Hi Divagar, Thanks for the patch. Please see my comments below.
On Tue, Aug 15, 2017 at 12:11:59AM +0530, Divagar Mohandass wrote: > 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. > > Signed-off-by: Divagar Mohandass <[email protected]> > --- > drivers/misc/eeprom/at24.c | 34 ++++++++++++++++++++++++++++++++++ > 1 file changed, 34 insertions(+) > > diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c > index 2199c42..0d26681 100644 > --- a/drivers/misc/eeprom/at24.c > +++ b/drivers/misc/eeprom/at24.c > @@ -24,6 +24,7 @@ > #include <linux/i2c.h> > #include <linux/nvmem-provider.h> > #include <linux/platform_data/at24.h> > +#include <linux/pm_runtime.h> > > /* > * 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; > + } > + at24_read() may fail between the two chunks here. You'll need pm_runtime_put() before returning the error code. > /* > * Read data from chip, protecting against concurrent updates > * from this host, but not from other I2C masters. > @@ -527,17 +538,29 @@ 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. Ditto for write. > @@ -559,6 +582,8 @@ 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; > } > > @@ -743,6 +768,13 @@ static int at24_probe(struct i2c_client *client, const > struct i2c_device_id *id) > > i2c_set_clientdata(client, at24); > > + /* enable runtime pm */ > + err = pm_runtime_set_active(&client->dev); > + if (err < 0) > + goto err_clients; > + > + pm_runtime_enable(&client->dev); > + Here, too: at24_read() below can fail, as well as nvmem_register(). > /* > * Perform a one-byte test read to verify that the > * chip is functional. > @@ -810,6 +842,8 @@ 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; > } > -- Regards, Sakari Ailus e-mail: [email protected]
