPIO expanders:" +config GPIO_BASIC_MMIO + tristate "Basic memory-mapped GPIO controllers support" + help + Say yes here to support basic memory-mapped GPIO controllers. + config GPIO_IT8761E tristate "IT8761E GPIO support" depends on GPIOLIB diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index fc6019d..3ff0651 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -10,6 +10,7 @@ obj-$(CONFIG_GPIOLIB) += gpiolib.o obj-$(CONFIG_GPIO_ADP5520) += adp5520-gpio.o obj-$(CONFIG_GPIO_ADP5588) += adp5588-gpio.o +obj-$(CONFIG_GPIO_BASIC_MMIO) += basic_mmio_gpio.o obj-$(CONFIG_GPIO_LANGWELL) += langwell_gpio.o obj-$(CONFIG_GPIO_MAX730X) += max730x.o obj-$(CONFIG_GPIO_MAX7300) += max7300.o diff --git a/drivers/gpio/basic_mmio_gpio.c b/drivers/gpio/basic_mmio_gpio.c new file mode 100644 index 0000000..3addea6 --- /dev/null +++ b/drivers/gpio/basic_mmio_gpio.c @@ -0,0 +1,297 @@ +/* + * Driver for basic memory-mapped GPIO controllers. + * + * Copyright 2008 MontaVista Software, Inc. + * Copyright 2008,2010 Anton Vorontsov <cbouatmailru@gmail.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * ....``.```~~~~````.`.`.`.`.```````'',,,.........`````......`....... + * ...`` ```````.. + * ..The simplest form of a GPIO controller that the driver supports is`` + * `.just a single "data" register, where GPIO state can be read and/or ` + * `,..written. ,,..``~~~~ .....``.`.`.~~.```.`.........``````.``````` + * ````````` + ___ +_/~~|___/~| . ```~~~~~~ ___/___\___ ,~.`.`.`.`````.~~...,,,,... +__________|~$@~~~ %~ /o*o*o*o*o*o\ .. Implementing such a GPIO . +o ` ~~~~\___/~~~~ ` controller in FPGA is ,.` + `....trivial..'~`.```.``` + * ``````` + * .```````~~~~`..`.``.``. + * . The driver supports `... ,..```.`~~~```````````````....````.``,, + * . big-endian notation, just`. .. A bit more sophisticated controllers , + * . register the device with -be`. .with a pair of set/clear-bit registers , + * `.. suffix. ```~~`````....`.` . affecting the data register and the .` + * ``.`.``...``` ```.. output pins are also supported.` + * ^^ `````.`````````.,``~``~``~~`````` + * . ^^ + * ,..`.`.`...````````````......`.`.`.`.`.`..`.`.`.. + * .. The expectation is that in at least some cases . ,-~~~-, + * .this will be used with roll-your-own ASIC/FPGA .` \ / + * .logic in Verilog or VHDL. ~~~`````````..`````~~` \ / + * ..````````......``````````` \o_ + * | + * ^^ / \ + * + * ...`````~~`.....``.`..........``````.`.``.```........``. + * ` 8, 16, 32 and 64 bits registers are supported, and``. + * . the number of GPIOs is determined by the width of ~ + * .. the registers. ,............```.`.`..`.`.~~~.`.`.`~ + * `.......````.``` + */ + +#include <linux/init.h> +#include <linux/bug.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/spinlock.h> +#include <linux/compiler.h> +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/log2.h> +#include <linux/ioport.h> +#include <linux/io.h> +#include <linux/gpio.h> +#include <linux/slab.h> +#include <linux/platform_device.h> +#include <linux/mod_devicetable.h> +#include <linux/basic_mmio_gpio.h> + +struct bgpio_chip { + struct gpio_chip gc; + void __iomem *reg_dat; + void __iomem *reg_set; + void __iomem *reg_clr; + + /* Number of bits (GPIOs): <register width> * 8. */ + int bits; + + /* + * Some GPIO controllers work with the big-endian bits notation, + * e.g. in a 8-bits register, GPIO7 is the least significant bit. + */ + int big_endian_bits; + + /* + * Used to lock bgpio_chip->data. Also, this is needed to keep + * shadowed and real data registers writes together. + */ + spinlock_t lock; + + /* Shadowed data register to clear/set bits safely. */ + unsigned long data; +}; + +static struct bgpio_chip *to_bgpio_chip(struct gpio_chip *gc) +{ + return container_of(gc, struct bgpio_chip, gc); +} + +static unsigned long bgpio_in(struct bgpio_chip *bgc) +{ + switch (bgc->bits) { + case 8: + return __raw_readb(bgc->reg_dat); + case 16: + return __raw_readw(bgc->reg_dat); + case 32: + return __raw_readl(bgc->reg_dat); +#if BITS_PER_LONG >= 64 + case 64: + return __raw_readq(bgc->reg_dat); +#endif + } + return -EINVAL; +} + +static void bgpio_out(struct bgpio_chip *bgc, void __iomem *reg, + unsigned long data) +{ + switch (bgc->bits) { + case 8: + __raw_writeb(data, reg); + return; + case 16: + __raw_writew(data, reg); + return; + case 32: + __raw_writel(data, reg); + return; +#if BITS_PER_LONG >= 64 + case 64: + __raw_writeq(data, reg); + return; +#endif + } +} + +static unsigned long bgpio_pin2mask(struct bgpio_chip *bgc, unsigned int pin) +{ + if (bgc->big_endian_bits) + return 1 << (bgc->bits - 1 - pin); + else + return 1 << pin; +} + +static int bgpio_get(struct gpio_chip *gc, unsigned int gpio) +{ + struct bgpio_chip *bgc = to_bgpio_chip(gc); + + return bgpio_in(bgc) & bgpio_pin2mask(bgc, gpio); +} + +static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val) +{ + struct bgpio_chip *bgc = to_bgpio_chip(gc); + unsigned long mask = bgpio_pin2mask(bgc, gpio); + unsigned long flags; + + if (bgc->reg_set) { + if (val) + bgpio_out(bgc, bgc->reg_set, mask); + else + bgpio_out(bgc, bgc->reg_clr, mask); + return; + } + + spin_lock_irqsave(&bgc->lock, flags); + + if (val) + bgc->data |= mask; + else + bgc->data &= ~mask; + + bgpio_out(bgc, bgc->reg_dat, bgc->data); + + spin_unlock_irqrestore(&bgc->lock, flags); +} + +static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio) +{ + return 0; +} + +static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) +{ + bgpio_set(gc, gpio, val); + return 0; +} + +static int __devinit bgpio_probe(struct platform_device *pdev) +{ + const struct platform_device_id *platid = platform_get_device_id(pdev); + struct device *dev = &pdev->dev; + struct bgpio_pdata *pdata = dev_get_platdata(dev); + struct bgpio_chip *bgc; + struct resource *res_dat; + struct resource *res_set; + struct resource *res_clr; + resource_size_t dat_sz; + int bits; + int ret; + + res_dat = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat"); + if (!res_dat) + return -EINVAL; + + dat_sz = resource_size(res_dat); + if (!is_power_of_2(dat_sz)) + return -EINVAL; + + bits = dat_sz * 8; + if (bits > BITS_PER_LONG) + return -EINVAL; + + bgc = devm_kzalloc(dev, sizeof(*bgc), GFP_KERNEL); + if (!bgc) + return -ENOMEM; + + bgc->reg_dat = devm_ioremap(dev, res_dat->start, dat_sz); + if (!bgc->reg_dat) + return -ENOMEM; + + res_set = platform_get_resource_byname(pdev, IORESOURCE_MEM, "set"); + res_clr = platform_get_resource_byname(pdev, IORESOURCE_MEM, "clr"); + if (res_set && res_clr) { + if (resource_size(res_set) != resource_size(res_clr) || + resource_size(res_set) != dat_sz) + return -EINVAL; + + bgc->reg_set = devm_ioremap(dev, res_set->start, dat_sz); + bgc->reg_clr = devm_ioremap(dev, res_clr->start, dat_sz); + if (!bgc->reg_set || !bgc->reg_clr) + return -ENOMEM; + } else if (res_set || res_clr) { + return -EINVAL; + } + + spin_lock_init(&bgc->lock); + + bgc->bits = bits; + bgc->big_endian_bits = !strcmp(platid->name, "basic-mmio-gpio-be"); + bgc->data = bgpio_in(bgc); + + bgc->gc.ngpio = bits; + bgc->gc.direction_input = bgpio_dir_in; + bgc->gc.direction_output = bgpio_dir_out; + bgc->gc.get = bgpio_get; + bgc->gc.set = bgpio_set; + bgc->gc.dev = dev; + bgc->gc.label = dev_name(dev); + + if (pdata) + bgc->gc.base = pdata->base; + else + bgc->gc.base = -1; + + dev_set_drvdata(dev, bgc); + + ret = gpiochip_add(&bgc->gc); + if (ret) + dev_err(dev, "gpiochip_add() failed: %d\n", ret); + + return ret; +} + +static int __devexit bgpio_remove(struct platform_device *pdev) +{ + struct bgpio_chip *bgc = dev_get_drvdata(&pdev->dev); + + return gpiochip_remove(&bgc->gc); +} + +static const struct platform_device_id bgpio_id_table[] = { + { "basic-mmio-gpio", }, + { "basic-mmio-gpio-be", }, + {}, +}; +MODULE_DEVICE_TABLE(platform, bgpio_id_table); + +static struct platform_driver bgpio_driver = { + .driver = { + .name = "basic-mmio-gpio", + }, + .id_table = bgpio_id_table, + .probe = bgpio_probe, + .remove = __devexit_p(bgpio_remove), +}; + +static int __init bgpio_init(void) +{ + return platform_driver_register(&bgpio_driver); +} +module_init(bgpio_init); + +static void __exit bgpio_exit(void) +{ + platform_driver_unregister(&bgpio_driver); +} +module_exit(bgpio_exit); + +MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers"); +MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>"); +MODULE_LICENSE("GPL"); |