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128 lines
3.4 KiB
128 lines
3.4 KiB
// SPDX-License-Identifier: GPL-2.0 |
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// Register map access API - SCCB support |
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#include <linux/i2c.h> |
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#include <linux/module.h> |
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#include <linux/regmap.h> |
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#include "internal.h" |
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/** |
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* sccb_is_available - Check if the adapter supports SCCB protocol |
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* @adap: I2C adapter |
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* |
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* Return true if the I2C adapter is capable of using SCCB helper functions, |
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* false otherwise. |
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*/ |
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static bool sccb_is_available(struct i2c_adapter *adap) |
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{ |
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u32 needed_funcs = I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_WRITE_BYTE_DATA; |
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/* |
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* If we ever want support for hardware doing SCCB natively, we will |
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* introduce a sccb_xfer() callback to struct i2c_algorithm and check |
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* for it here. |
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*/ |
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return (i2c_get_functionality(adap) & needed_funcs) == needed_funcs; |
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} |
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/** |
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* regmap_sccb_read - Read data from SCCB slave device |
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* @context: Device that will be interacted with |
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* @reg: Register to be read from |
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* @val: Pointer to store read value |
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* |
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* This executes the 2-phase write transmission cycle that is followed by a |
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* 2-phase read transmission cycle, returning negative errno else zero on |
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* success. |
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*/ |
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static int regmap_sccb_read(void *context, unsigned int reg, unsigned int *val) |
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{ |
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struct device *dev = context; |
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struct i2c_client *i2c = to_i2c_client(dev); |
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int ret; |
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union i2c_smbus_data data; |
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i2c_lock_bus(i2c->adapter, I2C_LOCK_SEGMENT); |
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ret = __i2c_smbus_xfer(i2c->adapter, i2c->addr, i2c->flags, |
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I2C_SMBUS_WRITE, reg, I2C_SMBUS_BYTE, NULL); |
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if (ret < 0) |
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goto out; |
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ret = __i2c_smbus_xfer(i2c->adapter, i2c->addr, i2c->flags, |
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I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &data); |
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if (ret < 0) |
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goto out; |
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*val = data.byte; |
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out: |
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i2c_unlock_bus(i2c->adapter, I2C_LOCK_SEGMENT); |
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return ret; |
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} |
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/** |
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* regmap_sccb_write - Write data to SCCB slave device |
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* @context: Device that will be interacted with |
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* @reg: Register to write to |
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* @val: Value to be written |
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* |
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* This executes the SCCB 3-phase write transmission cycle, returning negative |
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* errno else zero on success. |
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*/ |
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static int regmap_sccb_write(void *context, unsigned int reg, unsigned int val) |
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{ |
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struct device *dev = context; |
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struct i2c_client *i2c = to_i2c_client(dev); |
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return i2c_smbus_write_byte_data(i2c, reg, val); |
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} |
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static struct regmap_bus regmap_sccb_bus = { |
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.reg_write = regmap_sccb_write, |
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.reg_read = regmap_sccb_read, |
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}; |
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static const struct regmap_bus *regmap_get_sccb_bus(struct i2c_client *i2c, |
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const struct regmap_config *config) |
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{ |
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if (config->val_bits == 8 && config->reg_bits == 8 && |
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sccb_is_available(i2c->adapter)) |
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return ®map_sccb_bus; |
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return ERR_PTR(-ENOTSUPP); |
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} |
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struct regmap *__regmap_init_sccb(struct i2c_client *i2c, |
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const struct regmap_config *config, |
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struct lock_class_key *lock_key, |
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const char *lock_name) |
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{ |
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const struct regmap_bus *bus = regmap_get_sccb_bus(i2c, config); |
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if (IS_ERR(bus)) |
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return ERR_CAST(bus); |
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return __regmap_init(&i2c->dev, bus, &i2c->dev, config, |
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lock_key, lock_name); |
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} |
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EXPORT_SYMBOL_GPL(__regmap_init_sccb); |
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struct regmap *__devm_regmap_init_sccb(struct i2c_client *i2c, |
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const struct regmap_config *config, |
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struct lock_class_key *lock_key, |
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const char *lock_name) |
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{ |
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const struct regmap_bus *bus = regmap_get_sccb_bus(i2c, config); |
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if (IS_ERR(bus)) |
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return ERR_CAST(bus); |
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return __devm_regmap_init(&i2c->dev, bus, &i2c->dev, config, |
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lock_key, lock_name); |
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} |
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EXPORT_SYMBOL_GPL(__devm_regmap_init_sccb); |
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MODULE_LICENSE("GPL v2");
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