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greybus: spi: add bridged-PHY spi protocol driver

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Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
This commit is contained in:
Viresh Kumar 2015-01-23 13:07:45 +05:30 committed by Greg Kroah-Hartman
parent 45a706368d
commit 15d651b0db
4 changed files with 454 additions and 0 deletions
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1
drivers/staging/greybus/Makefile
View File

@ -15,6 +15,7 @@ gb-phy-y := gpb.o \
pwm.o \
gpio.o \
i2c.o \
spi.o \
usb.o
# Prefix all modules with gb-

7
drivers/staging/greybus/gpb.c
View File

@ -45,8 +45,14 @@ static int __init gpbridge_init(void)
pr_err("error initializing usb protocol\n");
goto error_i2c;
}
if (gb_spi_protocol_init()) {
pr_err("error initializing usb protocol\n");
goto error_spi;
}
return 0;
error_spi:
gb_i2c_protocol_exit();
error_i2c:
gb_usb_protocol_exit();
error_usb:
@ -63,6 +69,7 @@ error_gpio:
static void __exit gpbridge_exit(void)
{
gb_spi_protocol_exit();
gb_i2c_protocol_exit();
gb_usb_protocol_exit();
gb_sdio_protocol_exit();

3
drivers/staging/greybus/protocol.h
View File

@ -81,6 +81,9 @@ extern void gb_usb_protocol_exit(void);
extern int gb_i2c_protocol_init(void);
extern void gb_i2c_protocol_exit(void);
extern int gb_spi_protocol_init(void);
extern void gb_spi_protocol_exit(void);
#define gb_protocol_driver(__protocol) \
static int __init protocol_init(void) \
{ \

443
drivers/staging/greybus/spi.c Normal file
View File

@ -0,0 +1,443 @@
/*
* SPI bridge driver for the Greybus "generic" SPI module.
*
* Copyright 2014 Google Inc.
* Copyright 2014 Linaro Ltd.
*
* Released under the GPLv2 only.
*/
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include "greybus.h"
struct gb_spi {
struct gb_connection *connection;
u8 version_major;
u8 version_minor;
/* Modes supported by spi controller */
u16 mode;
/* constraints of the spi controller */
u16 flags;
/*
* copied from kernel:
*
* A mask indicating which values of bits_per_word are supported by the
* controller. Bit n indicates that a bits_per_word n+1 is suported. If
* set, the SPI core will reject any transfer with an unsupported
* bits_per_word. If not set, this value is simply ignored, and it's up
* to the individual driver to perform any validation.
*/
u32 bits_per_word_mask;
/*
* chipselects will be integral to many controllers; some others might
* use board-specific GPIOs.
*/
u16 num_chipselect;
};
/* Version of the Greybus spi protocol we support */
#define GB_SPI_VERSION_MAJOR 0x00
#define GB_SPI_VERSION_MINOR 0x01
/* Should match up with modes in linux/spi/spi.h */
#define GB_SPI_MODE_CPHA 0x01 /* clock phase */
#define GB_SPI_MODE_CPOL 0x02 /* clock polarity */
#define GB_SPI_MODE_MODE_0 (0|0) /* (original MicroWire) */
#define GB_SPI_MODE_MODE_1 (0|GB_SPI_MODE_CPHA)
#define GB_SPI_MODE_MODE_2 (GB_SPI_MODE_CPOL|0)
#define GB_SPI_MODE_MODE_3 (GB_SPI_MODE_CPOL|GB_SPI_MODE_CPHA)
#define GB_SPI_MODE_CS_HIGH 0x04 /* chipselect active high? */
#define GB_SPI_MODE_LSB_FIRST 0x08 /* per-word bits-on-wire */
#define GB_SPI_MODE_3WIRE 0x10 /* SI/SO signals shared */
#define GB_SPI_MODE_LOOP 0x20 /* loopback mode */
#define GB_SPI_MODE_NO_CS 0x40 /* 1 dev/bus, no chipselect */
#define GB_SPI_MODE_READY 0x80 /* slave pulls low to pause */
/* Should match up with flags in linux/spi/spi.h */
#define GB_SPI_FLAG_HALF_DUPLEX BIT(0) /* can't do full duplex */
#define GB_SPI_FLAG_NO_RX BIT(1) /* can't do buffer read */
#define GB_SPI_FLAG_NO_TX BIT(2) /* can't do buffer write */
/* Greybus spi request types */
#define GB_SPI_TYPE_INVALID 0x00
#define GB_SPI_TYPE_PROTOCOL_VERSION 0x01
#define GB_SPI_TYPE_MODE 0x02
#define GB_SPI_TYPE_FLAGS 0x03
#define GB_SPI_TYPE_BITS_PER_WORD_MASK 0x04
#define GB_SPI_TYPE_NUM_CHIPSELECT 0x05
#define GB_SPI_TYPE_TRANSFER 0x06
#define GB_SPI_TYPE_RESPONSE 0x80 /* OR'd with rest */
/* mode request has no payload */
struct gb_spi_mode_response {
__le16 mode;
};
/* flags request has no payload */
struct gb_spi_flags_response {
__le16 flags;
};
/* bits-per-word request has no payload */
struct gb_spi_bpw_response {
__le32 bits_per_word_mask;
};
/* num-chipselects request has no payload */
struct gb_spi_chipselect_response {
__le16 num_chipselect;
};
/**
* struct gb_spi_transfer - a read/write buffer pair
* @speed_hz: Select a speed other than the device default for this transfer. If
* 0 the default (from @spi_device) is used.
* @len: size of rx and tx buffers (in bytes)
* @delay_usecs: microseconds to delay after this transfer before (optionally)
* changing the chipselect status, then starting the next transfer or
* completing this spi_message.
* @cs_change: affects chipselect after this transfer completes
* @bits_per_word: select a bits_per_word other than the device default for this
* transfer. If 0 the default (from @spi_device) is used.
*/
struct gb_spi_transfer {
__le32 speed_hz;
__le32 len;
__le16 delay_usecs;
__u8 cs_change;
__u8 bits_per_word;
};
struct gb_spi_transfer_request {
__u8 chip_select; /* of the spi device */
__u8 mode; /* of the spi device */
__le16 count;
struct gb_spi_transfer transfers[0]; /* trnasfer_count of these */
};
struct gb_spi_transfer_response {
__u8 data[0]; /* inbound data */
};
/* Routines to transfer data */
static struct gb_operation *
gb_spi_operation_create(struct gb_connection *connection,
struct spi_message *msg, u32 *total_len)
{
struct gb_spi_transfer_request *request;
struct spi_device *dev = msg->spi;
struct spi_transfer *xfer;
struct gb_spi_transfer *gb_xfer;
struct gb_operation *operation;
u32 tx_size = 0, rx_size = 0, count = 0, request_size;
void *tx_data;
/* Find number of transfers queued and tx/rx length in the message */
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if (!xfer->tx_buf && !xfer->rx_buf) {
gb_connection_err(connection,
"Bufferless transfer, length %u\n",
xfer->len);
return NULL;
}
if (xfer->tx_buf)
tx_size += xfer->len;
if (xfer->rx_buf)
rx_size += xfer->len;
*total_len += xfer->len;
count++;
}
/* Too many transfers ? */
if (count > (u32)U16_MAX) {
gb_connection_err(connection, "transfer count (%u) too big",
count);
return NULL;
}
/*
* In addition to space for all message descriptors we need
* to have enough to hold all tx data.
*/
request_size = sizeof(*request);
request_size += count * sizeof(*gb_xfer);
request_size += tx_size;
/* Response consists only of incoming data */
operation = gb_operation_create(connection, GB_SPI_TYPE_TRANSFER,
request_size, rx_size);
if (!operation)
return NULL;
request = operation->request->payload;
request->count = count;
request->mode = dev->mode;
request->chip_select = dev->chip_select;
gb_xfer = &request->transfers[0];
tx_data = gb_xfer + count; /* place tx data after last gb_xfer */
/* Fill in the transfers array */
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
gb_xfer->speed_hz = cpu_to_le16(xfer->speed_hz);
gb_xfer->len = cpu_to_le32(xfer->len);
gb_xfer->delay_usecs = cpu_to_le16(xfer->delay_usecs);
gb_xfer->cs_change = xfer->cs_change;
gb_xfer->bits_per_word = xfer->bits_per_word;
gb_xfer++;
/* Copy tx data */
if (xfer->tx_buf) {
memcpy(tx_data, xfer->tx_buf, xfer->len);
tx_data += xfer->len;
}
}
return operation;
}
static void gb_spi_decode_response(struct spi_message *msg,
struct gb_spi_transfer_response *response)
{
struct spi_transfer *xfer;
void *rx_data = response->data;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
/* Copy rx data */
if (xfer->rx_buf) {
memcpy(xfer->rx_buf, rx_data, xfer->len);
rx_data += xfer->len;
}
}
}
static int gb_spi_transfer_one_message(struct spi_master *master,
struct spi_message *msg)
{
struct gb_spi *spi = spi_master_get_devdata(master);
struct gb_connection *connection = spi->connection;
struct gb_spi_transfer_response *response;
struct gb_operation *operation;
u32 len = 0;
int ret;
operation = gb_spi_operation_create(connection, msg, &len);
if (!operation)
return -ENOMEM;
ret = gb_operation_request_send_sync(operation);
if (!ret) {
response = operation->response->payload;
if (response)
gb_spi_decode_response(msg, response);
} else {
pr_err("transfer operation failed (%d)\n", ret);
}
gb_operation_destroy(operation);
msg->actual_length = len;
msg->status = 0;
spi_finalize_current_message(master);
return ret;
}
static int gb_spi_setup(struct spi_device *spi)
{
/* Nothing to do for now */
return 0;
}
static void gb_spi_cleanup(struct spi_device *spi)
{
/* Nothing to do for now */
}
/* Routines to get controller infomation */
/* Define get_version() routine */
define_get_version(gb_spi, SPI);
/*
* Map Greybus spi mode bits/flags/bpw into Linux ones.
* All bits are same for now and so these macro's return same values.
*/
#define gb_spi_mode_map(mode) mode
#define gb_spi_flags_map(flags) flags
static int gb_spi_mode_operation(struct gb_spi *spi)
{
struct gb_spi_mode_response response;
u16 mode;
int ret;
ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_MODE,
NULL, 0, &response, sizeof(response));
if (ret)
return ret;
mode = le16_to_cpu(response.mode);
spi->mode = gb_spi_mode_map(mode);
return 0;
}
static int gb_spi_flags_operation(struct gb_spi *spi)
{
struct gb_spi_flags_response response;
u16 flags;
int ret;
ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_FLAGS,
NULL, 0, &response, sizeof(response));
if (ret)
return ret;
flags = le16_to_cpu(response.flags);
spi->flags = gb_spi_flags_map(flags);
return 0;
}
static int gb_spi_bpw_operation(struct gb_spi *spi)
{
struct gb_spi_bpw_response response;
int ret;
ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_BITS_PER_WORD_MASK,
NULL, 0, &response, sizeof(response));
if (ret)
return ret;
spi->bits_per_word_mask = le32_to_cpu(response.bits_per_word_mask);
return 0;
}
static int gb_spi_chipselect_operation(struct gb_spi *spi)
{
struct gb_spi_chipselect_response response;
int ret;
ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_NUM_CHIPSELECT,
NULL, 0, &response, sizeof(response));
if (ret)
return ret;
spi->num_chipselect = le32_to_cpu(response.num_chipselect);
return 0;
}
/*
* Initialize the spi device. This includes verifying we can support it (based
* on the protocol version it advertises). If that's OK, we get and cached its
* mode bits & flags.
*/
static int gb_spi_init(struct gb_spi *spi)
{
int ret;
/* First thing we need to do is check the version */
ret = get_version(spi);
if (ret)
return ret;
/* mode never changes, just get it once */
ret = gb_spi_mode_operation(spi);
if (ret)
return ret;
/* flags never changes, just get it once */
ret = gb_spi_flags_operation(spi);
if (ret)
return ret;
/* total number of chipselects never changes, just get it once */
ret = gb_spi_chipselect_operation(spi);
if (ret)
return ret;
/* bits-per-word-mask never changes, just get it once */
return gb_spi_bpw_operation(spi);
}
static int gb_spi_connection_init(struct gb_connection *connection)
{
struct gb_spi *spi;
struct spi_master *master;
int ret;
/* Allocate master with space for data */
master = spi_alloc_master(&connection->dev, sizeof(*spi));
if (!master) {
gb_connection_err(connection, "cannot alloc SPI master\n");
return -ENOMEM;
}
spi = spi_master_get_devdata(master);
spi->connection = connection;
connection->private = master;
ret = gb_spi_init(spi);
if (ret)
goto out_err;
master->bus_num = 0; /* How do we get controller id here? */
master->num_chipselect = spi->num_chipselect;
master->mode_bits = spi->mode;
master->flags = spi->flags;
master->bits_per_word_mask = spi->bits_per_word_mask;
/* Attach methods */
master->cleanup = gb_spi_cleanup;
master->setup = gb_spi_setup;
master->transfer_one_message = gb_spi_transfer_one_message;
ret = spi_register_master(master);
if (!ret)
return 0;
out_err:
spi_master_put(master);
return ret;
}
static void gb_spi_connection_exit(struct gb_connection *connection)
{
struct spi_master *master = connection->private;
spi_unregister_master(master);
}
static struct gb_protocol spi_protocol = {
.name = "spi",
.id = GREYBUS_PROTOCOL_SPI,
.major = 0,
.minor = 1,
.connection_init = gb_spi_connection_init,
.connection_exit = gb_spi_connection_exit,
.request_recv = NULL,
};
int gb_spi_protocol_init(void)
{
return gb_protocol_register(&spi_protocol);
}
void gb_spi_protocol_exit(void)
{
gb_protocol_deregister(&spi_protocol);
}