[RFC] i2c algo, Add i2c-algo-i801 driver [v1]

Message ID	1397060563-30431-1-git-send-email-prarit@redhat.com (mailing list archive)
State	RFC, archived
Headers	show Return-Path: <linux-acpi-owner@kernel.org> From: Prarit Bhargava <prarit@redhat.com> To: linux-i2c@vger.kernel.org Cc: Prarit Bhargava <prarit@redhat.com>, Jean Delvare <khali@linux-fr.org>, linux-acpi@vger.kernel.org, Seth Heasley <seth.heasley@intel.com>, Matthew Garrett <matthew.garrett@nebula.com>, Bjorn Helgaas <bhelgaas@google.com>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Janet Morgan <janet.morgan@intel.com>, Myron Stowe <mstowe@redhat.com> Subject: [PATCH RFC] i2c algo, Add i2c-algo-i801 driver [v1] Date: Wed, 9 Apr 2014 12:22:43 -0400 Message-Id: <1397060563-30431-1-git-send-email-prarit@redhat.com> Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk

diff --git a/drivers/i2c/algos/Kconfig b/drivers/i2c/algos/Kconfig index f1cfe7e..98b382c 100644 --- a/drivers/i2c/algos/Kconfig +++ b/drivers/i2c/algos/Kconfig @@ -14,4 +14,7 @@ config I2C_ALGOPCF config I2C_ALGOPCA tristate "I2C PCA 9564 interfaces" +config I2C_ALGOI801 + tristate "I2C I801 interfaces" + endmenu diff --git a/drivers/i2c/algos/Makefile b/drivers/i2c/algos/Makefile index 215303f..2c7cc99 100644 --- a/drivers/i2c/algos/Makefile +++ b/drivers/i2c/algos/Makefile @@ -5,5 +5,6 @@ obj-$(CONFIG_I2C_ALGOBIT) += i2c-algo-bit.o obj-$(CONFIG_I2C_ALGOPCF) += i2c-algo-pcf.o obj-$(CONFIG_I2C_ALGOPCA) += i2c-algo-pca.o +obj-$(CONFIG_I2C_ALGOI801) += i2c-algo-i801.o ccflags-$(CONFIG_I2C_DEBUG_ALGO) := -DDEBUG diff --git a/drivers/i2c/algos/i2c-algo-i801.c b/drivers/i2c/algos/i2c-algo-i801.c new file mode 100644 index 0000000..c7e615c3 --- /dev/null +++ b/drivers/i2c/algos/i2c-algo-i801.c @@ -0,0 +1,211 @@ +#include <linux/module.h> +#include <linux/init.h> +#include <linux/acpi.h> +#include <linux/i2c.h> + +/* From an ACPI dump the supported ACPI SBUS operations are: + * + * SSXB + * transmit one byte + * SRXB + * receive one byte + * SWRB + * write one byte + * SRDB + * read one byte + * SWRW + * write one word + * SRDW + * read one word + * SBLW + * write block + * SBRW + * read block + * + * A lot of this code is based on what the existing i2c-i801.c driver is + * doing. Note that the i2c-i801.c driver also implements I2C_SMBUS_QUICK, + * and I2C_SMBUS_I2C_BLOCK_DATA which do not appear to be implemented in the + * ACPI driver. + */ + +struct i2c_adapter i2c_acpi_sbus_adapter; + +/* all operations are noted as being serialized in the acpidump so no + * locking should be required. + */ +static s32 i2c_acpi_sbus_access(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, + union i2c_smbus_data *data) +{ + acpi_status status; + acpi_handle handle = adap->algo_data; + char *op; + struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; + struct acpi_object_list args; + union acpi_object *buffer_obj; + union acpi_object objects[4]; + unsigned long long value; + + args.pointer = objects; + objects[0].type = ACPI_TYPE_INTEGER; + /* taken directly from i2c-smbus.c */ + objects[0].integer.value = ((addr & 0x7f) << 1) | (read_write & 0x01); + + switch (size) { + case I2C_SMBUS_BYTE: + if (read_write == I2C_SMBUS_WRITE) { + op = "SSXB"; + args.count = 2; + objects[1].type = ACPI_TYPE_INTEGER; + objects[1].integer.value = command; + } else { + op = "SRXB"; + args.count = 1; + } + status = acpi_evaluate_integer(handle, op, &args, &value); + data->byte = value; + break; + case I2C_SMBUS_BYTE_DATA: + objects[1].type = ACPI_TYPE_INTEGER; + objects[1].integer.value = command; + if (read_write == I2C_SMBUS_WRITE) { + op = "SWRB"; + args.count = 3; + objects[2].type = ACPI_TYPE_INTEGER; + objects[2].integer.value = data->byte; + } else { + op = "SRDB"; + args.count = 2; + } + status = acpi_evaluate_integer(handle, op, &args, &value); + data->byte = value; + break; + case I2C_SMBUS_WORD_DATA: + objects[1].type = ACPI_TYPE_INTEGER; + objects[1].integer.value = command; + if (read_write == I2C_SMBUS_WRITE) { + op = "SWRW"; + args.count = 3; + objects[2].type = ACPI_TYPE_INTEGER; + objects[2].integer.value = data->word; + } else { + op = "SRDW"; + args.count = 2; + } + status = acpi_evaluate_integer(handle, op, &args, &value); + data->word = value; + break; + case I2C_SMBUS_BLOCK_DATA: + objects[1].type = ACPI_TYPE_INTEGER; + objects[1].integer.value = command; + if (read_write == I2C_SMBUS_WRITE) { + op = "SBLW"; + args.count = 3; + objects[2].buffer.length = data->block[0]; + objects[2].buffer.pointer = data->block + 1; + status = acpi_evaluate_integer(handle, op, &args, + &value); + data->byte = value; + } else { + op = "SBLR"; + args.count = 2; + status = acpi_evaluate_object(handle, op, &args, + &buffer); + if (ACPI_SUCCESS(status)) { + buffer_obj = buffer.pointer; + memcpy(data->block, + buffer_obj->buffer.pointer, + buffer_obj->buffer.length); + } + } + break; + default: + pr_warn("%s: Unsupported transaction %d\n", + i2c_acpi_sbus_adapter.name, size); + return -EOPNOTSUPP; + } + + if (ACPI_FAILURE(status)) { + pr_warn("%s: Transaction failure.\n", + i2c_acpi_sbus_adapter.name); + return -ENXIO; + } + + return 0; +} + +static u32 i2c_acpi_sbus_func(struct i2c_adapter *adapter) +{ + return (I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BLOCK_DATA); +} + +static const struct i2c_algorithm i2c_acpi_sbus_algorithm = { + .smbus_xfer = i2c_acpi_sbus_access, + .functionality = i2c_acpi_sbus_func, +}; + +struct i2c_adapter i2c_acpi_sbus_adapter = { + .owner = THIS_MODULE, + .class = I2C_CLASS_HWMON, + .algo = &i2c_acpi_sbus_algorithm, + .name = "i2c ACPI(SBUS) SMBus", +}; + +static acpi_status i2c_acpi_sbus_find_device(acpi_handle handle, u32 level, + void *context, void **return_value) +{ + acpi_status status; + char node_name[5]; + struct acpi_buffer buffer = {sizeof(node_name), node_name}; + struct acpi_device *device = NULL; + int ret; + + status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer); + if (ACPI_FAILURE(status) || strcmp("SBUS", node_name) != 0) + return AE_OK; + + acpi_bus_get_device(handle, &device); + if (!device) { + pr_err("%s: SBUS name found but no matching device\n", + i2c_acpi_sbus_adapter.name); + return AE_NOT_FOUND; + } + + i2c_acpi_sbus_adapter.dev.parent = &device->dev; + i2c_acpi_sbus_adapter.algo_data = handle; + + ret = i2c_add_adapter(&i2c_acpi_sbus_adapter); + if (ret) + pr_err("%s: i2c core failed to add i2c_sbus\n", + i2c_acpi_sbus_adapter.name); + return AE_ERROR; + } + + pr_info("%s device found.\n", i2c_acpi_sbus_adapter.name); + return AE_OK; +} + +static int __init i2c_acpi_sbus_init(void) +{ + acpi_status status; + + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, + ACPI_UINT32_MAX, i2c_acpi_sbus_find_device, + NULL, NULL, NULL); + if (ACPI_FAILURE(status)) { + pr_debug("%s no device found\n", i2c_acpi_sbus_adapter.name); + return -ENODEV; + } + + return 0; +} + +static void __exit i2c_acpi_sbus_exit(void) +{ + i2c_del_adapter(&i2c_acpi_sbus_adapter); +} + +module_init(i2c_acpi_sbus_init); +module_exit(i2c_acpi_sbus_exit); diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 014afab..a4d97ae 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -81,6 +81,7 @@ config I2C_I801 tristate "Intel 82801 (ICH/PCH)" depends on PCI select CHECK_SIGNATURE if X86 && DMI + select I2C_ALGOI801 help If you say yes to this option, support will be included for the Intel 801 family of mainboard I2C interfaces. Specifically, the following

[RFC] i2c algo, Add i2c-algo-i801 driver [v1]

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