Merge "NFC: Add support for LDO voting"

drivers/nfc/qti/nfc_common.c

@@ -10,9 +10,10 @@
 
 
 int nfc_parse_dt(struct device *dev, struct platform_gpio *nfc_gpio,
-		 uint8_t interface)
+		 struct platform_ldo *ldo, uint8_t interface)
 {
 	struct device_node *np = dev->of_node;
+	int ret;
 
 	if (!np) {
 		pr_err("nfc of_node NULL\n");
@@ -49,9 +50,139 @@ int nfc_parse_dt(struct device *dev, struct platform_gpio *nfc_gpio,
 	pr_info("%s: ven %d, dwl req %d, clkreq %d\n", __func__,
 		nfc_gpio->ven, nfc_gpio->dwl_req, nfc_gpio->clkreq);
 
+	// optional property
+	ret = of_property_read_u32_array(np, NFC_LDO_VOL_DT_NAME,
+			(u32 *) ldo->vdd_levels,
+			ARRAY_SIZE(ldo->vdd_levels));
+	if (ret) {
+		dev_err(dev, "error reading NFC VDDIO min and max value\n");
+		// set default as per datasheet
+		ldo->vdd_levels[0] = NFC_VDDIO_MIN;
+		ldo->vdd_levels[1] = NFC_VDDIO_MAX;
+	}
+
+	// optional property
+	ret = of_property_read_u32(np, NFC_LDO_CUR_DT_NAME, &ldo->max_current);
+	if (ret) {
+		dev_err(dev, "error reading NFC current value\n");
+		// set default as per datasheet
+		ldo->max_current = NFC_CURRENT_MAX;
+	}
+
 	return 0;
 }
 
+/**
+ * nfc_ldo_vote()
+ * @nfc_dev: NFC device containing regulator handle
+ *
+ * LDO voting based on voltage and current entries in DT
+ *
+ * Return: 0 on success and -ve on failure
+ */
+int nfc_ldo_vote(struct nfc_dev *nfc_dev)
+{
+	int ret;
+
+	ret =  regulator_set_voltage(nfc_dev->reg,
+			nfc_dev->ldo.vdd_levels[0],
+			nfc_dev->ldo.vdd_levels[1]);
+	if (ret < 0) {
+		pr_err("%s: set voltage failed\n", __func__);
+		return ret;
+	}
+
+	/* pass expected current from NFC in uA */
+	ret = regulator_set_load(nfc_dev->reg, nfc_dev->ldo.max_current);
+	if (ret < 0) {
+		pr_err("%s: set load failed\n", __func__);
+		return ret;
+	}
+
+	ret = regulator_enable(nfc_dev->reg);
+	if (ret < 0)
+		pr_err("%s: regulator_enable failed\n", __func__);
+	else
+		nfc_dev->is_vreg_enabled = true;
+	return ret;
+}
+
+/**
+ * nfc_ldo_config()
+ * @dev: device instance to read DT entry
+ * @nfc_dev: NFC device containing regulator handle
+ *
+ * Configure LDO if entry is present in DT file otherwise
+ * return with success as it's optional
+ *
+ * Return: 0 on success and -ve on failure
+ */
+int nfc_ldo_config(struct device *dev, struct nfc_dev *nfc_dev)
+{
+	int ret;
+
+	if (of_get_property(dev->of_node, NFC_LDO_SUPPLY_NAME, NULL)) {
+		// Get the regulator handle
+		nfc_dev->reg = regulator_get(dev, NFC_LDO_SUPPLY_DT_NAME);
+		if (IS_ERR(nfc_dev->reg)) {
+			ret = PTR_ERR(nfc_dev->reg);
+			nfc_dev->reg = NULL;
+			pr_err("%s: regulator_get failed, ret = %d\n",
+				__func__, ret);
+			return ret;
+		}
+	} else {
+		nfc_dev->reg = NULL;
+		pr_err("%s: regulator entry not present\n", __func__);
+		// return success as it's optional to configure LDO
+		return 0;
+	}
+
+	// LDO config supported by platform DT
+	ret = nfc_ldo_vote(nfc_dev);
+	if (ret < 0) {
+		pr_err("%s: LDO voting failed, ret = %d\n", __func__, ret);
+		regulator_put(nfc_dev->reg);
+	}
+	return ret;
+}
+
+/**
+ * nfc_ldo_unvote()
+ * @nfc_dev: NFC device containing regulator handle
+ *
+ * set voltage and load to zero and disable regulator
+ *
+ * Return: 0 on success and -ve on failure
+ */
+int nfc_ldo_unvote(struct nfc_dev *nfc_dev)
+{
+	int ret;
+
+	if (!nfc_dev->is_vreg_enabled) {
+		pr_err("%s: regulator already disabled\n", __func__);
+		return -EINVAL;
+	}
+
+	ret = regulator_disable(nfc_dev->reg);
+	if (ret < 0) {
+		pr_err("%s: regulator_disable failed\n", __func__);
+		return ret;
+	}
+	nfc_dev->is_vreg_enabled = false;
+
+	ret =  regulator_set_voltage(nfc_dev->reg, 0, NFC_VDDIO_MAX);
+	if (ret < 0) {
+		pr_err("%s: set voltage failed\n", __func__);
+		return ret;
+	}
+
+	ret = regulator_set_load(nfc_dev->reg, 0);
+	if (ret < 0)
+		pr_err("%s: set load failed\n", __func__);
+	return ret;
+}
+
 void gpio_set_ven(struct nfc_dev *nfc_dev, int value)
 {
 	if (gpio_get_value(nfc_dev->gpio.ven) != value) {
@@ -295,6 +426,7 @@ int nfc_ese_pwr(struct nfc_dev *nfc_dev, unsigned long arg)
 		} else {
 			pr_debug("ven already HIGH\n");
 		}
+		nfc_dev->is_ese_session_active = true;
 	} else if (arg == ESE_POWER_OFF) {
 		if (!nfc_dev->nfc_ven_enabled) {
 			pr_debug("NFC not enabled, disabling ven\n");
@@ -302,6 +434,7 @@ int nfc_ese_pwr(struct nfc_dev *nfc_dev, unsigned long arg)
 		} else {
 			pr_debug("keep ven high as NFC is enabled\n");
 		}
+		nfc_dev->is_ese_session_active = false;
 	} else if (arg == ESE_COLD_RESET) {
 
 		// set default value for status as failure

drivers/nfc/qti/nfc_common.h

@@ -23,6 +23,7 @@
 #include <linux/uaccess.h>
 #include <linux/slab.h>
 #include <linux/nfcinfo.h>
+#include <linux/regulator/consumer.h>
 
 #include "nfc_i2c_drv.h"
 #include "nfc_i3c_drv.h"
@@ -86,6 +87,15 @@
 #define DTS_FWDN_GPIO_STR	"qcom,sn-firm"
 #define DTS_CLKREQ_GPIO_STR	"qcom,sn-clkreq"
 #define DTS_CLKSRC_GPIO_STR	"qcom,clk-src"
+#define NFC_LDO_SUPPLY_DT_NAME	"qcom,nq-vdd-1p8"
+#define NFC_LDO_SUPPLY_NAME	"qcom,nq-vdd-1p8-supply"
+#define NFC_LDO_VOL_DT_NAME	"qcom,nq-vdd-1p8-voltage"
+#define NFC_LDO_CUR_DT_NAME	"qcom,nq-vdd-1p8-current"
+
+//as per SN1x0 datasheet
+#define NFC_VDDIO_MIN		1650000 //in uV
+#define NFC_VDDIO_MAX		1950000 //in uV
+#define NFC_CURRENT_MAX		157000 //in uA
 
 enum ese_ioctl_request {
 	/* eSE POWER ON */
@@ -163,6 +173,12 @@ struct platform_gpio {
 	unsigned int dwl_req;
 };
 
+// NFC LDO entries from DT
+struct platform_ldo {
+	int vdd_levels[2];
+	int max_current;
+};
+
 //Features specific Parameters
 struct cold_reset {
 	wait_queue_head_t read_wq;
@@ -186,12 +202,16 @@ struct nfc_dev {
 	uint8_t interface;
 	/* NFC VEN pin state */
 	bool nfc_ven_enabled;
+	bool is_vreg_enabled;
+	bool is_ese_session_active;
 	union {
 		struct i2c_dev i2c_dev;
 		struct i3c_dev i3c_dev;
 	};
 	struct platform_gpio gpio;
+	struct platform_ldo ldo;
 	struct cold_reset cold_reset;
+	struct regulator *reg;
 
 	/* read buffer*/
 	size_t kbuflen;
@@ -211,7 +231,7 @@ int nfc_dev_open(struct inode *inode, struct file *filp);
 int nfc_dev_close(struct inode *inode, struct file *filp);
 long nfc_dev_ioctl(struct file *pfile, unsigned int cmd, unsigned long arg);
 int nfc_parse_dt(struct device *dev, struct platform_gpio *nfc_gpio,
-		 uint8_t interface);
+		 struct platform_ldo *ldo, uint8_t interface);
 int nfc_misc_probe(struct nfc_dev *nfc_dev,
 		      const struct file_operations *nfc_fops, int count,
 		      char *devname, char *classname);
@@ -220,5 +240,8 @@ int configure_gpio(unsigned int gpio, int flag);
 void read_cold_reset_rsp(struct nfc_dev *nfc_dev, char *header);
 void gpio_set_ven(struct nfc_dev *nfc_dev, int value);
 int nfcc_hw_check(struct nfc_dev *nfc_dev);
+int nfc_ldo_config(struct device *dev, struct nfc_dev *nfc_dev);
+int nfc_ldo_vote(struct nfc_dev *nfc_dev);
+int nfc_ldo_unvote(struct nfc_dev *nfc_dev);
 
 #endif //_NFC_COMMON_H_

drivers/nfc/qti/nfc_i2c_drv.c

@@ -256,12 +256,13 @@ int nfc_i2c_dev_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	struct nfc_dev *nfc_dev = NULL;
 	struct i2c_dev *i2c_dev = NULL;
 	struct platform_gpio nfc_gpio;
+	struct platform_ldo nfc_ldo;
 
 	pr_debug("%s: enter\n", __func__);
 
 	//retrieve details of gpios from dt
 
-	ret = nfc_parse_dt(&client->dev, &nfc_gpio, PLATFORM_IF_I2C);
+	ret = nfc_parse_dt(&client->dev, &nfc_gpio, &nfc_ldo, PLATFORM_IF_I2C);
 	if (ret) {
 		pr_err("%s : failed to parse dt\n", __func__);
 		goto err;
@@ -341,6 +342,12 @@ int nfc_i2c_dev_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	i2c_disable_irq(nfc_dev);
 	i2c_set_clientdata(client, nfc_dev);
 
+	ret = nfc_ldo_config(&client->dev, nfc_dev);
+	if (ret) {
+		pr_err("LDO config failed\n");
+		goto err_ldo_config_failed;
+	}
+
 	ret = nfcc_hw_check(nfc_dev);
 	if (ret) {
 		pr_err("nfc hw check failed ret %d\n", ret);
@@ -349,11 +356,17 @@ int nfc_i2c_dev_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 	device_init_wakeup(&client->dev, true);
 	i2c_dev->irq_wake_up = false;
+	nfc_dev->is_ese_session_active = false;
 
 	pr_info("%s success\n", __func__);
 	return 0;
 
 err_nfcc_hw_check:
+	if (nfc_dev->reg) {
+		nfc_ldo_unvote(nfc_dev);
+		regulator_put(nfc_dev->reg);
+	}
+err_ldo_config_failed:
 	free_irq(client->irq, nfc_dev);
 err_nfc_misc_remove:
 	nfc_misc_remove(nfc_dev, DEV_COUNT);
@@ -386,6 +399,15 @@ int nfc_i2c_dev_remove(struct i2c_client *client)
 		ret = -ENODEV;
 		return ret;
 	}
+
+	gpio_set_value(nfc_dev->gpio.ven, 0);
+	// HW dependent delay before LDO goes into LPM mode
+	usleep_range(10000, 10100);
+	if (nfc_dev->reg) {
+		nfc_ldo_unvote(nfc_dev);
+		regulator_put(nfc_dev->reg);
+	}
+
 	device_init_wakeup(&client->dev, false);
 	free_irq(client->irq, nfc_dev);
 	nfc_misc_remove(nfc_dev, DEV_COUNT);

drivers/nfc/qti/nfc_i3c_drv.c

@@ -584,12 +584,13 @@ int nfc_i3c_dev_probe(struct i3c_device *device)
 	int ret = 0;
 	struct nfc_dev *nfc_dev = NULL;
 	struct platform_gpio nfc_gpio;
+	struct platform_ldo nfc_ldo;
 
 	pr_debug("%s: enter\n", __func__);
 
 	//retrieve gpio details from dt
 
-	ret = nfc_parse_dt(&device->dev, &nfc_gpio, PLATFORM_IF_I3C);
+	ret = nfc_parse_dt(&device->dev, &nfc_gpio, &nfc_ldo, PLATFORM_IF_I3C);
 	if (ret) {
 		pr_err("%s : failed to parse nfc dt node\n", __func__);
 		goto err;