Re: [PATCH v0 1/1] spi: spi-rockchip: add support for spi slave_mode
From: Chris Ruehl
Date: Fri May 08 2020 - 20:10:44 EST
Hi Emil,
thanks for the review and your comments
On 8/5/2020 9:13 pm, Emil Renner Berthing wrote:
Hi Chris,
On Fri, 8 May 2020 at 10:47, Chris Ruehl <chris.ruehl@xxxxxxxxxxxx> wrote:
This patch aim to add spi slave mode support to the rockchip driver.
Fix the wrong usage of num_cs set fix to ROCKCHIP_SPI_MAX_CS_NUM,
instead use max_native_cs flag to set the limit of native chip-select.
Enable use_gpio_descriptors to have cs_gpiod for gpio based chip-selects.
Signed-off-by: Chris Ruehl <chris.ruehl@xxxxxxxxxxxx>
---
drivers/spi/spi-rockchip.c | 46 +++++++++++++++++++++++++++++++++-----
1 file changed, 41 insertions(+), 5 deletions(-)
diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index 70ef63e0b6b8..9c1ff52c0f85 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -183,6 +183,9 @@ struct rockchip_spi {
u8 rsd;
bool cs_asserted[ROCKCHIP_SPI_MAX_CS_NUM];
+
+ bool slave_mode;
+ bool slave_abort;
};
static inline void spi_enable_chip(struct rockchip_spi *rs, bool enable)
@@ -359,7 +362,7 @@ static void rockchip_spi_dma_rxcb(void *data)
struct rockchip_spi *rs = spi_master_get_devdata(master);
int state = atomic_fetch_andnot(RXDMA, &rs->state);
- if (state & TXDMA)
+ if (state & TXDMA && !rs->slave_abort)
return;
spi_enable_chip(rs, false);
@@ -372,7 +375,7 @@ static void rockchip_spi_dma_txcb(void *data)
struct rockchip_spi *rs = spi_master_get_devdata(master);
int state = atomic_fetch_andnot(TXDMA, &rs->state);
- if (state & RXDMA)
+ if (state & RXDMA && !rs->slave_abort)
return;
/* Wait until the FIFO data completely. */
@@ -466,6 +469,10 @@ static void rockchip_spi_config(struct rockchip_spi *rs,
u32 cr1;
u32 dmacr = 0;
+ if (rs->slavemode)
+ cr0 |= CR0_OPM_SLAVE << CR0_OPM_OFFSET;
+ rs->slave_abort = false;
+
cr0 |= rs->rsd << CR0_RSD_OFFSET;
cr0 |= (spi->mode & 0x3U) << CR0_SCPH_OFFSET;
if (spi->mode & SPI_LSB_FIRST)
@@ -535,6 +542,16 @@ static size_t rockchip_spi_max_transfer_size(struct spi_device *spi)
return ROCKCHIP_SPI_MAX_TRANLEN;
}
+static int rockchip_spi_slave_abort(struct spi_master *master)
+{
+ struct rockchip_spi *rs = spi_master_get_devdata(master);
+
+ rs->slave_abort = true;
+ complete(master);
+
+ return 0;
+}
+
static int rockchip_spi_transfer_one(
struct spi_master *master,
struct spi_device *spi,
@@ -589,14 +606,25 @@ static int rockchip_spi_probe(struct platform_device *pdev)
struct spi_master *master;
struct resource *mem;
u32 rsd_nsecs;
+ bool slave_mode;
+ u32 num_cs = 1;
+
+ slave_mode = of_property_read_bool(np, "spi-slave");
+
+ if (slave_mode)
+ master = spi_alloc_slave(&pdev->dev,
+ sizeof(struct rockchip_spi));
+ else
+ master = spi_alloc_master(&pdev->dev,
+ sizeof(struct rockchip_spi));
- master = spi_alloc_master(&pdev->dev, sizeof(struct rockchip_spi));
if (!master)
return -ENOMEM;
platform_set_drvdata(pdev, master);
rs = spi_master_get_devdata(master);
+ rs->slave_mode = slave_mode;
This entry doesn't seem to be read from any of your code, and even it
it was, the same information is available in master->slave, so I don't
see why you need it in the rockchip_spi struct.
I haven't see the slave flag in the spi_controller struct, I will store the
information
there.
Also spi_master is just #defined to spi_controller in spi.h, so maybe
consider changing all 'struct spi_master *master' to 'struct
spi_controller *ctrl' now that the driver supports both modes.
Can do, but I think that is better to have a separate patch for it,
make it easier for review.
/* Get basic io resource and map it */
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -676,7 +704,16 @@ static int rockchip_spi_probe(struct platform_device *pdev)
master->auto_runtime_pm = true;
master->bus_num = pdev->id;
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP | SPI_LSB_FIRST;
- master->num_chipselect = ROCKCHIP_SPI_MAX_CS_NUM;
+ if (slave_mode) {
+ master->mode_bits |= SPI_NO_CS;
+ master->slave_abort = rockchip_spi_slave_abort;
+ } else {
+ of_property_read_u32(np, "num-cs", &num_cs);
+ master->num_chipselect = num_cs;
If you do something like this you won't need the temporary num_cs variable:
if (of_property_read_u32(np, "num-cs", &master->num_chipselect))
master->num_chipselect = 1;
Like it , can see clearly the fallback to a default if num-cs isn't set in the
dts.
Also it seems like you're changing the default from
ROCKCHIP_SPI_MAX_CS_NUM to 1 if there is no num-cs property. Did you
check that all boards either have the num-cs property defined or only
needs num_chipselect = 1?
Only spi0 of the rockchip has a 2nd native chip select, all others a single only
therefore I find it less evil to use 1 vs. ROCKCHIP_SPI_MAX_CS_NUM
+ master->use_gpio_descriptors = true;
+ master->max_native_cs = ROCKCHIP_SPI_MAX_CS_NUM;
+ master->flags = SPI_MASTER_GPIO_SS;
+ }
master->dev.of_node = pdev->dev.of_node;
master->bits_per_word_mask = SPI_BPW_MASK(16) | SPI_BPW_MASK(8) | SPI_BPW_MASK(4);
master->min_speed_hz = rs->freq / BAUDR_SCKDV_MAX;
@@ -686,7 +723,6 @@ static int rockchip_spi_probe(struct platform_device *pdev)
master->transfer_one = rockchip_spi_transfer_one;
master->max_transfer_size = rockchip_spi_max_transfer_size;
master->handle_err = rockchip_spi_handle_err;
- master->flags = SPI_MASTER_GPIO_SS;
master->dma_tx = dma_request_chan(rs->dev, "tx");
if (IS_ERR(master->dma_tx)) {
--
2.20.1
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