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    Subject[PATCH v4 5/6] can: tcan4x5x: Add support for tcan4552/4553
    Date
    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>
    ---
    drivers/net/can/m_can/tcan4x5x-core.c | 104 ++++++++++++++++++++++----
    1 file changed, 90 insertions(+), 14 deletions(-)

    diff --git a/drivers/net/can/m_can/tcan4x5x-core.c b/drivers/net/can/m_can/tcan4x5x-core.c
    index fb9375fa20ec..2d329b4e4f52 100644
    --- 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;

    --
    2.40.1
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