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Date: Thu, 18 Feb 2016 11:22:07 +0100 From: Bartosz Golaszewski <bgolaszewski@...libre.com> To: Andrew Lunn <andrew@...n.ch> Cc: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>, GregKH <greg@...ah.com>, Maxime Ripard <maxime.ripard@...e-electrons.com>, Wolfram Sang <wsa@...-dreams.de>, broonie@...nel.org, vz@...ia.com, LKML <linux-kernel@...r.kernel.org>, Pantelis Antoniou <pantelis.antoniou@...sulko.com> Subject: Re: [PATCHv5 3/7] eeprom: at24: extend driver to plug into the NVMEM framework 2016-02-17 21:07 GMT+01:00 Andrew Lunn <andrew@...n.ch>: > Add a regmap for accessing the EEPROM, and then use that with the > NVMEM framework. Set the NVMEM config structure to enable backward, so > that the 'eeprom' file in sys is provided by the framework. > > Signed-off-by: Andrew Lunn <andrew@...n.ch> > Acked-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org> > --- > drivers/misc/eeprom/Kconfig | 2 + > drivers/misc/eeprom/at24.c | 121 +++++++++++++++++++++++++++++--------------- > 2 files changed, 82 insertions(+), 41 deletions(-) > > diff --git a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig > index 04f2e1fa9dd1..24935473393b 100644 > --- a/drivers/misc/eeprom/Kconfig > +++ b/drivers/misc/eeprom/Kconfig > @@ -3,6 +3,8 @@ menu "EEPROM support" > config EEPROM_AT24 > tristate "I2C EEPROMs / RAMs / ROMs from most vendors" > depends on I2C && SYSFS > + select REGMAP > + select NVMEM > help > Enable this driver to get read/write support to most I2C EEPROMs > and compatible devices like FRAMs, SRAMs, ROMs etc. After you > diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c > index 5d7c0900fa1b..f15cda93fc4c 100644 > --- a/drivers/misc/eeprom/at24.c > +++ b/drivers/misc/eeprom/at24.c > @@ -15,7 +15,6 @@ > #include <linux/slab.h> > #include <linux/delay.h> > #include <linux/mutex.h> > -#include <linux/sysfs.h> > #include <linux/mod_devicetable.h> > #include <linux/log2.h> > #include <linux/bitops.h> > @@ -23,6 +22,8 @@ > #include <linux/of.h> > #include <linux/acpi.h> > #include <linux/i2c.h> > +#include <linux/nvmem-provider.h> > +#include <linux/regmap.h> > #include <linux/platform_data/at24.h> > > /* > @@ -64,12 +65,15 @@ struct at24_data { > * but not from changes by other I2C masters. > */ > struct mutex lock; > - struct bin_attribute bin; > > u8 *writebuf; > unsigned write_max; > unsigned num_addresses; > > + struct regmap_config regmap_config; > + struct nvmem_config nvmem_config; > + struct nvmem_device *nvmem; > + > /* > * Some chips tie up multiple I2C addresses; dummy devices reserve > * them for us, and we'll use them with SMBus calls. > @@ -283,17 +287,6 @@ static ssize_t at24_read(struct at24_data *at24, > return retval; > } > > -static ssize_t at24_bin_read(struct file *filp, struct kobject *kobj, > - struct bin_attribute *attr, > - char *buf, loff_t off, size_t count) > -{ > - struct at24_data *at24; > - > - at24 = dev_get_drvdata(container_of(kobj, struct device, kobj)); > - return at24_read(at24, buf, off, count); > -} > - > - > /* > * Note that if the hardware write-protect pin is pulled high, the whole > * chip is normally write protected. But there are plenty of product > @@ -414,16 +407,6 @@ static ssize_t at24_write(struct at24_data *at24, const char *buf, loff_t off, > return retval; > } > > -static ssize_t at24_bin_write(struct file *filp, struct kobject *kobj, > - struct bin_attribute *attr, > - char *buf, loff_t off, size_t count) > -{ > - struct at24_data *at24; > - > - at24 = dev_get_drvdata(container_of(kobj, struct device, kobj)); > - return at24_write(at24, buf, off, count); > -} > - > /*-------------------------------------------------------------------------*/ > > /* > @@ -450,6 +433,49 @@ static ssize_t at24_macc_write(struct memory_accessor *macc, const char *buf, > > /*-------------------------------------------------------------------------*/ > > +/* > + * Provide a regmap interface, which is registered with the NVMEM > + * framework > +*/ > +static int at24_regmap_read(void *context, const void *reg, size_t reg_size, > + void *val, size_t val_size) > +{ > + struct at24_data *at24 = context; > + off_t offset = *(u32 *)reg; > + int err; > + > + err = at24_read(at24, val, offset, val_size); > + if (err) > + return err; > + return 0; > +} > + > +static int at24_regmap_write(void *context, const void *data, size_t count) > +{ > + struct at24_data *at24 = context; > + const char *buf; > + u32 offset; > + size_t len; > + int err; > + > + memcpy(&offset, data, sizeof(offset)); > + buf = (const char *)data + sizeof(offset); > + len = count - sizeof(offset); > + > + err = at24_write(at24, buf, offset, len); > + if (err) > + return err; > + return 0; > +} > + > +static const struct regmap_bus at24_regmap_bus = { > + .read = at24_regmap_read, > + .write = at24_regmap_write, > + .reg_format_endian_default = REGMAP_ENDIAN_NATIVE, > +}; > + > +/*-------------------------------------------------------------------------*/ > + > #ifdef CONFIG_OF > static void at24_get_ofdata(struct i2c_client *client, > struct at24_platform_data *chip) > @@ -481,6 +507,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) > struct at24_data *at24; > int err; > unsigned i, num_addresses; > + struct regmap *regmap; > > if (client->dev.platform_data) { > chip = *(struct at24_platform_data *)client->dev.platform_data; > @@ -573,16 +600,6 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) > at24->chip = chip; > at24->num_addresses = num_addresses; > > - /* > - * Export the EEPROM bytes through sysfs, since that's convenient. > - * By default, only root should see the data (maybe passwords etc) > - */ > - sysfs_bin_attr_init(&at24->bin); > - at24->bin.attr.name = "eeprom"; > - at24->bin.attr.mode = chip.flags & AT24_FLAG_IRUGO ? S_IRUGO : S_IRUSR; > - at24->bin.read = at24_bin_read; > - at24->bin.size = chip.byte_len; > - > at24->macc.read = at24_macc_read; > > writable = !(chip.flags & AT24_FLAG_READONLY); > @@ -593,9 +610,6 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) > > at24->macc.write = at24_macc_write; > > - at24->bin.write = at24_bin_write; > - at24->bin.attr.mode |= S_IWUSR; > - > if (write_max > io_limit) > write_max = io_limit; > if (use_smbus && write_max > I2C_SMBUS_BLOCK_MAX) > @@ -627,14 +641,38 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) > } > } > > - err = sysfs_create_bin_file(&client->dev.kobj, &at24->bin); > - if (err) > + at24->regmap_config.reg_bits = 32; > + at24->regmap_config.val_bits = 8; > + at24->regmap_config.reg_stride = 1; > + at24->regmap_config.max_register = chip.byte_len - 1; > + > + regmap = devm_regmap_init(&client->dev, &at24_regmap_bus, at24, > + &at24->regmap_config); > + if (IS_ERR(regmap)) { > + dev_err(&client->dev, "regmap init failed\n"); > + err = PTR_ERR(regmap); > goto err_clients; > + } > + > + at24->nvmem_config.name = dev_name(&client->dev); > + at24->nvmem_config.dev = &client->dev; > + at24->nvmem_config.read_only = !writable; > + at24->nvmem_config.root_only = true; > + at24->nvmem_config.owner = THIS_MODULE; > + at24->nvmem_config.compat = true; > + at24->nvmem_config.base_dev = &client->dev; > + > + at24->nvmem = nvmem_register(&at24->nvmem_config); > + > + if (IS_ERR(at24->nvmem)) { > + err = PTR_ERR(at24->nvmem); > + goto err_clients; > + } > > i2c_set_clientdata(client, at24); > > - dev_info(&client->dev, "%zu byte %s EEPROM, %s, %u bytes/write\n", > - at24->bin.size, client->name, > + dev_info(&client->dev, "%u byte %s EEPROM, %s, %u bytes/write\n", > + chip.byte_len, client->name, > writable ? "writable" : "read-only", at24->write_max); > if (use_smbus == I2C_SMBUS_WORD_DATA || > use_smbus == I2C_SMBUS_BYTE_DATA) { > @@ -663,7 +701,8 @@ static int at24_remove(struct i2c_client *client) > int i; > > at24 = i2c_get_clientdata(client); > - sysfs_remove_bin_file(&client->dev.kobj, &at24->bin); > + > + nvmem_unregister(at24->nvmem); > > for (i = 1; i < at24->num_addresses; i++) > i2c_unregister_device(at24->client[i]); > -- > 2.7.0 > Tested-by: Bartosz Golaszewski <bgolaszewski@...libre.com> Best regards, Bartosz Golaszewski
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