549 lines
13 KiB
C
549 lines
13 KiB
C
/*
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* Generic driver for memory-mapped GPIO controllers.
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*
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* Copyright 2008 MontaVista Software, Inc.
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* Copyright 2008,2010 Anton Vorontsov <cbouatmailru@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* ....``.```~~~~````.`.`.`.`.```````'',,,.........`````......`.......
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* ...`` ```````..
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* ..The simplest form of a GPIO controller that the driver supports is``
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* `.just a single "data" register, where GPIO state can be read and/or `
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* `,..written. ,,..``~~~~ .....``.`.`.~~.```.`.........``````.```````
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* `````````
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___
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_/~~|___/~| . ```~~~~~~ ___/___\___ ,~.`.`.`.`````.~~...,,,,...
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__________|~$@~~~ %~ /o*o*o*o*o*o\ .. Implementing such a GPIO .
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o ` ~~~~\___/~~~~ ` controller in FPGA is ,.`
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`....trivial..'~`.```.```
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* ```````
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* .```````~~~~`..`.``.``.
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* . The driver supports `... ,..```.`~~~```````````````....````.``,,
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* . big-endian notation, just`. .. A bit more sophisticated controllers ,
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* . register the device with -be`. .with a pair of set/clear-bit registers ,
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* `.. suffix. ```~~`````....`.` . affecting the data register and the .`
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* ``.`.``...``` ```.. output pins are also supported.`
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* ^^ `````.`````````.,``~``~``~~``````
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* . ^^
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* ,..`.`.`...````````````......`.`.`.`.`.`..`.`.`..
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* .. The expectation is that in at least some cases . ,-~~~-,
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* .this will be used with roll-your-own ASIC/FPGA .` \ /
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* .logic in Verilog or VHDL. ~~~`````````..`````~~` \ /
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* ..````````......``````````` \o_
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* |
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* ^^ / \
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*
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* ...`````~~`.....``.`..........``````.`.``.```........``.
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* ` 8, 16, 32 and 64 bits registers are supported, and``.
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* . the number of GPIOs is determined by the width of ~
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* .. the registers. ,............```.`.`..`.`.~~~.`.`.`~
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* `.......````.```
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*/
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/bug.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/log2.h>
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#include <linux/ioport.h>
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#include <linux/io.h>
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#include <linux/gpio.h>
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#include <linux/slab.h>
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#include <linux/platform_device.h>
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#include <linux/mod_devicetable.h>
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#include <linux/basic_mmio_gpio.h>
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static void bgpio_write8(void __iomem *reg, unsigned long data)
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{
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writeb(data, reg);
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}
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static unsigned long bgpio_read8(void __iomem *reg)
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{
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return readb(reg);
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}
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static void bgpio_write16(void __iomem *reg, unsigned long data)
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{
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writew(data, reg);
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}
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static unsigned long bgpio_read16(void __iomem *reg)
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{
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return readw(reg);
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}
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static void bgpio_write32(void __iomem *reg, unsigned long data)
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{
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writel(data, reg);
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}
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static unsigned long bgpio_read32(void __iomem *reg)
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{
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return readl(reg);
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}
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#if BITS_PER_LONG >= 64
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static void bgpio_write64(void __iomem *reg, unsigned long data)
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{
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writeq(data, reg);
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}
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static unsigned long bgpio_read64(void __iomem *reg)
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{
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return readq(reg);
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}
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#endif /* BITS_PER_LONG >= 64 */
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static unsigned long bgpio_pin2mask(struct bgpio_chip *bgc, unsigned int pin)
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{
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return 1 << pin;
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}
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static unsigned long bgpio_pin2mask_be(struct bgpio_chip *bgc,
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unsigned int pin)
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{
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return 1 << (bgc->bits - 1 - pin);
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}
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static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
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{
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struct bgpio_chip *bgc = to_bgpio_chip(gc);
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return bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio);
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}
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static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
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{
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struct bgpio_chip *bgc = to_bgpio_chip(gc);
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unsigned long mask = bgc->pin2mask(bgc, gpio);
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unsigned long flags;
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spin_lock_irqsave(&bgc->lock, flags);
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if (val)
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bgc->data |= mask;
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else
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bgc->data &= ~mask;
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bgc->write_reg(bgc->reg_dat, bgc->data);
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spin_unlock_irqrestore(&bgc->lock, flags);
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}
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static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
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int val)
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{
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struct bgpio_chip *bgc = to_bgpio_chip(gc);
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unsigned long mask = bgc->pin2mask(bgc, gpio);
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if (val)
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bgc->write_reg(bgc->reg_set, mask);
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else
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bgc->write_reg(bgc->reg_clr, mask);
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}
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static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
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{
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struct bgpio_chip *bgc = to_bgpio_chip(gc);
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unsigned long mask = bgc->pin2mask(bgc, gpio);
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unsigned long flags;
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spin_lock_irqsave(&bgc->lock, flags);
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if (val)
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bgc->data |= mask;
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else
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bgc->data &= ~mask;
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bgc->write_reg(bgc->reg_set, bgc->data);
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spin_unlock_irqrestore(&bgc->lock, flags);
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}
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static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
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{
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return 0;
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}
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static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
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int val)
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{
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gc->set(gc, gpio, val);
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return 0;
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}
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static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
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{
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struct bgpio_chip *bgc = to_bgpio_chip(gc);
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unsigned long flags;
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spin_lock_irqsave(&bgc->lock, flags);
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bgc->dir &= ~bgc->pin2mask(bgc, gpio);
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bgc->write_reg(bgc->reg_dir, bgc->dir);
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spin_unlock_irqrestore(&bgc->lock, flags);
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return 0;
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}
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static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
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{
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struct bgpio_chip *bgc = to_bgpio_chip(gc);
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unsigned long flags;
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gc->set(gc, gpio, val);
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spin_lock_irqsave(&bgc->lock, flags);
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bgc->dir |= bgc->pin2mask(bgc, gpio);
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bgc->write_reg(bgc->reg_dir, bgc->dir);
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spin_unlock_irqrestore(&bgc->lock, flags);
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return 0;
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}
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static int bgpio_dir_in_inv(struct gpio_chip *gc, unsigned int gpio)
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{
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struct bgpio_chip *bgc = to_bgpio_chip(gc);
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unsigned long flags;
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spin_lock_irqsave(&bgc->lock, flags);
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bgc->dir |= bgc->pin2mask(bgc, gpio);
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bgc->write_reg(bgc->reg_dir, bgc->dir);
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spin_unlock_irqrestore(&bgc->lock, flags);
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return 0;
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}
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static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
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{
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struct bgpio_chip *bgc = to_bgpio_chip(gc);
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unsigned long flags;
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gc->set(gc, gpio, val);
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spin_lock_irqsave(&bgc->lock, flags);
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bgc->dir &= ~bgc->pin2mask(bgc, gpio);
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bgc->write_reg(bgc->reg_dir, bgc->dir);
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spin_unlock_irqrestore(&bgc->lock, flags);
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return 0;
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}
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static int bgpio_setup_accessors(struct device *dev,
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struct bgpio_chip *bgc,
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bool be)
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{
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switch (bgc->bits) {
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case 8:
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bgc->read_reg = bgpio_read8;
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bgc->write_reg = bgpio_write8;
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break;
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case 16:
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bgc->read_reg = bgpio_read16;
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bgc->write_reg = bgpio_write16;
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break;
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case 32:
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bgc->read_reg = bgpio_read32;
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bgc->write_reg = bgpio_write32;
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break;
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#if BITS_PER_LONG >= 64
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case 64:
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bgc->read_reg = bgpio_read64;
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bgc->write_reg = bgpio_write64;
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break;
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#endif /* BITS_PER_LONG >= 64 */
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default:
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dev_err(dev, "unsupported data width %u bits\n", bgc->bits);
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return -EINVAL;
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}
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bgc->pin2mask = be ? bgpio_pin2mask_be : bgpio_pin2mask;
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return 0;
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}
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/*
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* Create the device and allocate the resources. For setting GPIO's there are
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* three supported configurations:
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*
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* - single input/output register resource (named "dat").
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* - set/clear pair (named "set" and "clr").
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* - single output register resource and single input resource ("set" and
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* dat").
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*
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* For the single output register, this drives a 1 by setting a bit and a zero
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* by clearing a bit. For the set clr pair, this drives a 1 by setting a bit
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* in the set register and clears it by setting a bit in the clear register.
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* The configuration is detected by which resources are present.
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*
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* For setting the GPIO direction, there are three supported configurations:
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*
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* - simple bidirection GPIO that requires no configuration.
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* - an output direction register (named "dirout") where a 1 bit
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* indicates the GPIO is an output.
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* - an input direction register (named "dirin") where a 1 bit indicates
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* the GPIO is an input.
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*/
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static int bgpio_setup_io(struct bgpio_chip *bgc,
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void __iomem *dat,
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void __iomem *set,
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void __iomem *clr)
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{
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bgc->reg_dat = dat;
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if (!bgc->reg_dat)
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return -EINVAL;
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if (set && clr) {
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bgc->reg_set = set;
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bgc->reg_clr = clr;
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bgc->gc.set = bgpio_set_with_clear;
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} else if (set && !clr) {
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bgc->reg_set = set;
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bgc->gc.set = bgpio_set_set;
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} else {
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bgc->gc.set = bgpio_set;
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}
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bgc->gc.get = bgpio_get;
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return 0;
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}
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static int bgpio_setup_direction(struct bgpio_chip *bgc,
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void __iomem *dirout,
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void __iomem *dirin)
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{
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if (dirout && dirin) {
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return -EINVAL;
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} else if (dirout) {
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bgc->reg_dir = dirout;
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bgc->gc.direction_output = bgpio_dir_out;
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bgc->gc.direction_input = bgpio_dir_in;
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} else if (dirin) {
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bgc->reg_dir = dirin;
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bgc->gc.direction_output = bgpio_dir_out_inv;
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bgc->gc.direction_input = bgpio_dir_in_inv;
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} else {
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bgc->gc.direction_output = bgpio_simple_dir_out;
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bgc->gc.direction_input = bgpio_simple_dir_in;
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}
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return 0;
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}
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int __devexit bgpio_remove(struct bgpio_chip *bgc)
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{
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int err = gpiochip_remove(&bgc->gc);
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kfree(bgc);
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return err;
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}
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EXPORT_SYMBOL_GPL(bgpio_remove);
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int __devinit bgpio_init(struct bgpio_chip *bgc,
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struct device *dev,
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unsigned long sz,
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void __iomem *dat,
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void __iomem *set,
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void __iomem *clr,
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void __iomem *dirout,
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void __iomem *dirin,
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bool big_endian)
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{
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int ret;
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if (!is_power_of_2(sz))
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return -EINVAL;
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bgc->bits = sz * 8;
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if (bgc->bits > BITS_PER_LONG)
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return -EINVAL;
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spin_lock_init(&bgc->lock);
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bgc->gc.dev = dev;
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bgc->gc.label = dev_name(dev);
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bgc->gc.base = -1;
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bgc->gc.ngpio = bgc->bits;
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ret = bgpio_setup_io(bgc, dat, set, clr);
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if (ret)
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return ret;
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ret = bgpio_setup_accessors(dev, bgc, big_endian);
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if (ret)
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return ret;
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ret = bgpio_setup_direction(bgc, dirout, dirin);
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if (ret)
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return ret;
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bgc->data = bgc->read_reg(bgc->reg_dat);
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return ret;
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}
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EXPORT_SYMBOL_GPL(bgpio_init);
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#ifdef CONFIG_GPIO_GENERIC_PLATFORM
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static void __iomem *bgpio_map(struct platform_device *pdev,
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const char *name,
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resource_size_t sane_sz,
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int *err)
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{
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struct device *dev = &pdev->dev;
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struct resource *r;
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resource_size_t start;
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resource_size_t sz;
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void __iomem *ret;
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*err = 0;
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r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
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if (!r)
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return NULL;
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sz = resource_size(r);
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if (sz != sane_sz) {
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*err = -EINVAL;
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return NULL;
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}
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start = r->start;
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if (!devm_request_mem_region(dev, start, sz, r->name)) {
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*err = -EBUSY;
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return NULL;
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}
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ret = devm_ioremap(dev, start, sz);
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if (!ret) {
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*err = -ENOMEM;
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return NULL;
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}
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return ret;
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}
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static int __devinit bgpio_pdev_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct resource *r;
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void __iomem *dat;
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void __iomem *set;
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void __iomem *clr;
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void __iomem *dirout;
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void __iomem *dirin;
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unsigned long sz;
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bool be;
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int err;
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struct bgpio_chip *bgc;
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struct bgpio_pdata *pdata = dev_get_platdata(dev);
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r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
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if (!r)
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return -EINVAL;
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sz = resource_size(r);
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dat = bgpio_map(pdev, "dat", sz, &err);
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if (!dat)
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return err ? err : -EINVAL;
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set = bgpio_map(pdev, "set", sz, &err);
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if (err)
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return err;
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clr = bgpio_map(pdev, "clr", sz, &err);
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if (err)
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return err;
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dirout = bgpio_map(pdev, "dirout", sz, &err);
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if (err)
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return err;
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dirin = bgpio_map(pdev, "dirin", sz, &err);
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if (err)
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return err;
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be = !strcmp(platform_get_device_id(pdev)->name, "basic-mmio-gpio-be");
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bgc = devm_kzalloc(&pdev->dev, sizeof(*bgc), GFP_KERNEL);
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if (!bgc)
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return -ENOMEM;
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err = bgpio_init(bgc, dev, sz, dat, set, clr, dirout, dirin, be);
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if (err)
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return err;
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if (pdata) {
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bgc->gc.base = pdata->base;
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if (pdata->ngpio > 0)
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bgc->gc.ngpio = pdata->ngpio;
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}
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platform_set_drvdata(pdev, bgc);
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return gpiochip_add(&bgc->gc);
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}
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static int __devexit bgpio_pdev_remove(struct platform_device *pdev)
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{
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struct bgpio_chip *bgc = platform_get_drvdata(pdev);
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return bgpio_remove(bgc);
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}
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static const struct platform_device_id bgpio_id_table[] = {
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{ "basic-mmio-gpio", },
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{ "basic-mmio-gpio-be", },
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{},
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};
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MODULE_DEVICE_TABLE(platform, bgpio_id_table);
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static struct platform_driver bgpio_driver = {
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.driver = {
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.name = "basic-mmio-gpio",
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},
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.id_table = bgpio_id_table,
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.probe = bgpio_pdev_probe,
|
|
.remove = __devexit_p(bgpio_pdev_remove),
|
|
};
|
|
|
|
static int __init bgpio_platform_init(void)
|
|
{
|
|
return platform_driver_register(&bgpio_driver);
|
|
}
|
|
module_init(bgpio_platform_init);
|
|
|
|
static void __exit bgpio_platform_exit(void)
|
|
{
|
|
platform_driver_unregister(&bgpio_driver);
|
|
}
|
|
module_exit(bgpio_platform_exit);
|
|
|
|
#endif /* CONFIG_GPIO_GENERIC_PLATFORM */
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|
|
|
MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
|
|
MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
|
|
MODULE_LICENSE("GPL");
|