Initial source upload
parent
d214f74deb
commit
7e06316229
@ -0,0 +1,23 @@
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KERNELDIR := /usr/src/linux-headers-6.1.21-v8+
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MODULE_NAME=ads1278
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SRC := ads1278_core.c
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ifneq ($(KERNELRELEASE),)
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$(MODULE_NAME)-objs = $(SRC:.c=.o)
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obj-m := $(MODULE_NAME).o
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else
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PWD := $(shell pwd)
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default:
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ifeq ($(strip $(KERNELDIR)),)
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$(error "KERNELDIR is undefined!")
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else
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$(MAKE) -C $(KERNELDIR) scripts
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$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
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endif
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clean:
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rm -rf *~ *.ko *.o *.mod.c modules.order Module.symvers .${MODULE_NAME}* .tmp_versions
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endif
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@ -0,0 +1,43 @@
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/dts-v1/;
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/plugin/;
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/ {
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compatible = "brcm,bcm2835";
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fragment@0 {
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target = <&spi0>;
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__overlay__ {
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status = "okay";
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};
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};
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fragment@1 {
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target = <&spidev0>;
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__overlay__ {
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status = "disabled";
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};
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};
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fragment@2 {
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target = <&spidev1>;
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__overlay__ {
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status = "disabled";
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};
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};
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fragment@3 {
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target = <&spi0>;
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__overlay__ {
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#address-cells = <1>;
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#size-cells = <0>;
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ads1278: ads1278@0 {
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compatible = "ti,ads1278-fs";
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status = "okay";
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reg = <0>;
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pinctrl-names = "default";
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};
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};
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};
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};
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@ -0,0 +1,214 @@
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#include <linux/delay.h>
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#include <linux/dma-mapping.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/spi/spi.h>
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#define FRAME_SIZE (24)
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#define TRANSFER_SIZE (FRAME_SIZE * 10)
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// 27'648'000 Hz = 144 kSPS
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// 25'000'000 Hz = 130 kSPS
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// 10'000'000 Hz = 52 kSPS
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#define TRANSFER_HZ (27000000)
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// TODO: minimize 45us delay between xfers
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// 24-11-23: We're hitting 130 kSPS initially, but are eventually slowed down
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// to 87 kSPS. Need to investigate high-priority workers, forcing a high SPI
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// clock speed, and/or minimizing overall latency.
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struct ads1278
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{
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unsigned char *rx;
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unsigned char *tx;
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dma_addr_t rx_dma_handle;
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dma_addr_t tx_dma_handle;
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struct spi_message msg[2];
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struct spi_transfer tr[2];
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int stop_requested;
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int running[2];
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};
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static void ads1278_transfer_callback1(void *context)
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{
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struct spi_device *spi = (struct spi_device *)context;
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struct ads1278 *ads = spi_get_drvdata(spi);
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if (!ads->stop_requested)
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spi_async(spi, &ads->msg[0]);
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else
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ads->running[0] = 0;
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}
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static void ads1278_transfer_callback2(void *context)
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{
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struct spi_device *spi = (struct spi_device *)context;
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struct ads1278 *ads = spi_get_drvdata(spi);
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if (!ads->stop_requested)
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spi_async(spi, &ads->msg[1]);
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else
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ads->running[1] = 0;
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}
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static int ads1278_build_transfers(struct spi_device *spi)
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{
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struct ads1278 *ads = spi_get_drvdata(spi);
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int i;
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dma_set_coherent_mask(&spi->dev, 0xFFFFFFFF);
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ads->tx = (unsigned char *)dma_alloc_coherent(&spi->dev, TRANSFER_SIZE * 2,
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&ads->tx_dma_handle, GFP_KERNEL);
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if (!ads->tx)
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return -1;
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ads->rx = (unsigned char *)dma_alloc_coherent(&spi->dev, TRANSFER_SIZE * 2,
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&ads->rx_dma_handle, GFP_KERNEL);
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if (!ads->rx)
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return -1;
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memset(ads->tr, 0, sizeof(ads->tr));
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memset(ads->tx, 0, TRANSFER_SIZE * 2);
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memset(ads->rx, 0, TRANSFER_SIZE * 2);
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for (i = 0; i < TRANSFER_SIZE * 2; i += FRAME_SIZE) {
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ads->tx[i] = 0xC0;
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}
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ads->tr[0].tx_buf = ads->tx;
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ads->tr[0].rx_buf = ads->rx;
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ads->tr[0].len = TRANSFER_SIZE;
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ads->tr[0].cs_off = 1;
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ads->tr[0].bits_per_word = 8;
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ads->tr[0].speed_hz = TRANSFER_HZ;
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ads->tr[1].tx_buf = ads->tx + TRANSFER_SIZE;
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ads->tr[1].rx_buf = ads->rx + TRANSFER_SIZE;
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ads->tr[1].len = TRANSFER_SIZE;
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ads->tr[1].cs_off = 1;
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ads->tr[1].bits_per_word = 8;
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ads->tr[1].speed_hz = TRANSFER_HZ;
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return 0;
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}
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static int ads1278_begin_transfer(struct spi_device *spi)
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{
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struct ads1278 *ads = spi_get_drvdata(spi);
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if (!ads)
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return -1;
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if (ads1278_build_transfers(spi)) {
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dev_err(&spi->dev, "error with building transfer!");
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return -1;
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}
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spi_message_init_with_transfers(&ads->msg[0], &ads->tr[0], 1);
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spi_message_init_with_transfers(&ads->msg[1], &ads->tr[1], 1);
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ads->msg[0].complete = ads1278_transfer_callback1;
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ads->msg[1].complete = ads1278_transfer_callback2;
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ads->msg[0].context = spi;
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ads->msg[1].context = spi;
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//spi_optimize_message(spi, msg);
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ads->stop_requested = 0;
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ads->running[0] = 1;
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ads->running[1] = 1;
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/* TODO ret = */ spi_async(spi, &ads->msg[0]);
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return spi_async(spi, &ads->msg[1]);
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}
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static int ads1278_probe(struct spi_device *spi)
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{
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struct ads1278 *ads;
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dev_info(&spi->dev, "probing...");
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ads = kzalloc(sizeof(*ads), GFP_KERNEL);
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if (!ads)
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return -ENOMEM;
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spi_set_drvdata(spi, ads);
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spi->max_speed_hz = TRANSFER_HZ;
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spi->mode = 1;
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spi->bits_per_word = 8;
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spi->rt = 1;
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spi->word_delay.value = 0;
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spi->cs_setup.value = 0;
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spi->cs_hold.value = 0;
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spi->cs_inactive.value = 0;
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if (spi_setup(spi)) {
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dev_err(&spi->dev, "error with spi setup!");
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goto end_free_ads;
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}
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dev_info(&spi->dev, "ready to go!");
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if (ads1278_begin_transfer(spi)) {
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dev_err(&spi->dev, "error with initial transfer!");
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goto end_free_ads;
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}
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return 0;
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end_free_ads:
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kfree(ads);
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return -1;
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}
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static void ads1278_remove(struct spi_device *spi)
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{
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struct ads1278 *ads = spi_get_drvdata(spi);
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int i;
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dev_info(&spi->dev, "cleaning up...");
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if (ads) {
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ads->stop_requested = 1;
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for (i = 0; i < 100; i++) {
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if (ads->running[0] <= 0 && ads->running[1] <= 0)
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break;
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mdelay(10);
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}
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//spi_unoptimize_message(&ads->msg);
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dma_free_coherent(&spi->dev, TRANSFER_SIZE * 2, ads->tx, ads->tx_dma_handle);
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dma_free_coherent(&spi->dev, TRANSFER_SIZE * 2, ads->rx, ads->rx_dma_handle);
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kfree(ads);
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}
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dev_info(&spi->dev, "done.");
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}
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static struct of_device_id ads1278_id_table[] = {
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{ .compatible = "ti,ads1278-fs", },
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{}
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};
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MODULE_DEVICE_TABLE(spi, ads1278_id_table);
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static struct spi_driver ads1278_spi_driver =
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{
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.driver = {
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.name = "ti,ads1278-fs",
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.of_match_table = ads1278_id_table,
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},
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.probe = ads1278_probe,
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.remove = ads1278_remove,
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};
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module_spi_driver(ads1278_spi_driver);
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MODULE_DESCRIPTION("SPI/Frame-sync protocol driver for ADS1278");
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MODULE_AUTHOR("Clyne Sullivan <clyne@bitgloo.com");
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MODULE_LICENSE("GPL");
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