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Message-Id: <20251002-spi-dw-target-v1-2-993e91c1a712@bootlin.com>
Date: Thu, 02 Oct 2025 14:14:38 +0200
From: Benoît Monin <benoit.monin@...tlin.com>
To: Mark Brown <broonie@...nel.org>
Cc: Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Vladimir Kondratiev <vladimir.kondratiev@...ileye.com>,
Tawfik Bayouk <tawfik.bayouk@...ileye.com>, linux-spi@...r.kernel.org,
linux-kernel@...r.kernel.org,
Benoît Monin <benoit.monin@...tlin.com>
Subject: [PATCH RFC 2/2] spi: dw: add target mode support
Implement target mode for the DesignWare controller with the following
changes:
Allocate an SPI controller of the correct type based on the spi-slave
property in dw_spi_add_controller() and set the controller properties
depending on its type. Since they are only relevant when acting as a host
controller, settings related to chip-select control and the set_cs()
callback are only set in host mode, as are the loopback support, the
memory operations and the maximum frequency. The target_abort() callback
is set only when configured in target mode.
The number of chip-select is set to 1 in dw_spi_hw_init() since the
controller only has one CS input in target mode.
In dw_spi_update_config(), return after setting the CTRLR0 register as
the other registers are only relevant in host mode and are read-only
in target mode. This function is called as part of the transfer_one()
callback, which is identical in both the host and target mode.
Move the code implementing the handle_err() callback to a new function
named dw_spi_abort(), and use it to implement both the handle_err()
and the target_abort() callbacks.
Finally, drop the error path on the spi-slave property in
dw_spi_mmio_probe(), as it is now a valid configuration.
Signed-off-by: Benoît Monin <benoit.monin@...tlin.com>
---
drivers/spi/spi-dw-core.c | 82 ++++++++++++++++++++++++++++++++---------------
drivers/spi/spi-dw-mmio.c | 5 ---
2 files changed, 57 insertions(+), 30 deletions(-)
diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index 90dea6f9b3dab773204c667cb12f3ecaef1d7108..9ebf244294f89db1c5f26471d18eb298ae804cd9 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -332,6 +332,9 @@ void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
dw_writel(dws, DW_SPI_CTRLR0, cr0);
+ if (spi_controller_is_target(dws->ctlr))
+ return;
+
if (cfg->tmode == DW_SPI_CTRLR0_TMOD_EPROMREAD ||
cfg->tmode == DW_SPI_CTRLR0_TMOD_RO)
dw_writel(dws, DW_SPI_CTRLR1, cfg->ndf ? cfg->ndf - 1 : 0);
@@ -462,8 +465,7 @@ static int dw_spi_transfer_one(struct spi_controller *ctlr,
return 1;
}
-static void dw_spi_handle_err(struct spi_controller *ctlr,
- struct spi_message *msg)
+static inline void dw_spi_abort(struct spi_controller *ctlr)
{
struct dw_spi *dws = spi_controller_get_devdata(ctlr);
@@ -473,6 +475,19 @@ static void dw_spi_handle_err(struct spi_controller *ctlr,
dw_spi_reset_chip(dws);
}
+static void dw_spi_handle_err(struct spi_controller *ctlr,
+ struct spi_message *msg)
+{
+ dw_spi_abort(ctlr);
+}
+
+static int dw_spi_target_abort(struct spi_controller *ctlr)
+{
+ dw_spi_abort(ctlr);
+
+ return 0;
+}
+
static int dw_spi_adjust_mem_op_size(struct spi_mem *mem, struct spi_mem_op *op)
{
if (op->data.dir == SPI_MEM_DATA_IN)
@@ -834,18 +849,23 @@ static void dw_spi_hw_init(struct device *dev, struct dw_spi *dws)
DW_SPI_GET_BYTE(dws->ver, 1));
}
- /*
- * Try to detect the number of native chip-selects if the platform
- * driver didn't set it up. There can be up to 16 lines configured.
- */
- if (!dws->num_cs) {
- u32 ser;
+ if (spi_controller_is_target(dws->ctlr)) {
+ /* There is only one CS input signal in target mode */
+ dws->num_cs = 1;
+ } else {
+ /*
+ * Try to detect the number of native chip-selects if the platform
+ * driver didn't set it up. There can be up to 16 lines configured.
+ */
+ if (!dws->num_cs) {
+ u32 ser;
- dw_writel(dws, DW_SPI_SER, 0xffff);
- ser = dw_readl(dws, DW_SPI_SER);
- dw_writel(dws, DW_SPI_SER, 0);
+ dw_writel(dws, DW_SPI_SER, 0xffff);
+ ser = dw_readl(dws, DW_SPI_SER);
+ dw_writel(dws, DW_SPI_SER, 0);
- dws->num_cs = hweight16(ser);
+ dws->num_cs = hweight16(ser);
+ }
}
/*
@@ -901,12 +921,18 @@ static const struct spi_controller_mem_caps dw_spi_mem_caps = {
int dw_spi_add_controller(struct device *dev, struct dw_spi *dws)
{
struct spi_controller *ctlr;
+ bool target;
int ret;
if (!dws)
return -EINVAL;
- ctlr = spi_alloc_host(dev, 0);
+ target = device_property_read_bool(dev, "spi-slave");
+ if (target)
+ ctlr = spi_alloc_target(dev, 0);
+ else
+ ctlr = spi_alloc_host(dev, 0);
+
if (!ctlr)
return -ENOMEM;
@@ -929,8 +955,7 @@ int dw_spi_add_controller(struct device *dev, struct dw_spi *dws)
dw_spi_init_mem_ops(dws);
- ctlr->use_gpio_descriptors = true;
- ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP;
+ ctlr->mode_bits = SPI_CPOL | SPI_CPHA;
if (dws->caps & DW_SPI_CAP_DFS32)
ctlr->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
else
@@ -939,20 +964,27 @@ int dw_spi_add_controller(struct device *dev, struct dw_spi *dws)
ctlr->num_chipselect = dws->num_cs;
ctlr->setup = dw_spi_setup;
ctlr->cleanup = dw_spi_cleanup;
- if (dws->set_cs)
- ctlr->set_cs = dws->set_cs;
- else
- ctlr->set_cs = dw_spi_set_cs;
ctlr->transfer_one = dw_spi_transfer_one;
ctlr->handle_err = dw_spi_handle_err;
- if (dws->mem_ops.exec_op) {
- ctlr->mem_ops = &dws->mem_ops;
- ctlr->mem_caps = &dw_spi_mem_caps;
- }
- ctlr->max_speed_hz = dws->max_freq;
- ctlr->flags = SPI_CONTROLLER_GPIO_SS;
ctlr->auto_runtime_pm = true;
+ if (!target) {
+ ctlr->use_gpio_descriptors = true;
+ ctlr->mode_bits |= SPI_LOOP;
+ if (dws->set_cs)
+ ctlr->set_cs = dws->set_cs;
+ else
+ ctlr->set_cs = dw_spi_set_cs;
+ if (dws->mem_ops.exec_op) {
+ ctlr->mem_ops = &dws->mem_ops;
+ ctlr->mem_caps = &dw_spi_mem_caps;
+ }
+ ctlr->max_speed_hz = dws->max_freq;
+ ctlr->flags = SPI_CONTROLLER_GPIO_SS;
+ } else {
+ ctlr->target_abort = dw_spi_target_abort;
+ }
+
/* Get default rx sample delay */
device_property_read_u32(dev, "rx-sample-delay-ns",
&dws->def_rx_sample_dly_ns);
diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index cc16139e121bf2dae29a16e362db56ea8ad3a18b..f2cd675a9a1980fba447e13e356bb81a0395256e 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -321,11 +321,6 @@ static int dw_spi_mmio_probe(struct platform_device *pdev)
struct dw_spi *dws;
int ret;
- if (device_property_read_bool(&pdev->dev, "spi-slave")) {
- dev_warn(&pdev->dev, "spi-slave is not yet supported\n");
- return -ENODEV;
- }
-
dwsmmio = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_mmio),
GFP_KERNEL);
if (!dwsmmio)
--
2.51.0
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