Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756285Ab1FTXQv (ORCPT ); Mon, 20 Jun 2011 19:16:51 -0400 Received: from mailhost.informatik.uni-hamburg.de ([134.100.9.70]:39723 "EHLO mailhost.informatik.uni-hamburg.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756091Ab1FTXQu (ORCPT ); Mon, 20 Jun 2011 19:16:50 -0400 Message-ID: <4DFFD486.7020901@metafoo.de> Date: Tue, 21 Jun 2011 01:15:18 +0200 From: Lars-Peter Clausen User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20110505 Icedove/3.0.11 MIME-Version: 1.0 To: Mark Brown CC: linux-kernel@vger.kernel.org, Dimitris Papastamos , Liam Girdwood , Samuel Oritz , Graeme Gregory Subject: Re: [PATCH 1/8] regmap: Add generic non-memory mapped register access API References: <20110620124608.GB31140@opensource.wolfsonmicro.com> <1308574489-31322-1-git-send-email-broonie@opensource.wolfsonmicro.com> In-Reply-To: <1308574489-31322-1-git-send-email-broonie@opensource.wolfsonmicro.com> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6497 Lines: 224 Very nice! > [...] > diff --git a/drivers/regmap/regmap.c b/drivers/regmap/regmap.c > new file mode 100644 > index 0000000..a8610c7 > --- /dev/null > +++ b/drivers/regmap/regmap.c > @@ -0,0 +1,478 @@ > +/* > + * Register map access API > + * > + * Copyright 2011 Wolfson Microelectronics plc > + * > + * Author: Mark Brown > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + */ > + > +#include > +#include > +#include > +#include > + > +#include > + > +struct regmap; > + > +static DEFINE_MUTEX(regmap_bus_lock); > +static LIST_HEAD(regmap_bus_list); > + > +struct regmap_format { > + size_t buf_size; > + size_t reg_bytes; > + size_t val_bytes; > + void (*format_write)(struct regmap *map, > + unsigned int reg, unsigned int val); > + void (*format_reg)(void *buf, unsigned int reg); > + void (*format_val)(void *buf, unsigned int val); > + unsigned int (*parse_val)(void *buf); const void *buf. It probably also makes sense to pass the regmap to all callbacks, so we can write generic format/parser functions which use information for example from the regmap_format. > +}; > + > +struct regmap { > + struct mutex lock; > + > + struct device *dev; /* Device we do I/O on */ > + void *work_buf; /* Scratch buffer used to format I/O */ > + struct regmap_format format; /* Buffer format */ > + struct regmap_bus *bus; const struct regmap_bus > +}; > + > +static void regmap_format_4_12_write(struct regmap *map, > + unsigned int reg, unsigned int val) > +{ > + u16 *out = map->work_buf; > + *out = cpu_to_be16((reg << 12) | val); > +} > + > +static void regmap_format_7_9_write(struct regmap *map, > + unsigned int reg, unsigned int val) > +{ > + u16 *out = map->work_buf; > + *out = cpu_to_be16((reg << 9) | val); > +} It would make sense to keep val_bits around and implement these two generically: *out = cpu_to_be16((reg << map->format.val_bits) | val); > [...] > +/** > + * remap_init: Initialise register map > + * > + * dev: Device that will be interacted with > + * config: Configuration for register map > + * > + * The return value will be an ERR_PTR() on error or a valid pointer > + * to a struct regmap. > + */ > +struct regmap *regmap_init(struct device *dev, struct regmap_config *config) regmap_alloc would in my opinion be a better name. > [...] > +static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val, > + unsigned int val_len) > +{ > + u8 *u8 = map->work_buf; > + int ret; > + > + map->format.format_reg(map->work_buf, reg); > + > + /* > + * Some buses flag reads by setting the high bit in the > + * register addresss; since it's always the high bit for all > + * current formats we can do this here rather than in > + * formatting. This may break if we get interesting formats. > + */ > + if (map->bus->read_flag_in_reg) > + u8[0] |= 0x80; This is rather specific. Making this a per device mask or bit offset, would make more sense in my opinion. I have for example one SPI codec device which uses the 7th bit to indicate a read. And I also have devices on a custom bus, which needs to set the upper bit to indicate a write, so a mask for both write and read would be good. > + > + ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes, > + val, map->format.val_bytes); > + if (ret != 0) > + return ret; > + > + return 0; > +} > + > [...] > +/** > + * regmap_bulk_read: Read multiple registers from the device > + * > + * @map: Register map to write to > + * @reg: First register to be read from > + * @val: Pointer to store read value, in native register size for device > + * @val_count: Number of registers to read > + * > + * A value of zero will be returned on success, a negative errno will > + * be returned in error cases. > + */ > +int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val, > + size_t val_count) > +{ > + int ret, i; > + size_t val_bytes = map->format.val_bytes; > + > + if (!map->format.parse_val) > + return -EINVAL; > + > + ret = regmap_raw_read(map, reg, val, val_bytes); val_bytes * val_count > + if (ret != 0) > + return ret; > + > + for (i = 0; i < val_count * val_bytes; i += val_bytes) > + map->format.parse_val(val + i); This doesn't make sense. parse_val returns the parsed value, but doesn't modify the parsed data. It would make sense to make the interface similar to regmap_read and make the returned values a unsigned integer array and use a bounce buffer for reading them from the device. > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(regmap_bulk_read); > + > [...] > diff --git a/include/linux/regmap.h b/include/linux/regmap.h > new file mode 100644 > index 0000000..0c2e402 > --- /dev/null > +++ b/include/linux/regmap.h > @@ -0,0 +1,75 @@ > +#ifndef __LINUX_REGMAP_H > +#define __LINUX_REGMAP_H > + > +/* > + * Register map access API > + * > + * Copyright 2011 Wolfson Microelectronics plc > + * > + * Author: Mark Brown > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + */ > + > +#include > +#include #include > + > +struct regmap_config { > + int reg_bits; > + int val_bits; size_t for both? > +}; > + > ... > + > +struct regmap *regmap_init(struct device *dev, struct regmap_config *config); const struct regmap_config > +void regmap_free(struct regmap *map); > +int regmap_write(struct regmap *map, unsigned int reg, unsigned int val); > +int regmap_raw_write(struct regmap *map, unsigned int reg, > + const void *val, size_t val_len); > +int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val); > +int regmap_raw_read(struct regmap *map, unsigned int reg, > + void *val, size_t val_len); > +int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val, > + size_t val_count); What about bulk_write? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/