diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-pca-platform.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-pca-platform.c | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-pca-platform.c b/drivers/i2c/busses/i2c-pca-platform.c new file mode 100644 index 0000000..6bb15ad --- /dev/null +++ b/drivers/i2c/busses/i2c-pca-platform.c @@ -0,0 +1,298 @@ +/* + * i2c_pca_platform.c + * + * Platform driver for the PCA9564 I2C controller. + * + * Copyright (C) 2008 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. + + */ +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/delay.h> +#include <linux/errno.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/platform_device.h> +#include <linux/i2c-algo-pca.h> +#include <linux/i2c-pca-platform.h> +#include <linux/gpio.h> + +#include <asm/irq.h> +#include <asm/io.h> + +#define res_len(r) ((r)->end - (r)->start + 1) + +struct i2c_pca_pf_data { + void __iomem *reg_base; + int irq; /* if 0, use polling */ + int gpio; + wait_queue_head_t wait; + struct i2c_adapter adap; + struct i2c_algo_pca_data algo_data; + unsigned long io_base; + unsigned long io_size; +}; + +/* Read/Write functions for different register alignments */ + +static int i2c_pca_pf_readbyte8(void *pd, int reg) +{ + struct i2c_pca_pf_data *i2c = pd; + return ioread8(i2c->reg_base + reg); +} + +static int i2c_pca_pf_readbyte16(void *pd, int reg) +{ + struct i2c_pca_pf_data *i2c = pd; + return ioread8(i2c->reg_base + reg * 2); +} + +static int i2c_pca_pf_readbyte32(void *pd, int reg) +{ + struct i2c_pca_pf_data *i2c = pd; + return ioread8(i2c->reg_base + reg * 4); +} + +static void i2c_pca_pf_writebyte8(void *pd, int reg, int val) +{ + struct i2c_pca_pf_data *i2c = pd; + iowrite8(val, i2c->reg_base + reg); +} + +static void i2c_pca_pf_writebyte16(void *pd, int reg, int val) +{ + struct i2c_pca_pf_data *i2c = pd; + iowrite8(val, i2c->reg_base + reg * 2); +} + +static void i2c_pca_pf_writebyte32(void *pd, int reg, int val) +{ + struct i2c_pca_pf_data *i2c = pd; + iowrite8(val, i2c->reg_base + reg * 4); +} + + +static int i2c_pca_pf_waitforcompletion(void *pd) +{ + struct i2c_pca_pf_data *i2c = pd; + int ret = 0; + + if (i2c->irq) { + ret = wait_event_interruptible(i2c->wait, + i2c->algo_data.read_byte(i2c, I2C_PCA_CON) + & I2C_PCA_CON_SI); + } else { + /* + * Do polling... + * XXX: Could get stuck in extreme cases! + * Maybe add timeout, but using irqs is preferred anyhow. + */ + while ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON) + & I2C_PCA_CON_SI) == 0) + udelay(100); + } + + return ret; +} + +static void i2c_pca_pf_dummyreset(void *pd) +{ + struct i2c_pca_pf_data *i2c = pd; + printk(KERN_WARNING "%s: No reset-pin found. Chip may get stuck!\n", + i2c->adap.name); +} + +static void i2c_pca_pf_resetchip(void *pd) +{ + struct i2c_pca_pf_data *i2c = pd; + + gpio_set_value(i2c->gpio, 0); + ndelay(100); + gpio_set_value(i2c->gpio, 1); +} + +static irqreturn_t i2c_pca_pf_handler(int this_irq, void *dev_id) +{ + struct i2c_pca_pf_data *i2c = dev_id; + + if ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0) + return IRQ_NONE; + + wake_up_interruptible(&i2c->wait); + + return IRQ_HANDLED; +} + + +static int __devinit i2c_pca_pf_probe(struct platform_device *pdev) +{ + struct i2c_pca_pf_data *i2c; + struct resource *res; + struct i2c_pca9564_pf_platform_data *platform_data = + pdev->dev.platform_data; + int ret = 0; + int irq; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + irq = platform_get_irq(pdev, 0); + /* If irq is 0, we do polling. */ + + if (res == NULL) { + ret = -ENODEV; + goto e_print; + } + + if (!request_mem_region(res->start, res_len(res), res->name)) { + ret = -ENOMEM; + goto e_print; + } + + i2c = kzalloc(sizeof(struct i2c_pca_pf_data), GFP_KERNEL); + if (!i2c) { + ret = -ENOMEM; + goto e_alloc; + } + + init_waitqueue_head(&i2c->wait); + + i2c->reg_base = ioremap(res->start, res_len(res)); + if (!i2c->reg_base) { + ret = -ENOMEM; + goto e_remap; + } + i2c->io_base = res->start; + i2c->io_size = res_len(res); + i2c->irq = irq; + + i2c->adap.nr = pdev->id >= 0 ? pdev->id : 0; + i2c->adap.owner = THIS_MODULE; + snprintf(i2c->adap.name, sizeof(i2c->adap.name), "PCA9564 at 0x%08lx", + (unsigned long) res->start); + i2c->adap.algo_data = &i2c->algo_data; + i2c->adap.dev.parent = &pdev->dev; + i2c->adap.timeout = platform_data->timeout; + + i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed; + i2c->algo_data.data = i2c; + + switch (res->flags & IORESOURCE_MEM_TYPE_MASK) { + case IORESOURCE_MEM_32BIT: + i2c->algo_data.write_byte = i2c_pca_pf_writebyte32; + i2c->algo_data.read_byte = i2c_pca_pf_readbyte32; + break; + case IORESOURCE_MEM_16BIT: + i2c->algo_data.write_byte = i2c_pca_pf_writebyte16; + i2c->algo_data.read_byte = i2c_pca_pf_readbyte16; + break; + case IORESOURCE_MEM_8BIT: + default: + i2c->algo_data.write_byte = i2c_pca_pf_writebyte8; + i2c->algo_data.read_byte = i2c_pca_pf_readbyte8; + break; + } + + i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion; + + i2c->gpio = platform_data->gpio; + i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset; + + /* Use gpio_is_valid() when in mainline */ + if (i2c->gpio > -1) { + ret = gpio_request(i2c->gpio, i2c->adap.name); + if (ret == 0) { + gpio_direction_output(i2c->gpio, 1); + i2c->algo_data.reset_chip = i2c_pca_pf_resetchip; + } else { + printk(KERN_WARNING "%s: Registering gpio failed!\n", + i2c->adap.name); + i2c->gpio = ret; + } + } + + if (irq) { + ret = request_irq(irq, i2c_pca_pf_handler, + IRQF_TRIGGER_FALLING, i2c->adap.name, i2c); + if (ret) + goto e_reqirq; + } + + if (i2c_pca_add_numbered_bus(&i2c->adap) < 0) { + ret = -ENODEV; + goto e_adapt; + } + + platform_set_drvdata(pdev, i2c); + + printk(KERN_INFO "%s registered.\n", i2c->adap.name); + + return 0; + +e_adapt: + if (irq) + free_irq(irq, i2c); +e_reqirq: + if (i2c->gpio > -1) + gpio_free(i2c->gpio); + + iounmap(i2c->reg_base); +e_remap: + kfree(i2c); +e_alloc: + release_mem_region(res->start, res_len(res)); +e_print: + printk(KERN_ERR "Registering PCA9564 FAILED! (%d)\n", ret); + return ret; +} + +static int __devexit i2c_pca_pf_remove(struct platform_device *pdev) +{ + struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev); + platform_set_drvdata(pdev, NULL); + + i2c_del_adapter(&i2c->adap); + + if (i2c->irq) + free_irq(i2c->irq, i2c); + + if (i2c->gpio > -1) + gpio_free(i2c->gpio); + + iounmap(i2c->reg_base); + release_mem_region(i2c->io_base, i2c->io_size); + kfree(i2c); + + return 0; +} + +static struct platform_driver i2c_pca_pf_driver = { + .probe = i2c_pca_pf_probe, + .remove = __devexit_p(i2c_pca_pf_remove), + .driver = { + .name = "i2c-pca-platform", + .owner = THIS_MODULE, + }, +}; + +static int __init i2c_pca_pf_init(void) +{ + return platform_driver_register(&i2c_pca_pf_driver); +} + +static void __exit i2c_pca_pf_exit(void) +{ + platform_driver_unregister(&i2c_pca_pf_driver); +} + +MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>"); +MODULE_DESCRIPTION("I2C-PCA9564 platform driver"); +MODULE_LICENSE("GPL"); + +module_init(i2c_pca_pf_init); +module_exit(i2c_pca_pf_exit); + |
