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authorLinus Torvalds <torvalds@linux-foundation.org>2017-11-14 05:53:28 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-14 05:53:28 +0100
commit449fcf3ab0baf3dde9952385e6789f2ca10c3980 (patch)
tree180f10c2cdd63836e47725cddc8850ca7144091a /drivers/iio/adc/mcp320x.c
parentMerge tag 'devprop-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git... (diff)
parentstaging: lustre: add SPDX identifiers to all lustre files (diff)
downloadlinux-449fcf3ab0baf3dde9952385e6789f2ca10c3980.tar.xz
linux-449fcf3ab0baf3dde9952385e6789f2ca10c3980.zip
Merge tag 'staging-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
Pull staging and IIO updates from Greg KH: "Here is the "big" staging and IIO driver update for 4.15-rc1. Lots and lots of little changes, almost all minor code cleanups as the Outreachy application process happened during this development cycle. Also happened was a lot of IIO driver activity, and the typec USB code moving out of staging to drivers/usb (same commits are in the USB tree on a persistent branch to not cause merge issues.) Overall, it's a wash, I think we added a few hundred more lines than removed, but really only a few thousand were modified at all. All of these have been in linux-next for a while. There might be a merge issue with Al's vfs tree in the pi433 driver (take his changes, they are always better), and the media tree with some of the odd atomisp cleanups (take the media tree's version)" * tag 'staging-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (507 commits) staging: lustre: add SPDX identifiers to all lustre files staging: greybus: Remove redundant license text staging: greybus: add SPDX identifiers to all greybus driver files staging: ccree: simplify ioread/iowrite staging: ccree: simplify registers access staging: ccree: simplify error handling logic staging: ccree: remove dead code staging: ccree: handle limiting of DMA masks staging: ccree: copy IV to DMAable memory staging: fbtft: remove redundant initialization of buf staging: sm750fb: Fix parameter mistake in poke32 staging: wilc1000: Fix bssid buffer offset in Txq staging: fbtft: fb_ssd1331: fix mirrored display staging: android: Fix checkpatch.pl error staging: greybus: loopback: convert loopback to use generic async operations staging: greybus: operation: add private data with get/set accessors staging: greybus: loopback: Fix iteration count on async path staging: greybus: loopback: Hold per-connection mutex across operations staging: greybus/loopback: use ktime_get() for time intervals staging: fsl-dpaa2/eth: Extra headroom in RX buffers ...
Diffstat (limited to 'drivers/iio/adc/mcp320x.c')
-rw-r--r--drivers/iio/adc/mcp320x.c235
1 files changed, 156 insertions, 79 deletions
diff --git a/drivers/iio/adc/mcp320x.c b/drivers/iio/adc/mcp320x.c
index 071dd23a33d9..a04856d8afdb 100644
--- a/drivers/iio/adc/mcp320x.c
+++ b/drivers/iio/adc/mcp320x.c
@@ -19,6 +19,11 @@
* ------------
* 13 bit converter
* MCP3301
+ * ------------
+ * 22 bit converter
+ * MCP3550
+ * MCP3551
+ * MCP3553
*
* Datasheet can be found here:
* http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf mcp3001
@@ -28,6 +33,7 @@
* http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf mcp3202
* http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf mcp3204/08
* http://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf mcp3301
+ * http://ww1.microchip.com/downloads/en/DeviceDoc/21950D.pdf mcp3550/1/3
*
* 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
@@ -51,25 +57,45 @@ enum {
mcp3204,
mcp3208,
mcp3301,
+ mcp3550_50,
+ mcp3550_60,
+ mcp3551,
+ mcp3553,
};
struct mcp320x_chip_info {
const struct iio_chan_spec *channels;
unsigned int num_channels;
unsigned int resolution;
+ unsigned int conv_time; /* usec */
};
+/**
+ * struct mcp320x - Microchip SPI ADC instance
+ * @spi: SPI slave (parent of the IIO device)
+ * @msg: SPI message to select a channel and receive a value from the ADC
+ * @transfer: SPI transfers used by @msg
+ * @start_conv_msg: SPI message to start a conversion by briefly asserting CS
+ * @start_conv_transfer: SPI transfer used by @start_conv_msg
+ * @reg: regulator generating Vref
+ * @lock: protects read sequences
+ * @chip_info: ADC properties
+ * @tx_buf: buffer for @transfer[0] (not used on single-channel converters)
+ * @rx_buf: buffer for @transfer[1]
+ */
struct mcp320x {
struct spi_device *spi;
struct spi_message msg;
struct spi_transfer transfer[2];
+ struct spi_message start_conv_msg;
+ struct spi_transfer start_conv_transfer;
struct regulator *reg;
struct mutex lock;
const struct mcp320x_chip_info *chip_info;
u8 tx_buf ____cacheline_aligned;
- u8 rx_buf[2];
+ u8 rx_buf[4];
};
static int mcp320x_channel_to_tx_data(int device_index,
@@ -78,10 +104,6 @@ static int mcp320x_channel_to_tx_data(int device_index,
int start_bit = 1;
switch (device_index) {
- case mcp3001:
- case mcp3201:
- case mcp3301:
- return 0;
case mcp3002:
case mcp3202:
return ((start_bit << 4) | (!differential << 3) |
@@ -102,21 +124,24 @@ static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
{
int ret;
- adc->rx_buf[0] = 0;
- adc->rx_buf[1] = 0;
- adc->tx_buf = mcp320x_channel_to_tx_data(device_index,
- channel, differential);
-
- if (device_index != mcp3001 && device_index != mcp3201 && device_index != mcp3301) {
- ret = spi_sync(adc->spi, &adc->msg);
- if (ret < 0)
- return ret;
- } else {
- ret = spi_read(adc->spi, &adc->rx_buf, sizeof(adc->rx_buf));
+ if (adc->chip_info->conv_time) {
+ ret = spi_sync(adc->spi, &adc->start_conv_msg);
if (ret < 0)
return ret;
+
+ usleep_range(adc->chip_info->conv_time,
+ adc->chip_info->conv_time + 100);
}
+ memset(&adc->rx_buf, 0, sizeof(adc->rx_buf));
+ if (adc->chip_info->num_channels > 1)
+ adc->tx_buf = mcp320x_channel_to_tx_data(device_index, channel,
+ differential);
+
+ ret = spi_sync(adc->spi, &adc->msg);
+ if (ret < 0)
+ return ret;
+
switch (device_index) {
case mcp3001:
*val = (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
@@ -138,6 +163,31 @@ static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
*val = sign_extend32((adc->rx_buf[0] & 0x1f) << 8
| adc->rx_buf[1], 12);
return 0;
+ case mcp3550_50:
+ case mcp3550_60:
+ case mcp3551:
+ case mcp3553: {
+ u32 raw = be32_to_cpup((u32 *)adc->rx_buf);
+
+ if (!(adc->spi->mode & SPI_CPOL))
+ raw <<= 1; /* strip Data Ready bit in SPI mode 0,0 */
+
+ /*
+ * If the input is within -vref and vref, bit 21 is the sign.
+ * Up to 12% overrange or underrange are allowed, in which case
+ * bit 23 is the sign and bit 0 to 21 is the value.
+ */
+ raw >>= 8;
+ if (raw & BIT(22) && raw & BIT(23))
+ return -EIO; /* cannot have overrange AND underrange */
+ else if (raw & BIT(22))
+ raw &= ~BIT(22); /* overrange */
+ else if (raw & BIT(23) || raw & BIT(21))
+ raw |= GENMASK(31, 22); /* underrange or negative */
+
+ *val = (s32)raw;
+ return 0;
+ }
default:
return -EINVAL;
}
@@ -248,7 +298,6 @@ static const struct iio_chan_spec mcp3208_channels[] = {
static const struct iio_info mcp320x_info = {
.read_raw = mcp320x_read_raw,
- .driver_module = THIS_MODULE,
};
static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
@@ -297,6 +346,31 @@ static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
.num_channels = ARRAY_SIZE(mcp3201_channels),
.resolution = 13
},
+ [mcp3550_50] = {
+ .channels = mcp3201_channels,
+ .num_channels = ARRAY_SIZE(mcp3201_channels),
+ .resolution = 21,
+ /* 2% max deviation + 144 clock periods to exit shutdown */
+ .conv_time = 80000 * 1.02 + 144000 / 102.4,
+ },
+ [mcp3550_60] = {
+ .channels = mcp3201_channels,
+ .num_channels = ARRAY_SIZE(mcp3201_channels),
+ .resolution = 21,
+ .conv_time = 66670 * 1.02 + 144000 / 122.88,
+ },
+ [mcp3551] = {
+ .channels = mcp3201_channels,
+ .num_channels = ARRAY_SIZE(mcp3201_channels),
+ .resolution = 21,
+ .conv_time = 73100 * 1.02 + 144000 / 112.64,
+ },
+ [mcp3553] = {
+ .channels = mcp3201_channels,
+ .num_channels = ARRAY_SIZE(mcp3201_channels),
+ .resolution = 21,
+ .conv_time = 16670 * 1.02 + 144000 / 122.88,
+ },
};
static int mcp320x_probe(struct spi_device *spi)
@@ -304,7 +378,7 @@ static int mcp320x_probe(struct spi_device *spi)
struct iio_dev *indio_dev;
struct mcp320x *adc;
const struct mcp320x_chip_info *chip_info;
- int ret;
+ int ret, device_index;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
if (!indio_dev)
@@ -320,7 +394,8 @@ static int mcp320x_probe(struct spi_device *spi)
indio_dev->info = &mcp320x_info;
spi_set_drvdata(spi, indio_dev);
- chip_info = &mcp320x_chip_infos[spi_get_device_id(spi)->driver_data];
+ device_index = spi_get_device_id(spi)->driver_data;
+ chip_info = &mcp320x_chip_infos[device_index];
indio_dev->channels = chip_info->channels;
indio_dev->num_channels = chip_info->num_channels;
@@ -329,10 +404,41 @@ static int mcp320x_probe(struct spi_device *spi)
adc->transfer[0].tx_buf = &adc->tx_buf;
adc->transfer[0].len = sizeof(adc->tx_buf);
adc->transfer[1].rx_buf = adc->rx_buf;
- adc->transfer[1].len = sizeof(adc->rx_buf);
+ adc->transfer[1].len = DIV_ROUND_UP(chip_info->resolution, 8);
+
+ if (chip_info->num_channels == 1)
+ /* single-channel converters are rx only (no MOSI pin) */
+ spi_message_init_with_transfers(&adc->msg,
+ &adc->transfer[1], 1);
+ else
+ spi_message_init_with_transfers(&adc->msg, adc->transfer,
+ ARRAY_SIZE(adc->transfer));
- spi_message_init_with_transfers(&adc->msg, adc->transfer,
- ARRAY_SIZE(adc->transfer));
+ switch (device_index) {
+ case mcp3550_50:
+ case mcp3550_60:
+ case mcp3551:
+ case mcp3553:
+ /* rx len increases from 24 to 25 bit in SPI mode 0,0 */
+ if (!(spi->mode & SPI_CPOL))
+ adc->transfer[1].len++;
+
+ /* conversions are started by asserting CS pin for 8 usec */
+ adc->start_conv_transfer.delay_usecs = 8;
+ spi_message_init_with_transfers(&adc->start_conv_msg,
+ &adc->start_conv_transfer, 1);
+
+ /*
+ * If CS was previously kept low (continuous conversion mode)
+ * and then changed to high, the chip is in shutdown.
+ * Sometimes it fails to wake from shutdown and clocks out
+ * only 0xffffff. The magic sequence of performing two
+ * conversions without delay between them resets the chip
+ * and ensures all subsequent conversions succeed.
+ */
+ mcp320x_adc_conversion(adc, 0, 1, device_index, &ret);
+ mcp320x_adc_conversion(adc, 0, 1, device_index, &ret);
+ }
adc->reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(adc->reg))
@@ -370,62 +476,29 @@ static int mcp320x_remove(struct spi_device *spi)
#if defined(CONFIG_OF)
static const struct of_device_id mcp320x_dt_ids[] = {
/* NOTE: The use of compatibles with no vendor prefix is deprecated. */
- {
- .compatible = "mcp3001",
- .data = &mcp320x_chip_infos[mcp3001],
- }, {
- .compatible = "mcp3002",
- .data = &mcp320x_chip_infos[mcp3002],
- }, {
- .compatible = "mcp3004",
- .data = &mcp320x_chip_infos[mcp3004],
- }, {
- .compatible = "mcp3008",
- .data = &mcp320x_chip_infos[mcp3008],
- }, {
- .compatible = "mcp3201",
- .data = &mcp320x_chip_infos[mcp3201],
- }, {
- .compatible = "mcp3202",
- .data = &mcp320x_chip_infos[mcp3202],
- }, {
- .compatible = "mcp3204",
- .data = &mcp320x_chip_infos[mcp3204],
- }, {
- .compatible = "mcp3208",
- .data = &mcp320x_chip_infos[mcp3208],
- }, {
- .compatible = "mcp3301",
- .data = &mcp320x_chip_infos[mcp3301],
- }, {
- .compatible = "microchip,mcp3001",
- .data = &mcp320x_chip_infos[mcp3001],
- }, {
- .compatible = "microchip,mcp3002",
- .data = &mcp320x_chip_infos[mcp3002],
- }, {
- .compatible = "microchip,mcp3004",
- .data = &mcp320x_chip_infos[mcp3004],
- }, {
- .compatible = "microchip,mcp3008",
- .data = &mcp320x_chip_infos[mcp3008],
- }, {
- .compatible = "microchip,mcp3201",
- .data = &mcp320x_chip_infos[mcp3201],
- }, {
- .compatible = "microchip,mcp3202",
- .data = &mcp320x_chip_infos[mcp3202],
- }, {
- .compatible = "microchip,mcp3204",
- .data = &mcp320x_chip_infos[mcp3204],
- }, {
- .compatible = "microchip,mcp3208",
- .data = &mcp320x_chip_infos[mcp3208],
- }, {
- .compatible = "microchip,mcp3301",
- .data = &mcp320x_chip_infos[mcp3301],
- }, {
- }
+ { .compatible = "mcp3001" },
+ { .compatible = "mcp3002" },
+ { .compatible = "mcp3004" },
+ { .compatible = "mcp3008" },
+ { .compatible = "mcp3201" },
+ { .compatible = "mcp3202" },
+ { .compatible = "mcp3204" },
+ { .compatible = "mcp3208" },
+ { .compatible = "mcp3301" },
+ { .compatible = "microchip,mcp3001" },
+ { .compatible = "microchip,mcp3002" },
+ { .compatible = "microchip,mcp3004" },
+ { .compatible = "microchip,mcp3008" },
+ { .compatible = "microchip,mcp3201" },
+ { .compatible = "microchip,mcp3202" },
+ { .compatible = "microchip,mcp3204" },
+ { .compatible = "microchip,mcp3208" },
+ { .compatible = "microchip,mcp3301" },
+ { .compatible = "microchip,mcp3550-50" },
+ { .compatible = "microchip,mcp3550-60" },
+ { .compatible = "microchip,mcp3551" },
+ { .compatible = "microchip,mcp3553" },
+ { }
};
MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
#endif
@@ -440,6 +513,10 @@ static const struct spi_device_id mcp320x_id[] = {
{ "mcp3204", mcp3204 },
{ "mcp3208", mcp3208 },
{ "mcp3301", mcp3301 },
+ { "mcp3550-50", mcp3550_50 },
+ { "mcp3550-60", mcp3550_60 },
+ { "mcp3551", mcp3551 },
+ { "mcp3553", mcp3553 },
{ }
};
MODULE_DEVICE_TABLE(spi, mcp320x_id);
@@ -456,5 +533,5 @@ static struct spi_driver mcp320x_driver = {
module_spi_driver(mcp320x_driver);
MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
-MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08");
+MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08 and MCP3550/1/3");
MODULE_LICENSE("GPL v2");