This commit adds support to the eeprom_93x46 driver allowing a GPIO line
to function as a 'select' or 'enable' signal prior to accessing the
EEPROM.
Signed-off-by: Cory Tusar <cory.tu...@pid1solutions.com>
Tested-by: Chris Healy <chris.he...@zii.aero>
Reviewed-by: Vladimir Zapolskiy <v...@mleia.com>
---
drivers/misc/eeprom/eeprom_93xx46.c | 35 +++++++++++++++++++++++++++++++++++
include/linux/eeprom_93xx46.h | 3 +++
2 files changed, 38 insertions(+)
diff --git a/drivers/misc/eeprom/eeprom_93xx46.c
b/drivers/misc/eeprom/eeprom_93xx46.c
index d50bc17..d28fac2 100644
--- a/drivers/misc/eeprom/eeprom_93xx46.c
+++ b/drivers/misc/eeprom/eeprom_93xx46.c
@@ -10,11 +10,13 @@
#include <linux/delay.h>
#include <linux/device.h>
+#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_device.h>
+#include <linux/of_gpio.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
@@ -343,6 +345,20 @@ static ssize_t eeprom_93xx46_store_erase(struct device
*dev,
}
static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);
+static void select_assert(void *context)
+{
+ struct eeprom_93xx46_dev *edev = context;
+
+ gpiod_set_value_cansleep(edev->pdata->select, 1);
+}
+
+static void select_deassert(void *context)
+{
+ struct eeprom_93xx46_dev *edev = context;
+
+ gpiod_set_value_cansleep(edev->pdata->select, 0);
+}
+
static const struct of_device_id eeprom_93xx46_of_table[] = {
{ .compatible = "eeprom-93xx46", },
{ .compatible = "atmel,at93c46d", .data = &atmel_at93c46d_data, },
@@ -357,6 +373,8 @@ static int eeprom_93xx46_probe_dt(struct spi_device *spi)
struct device_node *np = spi->dev.of_node;
struct eeprom_93xx46_platform_data *pd;
u32 tmp;
+ int gpio;
+ enum of_gpio_flags of_flags;
int ret;
pd = devm_kzalloc(&spi->dev, sizeof(*pd), GFP_KERNEL);
@@ -381,6 +399,23 @@ static int eeprom_93xx46_probe_dt(struct spi_device *spi)
if (of_property_read_bool(np, "read-only"))
pd->flags |= EE_READONLY;
+ gpio = of_get_named_gpio_flags(np, "select-gpios", 0, &of_flags);
+ if (gpio_is_valid(gpio)) {
+ unsigned long flags =
+ of_flags == OF_GPIO_ACTIVE_LOW ? GPIOF_ACTIVE_LOW : 0;
+
+ ret = devm_gpio_request_one(&spi->dev, gpio, flags,
+ "eeprom_93xx46_select");
+ if (ret)
+ return ret;
+
+ pd->select = gpio_to_desc(gpio);
+ pd->prepare = select_assert;
+ pd->finish = select_deassert;
+
+ gpiod_direction_output(pd->select, 0);
+ }
+
if (of_id->data) {
const struct eeprom_93xx46_devtype_data *data = of_id->data;
diff --git a/include/linux/eeprom_93xx46.h b/include/linux/eeprom_93xx46.h
index 92fa4c3..885f587 100644
--- a/include/linux/eeprom_93xx46.h
+++ b/include/linux/eeprom_93xx46.h
@@ -3,6 +3,8 @@
* platform description for 93xx46 EEPROMs.
*/
+struct gpio_desc;
+
struct eeprom_93xx46_platform_data {
unsigned char flags;
#define EE_ADDR8 0x01 /* 8 bit addr. cfg */
@@ -21,4 +23,5 @@ struct eeprom_93xx46_platform_data {
*/
void (*prepare)(void *);
void (*finish)(void *);
+ struct gpio_desc *select;
};
--
2.4.10
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