Hi Eric,
Sorry for the late answer.
On Wed, 3 Sep 2008 14:12:26 +0800, Eric Miao wrote:
> Driver based on corgi_ssp.c and sharpsl_pm.c, previously done by Richard
> Purdie and many others.
>
> Now changed to generic HWMON device and expose all the ADC input value
> through sysfs.
>
> Signed-off-by: Eric Miao <eric.miao at marvell.com>
> ---
>
> Updated and incorporated most feedback. Jean, could you please take a
> look and Ack, or let me know know who's the right guy to ack this, thanks.
Code looks reasonable, so you get my:
Acked-by: Jean Delvare <khali at linux-fr.org>
However, please read my few suggestions below to make the driver even
better.
>
> drivers/hwmon/Kconfig | 9 ++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/max1111.c | 235 +++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 245 insertions(+), 0 deletions(-)
> create mode 100644 drivers/hwmon/max1111.c
>
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index d402e8d..3309e86 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -540,6 +540,15 @@ config SENSORS_LM93
> This driver can also be built as a module. If so, the module
> will be called lm93.
>
> +config SENSORS_MAX1111
> + tristate "Maxim MAX1111 Multichannel, Serial 8-bit ADC chip"
> + depends on SPI_MASTER
> + help
> + Say y here to support Maxim's MAX1111 ADC chips.
> +
> + This driver can also be built as a module. If so, the module
> + will be called max1111.
> +
> config SENSORS_MAX1619
> tristate "Maxim MAX1619 sensor chip"
> depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 950134a..6babc80 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -59,6 +59,7 @@ obj-$(CONFIG_SENSORS_LM87) += lm87.o
> obj-$(CONFIG_SENSORS_LM90) += lm90.o
> obj-$(CONFIG_SENSORS_LM92) += lm92.o
> obj-$(CONFIG_SENSORS_LM93) += lm93.o
> +obj-$(CONFIG_SENSORS_MAX1111) += max1111.o
> obj-$(CONFIG_SENSORS_MAX1619) += max1619.o
> obj-$(CONFIG_SENSORS_MAX6650) += max6650.o
> obj-$(CONFIG_SENSORS_PC87360) += pc87360.o
> diff --git a/drivers/hwmon/max1111.c b/drivers/hwmon/max1111.c
> new file mode 100644
> index 0000000..5a974f8
> --- /dev/null
> +++ b/drivers/hwmon/max1111.c
> @@ -0,0 +1,235 @@
> +/*
> + * max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs
> + *
> + * Based on arch/arm/mach-pxa/corgi_ssp.c
> + *
> + * Copyright (C) 2004-2005 Richard Purdie
> + *
> + * Copyright (C) 2008 Marvell International Ltd.
> + * Eric Miao <eric.miao at marvell.com>
> + *
> + * 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
> + * publishhed by the Free Software Foundation.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/spi/spi.h>
> +
> +#define MAX1111_TX_BUF_SIZE (1)
> +#define MAX1111_RX_BUF_SIZE (2)
Note that parentheses aren't needed here.
> +
> +/* MAX1111 Commands */
> +#define MAX1111_CTRL_PD0 (1u << 0)
> +#define MAX1111_CTRL_PD1 (1u << 1)
> +#define MAX1111_CTRL_SGL (1u << 2)
> +#define MAX1111_CTRL_UNI (1u << 3)
> +#define MAX1111_CTRL_SEL_SH (4)
> +#define MAX1111_CTRL_STR (1u << 7)
> +
> +static ssize_t show_adc(struct device *, struct device_attribute *, char *);
> +static ssize_t show_name(struct device *, struct device_attribute *, char *);
You could easily get rid of these forward declarations by moving the
attribute declarations below after the functions themselves.
> +static int max1111_read(struct device *, int);
> +
> +#define MAX1111_ADC_ATTR(_id) \
> + SENSOR_DEVICE_ATTR(adc##_id##_in, S_IRUGO, show_adc, NULL, _id)
> +
> +static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
> +static MAX1111_ADC_ATTR(0);
> +static MAX1111_ADC_ATTR(1);
> +static MAX1111_ADC_ATTR(2);
> +static MAX1111_ADC_ATTR(3);
> +
> +static struct attribute *max1111_attributes[] = {
> + &dev_attr_name.attr,
> + &sensor_dev_attr_adc0_in.dev_attr.attr,
> + &sensor_dev_attr_adc1_in.dev_attr.attr,
> + &sensor_dev_attr_adc2_in.dev_attr.attr,
> + &sensor_dev_attr_adc3_in.dev_attr.attr,
> + NULL,
> +};
> +
> +static const struct attribute_group max1111_attr_group = {
> + .attrs = max1111_attributes,
> +};
> +
> +/*
> + * NOTE: SPI devices do not have a default 'name' attribute, which is
> + * likely to be used by hwmon applications to distinguish between
> + * different devices, explicitly add a name attribute here.
> + */
> +static ssize_t show_name(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + return sprintf(buf, "max1111\n");
> +}
> +
> +static ssize_t show_adc(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + int channel = to_sensor_dev_attr(attr)->index;
> + int ret;
> +
> + ret = max1111_read(dev, channel);
> + if (ret < 0)
> + return ret;
> +
> + return sprintf(buf, "%d\n", ret);
> +}
> +
> +struct max1111_data {
> + struct spi_device *spi;
> + struct device *hwmon_dev;
> + struct spi_message msg;
> + struct spi_transfer xfer[2];
> + uint8_t *tx_buf;
> + uint8_t *rx_buf;
> +};
> +
> +static int max1111_read(struct device *dev, int channel)
> +{
> + struct max1111_data *data = dev_get_drvdata(dev);
> + uint8_t v1, v2;
> + int err;
> +
> + data->tx_buf[0] = (channel << MAX1111_CTRL_SEL_SH) |
> + MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 |
> + MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR;
> +
> + err = spi_sync(data->spi, &data->msg);
> + if (err < 0) {
> + dev_err(dev, "spi_sync failed with %d\n", err);
> + return err;
> + }
> +
> + v1 = data->rx_buf[0];
> + v2 = data->rx_buf[1];
> +
> + if ((v1 & 0xc0) || (v2 & 0x3f))
> + return -EINVAL;
> +
> + return ((v1 << 2) & 0xfc) | ((v2 >> 6) & 0x03);
The masking is not needed: you have explicitly checked right above that
the bits you're masking out are 0s.
> +}
> +
> +static int setup_transfer(struct max1111_data *data)
> +{
> + struct spi_message *m;
> + struct spi_transfer *x;
> +
> + data->tx_buf = kmalloc(MAX1111_TX_BUF_SIZE, GFP_KERNEL);
> + if (!data->tx_buf)
> + return -ENOMEM;
> +
> + data->rx_buf = kmalloc(MAX1111_RX_BUF_SIZE, GFP_KERNEL);
> + if (!data->rx_buf) {
> + kfree(data->tx_buf);
> + return -ENOMEM;
> + }
Allocating such small buffers using kmalloc seems pretty inefficient.
At the very least, I would allocate both buffers at once. But quite
frankly I don't get why you don't just make these buffers part of
struct max1111_data. This would even make the structure smaller!
> +
> + m = &data->msg;
> + x = &data->xfer[0];
> +
> + spi_message_init(m);
> +
> + x->tx_buf = &data->tx_buf[0];
> + x->len = 1;
> + spi_message_add_tail(x, m);
> +
> + x++;
> + x->rx_buf = &data->rx_buf[0];
> + x->len = 2;
> + spi_message_add_tail(x, m);
> +
> + return 0;
> +}
> +
> +static int __devinit max1111_probe(struct spi_device *spi)
> +{
> + struct max1111_data *data;
> + int err;
> +
> + spi->bits_per_word = 8;
> + spi->mode = SPI_MODE_0;
> + err = spi_setup(spi);
> + if (err < 0)
> + return err;
> +
> + data = kzalloc(sizeof(struct max1111_data), GFP_KERNEL);
> + if (data == NULL) {
> + dev_err(&spi->dev, "failed to allocate memory\n");
> + return -ENOMEM;
> + }
> +
> + err = setup_transfer(data);
> + if (err)
> + goto err_free_data;
> +
> + data->spi = spi;
> + spi_set_drvdata(spi, data);
> +
> + err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group);
> + if (err) {
> + dev_err(&spi->dev, "failed to create attribute group\n");
> + goto err_free_all;
> + }
> +
> + data->hwmon_dev = hwmon_device_register(&spi->dev);
> + if (IS_ERR(data->hwmon_dev)) {
> + dev_err(&spi->dev, "failed to create hwmon device\n");
> + err = PTR_ERR(data->hwmon_dev);
> + goto err_remove;
> + }
> +
> + return 0;
> +
> +err_remove:
> + sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
> +err_free_all:
> + kfree(data->rx_buf);
> + kfree(data->tx_buf);
> +err_free_data:
> + kfree(data);
> + return err;
> +}
> +
> +static int __devexit max1111_remove(struct spi_device *spi)
> +{
> + struct max1111_data *data = spi_get_drvdata(spi);
> +
> + hwmon_device_unregister(data->hwmon_dev);
> + sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
> + kfree(data->rx_buf);
> + kfree(data->tx_buf);
> + kfree(data);
> + return 0;
> +}
> +
> +static struct spi_driver max1111_driver = {
> + .driver = {
> + .name = "max1111",
> + .owner = THIS_MODULE,
> + },
> + .probe = max1111_probe,
> + .remove = __devexit_p(max1111_remove),
> +};
> +
> +static int __init max1111_init(void)
> +{
> + return spi_register_driver(&max1111_driver);
> +}
> +module_init(max1111_init);
> +
> +static void __exit max1111_exit(void)
> +{
> + spi_unregister_driver(&max1111_driver);
> +}
> +module_exit(max1111_exit);
> +
> +MODULE_AUTHOR("Eric Miao <eric.miao at marvell.com>");
> +MODULE_DESCRIPTION("MAX1111 ADC Driver");
> +MODULE_LICENSE("GPL");
--
Jean Delvare
