spi: designware_spi: Add reset ctrl to driver

Add code to reset all reset signals as in SPI DT node. A reset property
is an optional feature, so only print out a warning and do not fail if a
reset property is not present.

If a reset property is discovered, then use it to deassert, thus
bringing the IP out of reset.

Release reset when _remove().

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
Acked-by: Marek Vasut <marex@denx.de>
Reviewed-by: Jagan Teki <jagan@openedev.com>

diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c
index d8b73ea326f1ab8ee0b9537ae82be587548de5b9..5cca41448674aa497bd65228f2e82d25ad1122aa 100644 (file)
--- a/drivers/spi/designware_spi.c
+++ b/drivers/spi/designware_spi.c
@@ -17,6 +17,7 @@
 #include <malloc.h>
 #include <spi.h>
 #include <fdtdec.h>
+#include <reset.h>
 #include <linux/compat.h>
 #include <linux/iopoll.h>
 #include <asm/io.h>
@@ -111,6 +112,8 @@ struct dw_spi_priv {
        void *tx_end;
        void *rx;
        void *rx_end;
+
+       struct reset_ctl_bulk   resets;
 };
 
 static inline u32 dw_read(struct dw_spi_priv *priv, u32 offset)
@@ -231,6 +234,34 @@ err_rate:
        return -EINVAL;
 }
 
+static int dw_spi_reset(struct udevice *bus)
+{
+       int ret;
+       struct dw_spi_priv *priv = dev_get_priv(bus);
+
+       ret = reset_get_bulk(bus, &priv->resets);
+       if (ret) {
+               /*
+                * Return 0 if error due to !CONFIG_DM_RESET and reset
+                * DT property is not present.
+                */
+               if (ret == -ENOENT || ret == -ENOTSUPP)
+                       return 0;
+
+               dev_warn(bus, "Can't get reset: %d\n", ret);
+               return ret;
+       }
+
+       ret = reset_deassert_bulk(&priv->resets);
+       if (ret) {
+               reset_release_bulk(&priv->resets);
+               dev_err(bus, "Failed to reset: %d\n", ret);
+               return ret;
+       }
+
+       return 0;
+}
+
 static int dw_spi_probe(struct udevice *bus)
 {
        struct dw_spi_platdata *plat = dev_get_platdata(bus);
@@ -244,6 +275,10 @@ static int dw_spi_probe(struct udevice *bus)
        if (ret)
                return ret;
 
+       ret = dw_spi_reset(bus);
+       if (ret)
+               return ret;
+
        /* Currently only bits_per_word == 8 supported */
        priv->bits_per_word = 8;
 
@@ -478,6 +513,13 @@ static int dw_spi_set_mode(struct udevice *bus, uint mode)
        return 0;
 }
 
+static int dw_spi_remove(struct udevice *bus)
+{
+       struct dw_spi_priv *priv = dev_get_priv(bus);
+
+       return reset_release_bulk(&priv->resets);
+}
+
 static const struct dm_spi_ops dw_spi_ops = {
        .xfer           = dw_spi_xfer,
        .set_speed      = dw_spi_set_speed,
@@ -502,4 +544,5 @@ U_BOOT_DRIVER(dw_spi) = {
        .platdata_auto_alloc_size = sizeof(struct dw_spi_platdata),
        .priv_auto_alloc_size = sizeof(struct dw_spi_priv),
        .probe = dw_spi_probe,
+       .remove = dw_spi_remove,
 };