Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753793Ab1EEWAW (ORCPT ); Thu, 5 May 2011 18:00:22 -0400 Received: from the.earth.li ([46.43.34.31]:44259 "EHLO the.earth.li" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753136Ab1EEWAU (ORCPT ); Thu, 5 May 2011 18:00:20 -0400 Date: Thu, 5 May 2011 15:00:18 -0700 From: Jonathan McDowell To: Jonathan Cameron Cc: Grant Likely , LKML Subject: Re: [PATCH] Add support for VSC055 Enhanced Two-Wire Serial Backplane controller Message-ID: <20110505220018.GF28362@earth.li> References: <20110505041205.GY4835@earth.li> <4DC267E3.6080206@cam.ac.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4DC267E3.6080206@cam.ac.uk> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10495 Lines: 395 On Thu, May 05, 2011 at 10:03:31AM +0100, Jonathan Cameron wrote: > Sorry Jonathan and Grant. I accidentally sent this only to you and > not to lkml, hence the resend. That's my fault; I sent the initial revision to Grant and missed the lkml CC, then just bounced it to lkml. > Couple of suggestions for minor tidying up inline. Thanks. Things I've taken on board and updated: * Use u8, not uint8_t for 8 bit types. * Remove read_reg/write_reg wrappers and use i2c_smbus functions directly. * Fold container_of usage into struct vsc055_chip variable definition. * Use !! instead of ? 1 : 0. * Rename i2c_lock to reg_lock. * Move comment about cached status to correct location. Things I left: * pin/block - when they're used multiple times I think this is clearer and reflects how the data sheet talks about the GPIO lines. * Display version number - I think this is useful to indicate the device has been correctly found (I'd prefer it if there was a certain way to ID I2C devices). ----- Add support for the GPIOs on Maxim VSC055 I2C Enhanced Two-Wire Serial Backplane controller. This chip features 64 bits of user-definable, bidirectional GPIOs. It also has the ability to do PWM fan control output and LED flashing, but support for that functionality is not included at present. Signed-off-by: Jonathan McDowell diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index cc150db..4c5de65 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -255,6 +255,13 @@ config GPIO_TWL4030 Say yes here to access the GPIO signals of various multi-function power management chips from Texas Instruments. +config GPIO_VSC055 + tristate "VSC055 GPIOs" + depends on I2C + help + Say yes here to access the GPIOs found on the Maxim VSC055 Enhanced + Two-Wire Serial Backplane controller. + config GPIO_WM831X tristate "WM831x GPIOs" depends on MFD_WM831X diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index d2752b2..f82491d 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -42,4 +42,5 @@ obj-$(CONFIG_GPIO_RDC321X) += rdc321x-gpio.o obj-$(CONFIG_GPIO_JANZ_TTL) += janz-ttl.o obj-$(CONFIG_GPIO_SX150X) += sx150x.o obj-$(CONFIG_GPIO_VX855) += vx855_gpio.o +obj-$(CONFIG_GPIO_VSC055) += vsc055.o obj-$(CONFIG_GPIO_ML_IOH) += ml_ioh_gpio.o diff --git a/drivers/gpio/vsc055.c b/drivers/gpio/vsc055.c new file mode 100644 index 0000000..1ca6ae0 --- /dev/null +++ b/drivers/gpio/vsc055.c @@ -0,0 +1,283 @@ +/* + * vsc055.c - Enhanced Two-Wire Serial Backplane Control with 64 I/O lines. + * + * Copyright (C) 2011 Jonathan McDowell + * + * Derived from drivers/gpio/pca953x.c + * + * 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; version 2 of the License. + */ + +#include +#include +#include +#include +#include +#include + +#define VSC055_GPD0 0x00 +#define VSC055_DDP0 0x10 +#define VSC055_BCIS 0xF8 +#define VSC055_BCT 0xFC +#define VSC055_VER 0xFF + +static const struct i2c_device_id vsc055_id[] = { + { "vsc055" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, vsc055_id); + +struct vsc055_chip { + unsigned gpio_start; + u8 reg_output[8]; + u8 reg_direction[8]; + struct mutex reg_lock; + + struct i2c_client *client; + struct gpio_chip gpio_chip; + const char *const *names; +}; + +static int vsc055_gpio_direction_input(struct gpio_chip *gc, unsigned off) +{ + struct vsc055_chip *chip = container_of(gc, struct vsc055_chip, gpio_chip); + u8 reg_val; + int ret; + int block, pin; + + block = off >> 3; + pin = off & 7; + + mutex_lock(&chip->reg_lock); + reg_val = chip->reg_direction[block] | (1u << pin); + ret = i2c_smbus_write_byte_data(chip->client, VSC055_DDP0 + block, reg_val); + if (ret) + goto exit; + + chip->reg_direction[block] = reg_val; +exit: + mutex_unlock(&chip->reg_lock); + return ret; +} + +static int vsc055_gpio_direction_output(struct gpio_chip *gc, + unsigned off, int val) +{ + struct vsc055_chip *chip = container_of(gc, struct vsc055_chip, gpio_chip); + u8 reg_val; + int ret; + int block, pin; + + block = off >> 3; + pin = off & 7; + + mutex_lock(&chip->reg_lock); + /* set output level */ + if (val) + reg_val = chip->reg_output[block] | (1u << pin); + else + reg_val = chip->reg_output[block] & ~(1u << pin); + + ret = i2c_smbus_write_byte_data(chip->client, VSC055_GPD0 + block, reg_val); + if (ret) + goto exit; + + chip->reg_output[block] = reg_val; + + /* then direction */ + reg_val = chip->reg_direction[block] & ~(1u << off); + ret = i2c_smbus_write_byte_data(chip->client, VSC055_DDP0 + block, reg_val); + if (ret) + goto exit; + + chip->reg_direction[block] = reg_val; + ret = 0; +exit: + mutex_unlock(&chip->reg_lock); + return ret; +} + +static int vsc055_gpio_get_value(struct gpio_chip *gc, unsigned off) +{ + struct vsc055_chip *chip = container_of(gc, struct vsc055_chip, gpio_chip); + u8 reg_val; + + mutex_lock(&chip->reg_lock); + reg_val = i2c_smbus_read_byte_data(chip->client, VSC055_GPD0 + (off >> 3)); + mutex_unlock(&chip->reg_lock); + if (reg_val < 0) { + dev_err(&chip->client->dev, "failed to read GPIO value.\n"); + return 0; + } + + return !!(reg_val & (1u << (off & 7))); +} + +static void vsc055_gpio_set_value(struct gpio_chip *gc, unsigned off, int val) +{ + struct vsc055_chip *chip = container_of(gc, struct vsc055_chip, gpio_chip); + u8 reg_val; + int ret; + int block, pin; + + block = off >> 3; + pin = off & 7; + + mutex_lock(&chip->reg_lock); + if (val) + reg_val = chip->reg_output[block] | (1u << pin); + else + reg_val = chip->reg_output[block] & ~(1u << pin); + + ret = i2c_smbus_write_byte_data(chip->client, VSC055_GPD0 + block, reg_val); + if (ret) + goto exit; + + chip->reg_output[block] = reg_val; +exit: + mutex_unlock(&chip->reg_lock); +} + +static void vsc055_setup_gpio(struct vsc055_chip *chip) +{ + struct gpio_chip *gc = &chip->gpio_chip;; + + gc->direction_input = vsc055_gpio_direction_input; + gc->direction_output = vsc055_gpio_direction_output; + gc->get = vsc055_gpio_get_value; + gc->set = vsc055_gpio_set_value; + gc->can_sleep = 1; + + gc->base = chip->gpio_start; + gc->ngpio = 64; + gc->label = chip->client->name; + gc->dev = &chip->client->dev; + gc->owner = THIS_MODULE; + gc->names = chip->names; +} + +static int __devinit vsc055_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct vsc055_platform_data *pdata; + struct vsc055_chip *chip; + int ret; + int i; + + chip = kzalloc(sizeof(struct vsc055_chip), GFP_KERNEL); + if (chip == NULL) + return -ENOMEM; + + pdata = client->dev.platform_data; + if (pdata == NULL) { + dev_dbg(&client->dev, "no platform data\n"); + ret = -EINVAL; + goto out_failed; + } + + chip->client = client; + + chip->gpio_start = pdata->gpio_base; + + chip->names = pdata->names; + + mutex_init(&chip->reg_lock); + + vsc055_setup_gpio(chip); + + /* + * Initialize cached registers from their original values. + * We can't share this chip with another i2c master. + */ + for (i = 0; i < 8; i++) { + ret = i2c_smbus_read_byte_data(chip->client, VSC055_GPD0 + i); + if (ret < 0) + goto out_failed; + chip->reg_output[i] = ret; + + ret = i2c_smbus_read_byte_data(chip->client, VSC055_DDP0 + i); + if (ret < 0) + goto out_failed; + chip->reg_direction[i] = ret; + } + + ret = i2c_smbus_read_byte_data(chip->client, VSC055_VER); + if (ret < 0) + goto out_failed; + dev_info(&client->dev, "Found VSC055 revision %d.%d\n", ret >> 4, ret & 0xF); + + ret = gpiochip_add(&chip->gpio_chip); + if (ret) + goto out_failed; + + if (pdata->setup) { + ret = pdata->setup(client, chip->gpio_chip.base, + chip->gpio_chip.ngpio, pdata->context); + if (ret < 0) + dev_warn(&client->dev, "setup failed, %d\n", ret); + } + + i2c_set_clientdata(client, chip); + return 0; + +out_failed: + kfree(chip); + return ret; +} + +static int vsc055_remove(struct i2c_client *client) +{ + struct vsc055_platform_data *pdata = client->dev.platform_data; + struct vsc055_chip *chip = i2c_get_clientdata(client); + int ret = 0; + + if (pdata->teardown) { + ret = pdata->teardown(client, chip->gpio_chip.base, + chip->gpio_chip.ngpio, pdata->context); + if (ret < 0) { + dev_err(&client->dev, "%s failed, %d\n", + "teardown", ret); + return ret; + } + } + + ret = gpiochip_remove(&chip->gpio_chip); + if (ret) { + dev_err(&client->dev, "%s failed, %d\n", + "gpiochip_remove()", ret); + return ret; + } + + kfree(chip); + return 0; +} + +static struct i2c_driver vsc055_driver = { + .driver = { + .name = "vsc055", + }, + .probe = vsc055_probe, + .remove = vsc055_remove, + .id_table = vsc055_id, +}; + +static int __init vsc055_init(void) +{ + return i2c_add_driver(&vsc055_driver); +} +/* register after i2c postcore initcall and before + * subsys initcalls that may rely on these GPIOs + */ +subsys_initcall(vsc055_init); + +static void __exit vsc055_exit(void) +{ + i2c_del_driver(&vsc055_driver); +} +module_exit(vsc055_exit); + +MODULE_AUTHOR("Jonathan McDowell "); +MODULE_DESCRIPTION("GPIO driver for VSC055"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/i2c/vsc055.h b/include/linux/i2c/vsc055.h new file mode 100644 index 0000000..dc1462b --- /dev/null +++ b/include/linux/i2c/vsc055.h @@ -0,0 +1,22 @@ +#ifndef _LINUX_VSC055_H +#define _LINUX_VSC055_H + +#include +#include + +/* Platform data for the VSC055 64-bit I/O expander driver */ + +struct vsc055_platform_data { + unsigned gpio_base; /* number of the first GPIO */ + void *context; /* param to setup/teardown */ + + int (*setup)(struct i2c_client *client, + unsigned gpio, unsigned ngpio, + void *context); + int (*teardown)(struct i2c_client *client, + unsigned gpio, unsigned ngpio, + void *context); + const char *const *names; +}; + +#endif /* _LINUX_VSC055_H */ ----- J. -- /-\ | What's the worse that could |@/ Debian GNU/Linux Developer | happen? Smoke. - Anonymous \- | HWHacker -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/