Re: [PATCH v3] spi: mvebu_a3700_spi: add support for cs-gpios

[Stefan Roese]

On 30.09.20 16:28, George Hilliard wrote:

The device tree has a way to specify GPIO lines as chip selects.  From
the binding docs:

     So if for example the controller has 2 CS lines, and the cs-gpios
     property looks like this:

     cs-gpios = <&gpio1 0 0> <0> <&gpio1 1 0> <&gpio1 2 0>;

     Then it should be configured so that num_chipselect = 4 with the
     following mapping:

     cs0 : &gpio1 0 0
     cs1 : native
     cs2 : &gpio1 1 0
     cs3 : &gpio1 2 0

Add support for this, while retaining backward-compatibility with
existing device trees; the driver will preserve existing behavior if a
cs-gpios list is not given, or if a particular line is specified as <0>
(native).

This implementation is inspired by similar implementations in
neighboring drivers for other platforms: atmega, mxc, etc.

Signed-off-by: George Hilliard <ghill...@amazon.com>
Reviewed-by: Stefan Roese <s...@denx.de>

Applied to u-boot-marvell/master

Thanks,
Stefan

---
  drivers/spi/mvebu_a3700_spi.c | 41 ++++++++++++++++++++++++++++++-----
  1 file changed, 35 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/mvebu_a3700_spi.c b/drivers/spi/mvebu_a3700_spi.c
index e860b9ec64..eb13cf349e 100644
--- a/drivers/spi/mvebu_a3700_spi.c
+++ b/drivers/spi/mvebu_a3700_spi.c
@@ -15,6 +15,7 @@
  #include <asm/io.h>
  #include <dm/device_compat.h>
  #include <linux/bitops.h>
+#include <asm/gpio.h>

DECLARE_GLOBAL_DATA_PTR; @@ -27,6 +28,7 @@ DECLARE_GLOBAL_DATA_PTR;

  #define MVEBU_SPI_A3700_SPI_EN_0              BIT(16)
  #define MVEBU_SPI_A3700_CLK_PRESCALE_MASK     0x1f

+#define MAX_CS_COUNT 4 /* SPI registers */

  struct spi_reg {
@@ -39,16 +41,23 @@ struct spi_reg {
  struct mvebu_spi_platdata {
        struct spi_reg *spireg;
        struct clk clk;
+       struct gpio_desc cs_gpios[MAX_CS_COUNT];
  };

-static void spi_cs_activate(struct spi_reg *reg, int cs)

+static void spi_cs_activate(struct mvebu_spi_platdata *plat, int cs)
  {
-       setbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
+       if (CONFIG_IS_ENABLED(DM_GPIO) && dm_gpio_is_valid(&plat->cs_gpios[cs]))
+               dm_gpio_set_value(&plat->cs_gpios[cs], 1);
+       else
+               setbits_le32(&plat->spireg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << 
cs);
  }

-static void spi_cs_deactivate(struct spi_reg *reg, int cs)

+static void spi_cs_deactivate(struct mvebu_spi_platdata *plat, int cs)
  {
-       clrbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
+       if (CONFIG_IS_ENABLED(DM_GPIO) && dm_gpio_is_valid(&plat->cs_gpios[cs]))
+               dm_gpio_set_value(&plat->cs_gpios[cs], 0);
+       else
+               clrbits_le32(&plat->spireg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << 
cs);
  }

/**

@@ -150,7 +159,7 @@ static int mvebu_spi_xfer(struct udevice *dev, unsigned int 
bitlen,
        /* Activate CS */
        if (flags & SPI_XFER_BEGIN) {
                debug("SPI: activate cs.\n");
-               spi_cs_activate(reg, spi_chip_select(dev));
+               spi_cs_activate(plat, spi_chip_select(dev));
        }

/* Send and/or receive */

@@ -169,7 +178,7 @@ static int mvebu_spi_xfer(struct udevice *dev, unsigned int 
bitlen,
                        return ret;

debug("SPI: deactivate cs.\n");

-               spi_cs_deactivate(reg, spi_chip_select(dev));
+               spi_cs_deactivate(plat, spi_chip_select(dev));
        }

return 0;

@@ -247,6 +256,26 @@ static int mvebu_spi_probe(struct udevice *bus)

writel(data, &reg->cfg); + /* Set up CS GPIOs in device tree, if any */

+       if (CONFIG_IS_ENABLED(DM_GPIO) && gpio_get_list_count(bus, "cs-gpios") 
> 0) {
+               int i;
+
+               for (i = 0; i < ARRAY_SIZE(plat->cs_gpios); i++) {
+                       ret = gpio_request_by_name(bus, "cs-gpios", i, 
&plat->cs_gpios[i], 0);
+                       if (ret < 0 || !dm_gpio_is_valid(&plat->cs_gpios[i])) {
+                               /* Use the native CS function for this line */
+                               continue;
+                       }
+
+                       ret = dm_gpio_set_dir_flags(&plat->cs_gpios[i],
+                                                   GPIOD_IS_OUT | 
GPIOD_ACTIVE_LOW);
+                       if (ret) {
+                               dev_err(bus, "Setting cs %d error\n", i);
+                               return ret;
+                       }
+               }
+       }
+
        return 0;
  }

Viele Grüße,
Stefan

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