[PATCH v3] ARM: LPC32xx: ADC support
Jonathan Cameron
jic23 at cam.ac.uk
Tue Feb 14 17:28:30 UTC 2012
Roland Stigge <stigge at antcom.de> wrote:
>This patch adds a 3-channel ADC driver for the LPC32xx ARM SoC
>
>Signed-off-by: Roland Stigge <stigge at antcom.de>
>
Acked-by: Jonathan Cameron <jic23 at kernel.org> for split version... send iio part to Greg kh for merge ccing linux-iio. Please check it against staging-next just before you do as that can move fast.
>---
> arch/arm/mach-lpc32xx/clock.c | 36 +++++
> arch/arm/mach-lpc32xx/common.c | 22 +++
> arch/arm/mach-lpc32xx/common.h | 1
> arch/arm/mach-lpc32xx/phy3250.c | 3
> drivers/staging/iio/adc/Kconfig | 9 +
> drivers/staging/iio/adc/Makefile | 1
>drivers/staging/iio/adc/lpc32xx_adc.c | 237
>++++++++++++++++++++++++++++++++++
> 7 files changed, 309 insertions(+)
>
>--- linux-arm-soc.orig/arch/arm/mach-lpc32xx/clock.c
>+++ linux-arm-soc/arch/arm/mach-lpc32xx/clock.c
>@@ -721,6 +721,41 @@ static struct clk clk_tsc = {
> .get_rate = local_return_parent_rate,
> };
>
>+static int adc_onoff_enable(struct clk *clk, int enable)
>+{
>+ u32 tmp;
>+ u32 divider;
>+
>+ /* Use PERIPH_CLOCK */
>+ tmp = __raw_readl(LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
>+ tmp |= LPC32XX_CLKPWR_ADCCTRL1_PCLK_SEL;
>+ /*
>+ * Set clock divider so that we have equal to or less than
>+ * 4.5MHz clock at ADC
>+ */
>+ divider = clk->get_rate(clk) / 4500000 + 1;
>+ tmp |= divider;
>+ __raw_writel(tmp, LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
>+
>+ /* synchronize rate of this clock w/ actual HW setting */
>+ clk->rate = clk->get_rate(clk->parent) / divider;
>+
>+ if (enable == 0)
>+ __raw_writel(0, clk->enable_reg);
>+ else
>+ __raw_writel(clk->enable_mask, clk->enable_reg);
>+
>+ return 0;
>+}
>+
>+static struct clk clk_adc = {
>+ .parent = &clk_pclk,
>+ .enable = adc_onoff_enable,
>+ .enable_reg = LPC32XX_CLKPWR_ADC_CLK_CTRL,
>+ .enable_mask = LPC32XX_CLKPWR_ADC32CLKCTRL_CLK_EN,
>+ .get_rate = local_return_parent_rate,
>+};
>+
> static int mmc_onoff_enable(struct clk *clk, int enable)
> {
> u32 tmp;
>@@ -1055,6 +1090,7 @@ static struct clk_lookup lookups[] = {
> _REGISTER_CLOCK("dev:ssp1", NULL, clk_ssp1)
> _REGISTER_CLOCK("lpc32xx_keys.0", NULL, clk_kscan)
> _REGISTER_CLOCK("lpc32xx-nand.0", "nand_ck", clk_nand)
>+ _REGISTER_CLOCK("lpc32xx-adc", NULL, clk_adc)
> _REGISTER_CLOCK(NULL, "i2s0_ck", clk_i2s0)
> _REGISTER_CLOCK(NULL, "i2s1_ck", clk_i2s1)
> _REGISTER_CLOCK("ts-lpc32xx", NULL, clk_tsc)
>--- linux-arm-soc.orig/arch/arm/mach-lpc32xx/common.c
>+++ linux-arm-soc/arch/arm/mach-lpc32xx/common.c
>@@ -138,6 +138,28 @@ struct platform_device lpc32xx_rtc_devic
> };
>
> /*
>+ * ADC support
>+ */
>+static struct resource adc_resources[] = {
>+ {
>+ .start = LPC32XX_ADC_BASE,
>+ .end = LPC32XX_ADC_BASE + SZ_4K - 1,
>+ .flags = IORESOURCE_MEM,
>+ }, {
>+ .start = IRQ_LPC32XX_TS_IRQ,
>+ .end = IRQ_LPC32XX_TS_IRQ,
>+ .flags = IORESOURCE_IRQ,
>+ },
>+};
>+
>+struct platform_device lpc32xx_adc_device = {
>+ .name = "lpc32xx-adc",
>+ .id = -1,
>+ .num_resources = ARRAY_SIZE(adc_resources),
>+ .resource = adc_resources,
>+};
>+
>+/*
> * Returns the unique ID for the device
> */
> void lpc32xx_get_uid(u32 devid[4])
>--- linux-arm-soc.orig/arch/arm/mach-lpc32xx/common.h
>+++ linux-arm-soc/arch/arm/mach-lpc32xx/common.h
>@@ -29,6 +29,7 @@ extern struct platform_device lpc32xx_i2
> extern struct platform_device lpc32xx_i2c1_device;
> extern struct platform_device lpc32xx_i2c2_device;
> extern struct platform_device lpc32xx_tsc_device;
>+extern struct platform_device lpc32xx_adc_device;
> extern struct platform_device lpc32xx_rtc_device;
>
> /*
>--- linux-arm-soc.orig/arch/arm/mach-lpc32xx/phy3250.c
>+++ linux-arm-soc/arch/arm/mach-lpc32xx/phy3250.c
>@@ -252,6 +252,9 @@ static struct platform_device *phy3250_d
> &lpc32xx_i2c2_device,
> &lpc32xx_watchdog_device,
> &lpc32xx_gpio_led_device,
>+#if defined(CONFIG_LPC32XX_ADC)
>+ &lpc32xx_adc_device,
>+#endif
> };
>
> static struct amba_device *amba_devs[] __initdata = {
>--- linux-arm-soc.orig/drivers/staging/iio/adc/Kconfig
>+++ linux-arm-soc/drivers/staging/iio/adc/Kconfig
>@@ -193,4 +193,13 @@ config MAX1363_RING_BUFFER
> Say yes here to include ring buffer support in the MAX1363
> ADC driver.
>
>+config LPC32XX_ADC
>+ tristate "NXP LPC32XX ADC"
>+ depends on ARCH_LPC32XX && !TOUCHSCREEN_LPC32XX
>+ help
>+ Say yes here to build support for the integrated ADC inside the
>+ LPC32XX SoC. Note that this feature uses the same hardware as the
>+ touchscreen driver, so you can only select one of the two drivers
>+ (lpc32xx_adc or lpc32xx_ts). Provides direct access via sysfs.
>+
> endmenu
>--- linux-arm-soc.orig/drivers/staging/iio/adc/Makefile
>+++ linux-arm-soc/drivers/staging/iio/adc/Makefile
>@@ -37,3 +37,4 @@ obj-$(CONFIG_AD7192) += ad7192.o
> obj-$(CONFIG_ADT7310) += adt7310.o
> obj-$(CONFIG_ADT7410) += adt7410.o
> obj-$(CONFIG_AD7280) += ad7280a.o
>+obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
>--- /dev/null
>+++ linux-arm-soc/drivers/staging/iio/adc/lpc32xx_adc.c
>@@ -0,0 +1,237 @@
>+/*
>+ * lpc32xx_adc.c - Support for ADC in LPC32XX
>+ *
>+ * 3-channel, 10-bit ADC
>+ *
>+ * Copyright (C) 2011, 2012 Roland Stigge <stigge at antcom.de>
>+ *
>+ * 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.
>+ *
>+ * This program is distributed in the hope that it will be useful,
>+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
>+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>+ * GNU General Public License for more details.
>+ *
>+ * You should have received a copy of the GNU General Public License
>+ * along with this program; if not, write to the Free Software
>+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
>+ */
>+
>+#include <linux/module.h>
>+#include <linux/platform_device.h>
>+#include <linux/interrupt.h>
>+#include <linux/device.h>
>+#include <linux/kernel.h>
>+#include <linux/slab.h>
>+#include <linux/io.h>
>+#include <linux/clk.h>
>+#include <linux/err.h>
>+#include <linux/completion.h>
>+
>+#include "../iio.h"
>+#include "../sysfs.h"
>+
>+/*
>+ * LPC32XX registers definitions
>+ */
>+#define LPC32XX_ADC_SELECT(x) ((x) + 0x04)
>+#define LPC32XX_ADC_CTRL(x) ((x) + 0x08)
>+#define LPC32XX_ADC_VALUE(x) ((x) + 0x48)
>+
>+/* Bit definitions for LPC32XX_ADC_SELECT: */
>+#define AD_REFm 0x00000200 /* constant, always write this
>value! */
>+#define AD_REFp 0x00000080 /* constant, always write this value! */
>+#define AD_IN 0x00000010 /* multiple of this is the */
>+ /* channel number: 0, 1, 2 */
>+#define AD_INTERNAL 0x00000004 /* constant, always write this value!
>*/
>+
>+/* Bit definitions for LPC32XX_ADC_CTRL: */
>+#define AD_STROBE 0x00000002
>+#define AD_PDN_CTRL 0x00000004
>+
>+/* Bit definitions for LPC32XX_ADC_VALUE: */
>+#define ADC_VALUE_MASK 0x000003FF
>+
>+#define MOD_NAME "lpc32xx-adc"
>+
>+struct lpc32xx_adc_info {
>+ void __iomem *adc_base;
>+ struct clk *clk;
>+ struct completion completion;
>+
>+ u32 value;
>+};
>+
>+static int lpc32xx_read_raw(struct iio_dev *indio_dev,
>+ struct iio_chan_spec const *chan,
>+ int *val,
>+ int *val2,
>+ long mask)
>+{
>+ struct lpc32xx_adc_info *info = iio_priv(indio_dev);
>+
>+ if (mask == 0) {
>+ mutex_lock(&indio_dev->mlock);
>+ clk_enable(info->clk);
>+ /* Measurement setup */
>+ __raw_writel(AD_INTERNAL | (chan->address) | AD_REFp | AD_REFm,
>+ LPC32XX_ADC_SELECT(info->adc_base));
>+ /* Trigger conversion */
>+ __raw_writel(AD_PDN_CTRL | AD_STROBE,
>+ LPC32XX_ADC_CTRL(info->adc_base));
>+ wait_for_completion(&info->completion); /* set by ISR */
>+ clk_disable(info->clk);
>+ *val = info->value;
>+ mutex_unlock(&indio_dev->mlock);
>+
>+ return IIO_VAL_INT;
>+ }
>+
>+ return -EINVAL;
>+}
>+
>+static const struct iio_info lpc32xx_adc_iio_info = {
>+ .read_raw = &lpc32xx_read_raw,
>+ .driver_module = THIS_MODULE,
>+};
>+
>+#define LPC32XX_ADC_CHANNEL(_index) { \
>+ .type = IIO_VOLTAGE, \
>+ .indexed = 1, \
>+ .channel = _index, \
>+ .address = AD_IN * _index, \
>+ .scan_index = _index, \
>+}
>+
>+static struct iio_chan_spec lpc32xx_adc_iio_channels[] = {
>+ LPC32XX_ADC_CHANNEL(0),
>+ LPC32XX_ADC_CHANNEL(1),
>+ LPC32XX_ADC_CHANNEL(2),
>+};
>+
>+static irqreturn_t lpc32xx_adc_isr(int irq, void *dev_id)
>+{
>+ struct lpc32xx_adc_info *info = (struct lpc32xx_adc_info *) dev_id;
>+
>+ /* Read value and clear irq */
>+ info->value = __raw_readl(LPC32XX_ADC_VALUE(info->adc_base)) &
>+ ADC_VALUE_MASK;
>+ complete(&info->completion);
>+
>+ return IRQ_HANDLED;
>+}
>+
>+static int __devinit lpc32xx_adc_probe(struct platform_device *pdev)
>+{
>+ struct lpc32xx_adc_info *info = NULL;
>+ struct resource *res;
>+ int retval = -ENODEV;
>+ struct iio_dev *iodev = NULL;
>+ int irq;
>+
>+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>+ if (!res) {
>+ dev_err(&pdev->dev, "failed to get platform I/O memory\n");
>+ retval = -EBUSY;
>+ goto errout1;
>+ }
>+
>+ iodev = iio_allocate_device(sizeof(struct lpc32xx_adc_info));
>+ if (!iodev) {
>+ dev_err(&pdev->dev, "failed allocating iio device\n");
>+ retval = -ENOMEM;
>+ goto errout1;
>+ }
>+
>+ info = iio_priv(iodev);
>+
>+ info->adc_base = ioremap(res->start, res->end - res->start + 1);
>+ if (!info->adc_base) {
>+ dev_err(&pdev->dev, "failed mapping memory\n");
>+ retval = -EBUSY;
>+ goto errout2;
>+ }
>+
>+ info->clk = clk_get(&pdev->dev, NULL);
>+ if (IS_ERR(info->clk)) {
>+ dev_err(&pdev->dev, "failed getting clock\n");
>+ goto errout3;
>+ }
>+
>+ irq = platform_get_irq(pdev, 0);
>+ if ((irq < 0) || (irq >= NR_IRQS)) {
>+ dev_err(&pdev->dev, "failed getting interrupt resource\n");
>+ retval = -EINVAL;
>+ goto errout4;
>+ }
>+
>+ retval = request_irq(irq, lpc32xx_adc_isr, 0, MOD_NAME, info);
>+ if (retval < 0) {
>+ dev_err(&pdev->dev, "failed requesting interrupt\n");
>+ goto errout4;
>+ }
>+
>+ platform_set_drvdata(pdev, iodev);
>+
>+ init_completion(&info->completion);
>+
>+ iodev->name = MOD_NAME;
>+ iodev->dev.parent = &pdev->dev;
>+ iodev->info = &lpc32xx_adc_iio_info;
>+ iodev->modes = INDIO_DIRECT_MODE;
>+ iodev->channels = lpc32xx_adc_iio_channels;
>+ iodev->num_channels = ARRAY_SIZE(lpc32xx_adc_iio_channels);
>+
>+ retval = iio_device_register(iodev);
>+ if (retval)
>+ goto errout5;
>+
>+ dev_info(&pdev->dev, "LPC32XX ADC driver loaded, IRQ %d\n", irq);
>+
>+ return 0;
>+
>+errout5:
>+ free_irq(irq, iodev);
>+errout4:
>+ clk_put(info->clk);
>+errout3:
>+ iounmap(info->adc_base);
>+errout2:
>+ iio_free_device(iodev);
>+errout1:
>+ return retval;
>+}
>+
>+static int __devexit lpc32xx_adc_remove(struct platform_device *pdev)
>+{
>+ struct iio_dev *iodev = platform_get_drvdata(pdev);
>+ struct lpc32xx_adc_info *info = iio_priv(iodev);
>+ int irq = platform_get_irq(pdev, 0);
>+
>+ iio_device_unregister(iodev);
>+ free_irq(irq, iodev);
>+ platform_set_drvdata(pdev, NULL);
>+ clk_put(info->clk);
>+ iounmap(info->adc_base);
>+ iio_free_device(iodev);
>+
>+ return 0;
>+}
>+
>+static struct platform_driver lpc32xx_adc_driver = {
>+ .probe = lpc32xx_adc_probe,
>+ .remove = __devexit_p(lpc32xx_adc_remove),
>+ .driver = {
>+ .name = MOD_NAME,
>+ .owner = THIS_MODULE,
>+ },
>+};
>+
>+module_platform_driver(lpc32xx_adc_driver);
>+
>+MODULE_AUTHOR("Roland Stigge <stigge at antcom.de>");
>+MODULE_DESCRIPTION("LPC32XX ADC driver");
>+MODULE_LICENSE("GPL");
--
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