can: tcan4x5x: Add support for tcan4552/4553

tcan4552 and tcan4553 do not have wake or state pins, so they are
currently not compatible with the generic driver. The generic driver
uses tcan4x5x_disable_state() and tcan4x5x_disable_wake() if the gpios
are not defined. These functions use register bits that are not
available in tcan4552/4553.

This patch adds support by introducing version information to reflect if
the chip has wake and state pins. Also the version is now checked.

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Link: https://lore.kernel.org/all/20230728141923.162477-6-msp@baylibre.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/m_can/tcan4x5x-core.c b/drivers/net/can/m_can/tcan4x5x-core.c
index fb9375fa20ec0cb10a697abb8e355f04123b96b2..2d329b4e4f52cabf2a83853f163499eb45cc4ead 100644 (file)
--- a/drivers/net/can/m_can/tcan4x5x-core.c
+++ b/drivers/net/can/m_can/tcan4x5x-core.c
@@ -7,6 +7,7 @@
 #define TCAN4X5X_EXT_CLK_DEF 40000000
 
 #define TCAN4X5X_DEV_ID1 0x00
+#define TCAN4X5X_DEV_ID1_TCAN 0x4e414354 /* ASCII TCAN */
 #define TCAN4X5X_DEV_ID2 0x04
 #define TCAN4X5X_REV 0x08
 #define TCAN4X5X_STATUS 0x0C
@@ -103,6 +104,37 @@
 #define TCAN4X5X_WD_3_S_TIMER BIT(29)
 #define TCAN4X5X_WD_6_S_TIMER (BIT(28) | BIT(29))
 
+struct tcan4x5x_version_info {
+       const char *name;
+       u32 id2_register;
+
+       bool has_wake_pin;
+       bool has_state_pin;
+};
+
+enum {
+       TCAN4552 = 0,
+       TCAN4553,
+       TCAN4X5X,
+};
+
+static const struct tcan4x5x_version_info tcan4x5x_versions[] = {
+       [TCAN4552] = {
+               .name = "4552",
+               .id2_register = 0x32353534,
+       },
+       [TCAN4553] = {
+               .name = "4553",
+               .id2_register = 0x32353534,
+       },
+       /* generic version with no id2_register at the end */
+       [TCAN4X5X] = {
+               .name = "generic",
+               .has_wake_pin = true,
+               .has_state_pin = true,
+       },
+};
+
 static inline struct tcan4x5x_priv *cdev_to_priv(struct m_can_classdev *cdev)
 {
        return container_of(cdev, struct tcan4x5x_priv, cdev);
@@ -254,18 +286,53 @@ static int tcan4x5x_disable_state(struct m_can_classdev *cdev)
                                  TCAN4X5X_DISABLE_INH_MSK, 0x01);
 }
 
-static int tcan4x5x_get_gpios(struct m_can_classdev *cdev)
+static const struct tcan4x5x_version_info
+*tcan4x5x_find_version(struct tcan4x5x_priv *priv)
+{
+       u32 val;
+       int ret;
+
+       ret = regmap_read(priv->regmap, TCAN4X5X_DEV_ID1, &val);
+       if (ret)
+               return ERR_PTR(ret);
+
+       if (val != TCAN4X5X_DEV_ID1_TCAN) {
+               dev_err(&priv->spi->dev, "Not a tcan device %x\n", val);
+               return ERR_PTR(-ENODEV);
+       }
+
+       ret = regmap_read(priv->regmap, TCAN4X5X_DEV_ID2, &val);
+       if (ret)
+               return ERR_PTR(ret);
+
+       for (int i = 0; i != ARRAY_SIZE(tcan4x5x_versions); ++i) {
+               const struct tcan4x5x_version_info *vinfo = &tcan4x5x_versions[i];
+
+               if (!vinfo->id2_register || val == vinfo->id2_register) {
+                       dev_info(&priv->spi->dev, "Detected TCAN device version %s\n",
+                                vinfo->name);
+                       return vinfo;
+               }
+       }
+
+       return &tcan4x5x_versions[TCAN4X5X];
+}
+
+static int tcan4x5x_get_gpios(struct m_can_classdev *cdev,
+                             const struct tcan4x5x_version_info *version_info)
 {
        struct tcan4x5x_priv *tcan4x5x = cdev_to_priv(cdev);
        int ret;
 
-       tcan4x5x->device_wake_gpio = devm_gpiod_get(cdev->dev, "device-wake",
-                                                   GPIOD_OUT_HIGH);
-       if (IS_ERR(tcan4x5x->device_wake_gpio)) {
-               if (PTR_ERR(tcan4x5x->device_wake_gpio) == -EPROBE_DEFER)
-                       return -EPROBE_DEFER;
+       if (version_info->has_wake_pin) {
+               tcan4x5x->device_wake_gpio = devm_gpiod_get(cdev->dev, "device-wake",
+                                                           GPIOD_OUT_HIGH);
+               if (IS_ERR(tcan4x5x->device_wake_gpio)) {
+                       if (PTR_ERR(tcan4x5x->device_wake_gpio) == -EPROBE_DEFER)
+                               return -EPROBE_DEFER;
 
-               tcan4x5x_disable_wake(cdev);
+                       tcan4x5x_disable_wake(cdev);
+               }
        }
 
        tcan4x5x->reset_gpio = devm_gpiod_get_optional(cdev->dev, "reset",
@@ -277,12 +344,14 @@ static int tcan4x5x_get_gpios(struct m_can_classdev *cdev)
        if (ret)
                return ret;
 
-       tcan4x5x->device_state_gpio = devm_gpiod_get_optional(cdev->dev,
-                                                             "device-state",
-                                                             GPIOD_IN);
-       if (IS_ERR(tcan4x5x->device_state_gpio)) {
-               tcan4x5x->device_state_gpio = NULL;
-               tcan4x5x_disable_state(cdev);
+       if (version_info->has_state_pin) {
+               tcan4x5x->device_state_gpio = devm_gpiod_get_optional(cdev->dev,
+                                                                     "device-state",
+                                                                     GPIOD_IN);
+               if (IS_ERR(tcan4x5x->device_state_gpio)) {
+                       tcan4x5x->device_state_gpio = NULL;
+                       tcan4x5x_disable_state(cdev);
+               }
        }
 
        return 0;
@@ -299,6 +368,7 @@ static struct m_can_ops tcan4x5x_ops = {
 
 static int tcan4x5x_can_probe(struct spi_device *spi)
 {
+       const struct tcan4x5x_version_info *version_info;
        struct tcan4x5x_priv *priv;
        struct m_can_classdev *mcan_class;
        int freq, ret;
@@ -361,7 +431,13 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
        if (ret)
                goto out_m_can_class_free_dev;
 
-       ret = tcan4x5x_get_gpios(mcan_class);
+       version_info = tcan4x5x_find_version(priv);
+       if (IS_ERR(version_info)) {
+               ret = PTR_ERR(version_info);
+               goto out_power;
+       }
+
+       ret = tcan4x5x_get_gpios(mcan_class, version_info);
        if (ret)
                goto out_power;