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Subject[PATCH V2 1/5] spi: lpspi: Add slave mode support for imx7ulp
Date
Add SPI slave mode support for imx7ulp, in PIO mode.

Add "spi-slave" attribute in spi node of dts file to boot.

For now, slave has to send the message which is same as the length of
message master sent.

Wire connection:
GND, SCK, MISO(to MISO of slave), MOSI(to MOSI of slave), SCS

Signed-off-by: Xiaoning Wang <xiaoning.wang@nxp.com>
---
V2:
- No changes.
---
drivers/spi/spi-fsl-lpspi.c | 209 ++++++++++++++++++++++++------------
1 file changed, 139 insertions(+), 70 deletions(-)

diff --git a/drivers/spi/spi-fsl-lpspi.c b/drivers/spi/spi-fsl-lpspi.c
index 51670976faa3..86cb38d98a39 100644
--- a/drivers/spi/spi-fsl-lpspi.c
+++ b/drivers/spi/spi-fsl-lpspi.c
@@ -3,6 +3,7 @@
// Freescale i.MX7ULP LPSPI driver
//
// Copyright 2016 Freescale Semiconductor, Inc.
+// Copyright 2018 NXP

#include <linux/clk.h>
#include <linux/completion.h>
@@ -54,6 +55,7 @@
#define IER_RDIE BIT(1)
#define IER_TDIE BIT(0)
#define CFGR1_PCSCFG BIT(27)
+#define CFGR1_PINCFG (BIT(24)|BIT(25))
#define CFGR1_PCSPOL BIT(8)
#define CFGR1_NOSTALL BIT(3)
#define CFGR1_MASTER BIT(0)
@@ -79,6 +81,7 @@ struct fsl_lpspi_data {
struct device *dev;
void __iomem *base;
struct clk *clk;
+ bool is_slave;

void *rx_buf;
const void *tx_buf;
@@ -86,11 +89,14 @@ struct fsl_lpspi_data {
void (*rx)(struct fsl_lpspi_data *);

u32 remain;
+ u8 watermark;
u8 txfifosize;
u8 rxfifosize;

struct lpspi_config config;
struct completion xfer_done;
+
+ bool slave_aborted;
};

static const struct of_device_id fsl_lpspi_dt_ids[] = {
@@ -137,16 +143,18 @@ static void fsl_lpspi_intctrl(struct fsl_lpspi_data *fsl_lpspi,
writel(enable, fsl_lpspi->base + IMX7ULP_IER);
}

-static int lpspi_prepare_xfer_hardware(struct spi_master *master)
+static int lpspi_prepare_xfer_hardware(struct spi_controller *controller)
{
- struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
+ struct fsl_lpspi_data *fsl_lpspi =
+ spi_controller_get_devdata(controller);

return clk_prepare_enable(fsl_lpspi->clk);
}

-static int lpspi_unprepare_xfer_hardware(struct spi_master *master)
+static int lpspi_unprepare_xfer_hardware(struct spi_controller *controller)
{
- struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
+ struct fsl_lpspi_data *fsl_lpspi =
+ spi_controller_get_devdata(controller);

clk_disable_unprepare(fsl_lpspi->clk);

@@ -202,22 +210,26 @@ static void fsl_lpspi_set_cmd(struct fsl_lpspi_data *fsl_lpspi,
{
u32 temp = 0;

- temp |= fsl_lpspi->config.bpw - 1;
- temp |= fsl_lpspi->config.prescale << 27;
- temp |= (fsl_lpspi->config.mode & 0x3) << 30;
- temp |= (fsl_lpspi->config.chip_select & 0x3) << 24;
-
- /*
- * Set TCR_CONT will keep SS asserted after current transfer.
- * For the first transfer, clear TCR_CONTC to assert SS.
- * For subsequent transfer, set TCR_CONTC to keep SS asserted.
- */
- temp |= TCR_CONT;
- if (is_first_xfer)
- temp &= ~TCR_CONTC;
- else
- temp |= TCR_CONTC;
-
+ if (!fsl_lpspi->is_slave) {
+ temp |= fsl_lpspi->config.bpw - 1;
+ temp |= fsl_lpspi->config.prescale << 27;
+ temp |= (fsl_lpspi->config.mode & 0x3) << 30;
+ temp |= (fsl_lpspi->config.chip_select & 0x3) << 24;
+
+ /*
+ * Set TCR_CONT will keep SS asserted after current transfer.
+ * For the first transfer, clear TCR_CONTC to assert SS.
+ * For subsequent transfer, set TCR_CONTC to keep SS asserted.
+ */
+ temp |= TCR_CONT;
+ if (is_first_xfer)
+ temp &= ~TCR_CONTC;
+ else
+ temp |= TCR_CONTC;
+ } else {
+ temp |= fsl_lpspi->config.bpw - 1;
+ temp |= (fsl_lpspi->config.mode & 0x3) << 30;
+ }
writel(temp, fsl_lpspi->base + IMX7ULP_TCR);

dev_dbg(fsl_lpspi->dev, "TCR=0x%x\n", temp);
@@ -227,7 +239,7 @@ static void fsl_lpspi_set_watermark(struct fsl_lpspi_data *fsl_lpspi)
{
u32 temp;

- temp = fsl_lpspi->txfifosize >> 1 | (fsl_lpspi->rxfifosize >> 1) << 16;
+ temp = fsl_lpspi->watermark >> 1 | (fsl_lpspi->watermark >> 1) << 16;

writel(temp, fsl_lpspi->base + IMX7ULP_FCR);

@@ -253,7 +265,8 @@ static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi)
if (prescale == 8 && scldiv >= 256)
return -EINVAL;

- writel(scldiv, fsl_lpspi->base + IMX7ULP_CCR);
+ writel(scldiv | (scldiv << 8) | ((scldiv >> 1) << 16),
+ fsl_lpspi->base + IMX7ULP_CCR);

dev_dbg(fsl_lpspi->dev, "perclk=%d, speed=%d, prescale =%d, scldiv=%d\n",
perclk_rate, config.speed_hz, prescale, scldiv);
@@ -270,13 +283,18 @@ static int fsl_lpspi_config(struct fsl_lpspi_data *fsl_lpspi)
writel(temp, fsl_lpspi->base + IMX7ULP_CR);
writel(0, fsl_lpspi->base + IMX7ULP_CR);

- ret = fsl_lpspi_set_bitrate(fsl_lpspi);
- if (ret)
- return ret;
+ if (!fsl_lpspi->is_slave) {
+ ret = fsl_lpspi_set_bitrate(fsl_lpspi);
+ if (ret)
+ return ret;
+ }

fsl_lpspi_set_watermark(fsl_lpspi);

- temp = CFGR1_PCSCFG | CFGR1_MASTER;
+ if (!fsl_lpspi->is_slave)
+ temp = CFGR1_MASTER;
+ else
+ temp = CFGR1_PINCFG;
if (fsl_lpspi->config.mode & SPI_CS_HIGH)
temp |= CFGR1_PCSPOL;
writel(temp, fsl_lpspi->base + IMX7ULP_CFGR1);
@@ -291,7 +309,8 @@ static int fsl_lpspi_config(struct fsl_lpspi_data *fsl_lpspi)
static void fsl_lpspi_setup_transfer(struct spi_device *spi,
struct spi_transfer *t)
{
- struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(spi->master);
+ struct fsl_lpspi_data *fsl_lpspi =
+ spi_controller_get_devdata(spi->controller);

fsl_lpspi->config.mode = spi->mode;
fsl_lpspi->config.bpw = t ? t->bits_per_word : spi->bits_per_word;
@@ -315,14 +334,51 @@ static void fsl_lpspi_setup_transfer(struct spi_device *spi,
fsl_lpspi->tx = fsl_lpspi_buf_tx_u32;
}

+ if (t->len <= fsl_lpspi->txfifosize)
+ fsl_lpspi->watermark = t->len;
+ else
+ fsl_lpspi->watermark = fsl_lpspi->txfifosize;
+
fsl_lpspi_config(fsl_lpspi);
}

-static int fsl_lpspi_transfer_one(struct spi_master *master,
+static int fsl_lpspi_slave_abort(struct spi_controller *controller)
+{
+ struct fsl_lpspi_data *fsl_lpspi =
+ spi_controller_get_devdata(controller);
+
+ fsl_lpspi->slave_aborted = true;
+ complete(&fsl_lpspi->xfer_done);
+ return 0;
+}
+
+static int fsl_lpspi_wait_for_completion(struct spi_controller *controller)
+{
+ struct fsl_lpspi_data *fsl_lpspi =
+ spi_controller_get_devdata(controller);
+
+ if (fsl_lpspi->is_slave) {
+ if (wait_for_completion_interruptible(&fsl_lpspi->xfer_done) ||
+ fsl_lpspi->slave_aborted) {
+ dev_dbg(fsl_lpspi->dev, "interrupted\n");
+ return -EINTR;
+ }
+ } else {
+ if (!wait_for_completion_timeout(&fsl_lpspi->xfer_done, HZ)) {
+ dev_dbg(fsl_lpspi->dev, "wait for completion timeout\n");
+ return -ETIMEDOUT;
+ }
+ }
+
+ return 0;
+}
+
+static int fsl_lpspi_transfer_one(struct spi_controller *controller,
struct spi_device *spi,
struct spi_transfer *t)
{
- struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
+ struct fsl_lpspi_data *fsl_lpspi =
+ spi_controller_get_devdata(controller);
int ret;

fsl_lpspi->tx_buf = t->tx_buf;
@@ -330,13 +386,13 @@ static int fsl_lpspi_transfer_one(struct spi_master *master,
fsl_lpspi->remain = t->len;

reinit_completion(&fsl_lpspi->xfer_done);
+ fsl_lpspi->slave_aborted = false;
+
fsl_lpspi_write_tx_fifo(fsl_lpspi);

- ret = wait_for_completion_timeout(&fsl_lpspi->xfer_done, HZ);
- if (!ret) {
- dev_dbg(fsl_lpspi->dev, "wait for completion timeout\n");
- return -ETIMEDOUT;
- }
+ ret = fsl_lpspi_wait_for_completion(controller);
+ if (ret)
+ return ret;

ret = fsl_lpspi_txfifo_empty(fsl_lpspi);
if (ret)
@@ -347,10 +403,11 @@ static int fsl_lpspi_transfer_one(struct spi_master *master,
return 0;
}

-static int fsl_lpspi_transfer_one_msg(struct spi_master *master,
+static int fsl_lpspi_transfer_one_msg(struct spi_controller *controller,
struct spi_message *msg)
{
- struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
+ struct fsl_lpspi_data *fsl_lpspi =
+ spi_controller_get_devdata(controller);
struct spi_device *spi = msg->spi;
struct spi_transfer *xfer;
bool is_first_xfer = true;
@@ -366,7 +423,7 @@ static int fsl_lpspi_transfer_one_msg(struct spi_master *master,

is_first_xfer = false;

- ret = fsl_lpspi_transfer_one(master, spi, xfer);
+ ret = fsl_lpspi_transfer_one(controller, spi, xfer);
if (ret < 0)
goto complete;

@@ -374,13 +431,15 @@ static int fsl_lpspi_transfer_one_msg(struct spi_master *master,
}

complete:
- /* de-assert SS, then finalize current message */
- temp = readl(fsl_lpspi->base + IMX7ULP_TCR);
- temp &= ~TCR_CONTC;
- writel(temp, fsl_lpspi->base + IMX7ULP_TCR);
+ if (!fsl_lpspi->is_slave) {
+ /* de-assert SS, then finalize current message */
+ temp = readl(fsl_lpspi->base + IMX7ULP_TCR);
+ temp &= ~TCR_CONTC;
+ writel(temp, fsl_lpspi->base + IMX7ULP_TCR);
+ }

msg->status = ret;
- spi_finalize_current_message(master);
+ spi_finalize_current_message(controller);

return ret;
}
@@ -410,30 +469,39 @@ static irqreturn_t fsl_lpspi_isr(int irq, void *dev_id)
static int fsl_lpspi_probe(struct platform_device *pdev)
{
struct fsl_lpspi_data *fsl_lpspi;
- struct spi_master *master;
+ struct spi_controller *controller;
struct resource *res;
int ret, irq;
u32 temp;

- master = spi_alloc_master(&pdev->dev, sizeof(struct fsl_lpspi_data));
- if (!master)
+ if (of_property_read_bool((&pdev->dev)->of_node, "spi-slave"))
+ controller = spi_alloc_slave(&pdev->dev,
+ sizeof(struct fsl_lpspi_data));
+ else
+ controller = spi_alloc_master(&pdev->dev,
+ sizeof(struct fsl_lpspi_data));
+
+ if (!controller)
return -ENOMEM;

- platform_set_drvdata(pdev, master);
+ platform_set_drvdata(pdev, controller);

- master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 32);
- master->bus_num = pdev->id;
+ controller->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 32);
+ controller->bus_num = pdev->id;

- fsl_lpspi = spi_master_get_devdata(master);
+ fsl_lpspi = spi_controller_get_devdata(controller);
fsl_lpspi->dev = &pdev->dev;
-
- master->transfer_one_message = fsl_lpspi_transfer_one_msg;
- master->prepare_transfer_hardware = lpspi_prepare_xfer_hardware;
- master->unprepare_transfer_hardware = lpspi_unprepare_xfer_hardware;
- master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
- master->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;
- master->dev.of_node = pdev->dev.of_node;
- master->bus_num = pdev->id;
+ fsl_lpspi->is_slave = of_property_read_bool((&pdev->dev)->of_node,
+ "spi-slave");
+
+ controller->transfer_one_message = fsl_lpspi_transfer_one_msg;
+ controller->prepare_transfer_hardware = lpspi_prepare_xfer_hardware;
+ controller->unprepare_transfer_hardware = lpspi_unprepare_xfer_hardware;
+ controller->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+ controller->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;
+ controller->dev.of_node = pdev->dev.of_node;
+ controller->bus_num = pdev->id;
+ controller->slave_abort = fsl_lpspi_slave_abort;

init_completion(&fsl_lpspi->xfer_done);

@@ -441,32 +509,32 @@ static int fsl_lpspi_probe(struct platform_device *pdev)
fsl_lpspi->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(fsl_lpspi->base)) {
ret = PTR_ERR(fsl_lpspi->base);
- goto out_master_put;
+ goto out_controller_put;
}

irq = platform_get_irq(pdev, 0);
if (irq < 0) {
ret = irq;
- goto out_master_put;
+ goto out_controller_put;
}

ret = devm_request_irq(&pdev->dev, irq, fsl_lpspi_isr, 0,
dev_name(&pdev->dev), fsl_lpspi);
if (ret) {
dev_err(&pdev->dev, "can't get irq%d: %d\n", irq, ret);
- goto out_master_put;
+ goto out_controller_put;
}

fsl_lpspi->clk = devm_clk_get(&pdev->dev, "ipg");
if (IS_ERR(fsl_lpspi->clk)) {
ret = PTR_ERR(fsl_lpspi->clk);
- goto out_master_put;
+ goto out_controller_put;
}

ret = clk_prepare_enable(fsl_lpspi->clk);
if (ret) {
dev_err(&pdev->dev, "can't enable lpspi clock, ret=%d\n", ret);
- goto out_master_put;
+ goto out_controller_put;
}

temp = readl(fsl_lpspi->base + IMX7ULP_PARAM);
@@ -475,24 +543,25 @@ static int fsl_lpspi_probe(struct platform_device *pdev)

clk_disable_unprepare(fsl_lpspi->clk);

- ret = devm_spi_register_master(&pdev->dev, master);
+ ret = devm_spi_register_controller(&pdev->dev, controller);
if (ret < 0) {
- dev_err(&pdev->dev, "spi_register_master error.\n");
- goto out_master_put;
+ dev_err(&pdev->dev, "spi_register_controller error.\n");
+ goto out_controller_put;
}

return 0;

-out_master_put:
- spi_master_put(master);
+out_controller_put:
+ spi_controller_put(controller);

return ret;
}

static int fsl_lpspi_remove(struct platform_device *pdev)
{
- struct spi_master *master = platform_get_drvdata(pdev);
- struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
+ struct spi_controller *controller = platform_get_drvdata(pdev);
+ struct fsl_lpspi_data *fsl_lpspi =
+ spi_controller_get_devdata(controller);

clk_disable_unprepare(fsl_lpspi->clk);

@@ -509,6 +578,6 @@ static struct platform_driver fsl_lpspi_driver = {
};
module_platform_driver(fsl_lpspi_driver);

-MODULE_DESCRIPTION("LPSPI Master Controller driver");
+MODULE_DESCRIPTION("LPSPI Controller driver");
MODULE_AUTHOR("Gao Pan <pandy.gao@nxp.com>");
MODULE_LICENSE("GPL");
--
2.17.1
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