From 98e8201039afad5d2af87df9ac682f62f69c0c2f Mon Sep 17 00:00:00 2001 From: Divagar Mohandass Date: Tue, 10 Oct 2017 11:30:37 +0530 Subject: eeprom: at24: enable runtime pm support Currently the device is kept in D0, there is an opportunity to save power by enabling runtime pm. Device can be daisy chained from PMIC and we can't rely on I2C core for auto resume/suspend. Driver will decide when to resume/suspend. Reviewed-by: Sakari Ailus Signed-off-by: Divagar Mohandass Signed-off-by: Wolfram Sang --- drivers/misc/eeprom/at24.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) (limited to 'drivers/misc') diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c index 2199c42e1623..a466e40acb2c 100644 --- a/drivers/misc/eeprom/at24.c +++ b/drivers/misc/eeprom/at24.c @@ -24,6 +24,7 @@ #include #include #include +#include /* * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable. @@ -501,11 +502,21 @@ static ssize_t at24_eeprom_write_i2c(struct at24_data *at24, const char *buf, static int at24_read(void *priv, unsigned int off, void *val, size_t count) { struct at24_data *at24 = priv; + struct i2c_client *client; char *buf = val; + int ret; if (unlikely(!count)) return count; + client = at24_translate_offset(at24, &off); + + ret = pm_runtime_get_sync(&client->dev); + if (ret < 0) { + pm_runtime_put_noidle(&client->dev); + return ret; + } + /* * Read data from chip, protecting against concurrent updates * from this host, but not from other I2C masters. @@ -518,6 +529,7 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count) status = at24->read_func(at24, buf, off, count); if (status < 0) { mutex_unlock(&at24->lock); + pm_runtime_put(&client->dev); return status; } buf += status; @@ -527,17 +539,29 @@ static int at24_read(void *priv, unsigned int off, void *val, size_t count) mutex_unlock(&at24->lock); + pm_runtime_put(&client->dev); + return 0; } static int at24_write(void *priv, unsigned int off, void *val, size_t count) { struct at24_data *at24 = priv; + struct i2c_client *client; char *buf = val; + int ret; if (unlikely(!count)) return -EINVAL; + client = at24_translate_offset(at24, &off); + + ret = pm_runtime_get_sync(&client->dev); + if (ret < 0) { + pm_runtime_put_noidle(&client->dev); + return ret; + } + /* * Write data to chip, protecting against concurrent updates * from this host, but not from other I2C masters. @@ -550,6 +574,7 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count) status = at24->write_func(at24, buf, off, count); if (status < 0) { mutex_unlock(&at24->lock); + pm_runtime_put(&client->dev); return status; } buf += status; @@ -559,6 +584,8 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count) mutex_unlock(&at24->lock); + pm_runtime_put(&client->dev); + return 0; } @@ -743,11 +770,16 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) i2c_set_clientdata(client, at24); + /* enable runtime pm */ + pm_runtime_set_active(&client->dev); + pm_runtime_enable(&client->dev); + /* * Perform a one-byte test read to verify that the * chip is functional. */ err = at24_read(at24, 0, &test_byte, 1); + pm_runtime_idle(&client->dev); if (err) { err = -ENODEV; goto err_clients; @@ -795,6 +827,8 @@ err_clients: if (at24->client[i]) i2c_unregister_device(at24->client[i]); + pm_runtime_disable(&client->dev); + return err; } @@ -810,6 +844,9 @@ static int at24_remove(struct i2c_client *client) for (i = 1; i < at24->num_addresses; i++) i2c_unregister_device(at24->client[i]); + pm_runtime_disable(&client->dev); + pm_runtime_set_suspended(&client->dev); + return 0; } -- cgit