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path: root/drivers/nfc/st-nci/i2c.c
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Diffstat (limited to 'drivers/nfc/st-nci/i2c.c')
-rw-r--r--drivers/nfc/st-nci/i2c.c293
1 files changed, 293 insertions, 0 deletions
diff --git a/drivers/nfc/st-nci/i2c.c b/drivers/nfc/st-nci/i2c.c
new file mode 100644
index 0000000000..d20a337e90
--- /dev/null
+++ b/drivers/nfc/st-nci/i2c.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * I2C Link Layer for ST NCI NFC controller familly based Driver
+ * Copyright (C) 2014-2015 STMicroelectronics SAS. All rights reserved.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/gpio/consumer.h>
+#include <linux/acpi.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/nfc.h>
+#include <linux/of.h>
+
+#include "st-nci.h"
+
+#define DRIVER_DESC "NCI NFC driver for ST_NCI"
+
+/* ndlc header */
+#define ST_NCI_FRAME_HEADROOM 1
+#define ST_NCI_FRAME_TAILROOM 0
+
+#define ST_NCI_I2C_MIN_SIZE 4 /* PCB(1) + NCI Packet header(3) */
+#define ST_NCI_I2C_MAX_SIZE 250 /* req 4.2.1 */
+
+#define ST_NCI_DRIVER_NAME "st_nci"
+#define ST_NCI_I2C_DRIVER_NAME "st_nci_i2c"
+
+struct st_nci_i2c_phy {
+ struct i2c_client *i2c_dev;
+ struct llt_ndlc *ndlc;
+
+ bool irq_active;
+
+ struct gpio_desc *gpiod_reset;
+
+ struct st_nci_se_status se_status;
+};
+
+static int st_nci_i2c_enable(void *phy_id)
+{
+ struct st_nci_i2c_phy *phy = phy_id;
+
+ gpiod_set_value(phy->gpiod_reset, 0);
+ usleep_range(10000, 15000);
+ gpiod_set_value(phy->gpiod_reset, 1);
+ usleep_range(80000, 85000);
+
+ if (phy->ndlc->powered == 0 && phy->irq_active == 0) {
+ enable_irq(phy->i2c_dev->irq);
+ phy->irq_active = true;
+ }
+
+ return 0;
+}
+
+static void st_nci_i2c_disable(void *phy_id)
+{
+ struct st_nci_i2c_phy *phy = phy_id;
+
+ disable_irq_nosync(phy->i2c_dev->irq);
+ phy->irq_active = false;
+}
+
+/*
+ * Writing a frame must not return the number of written bytes.
+ * It must return either zero for success, or <0 for error.
+ * In addition, it must not alter the skb
+ */
+static int st_nci_i2c_write(void *phy_id, struct sk_buff *skb)
+{
+ int r;
+ struct st_nci_i2c_phy *phy = phy_id;
+ struct i2c_client *client = phy->i2c_dev;
+
+ if (phy->ndlc->hard_fault != 0)
+ return phy->ndlc->hard_fault;
+
+ r = i2c_master_send(client, skb->data, skb->len);
+ if (r < 0) { /* Retry, chip was in standby */
+ usleep_range(1000, 4000);
+ r = i2c_master_send(client, skb->data, skb->len);
+ }
+
+ if (r >= 0) {
+ if (r != skb->len)
+ r = -EREMOTEIO;
+ else
+ r = 0;
+ }
+
+ return r;
+}
+
+/*
+ * Reads an ndlc frame and returns it in a newly allocated sk_buff.
+ * returns:
+ * 0 : if received frame is complete
+ * -EREMOTEIO : i2c read error (fatal)
+ * -EBADMSG : frame was incorrect and discarded
+ * -ENOMEM : cannot allocate skb, frame dropped
+ */
+static int st_nci_i2c_read(struct st_nci_i2c_phy *phy,
+ struct sk_buff **skb)
+{
+ int r;
+ u8 len;
+ u8 buf[ST_NCI_I2C_MAX_SIZE];
+ struct i2c_client *client = phy->i2c_dev;
+
+ r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
+ if (r < 0) { /* Retry, chip was in standby */
+ usleep_range(1000, 4000);
+ r = i2c_master_recv(client, buf, ST_NCI_I2C_MIN_SIZE);
+ }
+
+ if (r != ST_NCI_I2C_MIN_SIZE)
+ return -EREMOTEIO;
+
+ len = be16_to_cpu(*(__be16 *) (buf + 2));
+ if (len > ST_NCI_I2C_MAX_SIZE) {
+ nfc_err(&client->dev, "invalid frame len\n");
+ return -EBADMSG;
+ }
+
+ *skb = alloc_skb(ST_NCI_I2C_MIN_SIZE + len, GFP_KERNEL);
+ if (*skb == NULL)
+ return -ENOMEM;
+
+ skb_reserve(*skb, ST_NCI_I2C_MIN_SIZE);
+ skb_put(*skb, ST_NCI_I2C_MIN_SIZE);
+ memcpy((*skb)->data, buf, ST_NCI_I2C_MIN_SIZE);
+
+ if (!len)
+ return 0;
+
+ r = i2c_master_recv(client, buf, len);
+ if (r != len) {
+ kfree_skb(*skb);
+ return -EREMOTEIO;
+ }
+
+ skb_put(*skb, len);
+ memcpy((*skb)->data + ST_NCI_I2C_MIN_SIZE, buf, len);
+
+ return 0;
+}
+
+/*
+ * Reads an ndlc frame from the chip.
+ *
+ * On ST_NCI, IRQ goes in idle state when read starts.
+ */
+static irqreturn_t st_nci_irq_thread_fn(int irq, void *phy_id)
+{
+ struct st_nci_i2c_phy *phy = phy_id;
+ struct sk_buff *skb = NULL;
+ int r;
+
+ if (!phy || !phy->ndlc || irq != phy->i2c_dev->irq) {
+ WARN_ON_ONCE(1);
+ return IRQ_NONE;
+ }
+
+ if (phy->ndlc->hard_fault)
+ return IRQ_HANDLED;
+
+ if (!phy->ndlc->powered) {
+ st_nci_i2c_disable(phy);
+ return IRQ_HANDLED;
+ }
+
+ r = st_nci_i2c_read(phy, &skb);
+ if (r == -EREMOTEIO || r == -ENOMEM || r == -EBADMSG)
+ return IRQ_HANDLED;
+
+ ndlc_recv(phy->ndlc, skb);
+
+ return IRQ_HANDLED;
+}
+
+static const struct nfc_phy_ops i2c_phy_ops = {
+ .write = st_nci_i2c_write,
+ .enable = st_nci_i2c_enable,
+ .disable = st_nci_i2c_disable,
+};
+
+static const struct acpi_gpio_params reset_gpios = { 1, 0, false };
+
+static const struct acpi_gpio_mapping acpi_st_nci_gpios[] = {
+ { "reset-gpios", &reset_gpios, 1 },
+ {},
+};
+
+static int st_nci_i2c_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct st_nci_i2c_phy *phy;
+ int r;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+ nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
+ return -ENODEV;
+ }
+
+ phy = devm_kzalloc(dev, sizeof(struct st_nci_i2c_phy), GFP_KERNEL);
+ if (!phy)
+ return -ENOMEM;
+
+ phy->i2c_dev = client;
+
+ i2c_set_clientdata(client, phy);
+
+ r = devm_acpi_dev_add_driver_gpios(dev, acpi_st_nci_gpios);
+ if (r)
+ dev_dbg(dev, "Unable to add GPIO mapping table\n");
+
+ /* Get RESET GPIO */
+ phy->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(phy->gpiod_reset)) {
+ nfc_err(dev, "Unable to get RESET GPIO\n");
+ return -ENODEV;
+ }
+
+ phy->se_status.is_ese_present =
+ device_property_read_bool(dev, "ese-present");
+ phy->se_status.is_uicc_present =
+ device_property_read_bool(dev, "uicc-present");
+
+ r = ndlc_probe(phy, &i2c_phy_ops, &client->dev,
+ ST_NCI_FRAME_HEADROOM, ST_NCI_FRAME_TAILROOM,
+ &phy->ndlc, &phy->se_status);
+ if (r < 0) {
+ nfc_err(&client->dev, "Unable to register ndlc layer\n");
+ return r;
+ }
+
+ phy->irq_active = true;
+ r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+ st_nci_irq_thread_fn,
+ IRQF_ONESHOT,
+ ST_NCI_DRIVER_NAME, phy);
+ if (r < 0)
+ nfc_err(&client->dev, "Unable to register IRQ handler\n");
+
+ return r;
+}
+
+static void st_nci_i2c_remove(struct i2c_client *client)
+{
+ struct st_nci_i2c_phy *phy = i2c_get_clientdata(client);
+
+ ndlc_remove(phy->ndlc);
+}
+
+static const struct i2c_device_id st_nci_i2c_id_table[] = {
+ {ST_NCI_DRIVER_NAME, 0},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, st_nci_i2c_id_table);
+
+static const struct acpi_device_id st_nci_i2c_acpi_match[] __maybe_unused = {
+ {"SMO2101"},
+ {"SMO2102"},
+ {}
+};
+MODULE_DEVICE_TABLE(acpi, st_nci_i2c_acpi_match);
+
+static const struct of_device_id of_st_nci_i2c_match[] __maybe_unused = {
+ { .compatible = "st,st21nfcb-i2c", },
+ { .compatible = "st,st21nfcb_i2c", },
+ { .compatible = "st,st21nfcc-i2c", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, of_st_nci_i2c_match);
+
+static struct i2c_driver st_nci_i2c_driver = {
+ .driver = {
+ .name = ST_NCI_I2C_DRIVER_NAME,
+ .of_match_table = of_match_ptr(of_st_nci_i2c_match),
+ .acpi_match_table = ACPI_PTR(st_nci_i2c_acpi_match),
+ },
+ .probe = st_nci_i2c_probe,
+ .id_table = st_nci_i2c_id_table,
+ .remove = st_nci_i2c_remove,
+};
+module_i2c_driver(st_nci_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(DRIVER_DESC);