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    Subject[PATCH v2 2/3] hwmon: (aspeed-pwm-tacho) Deassert reset in probe
    Date
    The ASPEED SoC must deassert a reset in order to use the PWM/tach
    peripheral.

    Signed-off-by: Joel Stanley <joel@jms.id.au>
    ---
    v2:
    - Correct horrible mistakes
    - Boot tested and hwmon sysfs files checked
    ---
    drivers/hwmon/aspeed-pwm-tacho.c | 21 +++++++++++++++++++++
    1 file changed, 21 insertions(+)

    diff --git a/drivers/hwmon/aspeed-pwm-tacho.c b/drivers/hwmon/aspeed-pwm-tacho.c
    index 63a95e23ca81..77bb7a4bbed4 100644
    --- a/drivers/hwmon/aspeed-pwm-tacho.c
    +++ b/drivers/hwmon/aspeed-pwm-tacho.c
    @@ -19,6 +19,7 @@
    #include <linux/of_platform.h>
    #include <linux/platform_device.h>
    #include <linux/regmap.h>
    +#include <linux/reset.h>
    #include <linux/sysfs.h>
    #include <linux/thermal.h>

    @@ -181,6 +182,7 @@ struct aspeed_cooling_device {

    struct aspeed_pwm_tacho_data {
    struct regmap *regmap;
    + struct reset_control *rst;
    unsigned long clk_freq;
    bool pwm_present[8];
    bool fan_tach_present[16];
    @@ -931,6 +933,15 @@ static int aspeed_pwm_tacho_probe(struct platform_device *pdev)
    &aspeed_pwm_tacho_regmap_config);
    if (IS_ERR(priv->regmap))
    return PTR_ERR(priv->regmap);
    +
    + priv->rst = devm_reset_control_get_exclusive(dev, NULL);
    + if (IS_ERR(priv->rst)) {
    + dev_err(dev,
    + "missing or invalid reset controller device tree entry");
    + return PTR_ERR(priv->rst);
    + }
    + reset_control_deassert(priv->rst);
    +
    regmap_write(priv->regmap, ASPEED_PTCR_TACH_SOURCE, 0);
    regmap_write(priv->regmap, ASPEED_PTCR_TACH_SOURCE_EXT, 0);

    @@ -960,6 +971,15 @@ static int aspeed_pwm_tacho_probe(struct platform_device *pdev)
    return PTR_ERR_OR_ZERO(hwmon);
    }

    +static int aspeed_pwm_tacho_remove(struct platform_device *pdev)
    +{
    + struct aspeed_pwm_tacho_data *priv = platform_get_drvdata(pdev);
    +
    + reset_control_assert(priv->rst);
    +
    + return 0;
    +}
    +
    static const struct of_device_id of_pwm_tacho_match_table[] = {
    { .compatible = "aspeed,ast2400-pwm-tacho", },
    { .compatible = "aspeed,ast2500-pwm-tacho", },
    @@ -969,6 +989,7 @@ MODULE_DEVICE_TABLE(of, of_pwm_tacho_match_table);

    static struct platform_driver aspeed_pwm_tacho_driver = {
    .probe = aspeed_pwm_tacho_probe,
    + .remove = aspeed_pwm_tacho_remove,
    .driver = {
    .name = "aspeed_pwm_tacho",
    .of_match_table = of_pwm_tacho_match_table,
    --
    2.14.1
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