[PATCH v3] spi: add Renesas RPC-IF driver

Sergei Shtylyov
2020-05-08T19:54:16Z

Add the SPI driver for the Renesas RPC-IF. It's the "front end" driver
using the "back end" APIs in the main driver to talk to the real hardware.
We only implement the 'spi-mem' interface -- there's no need to implement
the usual SPI driver methods...

Based on the original patch by Mason Yang <masonccyang@mxic.com.tw>.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

---
This patch is against the 'for-next' branch of Mark Brown's 'spi.git' repo.
It depends on the memory RPC-IF driver in order to build/work:

https://patchwork.kernel.org/patch/11521595/
https://patchwork.kernel.org/patch/11521597/

Changes in version 3:
- properly set up the direction field in rpcif_spi_mem_prepare() when there's
no data;
- renamed rpcif_io_xfer() to rpcif_manual_xfer();
- extended Cogent Embedded's copyright to this year.

Changes in version 2:
- removed unneeded transfer_one_message() method and the related code;
- fixed up #include's as we switch from MFD to the memory core driver;
- removed unneeded #include <linux/pm_runtime.h>;
- removed 'struct rpcif_spi', replacing it with 'struct rpcif' everywhere;
- added spi_mem_default_supports_op() call to rpcif_spi_mem_supports_op();
- added rpcif_sw_init() call in rpcif_spi_probe();
- set SPI_CONTROLLER_HALF_DUPLEX flag in rpcif_spi_probe();
- added a new variable 'struct device *parent' and renamed the 'ret' variable
to 'error' in rpcif_spi_probe();
- changed the order of calls in the error path of rpcif_spi_probe() and in
rpcif_spi_remove();
- changed from 'select' to 'depends on' the main driver Kconfig symbol,
removed 'depends on ARCH_RENESAS || COMPILE TEST';
- renamed rpcif_spi_mem_set_prep_op_cfg() to rpcif_spi_mem_prepare(), updated
the rpcif_io_xfer() call there to match the RPC-IF core driver, changed
'rpc_op' there from parameter into the local variable;
- changed the platform driver's name to "rpc-if-spi";
- fixed whitespace in rpcif_spi_mem_exec_op()'s prototype;
- beautified the whitespace in the initializers of 'rpcif_spi_mem_ops' and
'rpcif_spi_driver';
- changed the heading comment from /* */ to //;
- updated the patch description with more details.

drivers/spi/Kconfig | 6 +
drivers/spi/Makefile | 1
drivers/spi/spi-rpc-if.c | 216 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 223 insertions(+)

Index: spi/drivers/spi/Kconfig
===================================================================
--- spi.orig/drivers/spi/Kconfig
+++ spi/drivers/spi/Kconfig
@@ -602,6 +602,12 @@ config SPI_RB4XX
help
SPI controller driver for the Mikrotik RB4xx series boards.

+config SPI_RPCIF
+ tristate "Renesas RPC-IF SPI driver"
+ depends on RENESAS_RPCIF
+ help
+ SPI driver for Renesas R-Car Gen3 RPC-IF.
+
config SPI_RSPI
tristate "Renesas RSPI/QSPI controller"
depends on SUPERH || ARCH_RENESAS || COMPILE_TEST
Index: spi/drivers/spi/Makefile
===================================================================
--- spi.orig/drivers/spi/Makefile
+++ spi/drivers/spi/Makefile
@@ -91,6 +91,7 @@ obj-$(CONFIG_SPI_QCOM_QSPI) += spi-qcom
obj-$(CONFIG_SPI_QUP) += spi-qup.o
obj-$(CONFIG_SPI_ROCKCHIP) += spi-rockchip.o
obj-$(CONFIG_SPI_RB4XX) += spi-rb4xx.o
+obj-$(CONFIG_SPI_RPCIF) += spi-rpc-if.o
obj-$(CONFIG_SPI_RSPI) += spi-rspi.o
obj-$(CONFIG_SPI_S3C24XX) += spi-s3c24xx-hw.o
spi-s3c24xx-hw-y := spi-s3c24xx.o
Index: spi/drivers/spi/spi-rpc-if.c
===================================================================
--- /dev/null
+++ spi/drivers/spi/spi-rpc-if.c
@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// RPC-IF SPI/QSPI/Octa driver
+//
+// Copyright (C) 2018 ~ 2019 Renesas Solutions Corp.
+// Copyright (C) 2019 Macronix International Co., Ltd.
+// Copyright (C) 2019 - 2020 Cogent Embedded, Inc.
+//
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-mem.h>
+
+#include <memory/renesas-rpc-if.h>
+
+#include <asm/unaligned.h>
+
+static void rpcif_spi_mem_prepare(struct spi_device *spi_dev,
+ const struct spi_mem_op *spi_op,
+ u64 *offs, size_t *len)
+{
+ struct rpcif *rpc = spi_controller_get_devdata(spi_dev->controller);
+ struct rpcif_op rpc_op = { };
+
+ rpc_op.cmd.opcode = spi_op->cmd.opcode;
+ rpc_op.cmd.buswidth = spi_op->cmd.buswidth;
+
+ if (spi_op->addr.nbytes) {
+ rpc_op.addr.buswidth = spi_op->addr.buswidth;
+ rpc_op.addr.nbytes = spi_op->addr.nbytes;
+ rpc_op.addr.val = spi_op->addr.val;
+ }
+
+ if (spi_op->dummy.nbytes) {
+ rpc_op.dummy.buswidth = spi_op->dummy.buswidth;
+ rpc_op.dummy.ncycles = spi_op->dummy.nbytes * 8 /
+ spi_op->dummy.buswidth;
+ }
+
+ if (spi_op->data.nbytes || (offs && len)) {
+ rpc_op.data.buswidth = spi_op->data.buswidth;
+ rpc_op.data.nbytes = spi_op->data.nbytes;
+ switch (spi_op->data.dir) {
+ case SPI_MEM_DATA_IN:
+ rpc_op.data.dir = RPCIF_DATA_IN;
+ rpc_op.data.buf.in = spi_op->data.buf.in;
+ break;
+ case SPI_MEM_DATA_OUT:
+ rpc_op.data.dir = RPCIF_DATA_OUT;
+ rpc_op.data.buf.out = spi_op->data.buf.out;
+ break;
+ case SPI_MEM_NO_DATA:
+ rpc_op.data.dir = RPCIF_NO_DATA;
+ break;
+ }
+ } else {
+ rpc_op.data.dir = RPCIF_NO_DATA;
+ }
+
+ rpcif_prepare(rpc, &rpc_op, offs, len);
+}
+
+static bool rpcif_spi_mem_supports_op(struct spi_mem *mem,
+ const struct spi_mem_op *op)
+{
+ if (!spi_mem_default_supports_op(mem, op))
+ return false;
+
+ if (op->data.buswidth > 4 || op->addr.buswidth > 4 ||
+ op->dummy.buswidth > 4 || op->cmd.buswidth > 4 ||
+ op->addr.nbytes > 4)
+ return false;
+
+ return true;
+}
+
+static ssize_t rpcif_spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc,
+ u64 offs, size_t len, void *buf)
+{
+ struct rpcif *rpc =
+ spi_controller_get_devdata(desc->mem->spi->controller);
+
+ if (offs + desc->info.offset + len > U32_MAX)
+ return -EINVAL;
+
+ rpcif_spi_mem_prepare(desc->mem->spi, &desc->info.op_tmpl, &offs, &len);
+
+ return rpcif_dirmap_read(rpc, offs, len, buf);
+}
+
+static int rpcif_spi_mem_dirmap_create(struct spi_mem_dirmap_desc *desc)
+{
+ struct rpcif *rpc =
+ spi_controller_get_devdata(desc->mem->spi->controller);
+
+ if (desc->info.offset + desc->info.length > U32_MAX)
+ return -ENOTSUPP;
+
+ if (!rpcif_spi_mem_supports_op(desc->mem, &desc->info.op_tmpl))
+ return -ENOTSUPP;
+
+ if (!rpc->dirmap && desc->info.op_tmpl.data.dir == SPI_MEM_DATA_IN)
+ return -ENOTSUPP;
+
+ if (desc->info.op_tmpl.data.dir == SPI_MEM_DATA_OUT)
+ return -ENOTSUPP;
+
+ return 0;
+}
+
+static int rpcif_spi_mem_exec_op(struct spi_mem *mem,
+ const struct spi_mem_op *op)
+{
+ struct rpcif *rpc =
+ spi_controller_get_devdata(mem->spi->controller);
+
+ rpcif_spi_mem_prepare(mem->spi, op, NULL, NULL);
+
+ return rpcif_manual_xfer(rpc);
+}
+
+static const struct spi_controller_mem_ops rpcif_spi_mem_ops = {
+ .supports_op = rpcif_spi_mem_supports_op,
+ .exec_op = rpcif_spi_mem_exec_op,
+ .dirmap_create = rpcif_spi_mem_dirmap_create,
+ .dirmap_read = rpcif_spi_mem_dirmap_read,
+};
+
+static int rpcif_spi_probe(struct platform_device *pdev)
+{
+ struct device *parent = pdev->dev.parent;
+ struct spi_controller *ctlr;
+ struct rpcif *rpc;
+ int error;
+
+ ctlr = spi_alloc_master(&pdev->dev, sizeof(*rpc));
+ if (!ctlr)
+ return -ENOMEM;
+
+ rpc = spi_controller_get_devdata(ctlr);
+ rpcif_sw_init(rpc, parent);
+
+ platform_set_drvdata(pdev, ctlr);
+
+ ctlr->dev.of_node = parent->of_node;
+
+ rpcif_enable_rpm(rpc);
+
+ ctlr->num_chipselect = 1;
+ ctlr->mem_ops = &rpcif_spi_mem_ops;
+
+ ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
+ ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_TX_QUAD | SPI_RX_QUAD;
+ ctlr->flags = SPI_CONTROLLER_HALF_DUPLEX;
+
+ rpcif_hw_init(rpc, false);
+
+ error = spi_register_controller(ctlr);
+ if (error) {
+ dev_err(&pdev->dev, "spi_register_controller failed\n");
+ goto err_put_ctlr;
+ }
+ return 0;
+
+err_put_ctlr:
+ rpcif_disable_rpm(rpc);
+ spi_controller_put(ctlr);
+
+ return error;
+}
+
+static int rpcif_spi_remove(struct platform_device *pdev)
+{
+ struct spi_controller *ctlr = platform_get_drvdata(pdev);
+ struct rpcif *rpc = spi_controller_get_devdata(ctlr);
+
+ spi_unregister_controller(ctlr);
+ rpcif_disable_rpm(rpc);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int rpcif_spi_suspend(struct device *dev)
+{
+ struct spi_controller *ctlr = dev_get_drvdata(dev);
+
+ return spi_controller_suspend(ctlr);
+}
+
+static int rpcif_spi_resume(struct device *dev)
+{
+ struct spi_controller *ctlr = dev_get_drvdata(dev);
+
+ return spi_controller_resume(ctlr);
+}
+
+static SIMPLE_DEV_PM_OPS(rpcif_spi_pm_ops, rpcif_spi_suspend, rpcif_spi_resume);
+#define DEV_PM_OPS (&rpcif_spi_pm_ops)
+#else
+#define DEV_PM_OPS NULL
+#endif
+
+static struct platform_driver rpcif_spi_driver = {
+ .probe = rpcif_spi_probe,
+ .remove = rpcif_spi_remove,
+ .driver = {
+ .name = "rpc-if-spi",
+ .pm = DEV_PM_OPS,
+ },
+};
+module_platform_driver(rpcif_spi_driver);
+
+MODULE_DESCRIPTION("Renesas RPC-IF SPI driver");
+MODULE_LICENSE("GPL v2");