spi: new feature and fix for Marvell Orion driver

each time the spi_setup() is called.

Signed-off-by Marcin Wojtas <[email protected]>

Reviewed-by Stefan Chulski <[email protected]>

---

Quoted 5 lines

each time the spi_setup() is called.

Signed-off-by Marcin Wojtas <[email protected]>

Reviewed-by Stefan Chulski <[email protected]>

---

You've not provided a Signed-off-by for this so I can't do anything with it, please see Documentation/process/submitting-patches.rst for details on what this is and why it's important.

From: Marcin Wojtas <[email protected]>

Some SPI devices, such as SLIC (Subscriber Line Interface Card) require toggling the CS every transferred byte. Enable such possibility by creating a new DT property and enabling SPI device mode update. Add according support in the spi-orion driver.

Signed-off-by Marcin Wojtas <[email protected]>

Signed-off-by Konstantin Porotchkin <[email protected]>

---
 drivers/spi/spi-orion.c | 20 +++++++++++++++++++-
 drivers/spi/spi.c       |  6 ++++--
 include/linux/spi/spi.h |  1 +
 3 files changed, 24 insertions(+), 3 deletions(-)

drivers/spi/spi-orion.c +19 -1

index 3bfda4225d45..7db9034b0879 100644
@@ -369,8 +369,15 @@ orion_spi_write_read_8bit(struct spi_device *spi,
 {
        void __iomem *tx_reg, *rx_reg, *int_reg;
        struct orion_spi *orion_spi;
+       bool cs_single_byte;
+
+       cs_single_byte = spi->mode & SPI_1BYTE_CS;
 
        orion_spi = spi_master_get_devdata(spi->master);
+
+       if (cs_single_byte)
+               orion_spi_set_cs(spi, 0);
+
        tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
        rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
        int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);

@@ -384,6 +391,11 @@ orion_spi_write_read_8bit(struct spi_device *spi,
                writel(0, tx_reg);
 
        if (orion_spi_wait_till_ready(orion_spi) < 0) {
+               if (cs_single_byte) {
+                       orion_spi_set_cs(spi, 1);
+                       /* Satisfy some SLIC devices requirements */
+                       udelay(4);
+               }
                dev_err(&spi->dev, "TXS timed out\n");
                return -1;
        }

@@ -391,6 +403,12 @@ orion_spi_write_read_8bit(struct spi_device *spi,
        if (rx_buf && *rx_buf)
                *(*rx_buf)++ = readl(rx_reg);
 
+       if (cs_single_byte) {
+               orion_spi_set_cs(spi, 1);
+               /* Satisfy some SLIC devices requirements */
+               udelay(4);
+       }
+
        return 1;
 }
 

@@ -626,7 +644,7 @@ static int orion_spi_probe(struct platform_device *pdev)
        }
 
        /* we support all 4 SPI modes and LSB first option */
-       master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST;
+       master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST | SPI_1BYTE_CS;
        master->set_cs = orion_spi_set_cs;
        master->transfer_one = orion_spi_transfer_one;
        master->num_chipselect = ORION_NUM_CHIPSELECTS;

drivers/spi/spi.c +0 -0

index 51d7c004fbab..998579807a04 100644

drivers/spi/spi.c +2 -2

        /* Device DUAL/QUAD mode */
        if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {

@@ -3419,15 +3421,15 @@ int spi_setup(struct spi_device *spi)
                spi_set_thread_rt(spi->controller);
        }
 
-       dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
+       dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%s%u bits/w, %u Hz max --> %d\n",
                        (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
                        (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
                        (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
                        (spi->mode & SPI_3WIRE) ? "3wire, " : "",
                        (spi->mode & SPI_LOOP) ? "loopback, " : "",
+                       (spi->mode & SPI_1BYTE_CS) ? "single_cs_byte, " : "",
                        spi->bits_per_word, spi->max_speed_hz,
                        status);
-
        return status;
 }
 EXPORT_SYMBOL_GPL(spi_setup);

include/linux/spi/spi.h +1 -1

index aa09fdc8042d..7f65ff6fc25d 100644
@@ -186,6 +186,7 @@ struct spi_device {
 #define        SPI_TX_OCTAL    0x2000                  /* transmit with 8 wires */
 #define        SPI_RX_OCTAL    0x4000                  /* receive with 8 wires */
 #define        SPI_3WIRE_HIZ   0x8000                  /* high impedance turnaround */
+#define        SPI_1BYTE_CS    0x10000                 /* toggle cs after each byte */
        int                     irq;
        void                    *controller_state;
        void                    *controller_data;
--

2.17.1

Regarding your comment from patch 3/3 that "spi-1byte-cs" should be replaced by handling based on the compatible string - do you mean dropping above parsing and updating SPI bus mode field with SPI_1BYTE_CS flag in the relevant SPI device driver?

Quoted 5 lines

Regarding your comment from patch 3/3 that "spi-1byte-cs" should be replaced by handling based on the compatible string - do you mean dropping above parsing and updating SPI bus mode field with SPI_1BYTE_CS flag in the relevant SPI device driver?

There's more to it than that but like I said in reply to the patch AFAICT we already support this.

Please delete unneeded context from mails when replying. Doing this makes it much easier to find your reply in the message, helping ensure it won't be missed by people scrolling through the irrelevant quoted material.

Some SPI devices, such as SLIC (Subscriber Line Interface Card) require toggling the CS every transferred byte. Enable such possibility by creating a new DT property and enabling SPI device mode update. Add according support in the spi-orion driver.

---
 drivers/spi/spi-orion.c | 20 +++++++++++++++++++-
 drivers/spi/spi.c       |  6 ++++--
 include/linux/spi/spi.h |  1 +
 3 files changed, 24 insertions(+), 3 deletions(-)

Quoted 5 lines

Some SPI devices, such as SLIC (Subscriber Line Interface Card) require toggling the CS every transferred byte. Enable such possibility by creating a new DT property and enabling SPI device mode update. Add according support in the spi-orion driver.

I'm pretty sure we already support this - if the client driver sets the word length to 8 bits then SPI_CS_WORD ought to do what your change describes as far as I can see. What's missing there?

Quoted 6 lines

---
 drivers/spi/spi-orion.c | 20 +++++++++++++++++++-
 drivers/spi/spi.c       |  6 ++++--
 include/linux/spi/spi.h |  1 +
 3 files changed, 24 insertions(+), 3 deletions(-)

This is introducing something into the core and adding a user of it, it should be two separate patches.