[PATCH v2 2/3] pinctrl: bcm2835: Add support for generic pinctrl binding

[Matheus Castello]

To keep driver up to date we add generic pinctrl binding support, which covers
the features used in this driver and has additional node properties that this
SoC has compatibility, so enabling future implementations of these properties
without the need to create new node properties in the device trees.

The logic of this change maintain the old brcm legacy binding support in order
to keep the ABI stable.

Signed-off-by: Matheus Castello <matheus@xxxxxxxxxxxxxxx>
---

A brief explanation of what I did:

Add pinconf-generic header for use the defines and pinctrl-generic API.

Add dt-bindings pinctrl bcm2835 header to use functions selections and
pulls definitions, which functions definitions where duplicated in the
enum bcm2835_fsel, I removed the duplicate defines from enum.

In the bcm2835_pctl_dt_node_to_map_pull I used the generic macro for
pack the legacy param and arguments, since it will be unpacked along with
generic properties that is packed with this same macro.

In bcm2835_pctl_dt_node_to_map I thougt it was better, and simpler, to use
pinctrl-generic parse code instead of parsing it inside the driver, so code
first check for generic binding parse, if something is parsed then it is
assumed that are using the new generic style, and when nothing is found then
parse continues to search for legacy properties.

In the bcm2835_pinconf_set was changed the unpack legacy by the generic, and
was added a switch for the parameter tests, since pinctrl generic uses 3
properties to define the states of the pull instead of one with arguments, that
was the reason too that bcm2835_pull_config_set function was added, for reuse
the code that set state of pull.

 drivers/pinctrl/bcm/pinctrl-bcm2835.c | 83 +++++++++++++++++++++++------------
 1 file changed, 54 insertions(+), 29 deletions(-)

diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
index 785c366..755ea90 100644
--- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c
+++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
@@ -36,11 +36,13 @@
 #include <linux/pinctrl/pinconf.h>
 #include <linux/pinctrl/pinctrl.h>
 #include <linux/pinctrl/pinmux.h>
+#include <linux/pinctrl/pinconf-generic.h>
 #include <linux/platform_device.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
+#include <dt-bindings/pinctrl/bcm2835.h>

 #define MODULE_NAME "pinctrl-bcm2835"
 #define BCM2835_NUM_GPIOS 54
@@ -213,14 +215,6 @@ static const char * const bcm2835_gpio_groups[] = {
 };

 enum bcm2835_fsel {
-	BCM2835_FSEL_GPIO_IN = 0,
-	BCM2835_FSEL_GPIO_OUT = 1,
-	BCM2835_FSEL_ALT0 = 4,
-	BCM2835_FSEL_ALT1 = 5,
-	BCM2835_FSEL_ALT2 = 6,
-	BCM2835_FSEL_ALT3 = 7,
-	BCM2835_FSEL_ALT4 = 3,
-	BCM2835_FSEL_ALT5 = 2,
 	BCM2835_FSEL_COUNT = 8,
 	BCM2835_FSEL_MASK = 0x7,
 };
@@ -714,7 +708,7 @@ static int bcm2835_pctl_dt_node_to_map_pull(struct bcm2835_pinctrl *pc,
 	configs = kzalloc(sizeof(*configs), GFP_KERNEL);
 	if (!configs)
 		return -ENOMEM;
-	configs[0] = BCM2835_PINCONF_PACK(BCM2835_PINCONF_PARAM_PULL, pull);
+	configs[0] = PIN_CONF_PACKED(BCM2835_PINCONF_PARAM_PULL, pull);

 	map->type = PIN_MAP_TYPE_CONFIGS_PIN;
 	map->data.configs.group_or_pin = bcm2835_gpio_pins[pin].name;
@@ -736,6 +730,12 @@ static int bcm2835_pctl_dt_node_to_map(struct pinctrl_dev *pctldev,
 	int i, err;
 	u32 pin, func, pull;

+	/* Check for generic binding in this node */
+	err = pinconf_generic_dt_node_to_map_all(pctldev, np, map, num_maps);
+	if (err || *num_maps)
+		return err;
+
+	/* Generic binding did not find anything continue with legacy parse */
 	pins = of_find_property(np, "brcm,pins", NULL);
 	if (!pins) {
 		dev_err(pc->dev, "%pOF: missing brcm,pins property\n", np);
@@ -917,37 +917,62 @@ static int bcm2835_pinconf_get(struct pinctrl_dev *pctldev,
 	return -ENOTSUPP;
 }

+static void bcm2835_pull_config_set(struct bcm2835_pinctrl *pc,
+		unsigned pin, unsigned arg)
+{
+	u32 off, bit;
+
+	off = GPIO_REG_OFFSET(pin);
+	bit = GPIO_REG_SHIFT(pin);
+
+	bcm2835_gpio_wr(pc, GPPUD, arg & 3);
+	/*
+	* BCM2835 datasheet say to wait 150 cycles, but not of what.
+	* But the VideoCore firmware delay for this operation
+	* based nearly on the same amount of VPU cycles and this clock
+	* runs at 250 MHz.
+	*/
+	udelay(1);
+	bcm2835_gpio_wr(pc, GPPUDCLK0 + (off * 4), BIT(bit));
+	udelay(1);
+	bcm2835_gpio_wr(pc, GPPUDCLK0 + (off * 4), 0);
+}
+
 static int bcm2835_pinconf_set(struct pinctrl_dev *pctldev,
 			unsigned pin, unsigned long *configs,
 			unsigned num_configs)
 {
 	struct bcm2835_pinctrl *pc = pinctrl_dev_get_drvdata(pctldev);
-	enum bcm2835_pinconf_param param;
-	u16 arg;
-	u32 off, bit;
+	u16 param, arg;
 	int i;

 	for (i = 0; i < num_configs; i++) {
-		param = BCM2835_PINCONF_UNPACK_PARAM(configs[i]);
-		arg = BCM2835_PINCONF_UNPACK_ARG(configs[i]);
+		param = configs[i] & 0xffUL;
+		arg = configs[i] >> 8;

-		if (param != BCM2835_PINCONF_PARAM_PULL)
-			return -EINVAL;
+		switch (param) {
+		/* Set legacy brcm,pull */
+		case BCM2835_PINCONF_PARAM_PULL:
+			bcm2835_pull_config_set(pc, pin, arg);
+			break;

-		off = GPIO_REG_OFFSET(pin);
-		bit = GPIO_REG_SHIFT(pin);
+		/* Set pull generic bindings */
+		case PIN_CONFIG_BIAS_DISABLE:
+			bcm2835_pull_config_set(pc, pin, BCM2835_PUD_OFF);
+			break;

-		bcm2835_gpio_wr(pc, GPPUD, arg & 3);
-		/*
-		 * BCM2835 datasheet say to wait 150 cycles, but not of what.
-		 * But the VideoCore firmware delay for this operation
-		 * based nearly on the same amount of VPU cycles and this clock
-		 * runs at 250 MHz.
-		 */
-		udelay(1);
-		bcm2835_gpio_wr(pc, GPPUDCLK0 + (off * 4), BIT(bit));
-		udelay(1);
-		bcm2835_gpio_wr(pc, GPPUDCLK0 + (off * 4), 0);
+		case PIN_CONFIG_BIAS_PULL_DOWN:
+			bcm2835_pull_config_set(pc, pin, BCM2835_PUD_DOWN);
+			break;
+
+		case PIN_CONFIG_BIAS_PULL_UP:
+			bcm2835_pull_config_set(pc, pin, BCM2835_PUD_UP);
+			break;
+
+		default:
+			return -EINVAL;
+
+		} /* switch param type */
 	} /* for each config */

 	return 0;
--
2.7.4