linux-kernel - Re: [PATCH v10 0/4] firmware: arm_scmi: Add SCMI v3.2 pincontrol protocol basic support

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Date: Tue, 16 Apr 2024 21:20:11 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: "Peng Fan (OSS)" <peng.fan@....nxp.com>,
	Cristian Marussi <cristian.marussi@....com>,
	Linus Walleij <linus.walleij@...aro.org>
Cc: Sudeep Holla <sudeep.holla@....com>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>, Dhruva Gole <d-gole@...com>,
	Andy Shevchenko <andy.shevchenko@...il.com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org, linux-gpio@...r.kernel.org,
	Peng Fan <peng.fan@....com>,
	Oleksii Moisieiev <oleksii_moisieiev@...m.com>
Subject: Re: [PATCH v10 0/4] firmware: arm_scmi: Add SCMI v3.2 pincontrol
 protocol basic support

I'm trying to re-base AKASHI Takahiro's gpio driver on top of your scmi
pinctrl driver.
https://lore.kernel.org/all/20231005025843.508689-1-takahiro.akashi@linaro.org/
I need to do something like this below to save the gpio information.

So now, great, I have the information but I'm not sure how to export it
from the scmi pinctrl driver to the gpio driver...  (This is a probably
a stupid question but I am real newbie with regards to gpio).

The other thing is that the SCMI spec says:

    4.11.2.7
    PINCTRL_SETTINGS_GET

    This command can be used by an agent to get the pin or group
    configuration, and the function selected to be enabled. It can also
    be used to read the value of a pin when it is set to GPIO mode.

What does that mean?  Is that right, or is it something left over from a
previous revision of the spec.

regards,
dan carpenter

diff --git a/drivers/firmware/arm_scmi/pinctrl.c b/drivers/firmware/arm_scmi/pinctrl.c
index a2a7f880d6a3..f803be8a223f 100644
--- a/drivers/firmware/arm_scmi/pinctrl.c
+++ b/drivers/firmware/arm_scmi/pinctrl.c
@@ -26,6 +26,7 @@
 #define GET_PINS_NR(x)		le32_get_bits((x), GENMASK(15, 0))
 #define GET_FUNCTIONS_NR(x)	le32_get_bits((x), GENMASK(15, 0))
 
+#define IS_GPIO_FUNC(x)		le32_get_bits((x), BIT(17))
 #define EXT_NAME_FLAG(x)	le32_get_bits((x), BIT(31))
 #define NUM_ELEMS(x)		le32_get_bits((x), GENMASK(15, 0))
 
@@ -107,6 +108,7 @@ struct scmi_group_info {
 struct scmi_function_info {
 	char name[SCMI_MAX_STR_SIZE];
 	bool present;
+	bool gpio;
 	u32 *groups;
 	u32 nr_groups;
 };
@@ -189,7 +191,7 @@ static int scmi_pinctrl_validate_id(const struct scmi_protocol_handle *ph,
 
 static int scmi_pinctrl_attributes(const struct scmi_protocol_handle *ph,
 				   enum scmi_pinctrl_selector_type type,
-				   u32 selector, char *name,
+				   u32 selector, char *name, bool *gpio,
 				   u32 *n_elems)
 {
 	int ret;
@@ -216,17 +218,20 @@ static int scmi_pinctrl_attributes(const struct scmi_protocol_handle *ph,
 	tx->flags = cpu_to_le32(type);
 
 	ret = ph->xops->do_xfer(ph, t);
-	if (!ret) {
-		if (n_elems)
-			*n_elems = NUM_ELEMS(rx->attributes);
+	if (ret)
+		goto xfer_put;
 
-		strscpy(name, rx->name, SCMI_SHORT_NAME_MAX_SIZE);
+	if (n_elems)
+		*n_elems = NUM_ELEMS(rx->attributes);
 
-		ext_name_flag = !!EXT_NAME_FLAG(rx->attributes);
-	}
+	if (type == FUNCTION_TYPE && gpio)
+		*gpio = !!IS_GPIO_FUNC(rx->attributes);
 
-	ph->xops->xfer_put(ph, t);
+	strscpy(name, rx->name, SCMI_SHORT_NAME_MAX_SIZE);
+	ext_name_flag = !!EXT_NAME_FLAG(rx->attributes);
 
+xfer_put:
+	ph->xops->xfer_put(ph, t);
 	if (ret)
 		return ret;
 	/*
@@ -602,7 +607,7 @@ static int scmi_pinctrl_get_group_info(const struct scmi_protocol_handle *ph,
 	int ret;
 
 	ret = scmi_pinctrl_attributes(ph, GROUP_TYPE, selector, group->name,
-				      &group->nr_pins);
+				      NULL, &group->nr_pins);
 	if (ret)
 		return ret;
 
@@ -687,7 +692,7 @@ static int scmi_pinctrl_get_function_info(const struct scmi_protocol_handle *ph,
 	int ret;
 
 	ret = scmi_pinctrl_attributes(ph, FUNCTION_TYPE, selector, func->name,
-				      &func->nr_groups);
+				      &func->gpio, &func->nr_groups);
 	if (ret)
 		return ret;
 
@@ -778,7 +783,8 @@ static int scmi_pinctrl_get_pin_info(const struct scmi_protocol_handle *ph,
 	if (!pin)
 		return -EINVAL;
 
-	ret = scmi_pinctrl_attributes(ph, PIN_TYPE, selector, pin->name, NULL);
+	ret = scmi_pinctrl_attributes(ph, PIN_TYPE, selector, pin->name, NULL,
+				      NULL);
 	if (ret)
 		return ret;