--- /dev/null
+From 1f72dfe2738305c57605a8192176117e1641779c Mon Sep 17 00:00:00 2001
+From: popcornmix <popcornmix@gmail.com>
+Date: Wed, 17 Jun 2015 15:44:08 +0100
+Subject: [PATCH] Add Chris Boot's i2c driver
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+i2c-bcm2708: fixed baudrate
+
+Fixed issue where the wrong CDIV value was set for baudrates below 3815 Hz (for 250MHz bus clock).
+In that case the computed CDIV value was more than 0xffff. However the CDIV register width is only 16 bits.
+This resulted in incorrect setting of CDIV and higher baudrate than intended.
+Example: 3500Hz -> CDIV=0x11704 -> CDIV(16bit)=0x1704 -> 42430Hz
+After correction: 3500Hz -> CDIV=0x11704 -> CDIV(16bit)=0xffff -> 3815Hz
+The correct baudrate is shown in the log after the cdiv > 0xffff correction.
+
+Perform I2C combined transactions when possible
+
+Perform I2C combined transactions whenever possible, within the
+restrictions of the Broadcomm Serial Controller.
+
+Disable DONE interrupt during TA poll
+
+Prevent interrupt from being triggered if poll is missed and transfer
+starts and finishes.
+
+i2c: Make combined transactions optional and disabled by default
+
+i2c: bcm2708: add device tree support
+
+Add DT support to driver and add to .dtsi file.
+Setup pins in .dts file.
+i2c is disabled by default.
+
+Signed-off-by: Noralf Tronnes <notro@tronnes.org>
+
+bcm2708: don't register i2c controllers when using DT
+
+The devices for the i2c controllers are in the Device Tree.
+Only register devices when not using DT.
+
+Signed-off-by: Noralf Tronnes <notro@tronnes.org>
+
+I2C: Only register the I2C device for the current board revision
+
+i2c_bcm2708: Fix clock reference counting
+
+Fix grabbing lock from atomic context in i2c driver
+
+2 main changes:
+- check for timeouts in the bcm2708_bsc_setup function as indicated by this comment:
+ /* poll for transfer start bit (should only take 1-20 polls) */
+ This implies that the setup function can now fail so account for this everywhere it's called
+- Removed the clk_get_rate call from inside the setup function as it locks a mutex and that's not ok since we call it from under a spin lock.
+
+i2c-bcm2708: When using DT, leave the GPIO setup to pinctrl
+
+i2c-bcm2708: Increase timeouts to allow larger transfers
+
+Use the timeout value provided by the I2C_TIMEOUT ioctl when waiting
+for completion. The default timeout is 1 second.
+
+See: https://github.com/raspberrypi/linux/issues/260
+
+i2c-bcm2708/BCM270X_DT: Add support for I2C2
+
+The third I2C bus (I2C2) is normally reserved for HDMI use. Careless
+use of this bus can break an attached display - use with caution.
+
+It is recommended to disable accesses by VideoCore by setting
+hdmi_ignore_edid=1 or hdmi_edid_file=1 in config.txt.
+
+The interface is disabled by default - enable using the
+i2c2_iknowwhatimdoing DT parameter.
+
+bcm2708-spi: Don't use static pin configuration with DT
+
+Also remove superfluous error checking - the SPI framework ensures the
+validity of the chip_select value.
+
+i2c-bcm2708: Remove non-DT support
+
+Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
+
+Set the BSC_CLKT clock streching timeout to 35ms as per SMBus specs.
+
+Fixes i2c_bcm2708: Write to FIFO correctly - v2 (#1574)
+
+* i2c: fix i2c_bcm2708: Clear FIFO before sending data
+
+Make sure FIFO gets cleared before trying to send
+data in case of a repeated start (COMBINED=Y).
+
+* i2c: fix i2c_bcm2708: Only write to FIFO when not full
+
+Check if FIFO can accept data before writing.
+To avoid a peripheral read on the last iteration of a loop,
+both bcm2708_bsc_fifo_fill and ~drain are changed as well.
+---
+ drivers/i2c/busses/Kconfig | 19 ++
+ drivers/i2c/busses/Makefile | 2 +
+ drivers/i2c/busses/i2c-bcm2708.c | 512 +++++++++++++++++++++++++++++++
+ 3 files changed, 533 insertions(+)
+ create mode 100644 drivers/i2c/busses/i2c-bcm2708.c
+
+--- a/drivers/i2c/busses/Kconfig
++++ b/drivers/i2c/busses/Kconfig
+@@ -8,6 +8,25 @@ menu "I2C Hardware Bus support"
+ comment "PC SMBus host controller drivers"
+ depends on PCI
+
++config I2C_BCM2708
++ tristate "BCM2708 BSC"
++ depends on ARCH_BCM2835
++ help
++ Enabling this option will add BSC (Broadcom Serial Controller)
++ support for the BCM2708. BSC is a Broadcom proprietary bus compatible
++ with I2C/TWI/SMBus.
++
++config I2C_BCM2708_BAUDRATE
++ prompt "BCM2708 I2C baudrate"
++ depends on I2C_BCM2708
++ int
++ default 100000
++ help
++ Set the I2C baudrate. This will alter the default value. A
++ different baudrate can be set by using a module parameter as well. If
++ no parameter is provided when loading, this is the value that will be
++ used.
++
+ config I2C_ALI1535
+ tristate "ALI 1535"
+ depends on PCI
+--- a/drivers/i2c/busses/Makefile
++++ b/drivers/i2c/busses/Makefile
+@@ -3,6 +3,8 @@
+ # Makefile for the i2c bus drivers.
+ #
+
++obj-$(CONFIG_I2C_BCM2708) += i2c-bcm2708.o
++
+ # ACPI drivers
+ obj-$(CONFIG_I2C_SCMI) += i2c-scmi.o
+
+--- /dev/null
++++ b/drivers/i2c/busses/i2c-bcm2708.c
+@@ -0,0 +1,512 @@
++/*
++ * Driver for Broadcom BCM2708 BSC Controllers
++ *
++ * Copyright (C) 2012 Chris Boot & Frank Buss
++ *
++ * This driver is inspired by:
++ * i2c-ocores.c, by Peter Korsgaard <jacmet@sunsite.dk>
++ *
++ * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
++ */
++
++#include <linux/kernel.h>
++#include <linux/module.h>
++#include <linux/spinlock.h>
++#include <linux/clk.h>
++#include <linux/err.h>
++#include <linux/of.h>
++#include <linux/platform_device.h>
++#include <linux/io.h>
++#include <linux/slab.h>
++#include <linux/i2c.h>
++#include <linux/interrupt.h>
++#include <linux/sched.h>
++#include <linux/wait.h>
++
++/* BSC register offsets */
++#define BSC_C 0x00
++#define BSC_S 0x04
++#define BSC_DLEN 0x08
++#define BSC_A 0x0c
++#define BSC_FIFO 0x10
++#define BSC_DIV 0x14
++#define BSC_DEL 0x18
++#define BSC_CLKT 0x1c
++
++/* Bitfields in BSC_C */
++#define BSC_C_I2CEN 0x00008000
++#define BSC_C_INTR 0x00000400
++#define BSC_C_INTT 0x00000200
++#define BSC_C_INTD 0x00000100
++#define BSC_C_ST 0x00000080
++#define BSC_C_CLEAR_1 0x00000020
++#define BSC_C_CLEAR_2 0x00000010
++#define BSC_C_READ 0x00000001
++
++/* Bitfields in BSC_S */
++#define BSC_S_CLKT 0x00000200
++#define BSC_S_ERR 0x00000100
++#define BSC_S_RXF 0x00000080
++#define BSC_S_TXE 0x00000040
++#define BSC_S_RXD 0x00000020
++#define BSC_S_TXD 0x00000010
++#define BSC_S_RXR 0x00000008
++#define BSC_S_TXW 0x00000004
++#define BSC_S_DONE 0x00000002
++#define BSC_S_TA 0x00000001
++
++#define I2C_WAIT_LOOP_COUNT 200
++
++#define DRV_NAME "bcm2708_i2c"
++
++static unsigned int baudrate;
++module_param(baudrate, uint, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
++MODULE_PARM_DESC(baudrate, "The I2C baudrate");
++
++static bool combined = false;
++module_param(combined, bool, 0644);
++MODULE_PARM_DESC(combined, "Use combined transactions");
++
++struct bcm2708_i2c {
++ struct i2c_adapter adapter;
++
++ spinlock_t lock;
++ void __iomem *base;
++ int irq;
++ struct clk *clk;
++ u32 cdiv;
++ u32 clk_tout;
++
++ struct completion done;
++
++ struct i2c_msg *msg;
++ int pos;
++ int nmsgs;
++ bool error;
++};
++
++static inline u32 bcm2708_rd(struct bcm2708_i2c *bi, unsigned reg)
++{
++ return readl(bi->base + reg);
++}
++
++static inline void bcm2708_wr(struct bcm2708_i2c *bi, unsigned reg, u32 val)
++{
++ writel(val, bi->base + reg);
++}
++
++static inline void bcm2708_bsc_reset(struct bcm2708_i2c *bi)
++{
++ bcm2708_wr(bi, BSC_C, 0);
++ bcm2708_wr(bi, BSC_S, BSC_S_CLKT | BSC_S_ERR | BSC_S_DONE);
++}
++
++static inline void bcm2708_bsc_fifo_drain(struct bcm2708_i2c *bi)
++{
++ while ((bi->pos < bi->msg->len) && (bcm2708_rd(bi, BSC_S) & BSC_S_RXD))
++ bi->msg->buf[bi->pos++] = bcm2708_rd(bi, BSC_FIFO);
++}
++
++static inline void bcm2708_bsc_fifo_fill(struct bcm2708_i2c *bi)
++{
++ while ((bi->pos < bi->msg->len) && (bcm2708_rd(bi, BSC_S) & BSC_S_TXD))
++ bcm2708_wr(bi, BSC_FIFO, bi->msg->buf[bi->pos++]);
++}
++
++static inline int bcm2708_bsc_setup(struct bcm2708_i2c *bi)
++{
++ u32 cdiv, s, clk_tout;
++ u32 c = BSC_C_I2CEN | BSC_C_INTD | BSC_C_ST | BSC_C_CLEAR_1;
++ int wait_loops = I2C_WAIT_LOOP_COUNT;
++
++ /* Can't call clk_get_rate as it locks a mutex and here we are spinlocked.
++ * Use the value that we cached in the probe.
++ */
++ cdiv = bi->cdiv;
++ clk_tout = bi->clk_tout;
++
++ if (bi->msg->flags & I2C_M_RD)
++ c |= BSC_C_INTR | BSC_C_READ;
++ else
++ c |= BSC_C_INTT;
++
++ bcm2708_wr(bi, BSC_CLKT, clk_tout);
++ bcm2708_wr(bi, BSC_DIV, cdiv);
++ bcm2708_wr(bi, BSC_A, bi->msg->addr);
++ bcm2708_wr(bi, BSC_DLEN, bi->msg->len);
++ if (combined)
++ {
++ /* Do the next two messages meet combined transaction criteria?
++ - Current message is a write, next message is a read
++ - Both messages to same slave address
++ - Write message can fit inside FIFO (16 bytes or less) */
++ if ( (bi->nmsgs > 1) &&
++ !(bi->msg[0].flags & I2C_M_RD) && (bi->msg[1].flags & I2C_M_RD) &&
++ (bi->msg[0].addr == bi->msg[1].addr) && (bi->msg[0].len <= 16)) {
++
++ /* Clear FIFO */
++ bcm2708_wr(bi, BSC_C, BSC_C_CLEAR_1);
++
++ /* Fill FIFO with entire write message (16 byte FIFO) */
++ while (bi->pos < bi->msg->len) {
++ bcm2708_wr(bi, BSC_FIFO, bi->msg->buf[bi->pos++]);
++ }
++ /* Start write transfer (no interrupts, don't clear FIFO) */
++ bcm2708_wr(bi, BSC_C, BSC_C_I2CEN | BSC_C_ST);
++
++ /* poll for transfer start bit (should only take 1-20 polls) */
++ do {
++ s = bcm2708_rd(bi, BSC_S);
++ } while (!(s & (BSC_S_TA | BSC_S_ERR | BSC_S_CLKT | BSC_S_DONE)) && --wait_loops >= 0);
++
++ /* did we time out or some error occured? */
++ if (wait_loops < 0 || (s & (BSC_S_ERR | BSC_S_CLKT))) {
++ return -1;
++ }
++
++ /* Send next read message before the write transfer finishes. */
++ bi->nmsgs--;
++ bi->msg++;
++ bi->pos = 0;
++ bcm2708_wr(bi, BSC_DLEN, bi->msg->len);
++ c = BSC_C_I2CEN | BSC_C_INTD | BSC_C_INTR | BSC_C_ST | BSC_C_READ;
++ }
++ }
++ bcm2708_wr(bi, BSC_C, c);
++
++ return 0;
++}
++
++static irqreturn_t bcm2708_i2c_interrupt(int irq, void *dev_id)
++{
++ struct bcm2708_i2c *bi = dev_id;
++ bool handled = true;
++ u32 s;
++ int ret;
++
++ spin_lock(&bi->lock);
++
++ /* we may see camera interrupts on the "other" I2C channel
++ Just return if we've not sent anything */
++ if (!bi->nmsgs || !bi->msg) {
++ goto early_exit;
++ }
++
++ s = bcm2708_rd(bi, BSC_S);
++
++ if (s & (BSC_S_CLKT | BSC_S_ERR)) {
++ bcm2708_bsc_reset(bi);
++ bi->error = true;
++
++ bi->msg = 0; /* to inform the that all work is done */
++ bi->nmsgs = 0;
++ /* wake up our bh */
++ complete(&bi->done);
++ } else if (s & BSC_S_DONE) {
++ bi->nmsgs--;
++
++ if (bi->msg->flags & I2C_M_RD) {
++ bcm2708_bsc_fifo_drain(bi);
++ }
++
++ bcm2708_bsc_reset(bi);
++
++ if (bi->nmsgs) {
++ /* advance to next message */
++ bi->msg++;
++ bi->pos = 0;
++ ret = bcm2708_bsc_setup(bi);
++ if (ret < 0) {
++ bcm2708_bsc_reset(bi);
++ bi->error = true;
++ bi->msg = 0; /* to inform the that all work is done */
++ bi->nmsgs = 0;
++ /* wake up our bh */
++ complete(&bi->done);
++ goto early_exit;
++ }
++ } else {
++ bi->msg = 0; /* to inform the that all work is done */
++ bi->nmsgs = 0;
++ /* wake up our bh */
++ complete(&bi->done);
++ }
++ } else if (s & BSC_S_TXW) {
++ bcm2708_bsc_fifo_fill(bi);
++ } else if (s & BSC_S_RXR) {
++ bcm2708_bsc_fifo_drain(bi);
++ } else {
++ handled = false;
++ }
++
++early_exit:
++ spin_unlock(&bi->lock);
++
++ return handled ? IRQ_HANDLED : IRQ_NONE;
++}
++
++static int bcm2708_i2c_master_xfer(struct i2c_adapter *adap,
++ struct i2c_msg *msgs, int num)
++{
++ struct bcm2708_i2c *bi = adap->algo_data;
++ unsigned long flags;
++ int ret;
++
++ spin_lock_irqsave(&bi->lock, flags);
++
++ reinit_completion(&bi->done);
++ bi->msg = msgs;
++ bi->pos = 0;
++ bi->nmsgs = num;
++ bi->error = false;
++
++ ret = bcm2708_bsc_setup(bi);
++
++ spin_unlock_irqrestore(&bi->lock, flags);
++
++ /* check the result of the setup */
++ if (ret < 0)
++ {
++ dev_err(&adap->dev, "transfer setup timed out\n");
++ goto error_timeout;
++ }
++
++ ret = wait_for_completion_timeout(&bi->done, adap->timeout);
++ if (ret == 0) {
++ dev_err(&adap->dev, "transfer timed out\n");
++ goto error_timeout;
++ }
++
++ ret = bi->error ? -EIO : num;
++ return ret;
++
++error_timeout:
++ spin_lock_irqsave(&bi->lock, flags);
++ bcm2708_bsc_reset(bi);
++ bi->msg = 0; /* to inform the interrupt handler that there's nothing else to be done */
++ bi->nmsgs = 0;
++ spin_unlock_irqrestore(&bi->lock, flags);
++ return -ETIMEDOUT;
++}
++
++static u32 bcm2708_i2c_functionality(struct i2c_adapter *adap)
++{
++ return I2C_FUNC_I2C | /*I2C_FUNC_10BIT_ADDR |*/ I2C_FUNC_SMBUS_EMUL;
++}
++
++static struct i2c_algorithm bcm2708_i2c_algorithm = {
++ .master_xfer = bcm2708_i2c_master_xfer,
++ .functionality = bcm2708_i2c_functionality,
++};
++
++static int bcm2708_i2c_probe(struct platform_device *pdev)
++{
++ struct resource *regs;
++ int irq, err = -ENOMEM;
++ struct clk *clk;
++ struct bcm2708_i2c *bi;
++ struct i2c_adapter *adap;
++ unsigned long bus_hz;
++ u32 cdiv, clk_tout;
++ u32 baud;
++
++ baud = CONFIG_I2C_BCM2708_BAUDRATE;
++
++ if (pdev->dev.of_node) {
++ u32 bus_clk_rate;
++ pdev->id = of_alias_get_id(pdev->dev.of_node, "i2c");
++ if (pdev->id < 0) {
++ dev_err(&pdev->dev, "alias is missing\n");
++ return -EINVAL;
++ }
++ if (!of_property_read_u32(pdev->dev.of_node,
++ "clock-frequency", &bus_clk_rate))
++ baud = bus_clk_rate;
++ else
++ dev_warn(&pdev->dev,
++ "Could not read clock-frequency property\n");
++ }
++
++ if (baudrate)
++ baud = baudrate;
++
++ regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
++ if (!regs) {
++ dev_err(&pdev->dev, "could not get IO memory\n");
++ return -ENXIO;
++ }
++
++ irq = platform_get_irq(pdev, 0);
++ if (irq < 0) {
++ dev_err(&pdev->dev, "could not get IRQ\n");
++ return irq;
++ }
++
++ clk = clk_get(&pdev->dev, NULL);
++ if (IS_ERR(clk)) {
++ dev_err(&pdev->dev, "could not find clk: %ld\n", PTR_ERR(clk));
++ return PTR_ERR(clk);
++ }
++
++ err = clk_prepare_enable(clk);
++ if (err) {
++ dev_err(&pdev->dev, "could not enable clk: %d\n", err);
++ goto out_clk_put;
++ }
++
++ bi = kzalloc(sizeof(*bi), GFP_KERNEL);
++ if (!bi)
++ goto out_clk_disable;
++
++ platform_set_drvdata(pdev, bi);
++
++ adap = &bi->adapter;
++ adap->class = I2C_CLASS_HWMON | I2C_CLASS_DDC;
++ adap->algo = &bcm2708_i2c_algorithm;
++ adap->algo_data = bi;
++ adap->dev.parent = &pdev->dev;
++ adap->nr = pdev->id;
++ strlcpy(adap->name, dev_name(&pdev->dev), sizeof(adap->name));
++ adap->dev.of_node = pdev->dev.of_node;
++
++ switch (pdev->id) {
++ case 0:
++ adap->class = I2C_CLASS_HWMON;
++ break;
++ case 1:
++ adap->class = I2C_CLASS_DDC;
++ break;
++ case 2:
++ adap->class = I2C_CLASS_DDC;
++ break;
++ default:
++ dev_err(&pdev->dev, "can only bind to BSC 0, 1 or 2\n");
++ err = -ENXIO;
++ goto out_free_bi;
++ }
++
++ spin_lock_init(&bi->lock);
++ init_completion(&bi->done);
++
++ bi->base = ioremap(regs->start, resource_size(regs));
++ if (!bi->base) {
++ dev_err(&pdev->dev, "could not remap memory\n");
++ goto out_free_bi;
++ }
++
++ bi->irq = irq;
++ bi->clk = clk;
++
++ err = request_irq(irq, bcm2708_i2c_interrupt, IRQF_SHARED,
++ dev_name(&pdev->dev), bi);
++ if (err) {
++ dev_err(&pdev->dev, "could not request IRQ: %d\n", err);
++ goto out_iounmap;
++ }
++
++ bcm2708_bsc_reset(bi);
++
++ err = i2c_add_numbered_adapter(adap);
++ if (err < 0) {
++ dev_err(&pdev->dev, "could not add I2C adapter: %d\n", err);
++ goto out_free_irq;
++ }
++
++ bus_hz = clk_get_rate(bi->clk);
++ cdiv = bus_hz / baud;
++ if (cdiv > 0xffff) {
++ cdiv = 0xffff;
++ baud = bus_hz / cdiv;
++ }
++
++ clk_tout = 35/1000*baud; //35ms timeout as per SMBus specs.
++ if (clk_tout > 0xffff)
++ clk_tout = 0xffff;
++
++ bi->cdiv = cdiv;
++ bi->clk_tout = clk_tout;
++
++ dev_info(&pdev->dev, "BSC%d Controller at 0x%08lx (irq %d) (baudrate %d)\n",
++ pdev->id, (unsigned long)regs->start, irq, baud);
++
++ return 0;
++
++out_free_irq:
++ free_irq(bi->irq, bi);
++out_iounmap:
++ iounmap(bi->base);
++out_free_bi:
++ kfree(bi);
++out_clk_disable:
++ clk_disable_unprepare(clk);
++out_clk_put:
++ clk_put(clk);
++ return err;
++}
++
++static int bcm2708_i2c_remove(struct platform_device *pdev)
++{
++ struct bcm2708_i2c *bi = platform_get_drvdata(pdev);
++
++ platform_set_drvdata(pdev, NULL);
++
++ i2c_del_adapter(&bi->adapter);
++ free_irq(bi->irq, bi);
++ iounmap(bi->base);
++ clk_disable_unprepare(bi->clk);
++ clk_put(bi->clk);
++ kfree(bi);
++
++ return 0;
++}
++
++static const struct of_device_id bcm2708_i2c_of_match[] = {
++ { .compatible = "brcm,bcm2708-i2c" },
++ {},
++};
++MODULE_DEVICE_TABLE(of, bcm2708_i2c_of_match);
++
++static struct platform_driver bcm2708_i2c_driver = {
++ .driver = {
++ .name = DRV_NAME,
++ .owner = THIS_MODULE,
++ .of_match_table = bcm2708_i2c_of_match,
++ },
++ .probe = bcm2708_i2c_probe,
++ .remove = bcm2708_i2c_remove,
++};
++
++// module_platform_driver(bcm2708_i2c_driver);
++
++
++static int __init bcm2708_i2c_init(void)
++{
++ return platform_driver_register(&bcm2708_i2c_driver);
++}
++
++static void __exit bcm2708_i2c_exit(void)
++{
++ platform_driver_unregister(&bcm2708_i2c_driver);
++}
++
++module_init(bcm2708_i2c_init);
++module_exit(bcm2708_i2c_exit);
++
++
++
++MODULE_DESCRIPTION("BSC controller driver for Broadcom BCM2708");
++MODULE_AUTHOR("Chris Boot <bootc@bootc.net>");
++MODULE_LICENSE("GPL v2");
++MODULE_ALIAS("platform:" DRV_NAME);
projects / openwrt / staging / chunkeey.git / blobdiff