Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> --- drivers/misc/Kconfig | 5 + drivers/misc/Makefile | 2 + drivers/misc/mcp342x.c | 259 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 266 insertions(+) create mode 100644 drivers/misc/mcp342x.c diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index b95a7f6..8d44a5c 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -27,4 +27,9 @@ config LM75 depends on I2C depends on IODEVICE +config MCP342X + tristate "Microchip MCP342x ADC driver" + depends on I2C + depends on IODEVICE + endmenu diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index a257dfb..6680334 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -7,3 +7,5 @@ obj-$(CONFIG_SRAM) += sram.o obj-$(CONFIG_STATE_DRV) += state.o obj-$(CONFIG_IODEVICE) += iodevice.o obj-$(CONFIG_LM75) += lm75.o +obj-$(CONFIG_IODEVICE) += iodevice.o +obj-$(CONFIG_MCP342X) += mcp342x.o diff --git a/drivers/misc/mcp342x.c b/drivers/misc/mcp342x.c new file mode 100644 index 0000000..e498078 --- /dev/null +++ b/drivers/misc/mcp342x.c @@ -0,0 +1,259 @@ +/* + * mcp3422.c - driver for the Microchip mcp3422/3/4/6/7/8 chip family + * + * Copyright (C) 2013, Angelo Compagnucci + * Author: Angelo Compagnucci <angelo.compagnucci@xxxxxxxxx> + * + * Datasheet: http://ww1.microchip.com/downloads/en/devicedoc/22088b.pdf + * http://ww1.microchip.com/downloads/en/DeviceDoc/22226a.pdf + * + * This driver exports the value of analog input voltage to sysfs, the + * voltage unit is nV. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <common.h> +#include <init.h> +#include <iodevice.h> +#include <malloc.h> +#include <driver.h> +#include <xfuncs.h> +#include <i2c/i2c.h> + +/* Masks */ +#define MCP3422_CHANNEL_MASK 0x60 +#define MCP3422_PGA_MASK 0x03 +#define MCP3422_SRATE_MASK 0x0C +#define MCP3422_SRATE_240 0x0 +#define MCP3422_SRATE_60 0x1 +#define MCP3422_SRATE_15 0x2 +#define MCP3422_SRATE_3 0x3 +#define MCP3422_PGA_1 0 +#define MCP3422_PGA_2 1 +#define MCP3422_PGA_4 2 +#define MCP3422_PGA_8 3 +#define MCP3422_CONT_SAMPLING 0x10 + +#define MCP3422_CHANNEL(config) (((config) & MCP3422_CHANNEL_MASK) >> 5) +#define MCP3422_PGA(config) ((config) & MCP3422_PGA_MASK) +#define MCP3422_SAMPLE_RATE(config) (((config) & MCP3422_SRATE_MASK) >> 2) + +#define MCP3422_CHANNEL_VALUE(value) (((value) << 5) & MCP3422_CHANNEL_MASK) +#define MCP3422_PGA_VALUE(value) ((value) & MCP3422_PGA_MASK) +#define MCP3422_SAMPLE_RATE_VALUE(value) ((value << 2) & MCP3422_SRATE_MASK) + +/* Constant msleep times for data acquisitions */ +static const int mcp3422_read_times[4] = { + [MCP3422_SRATE_240] = 1000 / 240, + [MCP3422_SRATE_60] = 1000 / 60, + [MCP3422_SRATE_15] = 1000 / 15, + [MCP3422_SRATE_3] = 1000 / 3 }; + +static const int mcp3422_sample_rate_scales[4] = { + [MCP3422_SRATE_240] = 8000, + [MCP3422_SRATE_60] = 2000, + [MCP3422_SRATE_15] = 500, + [MCP3422_SRATE_3] = 125}; + +static const char *mcp342x_sample_rate_str[] = { + "240", "60", "15", "3" +}; + +static const char *mcp342x_gain_str[] = { + "1", "2", "4", "8" +}; + +/* sample rates to sign extension table */ +static const int mcp3422_sign_extend[4] = { + [MCP3422_SRATE_240] = 11, + [MCP3422_SRATE_60] = 13, + [MCP3422_SRATE_15] = 15, + [MCP3422_SRATE_3] = 17 }; + +struct mcp342x_channel { + int num; + int voltage; + int temp; + struct mcp342x *mcp342x; + struct iochannel iochan; + unsigned int gain; +}; + +struct mcp342x { + struct i2c_client *i2c; + struct iodevice iodev; + unsigned int sps; + u8 id; + u8 config; + u8 pga[4]; + int num_channels; + struct mcp342x_channel *channel[4]; + char *unit; +}; + +static int mcp3422_update_config(struct mcp342x *adc, u8 newconfig) +{ + int ret; + + ret = i2c_master_send(adc->i2c, &newconfig, 1); + if (ret > 0) { + adc->config = newconfig; + ret = 0; + } + + return ret; +} + +static int mcp3422_read(struct mcp342x_channel *channel) +{ + struct mcp342x *adc = channel->mcp342x; + int ret = 0; + u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config); + u8 buf[4] = {0, 0, 0, 0}; + u32 temp; + + if (sample_rate == MCP3422_SRATE_3) { + ret = i2c_master_recv(adc->i2c, buf, 4); + temp = buf[0] << 16 | buf[1] << 8 | buf[2]; + } else { + ret = i2c_master_recv(adc->i2c, buf, 3); + temp = buf[0] << 8 | buf[1]; + } + + channel->voltage = sign_extend32(temp, mcp3422_sign_extend[sample_rate]) * + mcp3422_sample_rate_scales[sample_rate] / (1 << channel->gain) / 8; + + return ret; +} + +static int mcp342x_get_voltage(struct iochannel *iochan, int *value) +{ + struct mcp342x_channel *channel = container_of(iochan, struct mcp342x_channel, iochan); + struct mcp342x *adc = channel->mcp342x; + u8 config; + int ret; + + config = MCP3422_CONT_SAMPLING | + MCP3422_CHANNEL_VALUE(channel->num) | + MCP3422_PGA_VALUE(channel->gain) | + MCP3422_SAMPLE_RATE_VALUE(adc->sps); + + if (config != adc->config) { + ret = mcp3422_update_config(adc, config); + if (ret < 0) + return ret; + + mdelay(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]); + } + + mcp3422_read(channel); + + *value = channel->voltage; + + return 0; +} + +static int mcp342x_probe(struct device_d *dev) +{ + struct mcp342x *adc; + int id , ret, i, num_channels; + + ret = dev_get_drvdata(dev, (const void **)&id); + if (ret) + return ret; + + adc = xzalloc(sizeof(*adc)); + + adc->i2c = to_i2c_client(dev); + adc->id = id; + adc->unit = "uV"; + + switch (id) { + case 1: + num_channels = 1; + break; + case 2: + case 3: + case 6: + case 7: + num_channels = 2; + break; + case 4: + case 8: + num_channels = 4; + break; + default: + return -EINVAL; + } + + adc->num_channels = num_channels; + + adc->sps = MCP3422_SRATE_15; + + adc->iodev.hwdev = dev; + + adc->iodev.channels = xmalloc(sizeof(void *) * num_channels); + adc->iodev.num_channels = num_channels; + adc->iodev.read = mcp342x_get_voltage; + + for (i = 0; i < num_channels; i++) { + struct mcp342x_channel *channel; + + channel = xzalloc(sizeof(*channel)); + adc->iodev.channels[i] = &channel->iochan; + channel->iochan.unit = "uV"; + adc->channel[i] = channel; + channel->num = i; + channel->mcp342x = adc; + } + + ret = iodevice_register(&adc->iodev); + if (ret) + return ret; + + dev_add_param_enum(&adc->iodev.dev, "in_sps", NULL, NULL, &adc->sps, + mcp342x_sample_rate_str, + ARRAY_SIZE(mcp342x_sample_rate_str), NULL); + + for (i = 0; i < num_channels; i++) { + struct mcp342x_channel *channel = adc->channel[i]; + char *name; + + name = asprintf("in_gain%d", i); + dev_add_param_enum(&adc->iodev.dev, name, NULL, NULL, &channel->gain, + mcp342x_gain_str, + ARRAY_SIZE(mcp342x_gain_str), NULL); + free(name); + } + + return 0; +} + +static const struct platform_device_id mcp342x_ids[] = { + { "mcp3421", 1 }, + { "mcp3422", 2 }, + { "mcp3423", 3 }, + { "mcp3424", 4 }, + { "mcp3426", 6 }, + { "mcp3427", 7 }, + { "mcp3428", 8 }, + { } +}; + +static struct driver_d mcp342x_driver = { + .name = "mcp342x", + .probe = mcp342x_probe, + .id_table = mcp342x_ids, +}; + +static int mcp342x_init(void) +{ + i2c_driver_register(&mcp342x_driver); + return 0; +} + +device_initcall(mcp342x_init); -- 2.6.2 _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
