at24 updates for linux v5.6

- minor maintenance: update the license tag, sort headers - move support for the write-protect pin into nvmem core - add a reference to the new wp-gpios property in nvmem to at25 bindings - add support for regulator and pm_runtime control -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEFp3rbAvDxGAT0sefEacuoBRx13IFAl4rHlAACgkQEacuoBRx 13J9Ug//dprb3sJZDiFrktJBVgCJ8+6l88gXwrkTNDGXGnrE3W4YGA12YO8NQPFR hGHLegV+LZCSebcxL7iY69UCMMCLQ5cGKUMXfIJqJQfSBV8em1+81DMHSFh0kJPn jVgPo4JAqq0JJPuXz7YQnqtJtksSsBVvxbglm7dSXpF61eqnFEO/Xi80IM3uoqSK 1FMgu+2PweH4CYPL272bgwRLFLGyzQaI8EQhCvzov+ye8Z1ctVXUmjojmtZCanTM 1XLTBdwNJKd6ogFpD6YGGBBg53mgANDY4P++DxO7yk7QjhyaculbDPDp43KvJcnO QR7PswnMT+78KmJOtxsShLMUCoaNe7aSgq+luby0Zdb2KwZY/K9gOUN6XbsqppEY qH3pQdzRZ6k8jZL8QWjemZ1g1B4z6qfbR10k0F5yg8bzXDFlpaRja2wFV63YZk6k ld9BHfGss/mR7XztfM4/Tb7Cj5asV6jnX4LGWvK4Va1UZE69QeUKTXYVQIc5v/fB hCzkYPW496Yoh0i785eJMwJ5PgwhYhXK+b/panMibFwGttIMxKf/sKejLeOxsMTv z20awOCCdo1soCcci6YkOrjN1Lj2EViWg/i0oWsV1FxkKUkPzR3fXRrPgSp0zZ7e vKIjU3Ej9QQyuMOxguVm2gB9gj6hB7oTBBlgNb1uQ7Zf1f9Z18Q= =jh24 -----END PGP SIGNATURE----- Merge tag 'at24-updates-for-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux into i2c/for-5.6 at24 updates for linux v5.6 - minor maintenance: update the license tag, sort headers - move support for the write-protect pin into nvmem core - add a reference to the new wp-gpios property in nvmem to at25 bindings - add support for regulator and pm_runtime control
2020-01-29 21:56:36 +01:00 · 2020-01-29 21:56:36 +01:00 · 6810df46c4
parent 878508aed4 cd5676db05
commit 6810df46c4
7 changed files with 92 additions and 28 deletions
--- a/Documentation/devicetree/bindings/eeprom/at24.yaml
+++ b/Documentation/devicetree/bindings/eeprom/at24.yaml
@ -145,10 +145,7 @@ properties:
      over reads to the next slave address. Please consult the manual of
      your device.

-  wp-gpios:
-    description:
-      GPIO to which the write-protect pin of the chip is connected.
-    maxItems: 1
+  wp-gpios: true

  address-width:
    allOf:
@ -167,6 +164,10 @@ properties:
    minimum: 1
    maximum: 8

+  vcc-supply:
+    description:
+      phandle of the regulator that provides the supply voltage.
+
 required:
  - compatible
  - reg
--- a/Documentation/devicetree/bindings/eeprom/at25.txt
+++ b/Documentation/devicetree/bindings/eeprom/at25.txt
@ -20,6 +20,7 @@ Optional properties:
 - spi-cpha : SPI shifted clock phase, as per spi-bus bindings.
 - spi-cpol : SPI inverse clock polarity, as per spi-bus bindings.
 - read-only : this parameter-less property disables writes to the eeprom
+- wp-gpios : GPIO to which the write-protect pin of the chip is connected

 Obsolete legacy properties can be used in place of "size", "pagesize",
 "address-width", and "read-only":
@ -36,6 +37,7 @@ Example:
 		spi-max-frequency = <5000000>;
 		spi-cpha;
 		spi-cpol;
+		wp-gpios = <&gpio1 3 0>;

 		pagesize = <64>;
 		size = <32768>;
--- a/Documentation/devicetree/bindings/nvmem/nvmem.yaml
+++ b/Documentation/devicetree/bindings/nvmem/nvmem.yaml
@ -34,6 +34,14 @@ properties:
    description:
      Mark the provider as read only.

+  wp-gpios:
+    description:
+      GPIO to which the write-protect pin of the chip is connected.
+      The write-protect GPIO is asserted, when it's driven high
+      (logical '1') to block the write operation. It's deasserted,
+      when it's driven low (logical '0') to allow writing.
+    maxItems: 1
+
 patternProperties:
  "^.*@[0-9a-f]+$":
    type: object
@ -63,9 +71,12 @@ patternProperties:

 examples:
  - |
+      #include <dt-bindings/gpio/gpio.h>
+
      qfprom: eeprom@700000 {
          #address-cells = <1>;
          #size-cells = <1>;
+          wp-gpios = <&gpio1 3 GPIO_ACTIVE_HIGH>;

          /* ... */

--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0+
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
 * at24.c - handle most I2C EEPROMs
 *
@ -6,23 +6,23 @@
 * Copyright (C) 2008 Wolfram Sang, Pengutronix
 */

-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/of_device.h>
-#include <linux/slab.h>
-#include <linux/delay.h>
-#include <linux/mutex.h>
-#include <linux/mod_devicetable.h>
-#include <linux/bitops.h>
-#include <linux/jiffies.h>
-#include <linux/property.h>
 #include <linux/acpi.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
 #include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/nvmem-provider.h>
-#include <linux/regmap.h>
+#include <linux/of_device.h>
 #include <linux/pm_runtime.h>
-#include <linux/gpio/consumer.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>

 /* Address pointer is 16 bit. */
 #define AT24_FLAG_ADDR16	BIT(7)
@ -88,8 +88,7 @@ struct at24_data {
 	u8 flags;

 	struct nvmem_device *nvmem;
-
-	struct gpio_desc *wp_gpio;
+	struct regulator *vcc_reg;

 	/*
 	 * Some chips tie up multiple I2C addresses; dummy devices reserve
@ -457,12 +456,10 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count)
 	 * from this host, but not from other I2C masters.
 	 */
 	mutex_lock(&at24->lock);
-	gpiod_set_value_cansleep(at24->wp_gpio, 0);

 	while (count) {
 		ret = at24_regmap_write(at24, buf, off, count);
 		if (ret < 0) {
-			gpiod_set_value_cansleep(at24->wp_gpio, 1);
 			mutex_unlock(&at24->lock);
 			pm_runtime_put(dev);
 			return ret;
@ -472,7 +469,6 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count)
 		count -= ret;
 	}

-	gpiod_set_value_cansleep(at24->wp_gpio, 1);
 	mutex_unlock(&at24->lock);

 	pm_runtime_put(dev);
@ -662,9 +658,9 @@ static int at24_probe(struct i2c_client *client)
 	at24->client[0].client = client;
 	at24->client[0].regmap = regmap;

-	at24->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_HIGH);
-	if (IS_ERR(at24->wp_gpio))
-		return PTR_ERR(at24->wp_gpio);
+	at24->vcc_reg = devm_regulator_get(dev, "vcc");
+	if (IS_ERR(at24->vcc_reg))
+		return PTR_ERR(at24->vcc_reg);

 	writable = !(flags & AT24_FLAG_READONLY);
 	if (writable) {
@ -701,6 +697,12 @@ static int at24_probe(struct i2c_client *client)

 	i2c_set_clientdata(client, at24);

+	err = regulator_enable(at24->vcc_reg);
+	if (err) {
+		dev_err(dev, "Failed to enable vcc regulator\n");
+		return err;
+	}
+
 	/* enable runtime pm */
 	pm_runtime_set_active(dev);
 	pm_runtime_enable(dev);
@ -713,6 +715,7 @@ static int at24_probe(struct i2c_client *client)
 	pm_runtime_idle(dev);
 	if (err) {
 		pm_runtime_disable(dev);
+		regulator_disable(at24->vcc_reg);
 		return -ENODEV;
 	}

@ -728,15 +731,42 @@ static int at24_probe(struct i2c_client *client)

 static int at24_remove(struct i2c_client *client)
 {
+	struct at24_data *at24 = i2c_get_clientdata(client);
+
 	pm_runtime_disable(&client->dev);
+	if (!pm_runtime_status_suspended(&client->dev))
+		regulator_disable(at24->vcc_reg);
 	pm_runtime_set_suspended(&client->dev);

 	return 0;
 }

+static int __maybe_unused at24_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct at24_data *at24 = i2c_get_clientdata(client);
+
+	return regulator_disable(at24->vcc_reg);
+}
+
+static int __maybe_unused at24_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct at24_data *at24 = i2c_get_clientdata(client);
+
+	return regulator_enable(at24->vcc_reg);
+}
+
+static const struct dev_pm_ops at24_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(at24_suspend, at24_resume, NULL)
+};
+
 static struct i2c_driver at24_driver = {
 	.driver = {
 		.name = "at24",
+		.pm = &at24_pm_ops,
 		.of_match_table = at24_of_match,
 		.acpi_match_table = ACPI_PTR(at24_acpi_ids),
 	},
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/nvmem-consumer.h>
 #include <linux/nvmem-provider.h>
+#include <linux/gpio/consumer.h>
 #include <linux/of.h>
 #include <linux/slab.h>
 #include "nvmem.h"
@ -54,8 +55,14 @@ static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
 static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
 			   void *val, size_t bytes)
 {
-	if (nvmem->reg_write)
-		return nvmem->reg_write(nvmem->priv, offset, val, bytes);
+	int ret;
+
+	if (nvmem->reg_write) {
+		gpiod_set_value_cansleep(nvmem->wp_gpio, 0);
+		ret = nvmem->reg_write(nvmem->priv, offset, val, bytes);
+		gpiod_set_value_cansleep(nvmem->wp_gpio, 1);
+		return ret;
+	}

 	return -EINVAL;
 }
@ -338,6 +345,14 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 		kfree(nvmem);
 		return ERR_PTR(rval);
 	}
+	if (config->wp_gpio)
+		nvmem->wp_gpio = config->wp_gpio;
+	else
+		nvmem->wp_gpio = gpiod_get_optional(config->dev, "wp",
+						    GPIOD_OUT_HIGH);
+	if (IS_ERR(nvmem->wp_gpio))
+		return ERR_CAST(nvmem->wp_gpio);
+

 	kref_init(&nvmem->refcnt);
 	INIT_LIST_HEAD(&nvmem->cells);
--- a/drivers/nvmem/nvmem.h
+++ b/drivers/nvmem/nvmem.h
@ -9,6 +9,7 @@
 #include <linux/list.h>
 #include <linux/nvmem-consumer.h>
 #include <linux/nvmem-provider.h>
+#include <linux/gpio/consumer.h>

 struct nvmem_device {
 	struct module		*owner;
@ -26,6 +27,7 @@ struct nvmem_device {
 	struct list_head	cells;
 	nvmem_reg_read_t	reg_read;
 	nvmem_reg_write_t	reg_write;
+	struct gpio_desc	*wp_gpio;
 	void *priv;
 };

--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@ -11,6 +11,7 @@

 #include <linux/err.h>
 #include <linux/errno.h>
+#include <linux/gpio/consumer.h>

 struct nvmem_device;
 struct nvmem_cell_info;
@ -45,6 +46,7 @@ enum nvmem_type {
 * @word_size:	Minimum read/write access granularity.
 * @stride:	Minimum read/write access stride.
 * @priv:	User context passed to read/write callbacks.
+ * @wp-gpio:   Write protect pin
 *
 * Note: A default "nvmem<id>" name will be assigned to the device if
 * no name is specified in its configuration. In such case "<id>" is
@ -58,6 +60,7 @@ struct nvmem_config {
 	const char		*name;
 	int			id;
 	struct module		*owner;
+	struct gpio_desc	*wp_gpio;
 	const struct nvmem_cell_info	*cells;
 	int			ncells;
 	enum nvmem_type		type;