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SubjectRe: [v2,2/3] hwmon: (aspeed-pwm-tacho) Deassert reset in probe
On Thu, Nov 02, 2017 at 02:53:48PM +1100, Joel wrote:
> The ASPEED SoC must deassert a reset in order to use the PWM/tach
> peripheral.
>
> Signed-off-by: Joel Stanley <joel@jms.id.au>

I have not heard from anyone objecting to this change, so I am going to
accept it. See below for a list of changes required to get there.

> ---
> 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);

This asserts reset before the hwmon device is removed. Please use
devm_add_action_or_reset() after reset_control_deassert() to avoid
this problem.

> +
> + 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,

... and by doing that you won't need the remove function, and you don't
have to fix the checkpatch error here.

> .driver = {
> .name = "aspeed_pwm_tacho",
> .of_match_table = of_pwm_tacho_match_table,

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