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eeprom: at24: Simplify WP management and make it optional #6

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1 change: 0 additions & 1 deletion arch/arm64/boot/dts/amlogic/gxtvbb_p301.dts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1760,7 +1760,6 @@
pagesize = <8>;
write_ops_interval= <10>;/*Write operation interval at24c32 at24c64 is 10ms at24c128 is 5ms in spec*/
wp_gpios = <&gpio GPIOY_7 GPIO_ACTIVE_HIGH>;
write_gpio_port_status = <0>;
};
};
&pinmux {
Expand Down
134 changes: 49 additions & 85 deletions drivers/misc/eeprom/at24.c
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Original file line number Diff line number Diff line change
Expand Up @@ -24,11 +24,9 @@
#include <linux/i2c.h>
#include <linux/platform_data/at24.h>
#include <linux/gpio.h>
#include <linux/amlogic/aml_gpio_consumer.h>
#include <linux/amlogic/gpio-amlogic.h>
#include <linux/io.h>
#include <linux/platform_device.h>

#include <linux/of_gpio.h>

/*
* I2C EEPROMs from most vendors are inexpensive and mostly interchangeable.
Expand Down Expand Up @@ -135,28 +133,23 @@ static const struct i2c_device_id at24_ids[] = {
{ /* END OF LIST */ }
};
MODULE_DEVICE_TABLE(i2c, at24_ids);
#define MODULE_NAME "at24"

static struct at24_data *gp_at24;
static ssize_t at24_wp_show(struct class *class,
struct class_attribute *attr, char *buf)
{

return sprintf(buf, "%d\n", gpiod_get_value(gp_at24->chip.wp_pin_desc));
return sprintf(buf, "%d\n", gpio_get_value(gp_at24->chip.wp_port));
}
static ssize_t at24_wp_store(struct class *class,
struct class_attribute *attr, const char *buf, size_t count)
{
u8 wp;
u8 ret;
ret = sscanf(buf, "%x", (int *)&wp);
u8 ret;
ret = sscanf(buf, "%hhx", &wp);

mutex_lock(&gp_at24->lock);
if (wp == 0)
amlogic_gpio_direction_output(gp_at24->chip.wp_port , 0 ,
MODULE_NAME);
else if (wp == 1)
amlogic_gpio_direction_output(gp_at24->chip.wp_port , 1 ,
MODULE_NAME);
if (wp <= 1)
gpio_set_value(gp_at24->chip.wp_port, wp);
else
pr_info("only support 1 or 0\n");

Expand All @@ -168,39 +161,14 @@ struct class *at24_class;
static CLASS_ATTR(at24_wp , S_IWUSR | S_IRUGO , at24_wp_show , at24_wp_store);


/*eeprom protect gpio enable*/
void at24_wp_enable(struct at24_platform_data *chip)
{
int ret;
if (chip->wp_port > 0) {
ret = gpio_request(chip->wp_port , MODULE_NAME);
if (ret)
pr_info("faild to alloc write protect (%d)!\n" ,
chip->wp_port);
else
amlogic_gpio_direction_output(chip->wp_port ,
chip->wp_port_level , MODULE_NAME);
} else {
pr_info("wrong wp port\n");
}
}
/* enable write protect*/
void at24_enable_write_operation(struct at24_platform_data *chip)
static void at24_enable_write_operation(struct at24_platform_data *chip,
bool enable)
{
if (chip->wp_port > 0) {
chip->wp_port_level = chip->wp_port_level_save;
amlogic_gpio_direction_output(chip->wp_port ,
chip->wp_port_level , MODULE_NAME);
}
}
/* disable write protect*/
void at24_disable_write_operation(struct at24_platform_data *chip)
{
if (chip->wp_port > 0) {
chip->wp_port_level = !chip->wp_port_level_save;
amlogic_gpio_direction_output(chip->wp_port ,
chip->wp_port_level , MODULE_NAME);
}
if (gpio_is_valid(chip->wp_port))
gpio_set_value(chip->wp_port,
enable ? !chip->wp_port_active_level :
chip->wp_port_active_level);
}

/*-------------------------------------------------------------------------*/
Expand Down Expand Up @@ -469,7 +437,7 @@ static ssize_t at24_write(struct at24_data *at24, const char *buf, loff_t off,
if (unlikely(!count))
return count;
/*enable write ops*/
at24_enable_write_operation(&at24->chip);
at24_enable_write_operation(&at24->chip, true);
mdelay(at24->chip.write_ops_interval);
/*
* Write data to chip, protecting against concurrent updates
Expand All @@ -496,7 +464,7 @@ static ssize_t at24_write(struct at24_data *at24, const char *buf, loff_t off,
mutex_unlock(&at24->lock);

/*write protect*/
at24_disable_write_operation(&at24->chip);
at24_enable_write_operation(&at24->chip, false);

return retval;
}
Expand Down Expand Up @@ -561,43 +529,33 @@ static void at24_get_ofdata(struct i2c_client *client,
{ }
#endif /* CONFIG_OF */

void at24_dt_parse(struct i2c_client *client , struct at24_platform_data *chip)
static int at24_dt_parse(struct i2c_client *client,
struct at24_platform_data *chip)
{
/* const char *str;*/
int ret;
enum of_gpio_flags flags;

struct device_node *node = client->dev.of_node;
enum of_gpio_flags flags;
int ret;

ret = of_property_read_u32(node, "write_ops_interval",
&(chip->write_ops_interval));
if (ret)
pr_info("faild to get write interval time !\n");

chip->wp_pin_desc = of_get_named_gpiod_flags(node , "wp_gpios" ,
0 , &flags);
chip->wp_port = desc_to_gpio(chip->wp_pin_desc);

ret = of_property_read_u32(node , "write_gpio_port_status",
&(chip->wp_port_level));
if (ret)
pr_info("faild to get write interval time !\n");

if (!chip->wp_port_level)
chip->wp_port_level_save = chip->wp_port_level = 0;
/*at24_wp_enable(chip);*/
else
chip->wp_port_level_save = chip->wp_port_level = 1;
/*at24_wp_enable(chip);*/

chip->wp_port_level = !chip->wp_port_level_save;
at24_wp_enable(chip);
chip->write_ops_interval = 0;
of_property_read_u32(node, "write_ops_interval",
&chip->write_ops_interval);

chip->wp_port = of_get_named_gpio_flags(node, "wp_gpios", 0, &flags);
if (gpio_is_valid(chip->wp_port)) {
chip->wp_port_active_level = !(flags & OF_GPIO_ACTIVE_LOW);

ret = gpio_request_one(chip->wp_port,
chip->wp_port_active_level ?
GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
dev_name(&client->dev));
if (ret) {
dev_err(&client->dev, "unable to request WP GPIO %d\n",
chip->wp_port);
return ret;
}
}

pr_info("EEPROM_AT%s " , client->name);
pr_info("write protect port level is %d" , chip->wp_port);
pr_info("wp_port=%d write_ops_interval=%dms\n" ,
chip->wp_port ,
chip->write_ops_interval);
return 0;
}


Expand Down Expand Up @@ -696,8 +654,10 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)

writable = !(chip.flags & AT24_FLAG_READONLY);
if (writable) {
err = at24_dt_parse(client, &at24->chip);
if (err)
return err;

at24_dt_parse(client , &at24->chip);
if (!use_smbus || i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {

Expand Down Expand Up @@ -758,10 +718,12 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
/* export data to kernel code */
if (chip.setup)
chip.setup(&at24->macc, chip.context);
at24_class = class_create(THIS_MODULE , "at24_wp");
err = class_create_file(at24_class , &class_attr_at24_wp);
if (writable && gpio_is_valid(chip.wp_port)) {
at24_class = class_create(THIS_MODULE , "at24_wp");
err = class_create_file(at24_class , &class_attr_at24_wp);
}

return 0;
return err;

err_clients:
for (i = 1; i < num_addresses; i++)
Expand All @@ -782,7 +744,9 @@ static int at24_remove(struct i2c_client *client)
for (i = 1; i < at24->num_addresses; i++)
i2c_unregister_device(at24->client[i]);

class_destroy(at24_class);
if (!(at24->chip.flags & AT24_FLAG_READONLY) &&
gpio_is_valid(at24->chip.wp_port))
class_destroy(at24_class);
return 0;
}

Expand Down
10 changes: 2 additions & 8 deletions include/linux/platform_data/at24.h
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Original file line number Diff line number Diff line change
Expand Up @@ -47,17 +47,11 @@ struct at24_platform_data {
#define AT24_FLAG_READONLY 0x40 /* sysfs-entry will be read-only */
#define AT24_FLAG_IRUGO 0x20 /* sysfs-entry will be world-readable */
#define AT24_FLAG_TAKE8ADDR 0x10 /* take always 8 addresses (24c00) */
unsigned int wp_port;
unsigned int wp_port_level;
unsigned int wp_port_level_save;
int wp_port;
unsigned int wp_port_active_level;
unsigned int write_ops_interval;
struct gpio_desc *wp_pin_desc;
void (*setup)(struct memory_accessor *, void *context);
void *context;
};
extern int amlogic_gpio_name_map_num(const char *name);
extern int amlogic_gpio_direction_output(unsigned int pin, int value,
const char *owner);
extern int amlogic_gpio_request(unsigned int pin, const char *label);

#endif /* _LINUX_AT24_H */