On Sun, 11 Dec 2022, Jeremy Kerr wrote:
> Simple syscon devices may require deassertion of a reset signal in order
> to access their register set. Rather than requiring a custom driver to
> implement this, we can use the generic "resets" specifiers to link a
> reset line to the syscon.
>
> This change adds an optional reset line to the syscon device
> description, and deasserts the reset if detected.
>
> Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxxxxxxxxxxxx>
>
> ---
> v2:
> * do reset control in the early of_syscon_register() path, rather than
> the platform device init, which isn't used.
> v3:
> * use a direct reset_control_deassert rather than handling in the
> regmap
> ---
> drivers/mfd/syscon.c | 27 +++++++++++++++++++++------
> 1 file changed, 21 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
> index bdb2ce7ff03b..05e286a69dbe 100644
> --- a/drivers/mfd/syscon.c
> +++ b/drivers/mfd/syscon.c
> @@ -20,6 +20,7 @@
> #include <linux/platform_data/syscon.h>
> #include <linux/platform_device.h>
> #include <linux/regmap.h>
> +#include <linux/reset.h>
> #include <linux/mfd/syscon.h>
> #include <linux/slab.h>
>
> @@ -31,6 +32,7 @@ static LIST_HEAD(syscon_list);
> struct syscon {
> struct device_node *np;
> struct regmap *regmap;
> + struct reset_control *reset;
> struct list_head list;
> };
>
> @@ -40,7 +42,7 @@ static const struct regmap_config syscon_regmap_config = {
> .reg_stride = 4,
> };
>
> -static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
> +static struct syscon *of_syscon_register(struct device_node *np, bool check_res)
> {
> struct clk *clk;
> struct syscon *syscon;
> @@ -50,6 +52,7 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
> int ret;
> struct regmap_config syscon_config = syscon_regmap_config;
> struct resource res;
> + struct reset_control *reset;
>
> syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
> if (!syscon)
> @@ -114,7 +117,7 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
> goto err_regmap;
> }
>
> - if (check_clk) {
> + if (check_res) {
> clk = of_clk_get(np, 0);
> if (IS_ERR(clk)) {
> ret = PTR_ERR(clk);
> @@ -124,7 +127,17 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
> } else {
> ret = regmap_mmio_attach_clk(regmap, clk);
> if (ret)
> - goto err_attach;
> + goto err_attach_clk;
> + }
> +
> + reset = of_reset_control_get_optional_exclusive(np, NULL);
> + if (IS_ERR(reset)) {
> + ret = PTR_ERR(reset);
> + goto err_attach_clk;
> + } else {
> + ret = reset_control_deassert(reset);
> + if (ret)
> + goto err_reset;
> }
The else is superfluous, right?
Arnd, besides this are you happy with the patch?
--
Lee Jones [李琼斯]
