On 12/11/19 6:45 AM, Masahiro Yamada wrote:
[...]
> diff --git a/drivers/mtd/nand/raw/denali_dt.c b/drivers/mtd/nand/raw/denali_dt.c
> index 8b779a899dcf..9a294c3f6ec8 100644
> --- a/drivers/mtd/nand/raw/denali_dt.c
> +++ b/drivers/mtd/nand/raw/denali_dt.c
> @@ -6,6 +6,7 @@
> */
>
> #include <linux/clk.h>
> +#include <linux/delay.h>
> #include <linux/err.h>
> #include <linux/io.h>
> #include <linux/ioport.h>
> @@ -14,6 +15,7 @@
> #include <linux/of.h>
> #include <linux/of_device.h>
> #include <linux/platform_device.h>
> +#include <linux/reset.h>
>
> #include "denali.h"
>
> @@ -22,6 +24,8 @@ struct denali_dt {
> struct clk *clk; /* core clock */
> struct clk *clk_x; /* bus interface clock */
> struct clk *clk_ecc; /* ECC circuit clock */
> + struct reset_control *rst; /* core reset */
> + struct reset_control *rst_reg; /* register reset */
> };
>
> struct denali_dt_data {
> @@ -151,6 +155,14 @@ static int denali_dt_probe(struct platform_device *pdev)
> if (IS_ERR(dt->clk_ecc))
> return PTR_ERR(dt->clk_ecc);
>
> + dt->rst = devm_reset_control_get_optional_shared(dev, "nand");
> + if (IS_ERR(dt->rst))
> + return PTR_ERR(dt->rst);
> +
> + dt->rst_reg = devm_reset_control_get_optional_shared(dev, "reg");
> + if (IS_ERR(dt->rst_reg))
> + return PTR_ERR(dt->rst_reg);
> +
> ret = clk_prepare_enable(dt->clk);
> if (ret)
> return ret;
> @@ -166,10 +178,30 @@ static int denali_dt_probe(struct platform_device *pdev)
> denali->clk_rate = clk_get_rate(dt->clk);
> denali->clk_x_rate = clk_get_rate(dt->clk_x);
>
> - ret = denali_init(denali);
> + /*
> + * Deassert the register reset, and the core reset in this order.
> + * Deasserting the core reset while the register reset is asserted
> + * will cause unpredictable behavior in the controller.
> + */
> + ret = reset_control_deassert(dt->rst_reg);
> if (ret)
> goto out_disable_clk_ecc;
>
> + ret = reset_control_deassert(dt->rst);
> + if (ret)
> + goto out_assert_rst_reg;
> +
> + /*
> + * When the reset is deasserted, the initialization sequence is kicked
> + * (bootstrap process). The driver must wait until it finished.
> + * Otherwise, it will result in unpredictable behavior.
> + */
> + usleep_range(200, 1000);
> +
> + ret = denali_init(denali);
> + if (ret)
> + goto out_assert_rst;
> +
> for_each_child_of_node(dev->of_node, np) {
> ret = denali_dt_chip_init(denali, np);
> if (ret) {
> @@ -184,6 +216,10 @@ static int denali_dt_probe(struct platform_device *pdev)
>
> out_remove_denali:
> denali_remove(denali);
> +out_assert_rst:
> + reset_control_assert(dt->rst);
> +out_assert_rst_reg:
> + reset_control_assert(dt->rst_reg);
Maybe you can use devm_add_action_or_reset() here , like in e.g.
drivers/input/touchscreen/ili210x.c , to avoid this unwinding ?
[...]
