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Subject[PATCH 1/2] spi: add support for DLN-2 USB-SPI adapter
Date
This adds support for Diolan DLN2 USB-SPI adapter.

Information about the USB protocol interface can be found in the
Programmer's Reference Manual [1], see section 5.4.6 for the SPI
master module commands and responses.

[1] https://www.diolan.com/downloads/dln-api-manual.pdf

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@intel.com>
---
drivers/spi/Kconfig | 10 +
drivers/spi/Makefile | 1 +
drivers/spi/spi-dln2.c | 795 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 806 insertions(+)
create mode 100644 drivers/spi/spi-dln2.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 62e2242..a52a910 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -176,6 +176,16 @@ config SPI_DAVINCI
help
SPI master controller for DaVinci/DA8x/OMAP-L/AM1x SPI modules.

+config SPI_DLN2
+ tristate "Diolan DLN-2 USB SPI adapter"
+ depends on MFD_DLN2
+ help
+ If you say yes to this option, support will be included for Diolan
+ DLN2, a USB to SPI interface.
+
+ This driver can also be built as a module. If so, the module
+ will be called spi-dln2.
+
config SPI_EFM32
tristate "EFM32 SPI controller"
depends on OF && ARM && (ARCH_EFM32 || COMPILE_TEST)
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 762da07..b315da2 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_SPI_CADENCE) += spi-cadence.o
obj-$(CONFIG_SPI_CLPS711X) += spi-clps711x.o
obj-$(CONFIG_SPI_COLDFIRE_QSPI) += spi-coldfire-qspi.o
obj-$(CONFIG_SPI_DAVINCI) += spi-davinci.o
+obj-$(CONFIG_SPI_DLN2) += spi-dln2.o
obj-$(CONFIG_SPI_DESIGNWARE) += spi-dw.o
obj-$(CONFIG_SPI_DW_MMIO) += spi-dw-mmio.o
obj-$(CONFIG_SPI_DW_PCI) += spi-dw-midpci.o
diff --git a/drivers/spi/spi-dln2.c b/drivers/spi/spi-dln2.c
new file mode 100644
index 0000000..bdd7a27
--- /dev/null
+++ b/drivers/spi/spi-dln2.c
@@ -0,0 +1,795 @@
+/*
+ * Driver for the Diolan DLN-2 USB-SPI adapter
+ *
+ * Copyright (c) 2014 Intel Corporation
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/dln2.h>
+#include <linux/spi/spi.h>
+
+#define DLN2_SPI_MODULE_ID 0x02
+#define DLN2_SPI_CMD(cmd) DLN2_CMD(cmd, DLN2_SPI_MODULE_ID)
+
+/* SPI commands */
+#define DLN2_SPI_GET_PORT_COUNT DLN2_SPI_CMD(0x00)
+#define DLN2_SPI_ENABLE DLN2_SPI_CMD(0x11)
+#define DLN2_SPI_DISABLE DLN2_SPI_CMD(0x12)
+#define DLN2_SPI_IS_ENABLED DLN2_SPI_CMD(0x13)
+#define DLN2_SPI_SET_MODE DLN2_SPI_CMD(0x14)
+#define DLN2_SPI_GET_MODE DLN2_SPI_CMD(0x15)
+#define DLN2_SPI_SET_FRAME_SIZE DLN2_SPI_CMD(0x16)
+#define DLN2_SPI_GET_FRAME_SIZE DLN2_SPI_CMD(0x17)
+#define DLN2_SPI_SET_FREQUENCY DLN2_SPI_CMD(0x18)
+#define DLN2_SPI_GET_FREQUENCY DLN2_SPI_CMD(0x19)
+#define DLN2_SPI_READ_WRITE DLN2_SPI_CMD(0x1A)
+#define DLN2_SPI_READ DLN2_SPI_CMD(0x1B)
+#define DLN2_SPI_WRITE DLN2_SPI_CMD(0x1C)
+#define DLN2_SPI_SET_DELAY_BETWEEN_SS DLN2_SPI_CMD(0x20)
+#define DLN2_SPI_GET_DELAY_BETWEEN_SS DLN2_SPI_CMD(0x21)
+#define DLN2_SPI_SET_DELAY_AFTER_SS DLN2_SPI_CMD(0x22)
+#define DLN2_SPI_GET_DELAY_AFTER_SS DLN2_SPI_CMD(0x23)
+#define DLN2_SPI_SET_DELAY_BETWEEN_FRAMES DLN2_SPI_CMD(0x24)
+#define DLN2_SPI_GET_DELAY_BETWEEN_FRAMES DLN2_SPI_CMD(0x25)
+#define DLN2_SPI_SET_SS DLN2_SPI_CMD(0x26)
+#define DLN2_SPI_GET_SS DLN2_SPI_CMD(0x27)
+#define DLN2_SPI_RELEASE_SS DLN2_SPI_CMD(0x28)
+#define DLN2_SPI_SS_VARIABLE_ENABLE DLN2_SPI_CMD(0x2B)
+#define DLN2_SPI_SS_VARIABLE_DISABLE DLN2_SPI_CMD(0x2C)
+#define DLN2_SPI_SS_VARIABLE_IS_ENABLED DLN2_SPI_CMD(0x2D)
+#define DLN2_SPI_SS_AAT_ENABLE DLN2_SPI_CMD(0x2E)
+#define DLN2_SPI_SS_AAT_DISABLE DLN2_SPI_CMD(0x2F)
+#define DLN2_SPI_SS_AAT_IS_ENABLED DLN2_SPI_CMD(0x30)
+#define DLN2_SPI_SS_BETWEEN_FRAMES_ENABLE DLN2_SPI_CMD(0x31)
+#define DLN2_SPI_SS_BETWEEN_FRAMES_DISABLE DLN2_SPI_CMD(0x32)
+#define DLN2_SPI_SS_BETWEEN_FRAMES_IS_ENABLED DLN2_SPI_CMD(0x33)
+#define DLN2_SPI_SET_CPHA DLN2_SPI_CMD(0x34)
+#define DLN2_SPI_GET_CPHA DLN2_SPI_CMD(0x35)
+#define DLN2_SPI_SET_CPOL DLN2_SPI_CMD(0x36)
+#define DLN2_SPI_GET_CPOL DLN2_SPI_CMD(0x37)
+#define DLN2_SPI_SS_MULTI_ENABLE DLN2_SPI_CMD(0x38)
+#define DLN2_SPI_SS_MULTI_DISABLE DLN2_SPI_CMD(0x39)
+#define DLN2_SPI_SS_MULTI_IS_ENABLED DLN2_SPI_CMD(0x3A)
+#define DLN2_SPI_GET_SUPPORTED_MODES DLN2_SPI_CMD(0x40)
+#define DLN2_SPI_GET_SUPPORTED_CPHA_VALUES DLN2_SPI_CMD(0x41)
+#define DLN2_SPI_GET_SUPPORTED_CPOL_VALUES DLN2_SPI_CMD(0x42)
+#define DLN2_SPI_GET_SUPPORTED_FRAME_SIZES DLN2_SPI_CMD(0x43)
+#define DLN2_SPI_GET_SS_COUNT DLN2_SPI_CMD(0x44)
+#define DLN2_SPI_GET_MIN_FREQUENCY DLN2_SPI_CMD(0x45)
+#define DLN2_SPI_GET_MAX_FREQUENCY DLN2_SPI_CMD(0x46)
+#define DLN2_SPI_GET_MIN_DELAY_BETWEEN_SS DLN2_SPI_CMD(0x47)
+#define DLN2_SPI_GET_MAX_DELAY_BETWEEN_SS DLN2_SPI_CMD(0x48)
+#define DLN2_SPI_GET_MIN_DELAY_AFTER_SS DLN2_SPI_CMD(0x49)
+#define DLN2_SPI_GET_MAX_DELAY_AFTER_SS DLN2_SPI_CMD(0x4A)
+#define DLN2_SPI_GET_MIN_DELAY_BETWEEN_FRAMES DLN2_SPI_CMD(0x4B)
+#define DLN2_SPI_GET_MAX_DELAY_BETWEEN_FRAMES DLN2_SPI_CMD(0x4C)
+
+#define DLN2_SPI_MAX_XFER_SIZE 256
+#define DLN2_SPI_BUF_SIZE (DLN2_SPI_MAX_XFER_SIZE + 16)
+#define DLN2_SPI_ATTR_LEAVE_SS_LOW BIT(0)
+#define DLN2_TRANSFERS_WAIT_COMPLETE 1
+#define DLN2_TRANSFERS_CANCEL 0
+
+struct dln2_spi {
+ struct platform_device *pdev;
+ struct spi_master *master;
+ u8 port;
+
+ void *buf;
+
+ u8 bpw;
+ u32 speed;
+ u16 mode;
+ u8 cs;
+};
+
+/*
+ * Enable/Disable SPI module. The disable command will wait for transfers to
+ * complete first.
+ */
+static int dln2_spi_enable(struct dln2_spi *dln2, bool enable)
+{
+ int ret;
+ u16 cmd;
+ struct {
+ u8 port;
+ u8 wait_for_completion;
+ } __packed tx;
+ unsigned len = sizeof(tx);
+
+ tx.port = dln2->port;
+
+ if (enable) {
+ cmd = DLN2_SPI_ENABLE;
+ len -= sizeof(tx.wait_for_completion);
+ } else {
+ tx.wait_for_completion = DLN2_TRANSFERS_WAIT_COMPLETE;
+ cmd = DLN2_SPI_DISABLE;
+ }
+
+ ret = dln2_transfer_tx(dln2->pdev, cmd, &tx, len);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+/*
+ * Select/unselect multiple CS lines. The selected lines will be automatically
+ * toggled LOW/HIGH by the board firmware during transfers, provided they're
+ * enabled first.
+ *
+ * Ex: cs_mask = 0x03 -> CS0 & CS1 will be selected and the next WR/RD operation
+ * will toggle the lines LOW/HIGH automatically.
+ */
+static int dln2_spi_cs_set(struct dln2_spi *dln2, u8 cs_mask)
+{
+ struct {
+ u8 port;
+ u8 cs;
+ } __packed tx;
+
+ tx.port = dln2->port;
+
+ /* According to Diolan docs, "a slave device can be selected by changing
+ * the corresponding bit value to 0". The rest must be set to 1. Hence
+ * the bitwise NOT in front.
+ */
+ tx.cs = ~cs_mask;
+
+ return dln2_transfer_tx(dln2->pdev, DLN2_SPI_SET_SS, &tx, sizeof(tx));
+}
+
+/*
+ * Select one CS line. The other lines will be un-selected.
+ */
+static int dln2_spi_cs_set_one(struct dln2_spi *dln2, u8 cs)
+{
+ return dln2_spi_cs_set(dln2, BIT(cs));
+}
+
+/*
+ * Enable/disable CS lines for usage. The module has to be disabled first.
+ */
+static int dln2_spi_cs_enable(struct dln2_spi *dln2, u8 cs_mask, bool enable)
+{
+ struct {
+ u8 port;
+ u8 cs;
+ } __packed tx;
+ u16 cmd;
+
+ tx.port = dln2->port;
+ tx.cs = cs_mask;
+ cmd = enable ? DLN2_SPI_SS_MULTI_ENABLE : DLN2_SPI_SS_MULTI_DISABLE;
+
+ return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
+}
+
+static int dln2_spi_cs_enable_all(struct dln2_spi *dln2, bool enable)
+{
+ u8 cs_mask = GENMASK(dln2->master->num_chipselect - 1, 0);
+
+ return dln2_spi_cs_enable(dln2, cs_mask, enable);
+}
+
+static int dln2_spi_get_cs_num(struct dln2_spi *dln2, u16 *cs_num)
+{
+ int ret;
+ struct {
+ u8 port;
+ } tx;
+ struct {
+ __le16 cs_count;
+ } *rx = dln2->buf;
+ unsigned rx_len = sizeof(*rx);
+
+ tx.port = dln2->port;
+ ret = dln2_transfer(dln2->pdev, DLN2_SPI_GET_SS_COUNT, &tx, sizeof(tx),
+ rx, &rx_len);
+ if (ret < 0)
+ return ret;
+ if (rx_len < sizeof(*rx))
+ return -EPROTO;
+
+ *cs_num = le16_to_cpu(rx->cs_count);
+
+ dev_dbg(&dln2->pdev->dev, "cs_num = %d\n", *cs_num);
+
+ return 0;
+}
+
+/*
+ * Get bus min/max frequencies.
+ */
+static int dln2_spi_get_speed_range(struct dln2_spi *dln2, u32 *fmin, u32 *fmax)
+{
+ int ret;
+ struct {
+ u8 port;
+ } tx;
+ struct {
+ __le32 speed;
+ } *rx = dln2->buf;
+ unsigned rx_len = sizeof(*rx);
+ int cmd[2] = {DLN2_SPI_GET_MIN_FREQUENCY, DLN2_SPI_GET_MAX_FREQUENCY};
+ u32 *speed[2] = {fmin, fmax};
+ int i;
+
+ tx.port = dln2->port;
+
+ for (i = 0; i < 2; i++) {
+ ret = dln2_transfer(dln2->pdev, cmd[i], &tx, sizeof(tx),
+ rx, &rx_len);
+ if (ret < 0)
+ return ret;
+ if (rx_len < sizeof(*rx))
+ return -EPROTO;
+
+ *speed[i] = le32_to_cpu(rx->speed);
+ }
+
+ dev_dbg(&dln2->pdev->dev, "freq_min = %d, freq_max = %d\n",
+ *fmin, *fmax);
+
+ return 0;
+}
+
+/*
+ * Set the bus speed. The module will automatically round down to the closest
+ * available frequency and returns it. The module has to be disabled first.
+ */
+static int dln2_spi_set_speed(struct dln2_spi *dln2, u32 speed,
+ u32 *probed_speed)
+{
+ int ret;
+ struct {
+ u8 port;
+ __le32 speed;
+ } __packed tx;
+ struct {
+ __le32 speed;
+ } __packed *rx = dln2->buf;
+ int rx_len = sizeof(*rx);
+
+ tx.port = dln2->port;
+ tx.speed = cpu_to_le32(speed);
+
+ ret = dln2_transfer(dln2->pdev, DLN2_SPI_SET_FREQUENCY, &tx, sizeof(tx),
+ rx, &rx_len);
+ if (ret < 0)
+ return ret;
+ if (rx_len < sizeof(*rx))
+ return -EPROTO;
+
+ if (probed_speed)
+ *probed_speed = le32_to_cpu(rx->speed);
+
+ return 0;
+}
+
+/*
+ * Change CPOL & CPHA. The module has to be disabled first.
+ */
+static int dln2_spi_set_mode(struct dln2_spi *dln2, u8 mode)
+{
+ struct {
+ u8 port;
+ u8 mode;
+ } __packed tx;
+
+ tx.port = dln2->port;
+ tx.mode = mode;
+
+ return dln2_transfer_tx(dln2->pdev, DLN2_SPI_SET_MODE, &tx, sizeof(tx));
+}
+
+/*
+ * Change frame size. The module has to be disabled first.
+ */
+static int dln2_spi_set_bpw(struct dln2_spi *dln2, u8 bpw)
+{
+ struct {
+ u8 port;
+ u8 bpw;
+ } __packed tx;
+
+ tx.port = dln2->port;
+ tx.bpw = bpw;
+
+ return dln2_transfer_tx(dln2->pdev, DLN2_SPI_SET_FRAME_SIZE,
+ &tx, sizeof(tx));
+}
+
+static int dln2_spi_get_supported_frame_sizes(struct dln2_spi *dln2,
+ u32 *bpw_mask)
+{
+ int ret;
+ struct {
+ u8 port;
+ } tx;
+ struct {
+ u8 count;
+ u8 frame_sizes[36];
+ } __packed *rx = dln2->buf;
+ unsigned rx_len = sizeof(*rx);
+ int i;
+
+ tx.port = dln2->port;
+
+ ret = dln2_transfer(dln2->pdev, DLN2_SPI_GET_SUPPORTED_FRAME_SIZES,
+ &tx, sizeof(tx), rx, &rx_len);
+ if (ret < 0)
+ return ret;
+ if (rx_len < sizeof(*rx))
+ return -EPROTO;
+
+ *bpw_mask = 0;
+ for (i = 0; i < rx->count; i++)
+ *bpw_mask |= BIT(rx->frame_sizes[i] - 1);
+
+ dev_dbg(&dln2->pdev->dev, "bpw_mask = 0x%X\n", *bpw_mask);
+
+ return 0;
+}
+
+/*
+ * Copy the data to DLN2 buffer and change the alignment to LE, requested by
+ * DLN2 module. SPI core makes sure that the data length is a multiple of word
+ * size.
+ */
+static int dln2_spi_copy_to_buf(u8 *dln2_buf, const u8 *src, u16 len, u8 bpw)
+{
+#ifdef __LITTLE_ENDIAN
+ memcpy(dln2_buf, src, len);
+#else
+ if (bpw <= 8)
+ memcpy(dln2_buf, src, len);
+ else if (bpw <= 16) {
+ __le16 *d = (__le16 *) dln2_buf;
+ u16 *s = (u16 *) src;
+
+ len = len / 2;
+ while (len--)
+ *d++ = cpu_to_le16p(s++);
+ } else {
+ __le32 *d = (__le32 *) dln2_buf;
+ u32 *s = (u32 *) src;
+
+ len = len / 4;
+ while (len--)
+ *d++ = cpu_to_le32p(s++);
+ }
+#endif
+
+ return 0;
+}
+
+/*
+ * Copy the data from DLN2 buffer and convert to CPU alignment since the DLN2
+ * buffer is LE aligned. SPI core makes sure that the data length is a multiple
+ * of word size.
+ */
+static int dln2_spi_copy_from_buf(u8 *dest, const u8 *dln2_buf, u16 len, u8 bpw)
+{
+#ifdef __LITTLE_ENDIAN
+ memcpy(dest, dln2_buf, len);
+#else
+ if (bpw <= 8)
+ memcpy(dest, dln2_buf, len);
+ else if (bpw <= 16) {
+ u16 *d = (u16 *) dest;
+ __le16 *s = (__le16 *) dln2_buf;
+
+ len = len / 2;
+ while (len--)
+ *d++ = le16_to_cpup(s++);
+ } else {
+ u32 *d = (u32 *) dest;
+ __le32 *s = (__le32 *) dln2_buf;
+
+ len = len / 4;
+ while (len--)
+ *d++ = le32_to_cpup(s++);
+ }
+#endif
+
+ return 0;
+}
+
+/*
+ * Perform one write operation.
+ */
+static int dln2_spi_write_one(struct dln2_spi *dln2, const u8 *data,
+ u16 data_len, u8 attr)
+{
+ struct {
+ u8 port;
+ __le16 size;
+ u8 attr;
+ u8 buf[DLN2_SPI_MAX_XFER_SIZE];
+ } __packed *tx = dln2->buf;
+ unsigned tx_len;
+
+ BUILD_BUG_ON(sizeof(*tx) > DLN2_SPI_BUF_SIZE);
+
+ if (data_len > DLN2_SPI_MAX_XFER_SIZE)
+ return -EINVAL;
+
+ tx->port = dln2->port;
+ tx->size = cpu_to_le16(data_len);
+ tx->attr = attr;
+
+ dln2_spi_copy_to_buf(tx->buf, data, data_len, dln2->bpw);
+
+ tx_len = sizeof(*tx) + data_len - DLN2_SPI_MAX_XFER_SIZE;
+ return dln2_transfer_tx(dln2->pdev, DLN2_SPI_WRITE, tx, tx_len);
+}
+
+/*
+ * Perform one read operation.
+ */
+static int dln2_spi_read_one(struct dln2_spi *dln2, u8 *data,
+ u16 data_len, u8 attr)
+{
+ int ret;
+ struct {
+ u8 port;
+ __le16 size;
+ u8 attr;
+ } __packed tx;
+ struct {
+ __le16 size;
+ u8 buf[DLN2_SPI_MAX_XFER_SIZE];
+ } __packed *rx = dln2->buf;
+ unsigned rx_len = sizeof(*rx);
+
+ BUILD_BUG_ON(sizeof(*rx) > DLN2_SPI_BUF_SIZE);
+
+ if (data_len > DLN2_SPI_MAX_XFER_SIZE)
+ return -EINVAL;
+
+ tx.port = dln2->port;
+ tx.size = cpu_to_le16(data_len);
+ tx.attr = attr;
+
+ ret = dln2_transfer(dln2->pdev, DLN2_SPI_READ, &tx, sizeof(tx),
+ rx, &rx_len);
+ if (ret < 0)
+ return ret;
+ if (rx_len < sizeof(rx->size) + data_len)
+ return -EPROTO;
+ if (le16_to_cpu(rx->size) != data_len)
+ return -EPROTO;
+
+ dln2_spi_copy_from_buf(data, rx->buf, data_len, dln2->bpw);
+
+ return 0;
+}
+
+/*
+ * Perform one write & read operation.
+ */
+static int dln2_spi_read_write_one(struct dln2_spi *dln2, const u8 *tx_data,
+ u8 *rx_data, u16 data_len, u8 attr)
+{
+ int ret;
+ struct {
+ u8 port;
+ __le16 size;
+ u8 attr;
+ u8 buf[DLN2_SPI_MAX_XFER_SIZE];
+ } __packed *tx;
+ struct {
+ __le16 size;
+ u8 buf[DLN2_SPI_MAX_XFER_SIZE];
+ } __packed *rx;
+ unsigned tx_len, rx_len;
+
+ BUILD_BUG_ON(sizeof(*tx) > DLN2_SPI_BUF_SIZE ||
+ sizeof(*rx) > DLN2_SPI_BUF_SIZE);
+
+ if (data_len > DLN2_SPI_MAX_XFER_SIZE)
+ return -EINVAL;
+
+ /* Since this is a pseudo full-duplex communication, we're perfectly
+ * safe to use the same buffer for both tx and rx. When DLN2 sends the
+ * response back, with the rx data, we don't need the tx buffer anymore.
+ */
+ tx = dln2->buf;
+ rx = dln2->buf;
+
+ tx->port = dln2->port;
+ tx->size = cpu_to_le16(data_len);
+ tx->attr = attr;
+
+ dln2_spi_copy_to_buf(tx->buf, tx_data, data_len, dln2->bpw);
+
+ tx_len = sizeof(*tx) + data_len - DLN2_SPI_MAX_XFER_SIZE;
+ rx_len = sizeof(*rx);
+
+ ret = dln2_transfer(dln2->pdev, DLN2_SPI_READ_WRITE, tx, tx_len,
+ rx, &rx_len);
+ if (ret < 0)
+ return ret;
+ if (rx_len < sizeof(rx->size) + data_len)
+ return -EPROTO;
+ if (le16_to_cpu(rx->size) != data_len)
+ return -EPROTO;
+
+ dln2_spi_copy_from_buf(rx_data, rx->buf, data_len, dln2->bpw);
+
+ return 0;
+}
+
+/*
+ * Read/Write wrapper. It will automatically split an operation into multiple
+ * single ones due to device buffer constraints.
+ */
+static int dln2_spi_rdwr(struct dln2_spi *dln2, const u8 *tx_data,
+ u8 *rx_data, u16 data_len, u8 attr) {
+ int ret;
+ u16 len;
+ u8 temp_attr;
+ u16 remaining = data_len;
+ u16 offset;
+
+ do {
+ if (remaining > DLN2_SPI_MAX_XFER_SIZE) {
+ len = DLN2_SPI_MAX_XFER_SIZE;
+ temp_attr = DLN2_SPI_ATTR_LEAVE_SS_LOW;
+ } else {
+ len = remaining;
+ temp_attr = attr;
+ }
+
+ offset = data_len - remaining;
+
+ if (tx_data && rx_data)
+ ret = dln2_spi_read_write_one(dln2,
+ tx_data + offset,
+ rx_data + offset,
+ len, temp_attr);
+ else if (tx_data)
+ ret = dln2_spi_write_one(dln2,
+ tx_data + offset,
+ len, temp_attr);
+ else if (rx_data)
+ ret = dln2_spi_read_one(dln2,
+ rx_data + offset,
+ len, temp_attr);
+ else
+ return -EINVAL;
+
+ if (ret < 0)
+ return ret;
+
+ remaining -= len;
+ } while (remaining);
+
+ return 0;
+}
+
+static int dln2_spi_prepare_message(struct spi_master *master,
+ struct spi_message *message)
+{
+ int ret;
+ struct dln2_spi *dln2 = spi_master_get_devdata(master);
+ struct spi_device *spi = message->spi;
+
+ if (dln2->cs != spi->chip_select) {
+ ret = dln2_spi_cs_set_one(dln2, spi->chip_select);
+ if (ret < 0)
+ return ret;
+
+ dln2->cs = spi->chip_select;
+ }
+
+ return 0;
+}
+
+static int dln2_spi_transfer_setup(struct dln2_spi *dln2, u32 speed,
+ u8 bpw, u8 mode)
+{
+ int ret;
+ bool bus_setup_change;
+
+ bus_setup_change = dln2->speed != speed || dln2->mode != mode ||
+ dln2->bpw != bpw;
+
+ if (!bus_setup_change)
+ return 0;
+
+ ret = dln2_spi_enable(dln2, false);
+ if (ret < 0)
+ return ret;
+
+ if (dln2->speed != speed) {
+ ret = dln2_spi_set_speed(dln2, speed, NULL);
+ if (ret < 0)
+ return ret;
+
+ dln2->speed = speed;
+ }
+
+ if (dln2->mode != mode) {
+ ret = dln2_spi_set_mode(dln2, mode & 0x3);
+ if (ret < 0)
+ return ret;
+
+ dln2->mode = mode;
+ }
+
+ if (dln2->bpw != bpw) {
+ ret = dln2_spi_set_bpw(dln2, bpw);
+ if (ret < 0)
+ return ret;
+
+ dln2->bpw = bpw;
+ }
+
+ ret = dln2_spi_enable(dln2, true);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int dln2_spi_transfer_one_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct dln2_spi *dln2 = spi_master_get_devdata(master);
+ struct spi_device *spi = msg->spi;
+ struct spi_transfer *xfer;
+ int status;
+
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ u8 attr = 0;
+
+ status = dln2_spi_transfer_setup(dln2, xfer->speed_hz,
+ xfer->bits_per_word,
+ spi->mode);
+ if (status < 0) {
+ dev_err(&dln2->pdev->dev, "Cannot setup transfer\n");
+ break;
+ }
+
+ if (!xfer->cs_change &&
+ !list_is_last(&xfer->transfer_list, &msg->transfers))
+ attr = xfer->cs_change ? 0 : DLN2_SPI_ATTR_LEAVE_SS_LOW;
+
+ status = dln2_spi_rdwr(dln2, xfer->tx_buf, xfer->rx_buf,
+ xfer->len, attr);
+ if (status < 0) {
+ dev_err(&dln2->pdev->dev, "write/read failed!\n");
+ break;
+ }
+
+ status = 0;
+ }
+
+ msg->status = status;
+ spi_finalize_current_message(master);
+ return status;
+}
+
+static int dln2_spi_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct dln2_spi *dln2;
+ struct dln2_platform_data *pdata = dev_get_platdata(&pdev->dev);
+ int ret;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(*dln2));
+ if (!master)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, master);
+
+ dln2 = spi_master_get_devdata(master);
+
+ dln2->buf = devm_kmalloc(&pdev->dev, DLN2_SPI_BUF_SIZE, GFP_KERNEL);
+ if (!dln2->buf) {
+ ret = -ENOMEM;
+ goto exit_free_master;
+ }
+
+ dln2->master = master;
+ dln2->pdev = pdev;
+ dln2->port = pdata->port;
+ /* cs number can never be 0xff, so the first transfer will set the cs */
+ dln2->cs = 0xff;
+
+ /* disable SPI module before continuing with the setup */
+ ret = dln2_spi_enable(dln2, false);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to disable SPI module\n");
+ goto exit_free_master;
+ }
+
+ ret = dln2_spi_get_cs_num(dln2, &master->num_chipselect);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to get number of CS pins\n");
+ goto exit_free_master;
+ }
+
+ ret = dln2_spi_get_speed_range(dln2,
+ &master->min_speed_hz,
+ &master->max_speed_hz);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to read bus min/max freqs\n");
+ goto exit_free_master;
+ }
+
+ ret = dln2_spi_get_supported_frame_sizes(dln2,
+ &master->bits_per_word_mask);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to read supported frame sizes\n");
+ goto exit_free_master;
+ }
+
+ ret = dln2_spi_cs_enable_all(dln2, true);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to enable CS pins\n");
+ goto exit_free_master;
+ }
+
+ master->bus_num = -1;
+ master->mode_bits = SPI_CPOL | SPI_CPHA;
+ master->prepare_message = dln2_spi_prepare_message;
+ master->transfer_one_message = dln2_spi_transfer_one_message;
+
+ /* enable SPI module, we're good to go */
+ ret = dln2_spi_enable(dln2, true);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to enable SPI module\n");
+ goto exit_free_master;
+ }
+
+ ret = devm_spi_register_master(&pdev->dev, master);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to register master\n");
+ goto exit_register;
+ }
+
+ return ret;
+
+exit_register:
+ if (dln2_spi_enable(dln2, false) < 0)
+ dev_err(&pdev->dev, "Failed to disable SPI module\n");
+exit_free_master:
+ spi_master_put(master);
+
+ return ret;
+}
+
+static int dln2_spi_remove(struct platform_device *pdev)
+{
+ struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
+ struct dln2_spi *dln2 = spi_master_get_devdata(master);
+
+ if (dln2_spi_enable(dln2, false) < 0)
+ dev_err(&pdev->dev, "Failed to disable SPI module\n");
+
+ spi_master_put(master);
+
+ return 0;
+}
+
+static struct platform_driver spi_dln2_driver = {
+ .driver.name = "dln2-spi",
+ .probe = dln2_spi_probe,
+ .remove = dln2_spi_remove,
+};
+module_platform_driver(spi_dln2_driver);
+
+MODULE_DESCRIPTION("Driver for the Diolan DLN2 SPI master interface");
+MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@intel.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:dln2-spi");
--
1.9.1


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