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Message-ID: <20130410170212.GB19533@roeck-us.net>
Date: Wed, 10 Apr 2013 10:02:12 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Kevin Strasser <kevin.strasser@...ux.intel.com>
Cc: linux-kernel@...r.kernel.org,
Michael Brunner <michael.brunner@...tron.com>,
Samuel Ortiz <sameo@...ux.intel.com>,
Wolfram Sang <wsa@...-dreams.de>,
Ben Dooks <ben-linux@...ff.org>, linux-i2c@...r.kernel.org,
Grant Likely <grant.likely@...retlab.ca>,
Linus Walleij <linus.walleij@...aro.org>,
Wim Van Sebroeck <wim@...ana.be>,
linux-watchdog@...r.kernel.org,
Darren Hart <dvhart@...ux.intel.com>,
Michael Brunner <mibru@....de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH 2/4] i2c: Kontron PLD i2c bus driver
On Mon, Apr 08, 2013 at 10:15:19AM -0700, Kevin Strasser wrote:
> From: Michael Brunner <michael.brunner@...tron.com>
>
> Add i2c support for the on-board PLD found on some Kontron embedded
> modules.
>
> Signed-off-by: Michael Brunner <michael.brunner@...tron.com>
> Signed-off-by: Kevin Strasser <kevin.strasser@...ux.intel.com>
Overall well written, though I have a couple of nitpicks.
I would prefer two separate drivers, one for the mux and one for the i2c bus.
If that is possible, it would help getting rid of the #ifdef in the code, which
is frowned upon in the kernel.
I dislike unnecessary ( ). Maintainer's call, though.
Couple of places have missing spaces around operators (checkpatch doesn't catch
all those).
As far as I know, devm_ functions are supposed to print an error message on
failure, so it should be unnecessary to print another one if that happens (this
might need some confirmation).
Thanks,
Guenter
> ---
> drivers/i2c/busses/Kconfig | 20 ++
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-kempld.c | 679 +++++++++++++++++++++++++++++++++++++++
> drivers/i2c/busses/i2c-kempld.h | 86 +++++
> 4 files changed, 786 insertions(+)
> create mode 100644 drivers/i2c/busses/i2c-kempld.c
> create mode 100644 drivers/i2c/busses/i2c-kempld.h
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index adfee98..7aecd61 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -494,6 +494,26 @@ config I2C_IOP3XX
> This driver can also be built as a module. If so, the module
> will be called i2c-iop3xx.
>
> +config I2C_KEMPLD
> + tristate "Kontron COM I2C"
> + depends on MFD_KEMPLD
> + help
> + This enables support for the I2C bus interface on some Kontron ETX
> + and COMexpress (ETXexpress) modules.
> +
> + This driver can also be built as a module. If so, the module
> + will be called i2c-kempld.
> +
> +config I2C_KEMPLD_MUX
> + bool "Enable MUXed I2C ports (EXPERIMENTAL)"
> + depends on I2C_KEMPLD && I2C_MUX
> + default n
> + help
> + This enables support for additional I2C ports available on some
> + modules. Usually those ports are for board internal usage and
> + not routed outside the module.
> + Do not use this option unless you know what you are doing!
> +
> config I2C_MPC
> tristate "MPC107/824x/85xx/512x/52xx/83xx/86xx"
> depends on PPC
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 8f4fc23..411b8ce 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -48,6 +48,7 @@ obj-$(CONFIG_I2C_IBM_IIC) += i2c-ibm_iic.o
> obj-$(CONFIG_I2C_IMX) += i2c-imx.o
> obj-$(CONFIG_I2C_INTEL_MID) += i2c-intel-mid.o
> obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
> +obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o
> obj-$(CONFIG_I2C_MPC) += i2c-mpc.o
> obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o
> obj-$(CONFIG_I2C_MXS) += i2c-mxs.o
> diff --git a/drivers/i2c/busses/i2c-kempld.c b/drivers/i2c/busses/i2c-kempld.c
> new file mode 100644
> index 0000000..c6b44e7
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-kempld.c
> @@ -0,0 +1,679 @@
> +/*
> + * i2c-kempld.c: I2C bus driver for Kontron COM modules
> + *
> + * Copyright (c) 2010-2013 Kontron Europe GmbH
> + * Author: Michael Brunner <michael.brunner@...tron.com>
> + *
> + * The driver is based on the i2c-ocores driver by Peter Korsgaard.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License 2 as published
> + * by the Free Software Foundation.
> + *
> + * 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; see the file COPYING. If not, write to
> + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/errno.h>
> +#include <linux/platform_device.h>
> +#include <linux/i2c.h>
> +#ifdef CONFIG_I2C_KEMPLD_MUX
> +#include <linux/i2c-mux.h>
> +#endif
> +#include <linux/delay.h>
> +#include <linux/slab.h>
> +#include <linux/mfd/kempld.h>
> +#include <linux/interrupt.h>
> +#include <linux/time.h>
> +
> +#include "i2c-kempld.h"
> +
> +static int scl_frequency;
> +static int i2c_bus = -1;
> +static int i2c_mx_bus = -1;
> +static bool force_polling;
> +static int i2c_gpio_mux = -1;
> +
> +#ifdef CONFIG_I2C_KEMPLD_MUX
> +static int kempld_i2cmux_select(struct i2c_adapter *adap, void *data, u32 chan)
> +{
> + struct kempld_i2c_data *i2c = data;
> + struct kempld_device_data *pld = i2c->pld;
> + int ret = 0;
> +
> + if ((i2c->state == STATE_DONE)
> + || (i2c->state == STATE_ERROR)) {
> + if (i2c->mx != chan) {
> + kempld_get_mutex_set_index(pld, KEMPLD_I2C_MX);
> + i2c->mx = chan & 0x0f;
> + kempld_write8(pld, KEMPLD_I2C_MX, i2c->mx);
> + kempld_release_mutex(pld);
> + }
> +
> + /* Reset controller if the last transfer ended with an error */
> + if (i2c->state == STATE_ERROR) {
> + u8 ctrl;
> +
> + kempld_get_mutex_set_index(pld, KEMPLD_I2C_CMD);
> + ctrl = kempld_read8(pld, KEMPLD_I2C_CONTROL);
> + ctrl &= ~OCI2C_CTRL_EN;
> + kempld_write8(pld, KEMPLD_I2C_CONTROL, ctrl);
> + kempld_write8(pld, KEMPLD_I2C_CMD, OCI2C_CMD_IACK);
> + ctrl |= OCI2C_CTRL_EN;
> + kempld_write8(pld, KEMPLD_I2C_CONTROL, ctrl);
> + kempld_release_mutex(pld);
> + }
> +
> + } else
> + ret = -EBUSY;
> +
> + return ret;
> +}
> +
> +static void kempld_i2cmux_del(struct kempld_i2c_data *i2c)
> +{
> + int i;
> +
> + for (i = 0; i <= i2c->mx_max; i++) {
> + if (i2c->mxadap[i]) {
> + i2c_del_mux_adapter(i2c->mxadap[i]);
> + i2c->mxadap[i] = NULL;
> + }
> + }
> +}
> +
> +static int kempld_i2cmux_add(struct kempld_i2c_data *i2c)
> +{
> + struct kempld_device_data *pld = i2c->pld;
> + int i;
> + int ret = -ENODEV;
> +
> + for (i = 0; (i <= (i2c->mx_max)); i++) {
> + i2c->mxadap[i] = i2c_add_mux_adapter(&i2c->adap,
> + NULL, i2c, 0, i, 0,
> + kempld_i2cmux_select,
> + NULL);
> + if (!i2c->mxadap[i]) {
> + ret = -ENODEV;
> + dev_err(pld->dev,
> + "Failed to register MUX adapter %d\n", i);
> + goto add_mux_adapter_failed;
> + }
> + }
> +
> + return 0;
> +
> +add_mux_adapter_failed:
> + kempld_i2cmux_del(i2c);
> +
> + return ret;
> +}
> +
> +#else
> +#define kempld_i2cmux_add(x) (0)
> +#define kempld_i2cmux_del(x) do {} while (0)
> +#endif
> +
> +static int kempld_i2c_process(struct kempld_i2c_data *i2c)
> +{
> + struct kempld_device_data *pld = i2c->pld;
> + struct i2c_msg *msg = i2c->msg;
> + u8 stat = kempld_read8(pld, KEMPLD_I2C_STATUS);
> +
> + /* ready? */
> + if (stat & OCI2C_STAT_TIP)
> + return -EBUSY;
> +
> + if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
> + /* stop has been sent */
> + kempld_write8(pld, KEMPLD_I2C_CMD, OCI2C_CMD_IACK);
> + if (i2c->irq)
> + wake_up(&i2c->wait);
> + if (i2c->state == STATE_ERROR)
> + return -EIO;
> + else
> + return 0;
> + }
> +
> + /* error? */
> + if (stat & OCI2C_STAT_ARBLOST) {
> + i2c->state = STATE_ERROR;
> + kempld_write8(pld, KEMPLD_I2C_CMD, OCI2C_CMD_STOP);
> + return -EAGAIN;
> + }
> +
> + if (i2c->state == STATE_INIT) {
> + /* check if bus is free */
> + if (stat & OCI2C_STAT_BUSY)
> + return -EBUSY;
> +
> + i2c->state = STATE_ADDR;
> + }
> +
> + if (i2c->state == STATE_ADDR) {
> + u8 addr;
> + /* 10 bit address? */
> + if (i2c->msg->flags & I2C_M_TEN) {
> + addr = 0xf0 | ((i2c->msg->addr >> 7) & 0x6);
> + i2c->state = STATE_ADDR10;
> + } else {
> + addr = (i2c->msg->addr << 1);
> + i2c->state = STATE_START;
> + }
> +
> + /* set read bit if necessary */
> + addr |= (i2c->msg->flags & I2C_M_RD) ? 1 : 0;
> +
> + kempld_write8(pld, KEMPLD_I2C_DATA, addr);
> + kempld_write8(pld, KEMPLD_I2C_CMD, OCI2C_CMD_START);
> +
> + return 0;
> + }
> +
> + /* second part of 10 bit addressing */
> + if (i2c->state == STATE_ADDR10) {
> + kempld_write8(pld, KEMPLD_I2C_DATA, i2c->msg->addr & 0xff);
> + kempld_write8(pld, KEMPLD_I2C_CMD, OCI2C_CMD_WRITE);
> +
> + i2c->state = STATE_START;
> + return 0;
> + }
> +
> + if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
> + i2c->state =
> + (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
> +
> + if (stat & OCI2C_STAT_NACK) {
> + i2c->state = STATE_ERROR;
> + kempld_write8(pld, KEMPLD_I2C_CMD, OCI2C_CMD_STOP);
> + return -ENXIO;
> + }
> + } else
> + msg->buf[i2c->pos++] = kempld_read8(pld, KEMPLD_I2C_DATA);
> +
> + /* end of msg? */
> + if (i2c->pos >= msg->len) {
> + i2c->nmsgs--;
> + i2c->msg++;
> + i2c->pos = 0;
> + msg = i2c->msg;
> +
> + if (i2c->nmsgs) { /* end? */
> + /* send start? */
> + if (!(msg->flags & I2C_M_NOSTART)) {
> + i2c->state = STATE_ADDR;
> + if (i2c->irq)
> + wake_up(&i2c->wait);
> + return 0;
> + } else
> + i2c->state = (msg->flags & I2C_M_RD)
> + ? STATE_READ : STATE_WRITE;
> + } else {
> + i2c->state = STATE_DONE;
> + kempld_write8(pld, KEMPLD_I2C_CMD, OCI2C_CMD_STOP);
> + return 0;
> + }
> + }
> +
> + if (i2c->state == STATE_READ) {
> + kempld_write8(pld, KEMPLD_I2C_CMD, i2c->pos == (msg->len-1) ?
> + OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
> + } else {
> + kempld_write8(pld, KEMPLD_I2C_DATA, msg->buf[i2c->pos++]);
> + kempld_write8(pld, KEMPLD_I2C_CMD, OCI2C_CMD_WRITE);
> + }
> +
> + return 0;
> +}
> +
> +static irqreturn_t kempld_i2c_isr(int irq, void *dev_id)
> +{
> + struct kempld_i2c_data *i2c = dev_id;
> +
> + /* The actual ISR handler is put into a tasklet as it may block
> + * and therefore rescheduling must be possible */
> + tasklet_schedule(&i2c->tasklet);
> +
> + return IRQ_HANDLED;
> +}
> +
> +void kempld_i2c_tasklet(unsigned long data)
> +{
> + struct kempld_i2c_data *i2c = (struct kempld_i2c_data *)data;
> + struct kempld_device_data *pld = i2c->pld;
> +
> + kempld_get_mutex_set_index(pld, KEMPLD_I2C_STATUS);
> + kempld_i2c_process(i2c);
> + kempld_release_mutex(pld);
> +}
> +
> +static int kempld_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
> + int num)
> +{
> + struct kempld_i2c_data *i2c = i2c_get_adapdata(adap);
> + struct kempld_device_data *pld = i2c->pld;
> + unsigned long timeout = jiffies + HZ;
> + int ret;
> +
> + i2c->msg = msgs;
> + i2c->pos = 0;
> + i2c->nmsgs = num;
> + i2c->state = STATE_INIT;
> +
> + /* handle the transfer */
> + while (time_before(jiffies, timeout)) {
> + kempld_get_mutex_set_index(pld, KEMPLD_I2C_STATUS);
> + ret = kempld_i2c_process(i2c);
> + kempld_release_mutex(pld);
> +
> + if (i2c->irq && ((i2c->state >= STATE_START)
> + || (i2c->state == STATE_ERROR))) {
> + wait_event_timeout(i2c->wait,
> + (i2c->state == STATE_ERROR) ||
> + (i2c->state == STATE_DONE) ||
> + (i2c->state == STATE_ADDR), HZ);
> + if (i2c->state == STATE_ERROR)
> + ret = -EIO;
> + }
> +
> + if ((i2c->state == STATE_DONE)
> + || (i2c->state == STATE_ERROR))
> + return (i2c->state == STATE_DONE) ? num : ret;
> +
> + if (ret == 0)
> + timeout = jiffies + HZ;
> +
> + usleep_range(5, 15);
> + }
> +
> + i2c->state = STATE_ERROR;
> +
> + return -ETIMEDOUT;
> +}
> +
> +static void kempld_i2c_device_init(struct kempld_i2c_data *i2c)
> +{
> + struct kempld_device_data *pld = i2c->pld;
> + long prescale;
> + u16 prescale_corr;
> + u8 cfg;
> + u8 ctrl;
> + u8 stat;
> + u8 mx;
> +
> + kempld_get_mutex_set_index(pld, KEMPLD_I2C_CONTROL);
> +
> + ctrl = kempld_read8(pld, KEMPLD_I2C_CONTROL);
> + if (ctrl & OCI2C_CTRL_EN)
> + i2c->was_active = 1;
> +
> + /* set bus frequency */
> + if (scl_frequency > 0) {
> + /* make sure the device is disabled */
> + ctrl &= ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN);
> + kempld_write8(pld, KEMPLD_I2C_CONTROL, ctrl);
> +
> + /* The clock frequency calculation has been changed a bit
> + * between the spec. revisions */
> + if (pld->info.spec_major == 1)
> + prescale = (pld->pld_clock / (scl_frequency*5)) - 1000;
> + else
> + prescale = (pld->pld_clock / (scl_frequency*4)) - 3000;
> +
> + /* Prevent negative prescaler values */
> + if (prescale < 0)
> + prescale = 0;
> +
> + /* Round to the best matching value */
> + prescale_corr = prescale / 1000;
> + if ((prescale % 1000) >= 500)
> + prescale_corr++;
> +
> + kempld_write8(pld, KEMPLD_I2C_PRELOW, prescale_corr & 0xff);
> + kempld_write8(pld, KEMPLD_I2C_PREHIGH, prescale_corr >> 8);
> + }
> +
> + /* Activate I2C bus output on GPIO pins */
> + if (i2c_gpio_mux > -1) {
> + cfg = kempld_read8(pld, KEMPLD_CFG);
> + if (i2c_gpio_mux)
> + cfg |= KEMPLD_CFG_GPIO_I2C_MUX;
> + else
> + cfg &= ~KEMPLD_CFG_GPIO_I2C_MUX;
> + kempld_write8(pld, KEMPLD_CFG, cfg);
> + }
> + cfg = kempld_read8(pld, KEMPLD_CFG);
> + if (cfg & KEMPLD_CFG_GPIO_I2C_MUX)
> + i2c->gpio_mux = 1;
> + else
> + i2c->gpio_mux = 0;
> + if (((i2c_gpio_mux > 0) && (!i2c->gpio_mux))
> + || ((i2c_gpio_mux == 0) && (i2c->gpio_mux)))
> + dev_warn(pld->dev, "Unable to change GPIO I2C MUX setting\n");
> +
> + /* Check how much multiplexed I2C busses we have */
> + mx = kempld_read8(pld, KEMPLD_I2C_MX);
> + if (pld->info.spec_major > 1) {
> + i2c->mx_max = KEMPLD_I2C_MX_GET_MAX(mx);
> + if (i2c->mx_max == 0xf) /* No multiplexer available */
> + i2c->mx_max = 0;
> + } else
> + i2c->mx_max = 1;
> + /* 2 busses should be enough for all
> + * boards using specification revision 1 */
> +
> + /* Check which MX setting should be set */
> + if ((i2c_mx_bus == -1) || (i2c_mx_bus > i2c->mx_max)) {
> + if (i2c_mx_bus > i2c->mx_max) {
> + dev_err(pld->dev,
> + "bus selected with i2c_mx_bus not available "
> + "- leaving MX setting unchanged\n");
> + }
> + i2c->mx = mx & KEMPLD_I2C_MX_MASK;
> + } else
> + i2c->mx = i2c_mx_bus;
> +
> + /* Connect the controller to the chosen bus output */
> + kempld_write8(pld, KEMPLD_I2C_MX, i2c->mx);
> +
> + /* enable the device */
> + kempld_write8(pld, KEMPLD_I2C_CMD, OCI2C_CMD_IACK);
> + ctrl |= OCI2C_CTRL_EN;
> + kempld_write8(pld, KEMPLD_I2C_CONTROL, ctrl);
> +
> + /* If bus is busy send a STOP signal to be sure the controller is
> + * not hanging... */
> + stat = kempld_read8(pld, KEMPLD_I2C_STATUS);
> + if (stat & OCI2C_STAT_BUSY) {
> + dev_warn(pld->dev,
> + "I2C bus is busy - generating stop signal\n");
> + kempld_write8(pld, KEMPLD_I2C_CMD, OCI2C_CMD_STOP);
> + }
> +
> + kempld_release_mutex(pld);
> +
> + if ((pld->info.spec_major == 1) && (i2c->mx == 0xf))
> + i2c->mx = 0;
> +}
> +
> +static void kempld_i2c_irq_enable(struct kempld_i2c_data *i2c)
> +{
> + struct kempld_device_data *pld = i2c->pld;
> + u8 irq, ctrl;
> + int ret;
> +
> + irq = i2c->irq;
> +
> + /* This only has to be done once */
> + if (i2c->irq == 0) {
> + kempld_get_mutex_set_index(pld, KEMPLD_IRQ_I2C);
> + irq = kempld_read8(pld, KEMPLD_IRQ_I2C);
> + kempld_release_mutex(pld);
> +
> + /* Leave if interrupts are not supported by the I2C core */
> + if ((irq & 0xf0) == 0xf0)
> + return;
> + irq &= 0x0f;
> + if (irq == 0)
> + return;
> +
> + /* Initialize interrupt handlers if not already done */
> + init_waitqueue_head(&i2c->wait);
> + tasklet_init(&i2c->tasklet, kempld_i2c_tasklet,
> + (unsigned long)i2c);
> +
> + ret = devm_request_irq(pld->dev, irq, kempld_i2c_isr,
> + IRQF_SHARED, i2c->adap.name, i2c);
> + if (ret) {
> + dev_err(pld->dev,
> + "Unable to claim IRQ - using polling mode\n");
> + return;
> + }
> + }
> +
> + /* Now enable interrupts in the controller */
> + kempld_get_mutex_set_index(pld, KEMPLD_I2C_CONTROL);
> + ctrl = kempld_read8(pld, KEMPLD_I2C_CONTROL);
> + ctrl |= OCI2C_CTRL_IEN;
> + kempld_write8(pld, KEMPLD_I2C_CONTROL, ctrl);
> + kempld_release_mutex(pld);
> +
> + i2c->irq = irq & 0x0f;
> +}
> +
> +static void kempld_i2c_irq_disable(struct kempld_i2c_data *i2c)
> +{
> + struct kempld_device_data *pld = i2c->pld;
> + u8 ctrl;
> + int irq;
> +
> + if (i2c->irq == 0)
> + return;
> +
> + irq = i2c->irq;
> + i2c->irq = 0;
> +
> + tasklet_kill(&i2c->tasklet);
> +
> + kempld_get_mutex_set_index(pld, KEMPLD_I2C_CONTROL);
> + ctrl = kempld_read8(pld, KEMPLD_I2C_CONTROL);
> + ctrl &= ~OCI2C_CTRL_IEN;
> + kempld_write8(pld, KEMPLD_I2C_CONTROL, ctrl);
> + kempld_release_mutex(pld);
> +
> + devm_free_irq(pld->dev, irq, i2c);
> +}
> +
> +static u32 kempld_i2c_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR
> + | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static const struct i2c_algorithm kempld_i2c_algorithm = {
> + .master_xfer = kempld_i2c_xfer,
> + .functionality = kempld_i2c_func,
> +};
> +
> +static struct i2c_adapter kempld_i2c_adapter = {
> + .owner = THIS_MODULE,
> + .name = "i2c-kempld",
> + .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
> + .algo = &kempld_i2c_algorithm,
> +};
> +
> +static int kempld_i2c_get_scl_frequency(struct kempld_i2c_data *i2c)
> +{
> + struct kempld_device_data *pld = i2c->pld;
> + int frequency;
> + u16 prescale;
> +
> + kempld_get_mutex_set_index(pld, KEMPLD_I2C_PRELOW);
> +
> + prescale = kempld_read8(pld, KEMPLD_I2C_PRELOW)
> + | kempld_read8(pld, KEMPLD_I2C_PREHIGH)<<8;
> +
> + kempld_release_mutex(pld);
> +
> + /* The clock frequency calculation has been changed a bit
> + * between the spec. revisions */
> + if (pld->info.spec_major == 1)
> + frequency = (pld->pld_clock / (prescale + 1)) / 5000;
> + else
> + frequency = (pld->pld_clock / (prescale + 3)) / 4000;
> +
> + return frequency;
> +}
> +
> +static int kempld_i2c_probe(struct platform_device *pdev)
> +{
> + struct kempld_i2c_data *i2c;
> + struct kempld_device_data *pld;
> + int ret;
> +
> + pld = dev_get_drvdata(pdev->dev.parent);
> +
> + i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
> + if (!i2c)
> + return -ENOMEM;
> +
> + i2c->pld = pld;
> +
> + kempld_i2c_device_init(i2c);
> +
> + /* hook up driver to tree */
> + platform_set_drvdata(pdev, i2c);
> + i2c->adap = kempld_i2c_adapter;
> + i2c_set_adapdata(&i2c->adap, i2c);
> + i2c->adap.dev.parent = &pdev->dev;
> +
> + i2c->irq = 0;
> + if (!force_polling)
> + kempld_i2c_irq_enable(i2c);
> +
> + /* add I2C adapter to I2C tree */
> + i2c->adap.nr = i2c_bus;
> + ret = i2c_add_numbered_adapter(&i2c->adap);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to add adapter\n");
> + goto add_adapter_failed;
> + }
> +
> + ret = kempld_i2cmux_add(i2c);
> + if (ret)
> + goto add_mux_adapters_failed;
> +
> + dev_info(pld->dev, "I2C bus initialized with %d kHz SCL frequency\n",
> + kempld_i2c_get_scl_frequency(i2c));
> + dev_info(pld->dev, "I2C MUX connected to bus %d (available: %s%d)\n",
> + i2c->mx, i2c->mx_max ? "0-" : "", i2c->mx_max);
> + dev_info(pld->dev, "I2C IRQs %s\n", i2c->irq ? "enabled" : "disabled");
> + if (i2c->gpio_mux)
> + dev_info(pld->dev, "GPIO I2C MUX pins enabled\n");
> +
> + return 0;
> +
> +add_mux_adapters_failed:
> + i2c_del_adapter(&i2c->adap);
> +add_adapter_failed:
> + kfree(i2c);
> +
> + return ret;
> +}
> +
> +static int kempld_i2c_remove(struct platform_device *pdev)
> +{
> + struct kempld_i2c_data *i2c = platform_get_drvdata(pdev);
> + struct kempld_device_data *pld = i2c->pld;
> + u8 ctrl;
> +
> + kempld_i2c_irq_disable(i2c);
> +
> + if (!i2c->was_active) {
> + /* disable I2C logic if it was not activated before the
> + * driver loaded */
> + kempld_get_mutex_set_index(pld, KEMPLD_I2C_CONTROL);
> + ctrl = kempld_read8(pld, KEMPLD_I2C_CONTROL);
> + ctrl &= ~OCI2C_CTRL_EN;
> + kempld_write8(pld, KEMPLD_I2C_CONTROL, ctrl);
> + kempld_release_mutex(pld);
> + }
> +
> + /* remove adapter & data */
> + kempld_i2cmux_del(i2c);
> + i2c_del_adapter(&i2c->adap);
> +
> + platform_set_drvdata(pdev, NULL);
> +
> + kfree(i2c);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int kempld_i2c_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> + struct kempld_i2c_data *i2c = platform_get_drvdata(pdev);
> + struct kempld_device_data *pld = i2c->pld;
> + u8 ctrl;
> +
> + kempld_i2c_irq_disable(i2c);
> +
> + if (!i2c->was_active) {
> + /* make sure the device is disabled */
> + kempld_get_mutex_set_index(pld, KEMPLD_I2C_CONTROL);
> + ctrl = kempld_read8(pld, KEMPLD_I2C_CONTROL);
> + ctrl &= ~OCI2C_CTRL_EN;
> + kempld_write8(pld, KEMPLD_I2C_CONTROL, ctrl);
> + kempld_release_mutex(pld);
> + }
> +
> + return 0;
> +}
> +
> +static int kempld_i2c_resume(struct platform_device *pdev)
> +{
> + struct kempld_i2c_data *i2c = platform_get_drvdata(pdev);
> +
> + kempld_i2c_device_init(i2c);
> + kempld_i2c_irq_enable(i2c);
> +
> + return 0;
> +}
> +#else
> +#define kempld_i2c_suspend NULL
> +#define kempld_i2c_resume NULL
> +#endif
> +
> +static struct platform_driver kempld_i2c_driver = {
> + .driver = {
> + .name = "kempld-i2c",
> + .owner = THIS_MODULE,
> + },
> + .probe = kempld_i2c_probe,
> + .remove = kempld_i2c_remove,
> + .suspend = kempld_i2c_suspend,
> + .resume = kempld_i2c_resume,
> +};
> +
> +static int __init kempld_i2c_init(void)
> +{
> + /* Check if a valid value for the i2c_mx_bus parameter is provided */
> + if ((i2c_mx_bus != -1) && (i2c_mx_bus & ~KEMPLD_I2C_MX_MASK))
> + return -EINVAL;
> +
> + return platform_driver_register(&kempld_i2c_driver);
> +}
> +
> +static void __exit kempld_i2c_exit(void)
> +{
> + platform_driver_unregister(&kempld_i2c_driver);
> +}
> +
> +module_init(kempld_i2c_init);
> +module_exit(kempld_i2c_exit);
> +
> +module_param(scl_frequency, int, 0);
> +module_param(i2c_bus, int, 0);
> +module_param(i2c_mx_bus, int, 0);
> +module_param(force_polling, bool, 0);
> +module_param(i2c_gpio_mux, int, 0);
> +
> +MODULE_DESCRIPTION("KEM PLD I2C Driver");
> +MODULE_AUTHOR("Michael Brunner <michael.brunner@...tron.com>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:kempld_i2c");
> +MODULE_PARM_DESC(scl_frequency, "Set I2C SCL frequency (in kHz) default=0");
> +MODULE_PARM_DESC(i2c_bus, "Set I2C bus (-1 for dynamic assignment");
> +MODULE_PARM_DESC(i2c_mx_bus, "Set I2C MX bus (0-15, default=-1 (FW default))");
> +MODULE_PARM_DESC(force_polling, "Force polling mode");
> +MODULE_PARM_DESC(i2c_gpio_mux, "Enable I2C port on GPIO out");
> diff --git a/drivers/i2c/busses/i2c-kempld.h b/drivers/i2c/busses/i2c-kempld.h
> new file mode 100644
> index 0000000..2229662
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-kempld.h
> @@ -0,0 +1,86 @@
> +/*
> + * i2c-kempld.h - Kontron PLD I2C driver definitions
> + *
> + * Copyright (c) 2010-2012 Kontron Europe GmbH
> + * Author: Michael Brunner <michael.brunner@...tron.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License 2 as published
> + * by the Free Software Foundation.
> + *
> + * 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; see the file COPYING. If not, write to
> + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
> + */
> +
> +#ifndef _KEMPLD_I2C_H_
> +#define _KEMPLD_I2C_H_
> +
> +struct kempld_i2c_data {
> + struct i2c_adapter adap;
> + struct i2c_adapter *mxadap[15];
> + struct i2c_msg *msg;
> + int pos;
> + int nmsgs;
> + int state; /* see STATE_ */
> + int was_active;
> + int mx;
> + int mx_max;
> + int gpio_mux;
> + wait_queue_head_t wait;
> + struct tasklet_struct tasklet;
> + int irq;
> + struct kempld_device_data *pld;
> +};
> +
> +/* I2C register definitions */
> +#define KEMPLD_I2C_PRELOW 0x0b
> +#define KEMPLD_I2C_PREHIGH 0x0c
> +#define KEMPLD_I2C_CONTROL 0x0d
> +#define KEMPLD_I2C_DATA 0x0e
> +#define KEMPLD_I2C_CMD 0x0f /* write only */
> +#define KEMPLD_I2C_CMD_STA 0x80
> +#define KEMPLD_I2C_CMD_STO 0x40
> +#define KEMPLD_I2C_CMD_RD 0x20
> +#define KEMPLD_I2C_CMD_WR 0x10
> +#define KEMPLD_I2C_CMD_NACK 0x08
> +#define KEMPLD_I2C_CMD_IACK 0x01
> +#define KEMPLD_I2C_STATUS 0x0f /* read only, same address as
> + KEMPLD_I2C_CMD */
> +#define KEMPLD_I2C_MX 0x15
> +#define KEMPLD_I2C_MX_GET_MAX(x) ((x & 0xf0)>>4)
> +#define KEMPLD_I2C_MX_MASK 0x0f
> +
> +#define STATE_DONE 0
> +#define STATE_INIT 1
> +#define STATE_ADDR 2
> +#define STATE_ADDR10 3
> +#define STATE_START 4
> +#define STATE_WRITE 5
> +#define STATE_READ 6
> +#define STATE_ERROR 7
> +
> +/* defines taken from i2c-ocores */
> +#define OCI2C_CTRL_IEN 0x40
> +#define OCI2C_CTRL_EN 0x80
> +
> +#define OCI2C_CMD_START 0x91
> +#define OCI2C_CMD_STOP 0x41
> +#define OCI2C_CMD_READ 0x21
> +#define OCI2C_CMD_WRITE 0x11
> +#define OCI2C_CMD_READ_ACK 0x21
> +#define OCI2C_CMD_READ_NACK 0x29
> +#define OCI2C_CMD_IACK 0x01
> +
> +#define OCI2C_STAT_IF 0x01
> +#define OCI2C_STAT_TIP 0x02
> +#define OCI2C_STAT_ARBLOST 0x20
> +#define OCI2C_STAT_BUSY 0x40
> +#define OCI2C_STAT_NACK 0x80
> +
> +#endif /* _KEMPLD_I2C_H_ */
> --
> 1.7.9.5
>
> --
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