[PATCH v11 3/4] spi: Add support for Intel LJCA USB SPI driver

Wentong Wu
2023-08-29T04:55:54Z

Implements the SPI function of Intel USB-I2C/GPIO/SPI adapter device
named "La Jolla Cove Adapter" (LJCA). It communicate with LJCA SPI
module with specific protocol through interfaces exported by LJCA USB
driver.

Signed-off-by: Wentong Wu <wentong.wu@intel.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
drivers/spi/Kconfig | 11 ++
drivers/spi/Makefile | 1 +
drivers/spi/spi-ljca.c | 297 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 309 insertions(+)
create mode 100644 drivers/spi/spi-ljca.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 8962b25..ad18864 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -583,6 +583,17 @@ config SPI_FSL_ESPI
From MPC8536, 85xx platform uses the controller, and all P10xx,
P20xx, P30xx,P40xx, P50xx uses this controller.

+config SPI_LJCA
+ tristate "Intel La Jolla Cove Adapter SPI support"
+ depends on USB_LJCA
+ default USB_LJCA
+ help
+ Select this option to enable SPI driver for the Intel
+ La Jolla Cove Adapter (LJCA) board.
+
+ This driver can also be built as a module. If so, the module
+ will be called spi-ljca.
+
config SPI_MESON_SPICC
tristate "Amlogic Meson SPICC controller"
depends on COMMON_CLK
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 080c2c1..0847962 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -70,6 +70,7 @@ obj-$(CONFIG_SPI_INTEL_PCI) += spi-intel-pci.o
obj-$(CONFIG_SPI_INTEL_PLATFORM) += spi-intel-platform.o
obj-$(CONFIG_SPI_LANTIQ_SSC) += spi-lantiq-ssc.o
obj-$(CONFIG_SPI_JCORE) += spi-jcore.o
+obj-$(CONFIG_SPI_LJCA) += spi-ljca.o
obj-$(CONFIG_SPI_LM70_LLP) += spi-lm70llp.o
obj-$(CONFIG_SPI_LP8841_RTC) += spi-lp8841-rtc.o
obj-$(CONFIG_SPI_MESON_SPICC) += spi-meson-spicc.o
diff --git a/drivers/spi/spi-ljca.c b/drivers/spi/spi-ljca.c
new file mode 100644
index 0000000..6a9ca39
--- /dev/null
+++ b/drivers/spi/spi-ljca.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel La Jolla Cove Adapter USB-SPI driver
+ *
+ * Copyright (c) 2023, Intel Corporation.
+ */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/dev_printk.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/usb/ljca.h>
+
+#define LJCA_SPI_BUS_MAX_HZ 48000000
+
+#define LJCA_SPI_BUF_SIZE 60u
+#define LJCA_SPI_MAX_XFER_SIZE \
+ (LJCA_SPI_BUF_SIZE - sizeof(struct ljca_spi_xfer_packet))
+
+#define LJCA_SPI_CLK_MODE_POLARITY BIT(0)
+#define LJCA_SPI_CLK_MODE_PHASE BIT(1)
+
+#define LJCA_SPI_XFER_INDICATOR_ID GENMASK(5, 0)
+#define LJCA_SPI_XFER_INDICATOR_CMPL BIT(6)
+#define LJCA_SPI_XFER_INDICATOR_INDEX BIT(7)
+
+/* SPI commands */
+enum ljca_spi_cmd {
+ LJCA_SPI_INIT = 1,
+ LJCA_SPI_READ,
+ LJCA_SPI_WRITE,
+ LJCA_SPI_WRITEREAD,
+ LJCA_SPI_DEINIT,
+};
+
+enum {
+ LJCA_SPI_BUS_SPEED_24M,
+ LJCA_SPI_BUS_SPEED_12M,
+ LJCA_SPI_BUS_SPEED_8M,
+ LJCA_SPI_BUS_SPEED_6M,
+ LJCA_SPI_BUS_SPEED_4_8M, /*4.8MHz*/
+ LJCA_SPI_BUS_SPEED_MIN = LJCA_SPI_BUS_SPEED_4_8M,
+};
+
+enum {
+ LJCA_SPI_CLOCK_LOW_POLARITY,
+ LJCA_SPI_CLOCK_HIGH_POLARITY,
+};
+
+enum {
+ LJCA_SPI_CLOCK_FIRST_PHASE,
+ LJCA_SPI_CLOCK_SECOND_PHASE,
+};
+
+struct ljca_spi_init_packet {
+ u8 index;
+ u8 speed;
+ u8 mode;
+} __packed;
+
+struct ljca_spi_xfer_packet {
+ u8 indicator;
+ u8 len;
+ u8 data[];
+} __packed;
+
+struct ljca_spi_dev {
+ struct ljca_client *ljca;
+ struct spi_controller *controller;
+ struct ljca_spi_info *spi_info;
+ u8 speed;
+ u8 mode;
+
+ u8 obuf[LJCA_SPI_BUF_SIZE];
+ u8 ibuf[LJCA_SPI_BUF_SIZE];
+};
+
+static int ljca_spi_read_write(struct ljca_spi_dev *ljca_spi, const u8 *w_data,
+ u8 *r_data, int len, int id, int complete,
+ int cmd)
+{
+ struct ljca_spi_xfer_packet *w_packet =
+ (struct ljca_spi_xfer_packet *)ljca_spi->obuf;
+ struct ljca_spi_xfer_packet *r_packet =
+ (struct ljca_spi_xfer_packet *)ljca_spi->ibuf;
+ int ret;
+
+ w_packet->indicator = FIELD_PREP(LJCA_SPI_XFER_INDICATOR_ID, id) |
+ FIELD_PREP(LJCA_SPI_XFER_INDICATOR_CMPL, complete) |
+ FIELD_PREP(LJCA_SPI_XFER_INDICATOR_INDEX,
+ ljca_spi->spi_info->id);
+
+ if (cmd == LJCA_SPI_READ) {
+ w_packet->len = sizeof(u16);
+ *(__le16 *)&w_packet->data[0] = cpu_to_le16(len);
+ } else {
+ w_packet->len = len;
+ memcpy(w_packet->data, w_data, len);
+ }
+
+ ret = ljca_transfer(ljca_spi->ljca, cmd, w_packet,
+ struct_size(w_packet, data, w_packet->len),
+ r_packet, LJCA_SPI_BUF_SIZE);
+ if (ret < 0)
+ return ret;
+ else if (ret < sizeof(*r_packet) || r_packet->len <= 0)
+ return -EIO;
+
+ if (r_data)
+ memcpy(r_data, r_packet->data, r_packet->len);
+
+ return 0;
+}
+
+static int ljca_spi_init(struct ljca_spi_dev *ljca_spi, u8 div, u8 mode)
+{
+ struct ljca_spi_init_packet w_packet = {};
+ int ret;
+
+ if (ljca_spi->mode == mode && ljca_spi->speed == div)
+ return 0;
+
+ w_packet.index = ljca_spi->spi_info->id;
+ w_packet.speed = div;
+ w_packet.mode = FIELD_PREP(LJCA_SPI_CLK_MODE_POLARITY,
+ (mode & SPI_CPOL) ? LJCA_SPI_CLOCK_HIGH_POLARITY :
+ LJCA_SPI_CLOCK_LOW_POLARITY) |
+ FIELD_PREP(LJCA_SPI_CLK_MODE_PHASE,
+ (mode & SPI_CPHA) ? LJCA_SPI_CLOCK_SECOND_PHASE :
+ LJCA_SPI_CLOCK_FIRST_PHASE);
+
+ ret = ljca_transfer(ljca_spi->ljca, LJCA_SPI_INIT, &w_packet,
+ sizeof(w_packet), NULL, 0);
+ if (ret < 0)
+ return ret;
+
+ ljca_spi->mode = mode;
+ ljca_spi->speed = div;
+
+ return 0;
+}
+
+static int ljca_spi_deinit(struct ljca_spi_dev *ljca_spi)
+{
+ struct ljca_spi_init_packet w_packet = {};
+ int ret;
+
+ w_packet.index = ljca_spi->spi_info->id;
+
+ ret = ljca_transfer(ljca_spi->ljca, LJCA_SPI_DEINIT, &w_packet,
+ sizeof(w_packet), NULL, 0);
+
+ return ret < 0 ? ret : 0;
+}
+
+static inline int ljca_spi_transfer(struct ljca_spi_dev *ljca_spi,
+ const u8 *tx_data, u8 *rx_data, u16 len)
+{
+ int complete, cur_len;
+ int remaining = len;
+ int cmd, ret, i;
+ int offset = 0;
+
+ if (tx_data && rx_data)
+ cmd = LJCA_SPI_WRITEREAD;
+ else if (tx_data)
+ cmd = LJCA_SPI_WRITE;
+ else if (rx_data)
+ cmd = LJCA_SPI_READ;
+ else
+ return -EINVAL;
+
+ for (i = 0; remaining > 0; i++) {
+ cur_len = min_t(unsigned int, remaining, LJCA_SPI_MAX_XFER_SIZE);
+ complete = (cur_len == remaining);
+
+ ret = ljca_spi_read_write(ljca_spi,
+ tx_data ? tx_data + offset : NULL,
+ rx_data ? rx_data + offset : NULL,
+ cur_len, i, complete, cmd);
+ if (ret)
+ return ret;
+
+ offset += cur_len;
+ remaining -= cur_len;
+ }
+
+ return 0;
+}
+
+static int ljca_spi_transfer_one(struct spi_controller *controller,
+ struct spi_device *spi,
+ struct spi_transfer *xfer)
+{
+ u8 div = DIV_ROUND_UP(controller->max_speed_hz, xfer->speed_hz) / 2 - 1;
+ struct ljca_spi_dev *ljca_spi = spi_controller_get_devdata(controller);
+ int ret;
+
+ div = min_t(u8, LJCA_SPI_BUS_SPEED_MIN, div);
+
+ ret = ljca_spi_init(ljca_spi, div, spi->mode);
+ if (ret) {
+ dev_err(&ljca_spi->ljca->auxdev.dev,
+ "cannot initialize transfer ret %d\n", ret);
+ return ret;
+ }
+
+ ret = ljca_spi_transfer(ljca_spi, xfer->tx_buf, xfer->rx_buf, xfer->len);
+ if (ret)
+ dev_err(&ljca_spi->ljca->auxdev.dev,
+ "transfer failed len: %d\n", xfer->len);
+
+ return ret;
+}
+
+static int ljca_spi_probe(struct auxiliary_device *auxdev,
+ const struct auxiliary_device_id *aux_dev_id)
+{
+ struct ljca_client *ljca = auxiliary_dev_to_ljca_client(auxdev);
+ struct spi_controller *controller;
+ struct ljca_spi_dev *ljca_spi;
+ int ret;
+
+ controller = devm_spi_alloc_master(&auxdev->dev, sizeof(*ljca_spi));
+ if (!controller)
+ return -ENOMEM;
+
+ ljca_spi = spi_controller_get_devdata(controller);
+ ljca_spi->ljca = ljca;
+ ljca_spi->spi_info = dev_get_platdata(&auxdev->dev);
+ ljca_spi->controller = controller;
+
+ controller->bus_num = -1;
+ controller->mode_bits = SPI_CPHA | SPI_CPOL;
+ controller->transfer_one = ljca_spi_transfer_one;
+ controller->auto_runtime_pm = false;
+ controller->max_speed_hz = LJCA_SPI_BUS_MAX_HZ;
+
+ device_set_node(&ljca_spi->controller->dev, dev_fwnode(&auxdev->dev));
+ auxiliary_set_drvdata(auxdev, controller);
+
+ ret = spi_register_controller(controller);
+ if (ret)
+ dev_err(&auxdev->dev, "Failed to register controller\n");
+
+ return ret;
+}
+
+static void ljca_spi_dev_remove(struct auxiliary_device *auxdev)
+{
+ struct spi_controller *controller = auxiliary_get_drvdata(auxdev);
+ struct ljca_spi_dev *ljca_spi = spi_controller_get_devdata(controller);
+
+ spi_unregister_controller(controller);
+ ljca_spi_deinit(ljca_spi);
+}
+
+static int ljca_spi_dev_suspend(struct device *dev)
+{
+ struct spi_controller *controller = dev_get_drvdata(dev);
+
+ return spi_controller_suspend(controller);
+}
+
+static int ljca_spi_dev_resume(struct device *dev)
+{
+ struct spi_controller *controller = dev_get_drvdata(dev);
+
+ return spi_controller_resume(controller);
+}
+
+static const struct dev_pm_ops ljca_spi_pm = {
+ SYSTEM_SLEEP_PM_OPS(ljca_spi_dev_suspend, ljca_spi_dev_resume)
+};
+
+static const struct auxiliary_device_id ljca_spi_id_table[] = {
+ { "usb_ljca.ljca-spi", 0 },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(auxiliary, ljca_spi_id_table);
+
+static struct auxiliary_driver ljca_spi_driver = {
+ .driver.pm = &ljca_spi_pm,
+ .probe = ljca_spi_probe,
+ .remove = ljca_spi_dev_remove,
+ .id_table = ljca_spi_id_table,
+};
+module_auxiliary_driver(ljca_spi_driver);
+
+MODULE_AUTHOR("Wentong Wu <wentong.wu@intel.com>");
+MODULE_AUTHOR("Zhifeng Wang <zhifeng.wang@intel.com>");
+MODULE_AUTHOR("Lixu Zhang <lixu.zhang@intel.com>");
+MODULE_DESCRIPTION("Intel La Jolla Cove Adapter USB-SPI driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(LJCA);
--
2.7.4