[PATCH 3/4] misc: Add Microchip MCP342x support
Sascha Hauer
s.hauer at pengutronix.de
Tue Dec 8 01:05:38 PST 2015
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
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 at gmail.com>
+ *
+ * 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
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