[PATCH v5] i2c: add driver for Rockchip RK3xxx SoC I2C adapter

From: Max Schwarz
Date: Sat Jun 07 2014 - 13:36:45 EST

Driver for the native I2C adapter found in Rockchip RK3xxx SoCs.

Configuration is only possible through devicetree. The driver is
interrupt driven and supports the I2C_M_IGNORE_NAK mangling bit.

Signed-off-by: Max Schwarz <max.schwarz@xxxxxxxxx>
---

The driver cannot be used without a proper clock driver
supporting rate calculation, such as Heiko Stübner's RK3xxx clock
driver series [1].

Changes since v4:
- fixed a bug in message counting in rk3x_i2c_xfer()
- Found/suggested by Wolfram Sang:
* fixed style issues
* fixed sorting in Kconfig, Makefile
* removed unneeded fields from struct rk3x_i2c
* REPEATED_START between msgs of one transfer
* fixed wrong error code on NAK
* support for SMB_QUICK (len == 0)
* removed unneeded DT check & alias handling
* sanity check for clock-frequency

Changes since v3:
- fixed style issues found by Maxime Ripard
- use dt alias id to calculate the bit offset in GRF,
as suggested by Maxime Ripard
- also use dt alias id for i2c_add_numbered_adapter()

Changes since v2:
- support for the new GRF syscon mapping by Heiko Stübner
- probe error handling improvements by Heiko Stübner
- fixed wrong remove() order found by Heiko Stübner
- removed unnecessary clk_enable() during probe
- removed switch back to old interface during remove

Changes since v1:
- dt property names "rockchip,*" suggested by Heiko Stübner
- fixed overly specific RK3188 comment (Heiko Stübner)

The dts files needed for testing on Radxa Rock are in my tree at

https://github.com/xqms/linux.git topic/i2c-rk3x-clean-v4

[1]: http://www.spinics.net/lists/arm-kernel/msg329102.html

Documentation/devicetree/bindings/i2c/i2c-rk3x.txt | 42 ++
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-rk3x.c | 769 +++++++++++++++++++++
4 files changed, 822 insertions(+)
create mode 100644 Documentation/devicetree/bindings/i2c/i2c-rk3x.txt
create mode 100644 drivers/i2c/busses/i2c-rk3x.c

diff --git a/Documentation/devicetree/bindings/i2c/i2c-rk3x.txt b/Documentation/devicetree/bindings/i2c/i2c-rk3x.txt
new file mode 100644
index 0000000..dde6c22
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-rk3x.txt
@@ -0,0 +1,42 @@
+* Rockchip RK3xxx I2C controller
+
+This driver interfaces with the native I2C controller present in Rockchip
+RK3xxx SoCs.
+
+Required properties :
+
+ - reg : Offset and length of the register set for the device
+ - compatible : should be "rockchip,rk3066-i2c", "rockchip,rk3188-i2c" or
+ "rockchip,rk3288-i2c".
+ - interrupts : interrupt number
+ - clocks : parent clock
+
+Required on RK3066, RK3188 :
+
+ - rockchip,grf : the phandle of the syscon node for the general register
+ file (GRF)
+ - on those SoCs an alias with the correct I2C bus ID (bit offset in the GRF)
+ is also required.
+
+Optional properties :
+
+ - clock-frequency : SCL frequency to use (in Hz). If omitted, 100kHz is used.
+
+Example:
+
+aliases {
+ i2c0 = &i2c0;
+}
+
+i2c0: i2c@2002d000 {
+ compatible = "rockchip,rk3188-i2c";
+ reg = <0x2002d000 0x1000>;
+ interrupts = <GIC_SPI 40 IRQ_TYPE_LEVEL_HIGH>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ rockchip,grf = <&grf>;
+
+ clock-names = "i2c";
+ clocks = <&cru PCLK_I2C0>;
+};
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 7ccc51e..39307d0 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -676,6 +676,16 @@ config I2C_RIIC
This driver can also be built as a module. If so, the module
will be called i2c-riic.

+config I2C_RK3X
+ tristate "Rockchip RK3xxx I2C adapter"
+ depends on OF
+ help
+ Say Y here to include support for the I2C adapter in Rockchip RK3xxx
+ SoCs.
+
+ This driver can also be built as a module. If so, the module will
+ be called i2c-rk3x.
+
config HAVE_S3C2410_I2C
bool
help
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 413d062..5582cf9 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -66,6 +66,7 @@ obj-$(CONFIG_I2C_PXA) += i2c-pxa.o
obj-$(CONFIG_I2C_PXA_PCI) += i2c-pxa-pci.o
obj-$(CONFIG_I2C_QUP) += i2c-qup.o
obj-$(CONFIG_I2C_RIIC) += i2c-riic.o
+obj-$(CONFIG_I2C_RK3X) += i2c-rk3x.o
obj-$(CONFIG_I2C_S3C2410) += i2c-s3c2410.o
obj-$(CONFIG_I2C_S6000) += i2c-s6000.o
obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o
diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
new file mode 100644
index 0000000..7a430f4
--- /dev/null
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -0,0 +1,769 @@
+/*
+ * Driver for I2C adapter in Rockchip RK3xxx SoC
+ *
+ * Max Schwarz <max.schwarz@xxxxxxxxx>
+ * based on the patches by Rockchip Inc.
+ *
+ * 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
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include <linux/i2c.h>
+#include <linux/time.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/spinlock.h>
+#include <linux/clk.h>
+#include <linux/wait.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+
+
+/* Register Map */
+#define REG_CON 0x00 /* control register */
+#define REG_CLKDIV 0x04 /* clock divisor register */
+#define REG_MRXADDR 0x08 /* slave address for REGISTER_TX */
+#define REG_MRXRADDR 0x0c /* slave register address for REGISTER_TX */
+#define REG_MTXCNT 0x10 /* number of bytes to be transmitted */
+#define REG_MRXCNT 0x14 /* number of bytes to be received */
+#define REG_IEN 0x18 /* interrupt enable */
+#define REG_IPD 0x1c /* interrupt pending */
+#define REG_FCNT 0x20 /* finished count */
+
+/* Data buffer offsets */
+#define TXBUFFER_BASE 0x100
+#define RXBUFFER_BASE 0x200
+
+/* REG_CON bits */
+#define REG_CON_EN BIT(0)
+enum {
+ REG_CON_MOD_TX = 0, /* transmit data */
+ REG_CON_MOD_REGISTER_TX, /* select register and restart */
+ REG_CON_MOD_RX, /* receive data */
+ REG_CON_MOD_REGISTER_RX, /* broken: transmits read addr AND writes
+ * register addr */
+};
+#define REG_CON_MOD(mod) ((mod) << 1)
+#define REG_CON_MOD_MASK (BIT(1) | BIT(2))
+#define REG_CON_START BIT(3)
+#define REG_CON_STOP BIT(4)
+#define REG_CON_LASTACK BIT(5) /* 1: do not send ACK after last receive */
+#define REG_CON_ACTACK BIT(6) /* 1: stop if NACK is received */
+
+/* REG_MRXADDR bits */
+#define REG_MRXADDR_VALID(x) BIT(24 + (x)) /* [x*8+7:x*8] of MRX[R]ADDR valid */
+
+/* REG_IEN/REG_IPD bits */
+#define REG_INT_BTF BIT(0) /* a byte was transmitted */
+#define REG_INT_BRF BIT(1) /* a byte was received */
+#define REG_INT_MBTF BIT(2) /* master data transmit finished */
+#define REG_INT_MBRF BIT(3) /* master data receive finished */
+#define REG_INT_START BIT(4) /* START condition generated */
+#define REG_INT_STOP BIT(5) /* STOP condition generated */
+#define REG_INT_NAKRCV BIT(6) /* NACK received */
+#define REG_INT_ALL 0x7f
+
+/* Constants */
+#define WAIT_TIMEOUT 200 /* ms */
+#define DEFAULT_SCL_RATE (100 * 1000) /* Hz */
+
+enum rk3x_i2c_state {
+ STATE_IDLE,
+ STATE_START,
+ STATE_READ,
+ STATE_WRITE,
+ STATE_STOP
+};
+
+/**
+ * @grf_offset: offset inside the grf regmap for setting the i2c type
+ */
+struct rk3x_i2c_soc_data {
+ int grf_offset;
+};
+
+struct rk3x_i2c {
+ struct i2c_adapter adap;
+ struct device *dev;
+ struct rk3x_i2c_soc_data *soc_data;
+
+ /* Hardware resources */
+ void __iomem *regs;
+ struct clk *clk;
+
+ /* Settings */
+ unsigned int scl_frequency;
+
+ /* Synchronization & notification */
+ spinlock_t lock;
+ wait_queue_head_t wait;
+ bool busy;
+
+ /* Current message */
+ struct i2c_msg *msg;
+ u8 addr;
+ unsigned int mode;
+ bool is_last_msg;
+
+ /* I2C state machine */
+ enum rk3x_i2c_state state;
+ unsigned int processed; /* sent/received bytes */
+ int error;
+};
+
+static inline void i2c_writel(struct rk3x_i2c *i2c, u32 value,
+ unsigned int offset)
+{
+ writel(value, i2c->regs + offset);
+}
+
+static inline u32 i2c_readl(struct rk3x_i2c *i2c, unsigned int offset)
+{
+ return readl(i2c->regs + offset);
+}
+
+/* Reset all interrupt pending bits */
+static inline void rk3x_i2c_clean_ipd(struct rk3x_i2c *i2c)
+{
+ i2c_writel(i2c, REG_INT_ALL, REG_IPD);
+}
+
+/**
+ * Generate a START condition, which triggers a REG_INT_START interrupt.
+ */
+static void rk3x_i2c_start(struct rk3x_i2c *i2c)
+{
+ u32 val;
+
+ dev_dbg(i2c->dev, "start\n");
+
+ rk3x_i2c_clean_ipd(i2c);
+ i2c_writel(i2c, REG_INT_START, REG_IEN);
+
+ /* enable adapter with correct mode, send START condition */
+ val = REG_CON_EN | REG_CON_MOD(i2c->mode) | REG_CON_START;
+
+ /* if we want to react to NACK, set ACTACK bit */
+ if (!(i2c->msg->flags & I2C_M_IGNORE_NAK))
+ val |= REG_CON_ACTACK;
+
+ i2c_writel(i2c, val, REG_CON);
+}
+
+/**
+ * Generate a STOP condition, which triggers a REG_INT_STOP interrupt.
+ *
+ * @error: Error code to return in rk3x_i2c_xfer
+ */
+static void rk3x_i2c_stop(struct rk3x_i2c *i2c, int error)
+{
+ unsigned int ctrl;
+
+ i2c->processed = 0;
+ i2c->msg = 0;
+ i2c->error = error;
+
+ if (i2c->is_last_msg) {
+ /* Enable stop interrupt */
+ i2c_writel(i2c, REG_INT_STOP, REG_IEN);
+
+ i2c->state = STATE_STOP;
+
+ ctrl = i2c_readl(i2c, REG_CON);
+ ctrl |= REG_CON_STOP;
+ i2c_writel(i2c, ctrl, REG_CON);
+ } else {
+ /* Signal rk3x_i2c_xfer to start the next message. */
+ i2c->busy = 0;
+ i2c->state = STATE_IDLE;
+
+ /*
+ * The HW is actually not capable of REPEATED START. But we can
+ * get the intended effect by resetting its internal state
+ * and issuing an ordinary START.
+ */
+ i2c_writel(i2c, 0, REG_CON);
+
+ /* signal that we are finished with the current msg */
+ wake_up(&i2c->wait);
+ }
+}
+
+/**
+ * Setup a read according to i2c->msg
+ */
+static void rk3x_i2c_prepare_read(struct rk3x_i2c *i2c)
+{
+ unsigned int len = i2c->msg->len - i2c->processed;
+ u32 con;
+
+ con = i2c_readl(i2c, REG_CON);
+
+ /*
+ * The hw can read up to 32 bytes at a time. If we need more than one
+ * chunk, send an ACK after the last byte of the current chunk.
+ */
+ if (unlikely(len > 32)) {
+ len = 32;
+ con &= ~REG_CON_LASTACK;
+ } else {
+ con |= REG_CON_LASTACK;
+ }
+
+ /* make sure we are in plain RX mode if we read a second chunk */
+ if (i2c->processed != 0) {
+ con &= ~REG_CON_MOD_MASK;
+ con |= REG_CON_MOD(REG_CON_MOD_RX);
+ }
+
+ i2c_writel(i2c, con, REG_CON);
+ i2c_writel(i2c, len, REG_MRXCNT);
+}
+
+/**
+ * Fill the transmit buffer with data from i2c->msg
+ */
+static void rk3x_i2c_fill_transmit_buf(struct rk3x_i2c *i2c)
+{
+ unsigned int i, j;
+ u32 cnt = 0;
+ u32 val;
+ u8 byte;
+
+ for (i = 0; i < 8; ++i) {
+ val = 0;
+ for (j = 0; j < 4; ++j) {
+ if (i2c->processed == i2c->msg->len)
+ break;
+
+ if (i2c->processed == 0 && cnt == 0)
+ byte = (i2c->addr & 0x7f) << 1;
+ else
+ byte = i2c->msg->buf[i2c->processed++];
+
+ val |= byte << (j * 8);
+ cnt++;
+ }
+
+ i2c_writel(i2c, val, TXBUFFER_BASE + 4 * i);
+
+ if (i2c->processed == i2c->msg->len)
+ break;
+ }
+
+ i2c_writel(i2c, cnt, REG_MTXCNT);
+}
+
+
+/* IRQ handlers for individual states */
+
+static void rk3x_i2c_handle_start(struct rk3x_i2c *i2c, unsigned int ipd)
+{
+ if (!(ipd & REG_INT_START)) {
+ rk3x_i2c_stop(i2c, -EIO);
+ dev_warn(i2c->dev, "unexpected irq in START: 0x%x\n", ipd);
+ rk3x_i2c_clean_ipd(i2c);
+ return;
+ }
+
+ /* ack interrupt */
+ i2c_writel(i2c, REG_INT_START, REG_IPD);
+
+ /* disable start bit */
+ i2c_writel(i2c, i2c_readl(i2c, REG_CON) & ~REG_CON_START, REG_CON);
+
+ /* enable appropriate interrupts and transition */
+ if (i2c->mode == REG_CON_MOD_TX) {
+ i2c_writel(i2c, REG_INT_MBTF | REG_INT_NAKRCV, REG_IEN);
+ i2c->state = STATE_WRITE;
+ rk3x_i2c_fill_transmit_buf(i2c);
+ } else {
+ /* in any other case, we are going to be reading. */
+ i2c_writel(i2c, REG_INT_MBRF | REG_INT_NAKRCV, REG_IEN);
+ i2c->state = STATE_READ;
+ rk3x_i2c_prepare_read(i2c);
+ }
+}
+
+static void rk3x_i2c_handle_write(struct rk3x_i2c *i2c, unsigned int ipd)
+{
+ if (!(ipd & REG_INT_MBTF)) {
+ rk3x_i2c_stop(i2c, -EIO);
+ dev_err(i2c->dev, "unexpected irq in WRITE: 0x%x\n", ipd);
+ rk3x_i2c_clean_ipd(i2c);
+ return;
+ }
+
+ /* ack interrupt */
+ i2c_writel(i2c, REG_INT_MBTF, REG_IPD);
+
+ /* are we finished? */
+ if (i2c->processed == i2c->msg->len)
+ rk3x_i2c_stop(i2c, i2c->error);
+ else
+ rk3x_i2c_fill_transmit_buf(i2c);
+}
+
+static void rk3x_i2c_handle_read(struct rk3x_i2c *i2c, unsigned int ipd)
+{
+ unsigned int i;
+ unsigned int len = i2c->msg->len - i2c->processed;
+ unsigned int val;
+ u8 byte;
+
+ /* we only care for MBRF here. */
+ if (!(ipd & REG_INT_MBRF))
+ return;
+
+ /* ack interrupt */
+ i2c_writel(i2c, REG_INT_MBRF, REG_IPD);
+
+ /* read the data from receive buffer */
+ for (i = 0; i < len; ++i) {
+ if (i % 4 == 0)
+ val = i2c_readl(i2c, RXBUFFER_BASE + (i / 4) * 4);
+
+ byte = (val >> ((i % 4) * 8)) & 0xff;
+ i2c->msg->buf[i2c->processed++] = byte;
+ }
+
+ /* are we finished? */
+ if (i2c->processed == i2c->msg->len)
+ rk3x_i2c_stop(i2c, i2c->error);
+ else
+ rk3x_i2c_prepare_read(i2c);
+}
+
+static void rk3x_i2c_handle_stop(struct rk3x_i2c *i2c, unsigned int ipd)
+{
+ unsigned int con;
+
+ if (!(ipd & REG_INT_STOP)) {
+ rk3x_i2c_stop(i2c, -EIO);
+ dev_err(i2c->dev, "unexpected irq in STOP: 0x%x\n", ipd);
+ rk3x_i2c_clean_ipd(i2c);
+ return;
+ }
+
+ /* ack interrupt */
+ i2c_writel(i2c, REG_INT_STOP, REG_IPD);
+
+ /* disable STOP bit */
+ con = i2c_readl(i2c, REG_CON);
+ con &= ~REG_CON_STOP;
+ i2c_writel(i2c, con, REG_CON);
+
+ i2c->busy = 0;
+ i2c->state = STATE_IDLE;
+
+ /* signal rk3x_i2c_xfer that we are finished */
+ wake_up(&i2c->wait);
+}
+
+static irqreturn_t rk3x_i2c_irq(int irqno, void *dev_id)
+{
+ struct rk3x_i2c *i2c = dev_id;
+ unsigned int ipd;
+
+ spin_lock(&i2c->lock);
+
+ ipd = i2c_readl(i2c, REG_IPD);
+ if (i2c->state == STATE_IDLE) {
+ dev_warn(i2c->dev, "irq in STATE_IDLE, ipd = 0x%x\n", ipd);
+ rk3x_i2c_clean_ipd(i2c);
+ goto out;
+ }
+
+ dev_dbg(i2c->dev, "IRQ: state %d, ipd: %x\n", i2c->state, ipd);
+
+ /* Clean interrupt bits we don't care about */
+ ipd &= ~(REG_INT_BRF | REG_INT_BTF);
+
+ if (ipd & REG_INT_NAKRCV) {
+ /*
+ * We got a NACK in the last operation. Depending on whether
+ * IGNORE_NAK is set, we have to stop the operation and report
+ * an error.
+ */
+ i2c_writel(i2c, REG_INT_NAKRCV, REG_IPD);
+
+ ipd &= ~REG_INT_NAKRCV;
+
+ if (!(i2c->msg->flags & I2C_M_IGNORE_NAK))
+ rk3x_i2c_stop(i2c, -ENXIO);
+ }
+
+ /* is there anything left to handle? */
+ if (unlikely(ipd == 0))
+ goto out;
+
+ switch (i2c->state) {
+ case STATE_START:
+ rk3x_i2c_handle_start(i2c, ipd);
+ break;
+ case STATE_WRITE:
+ rk3x_i2c_handle_write(i2c, ipd);
+ break;
+ case STATE_READ:
+ rk3x_i2c_handle_read(i2c, ipd);
+ break;
+ case STATE_STOP:
+ rk3x_i2c_handle_stop(i2c, ipd);
+ break;
+ case STATE_IDLE:
+ break;
+ }
+
+out:
+ spin_unlock(&i2c->lock);
+ return IRQ_HANDLED;
+}
+
+static void rk3x_i2c_set_scl_rate(struct rk3x_i2c *i2c, unsigned long scl_rate)
+{
+ unsigned long i2c_rate = clk_get_rate(i2c->clk);
+ unsigned int div;
+
+ /* SCL rate = (clk rate) / (8 * DIV) */
+ div = DIV_ROUND_UP(i2c_rate, scl_rate * 8);
+
+ /* The lower and upper half of the CLKDIV reg describe the length of
+ * SCL low & high periods. */
+ div = DIV_ROUND_UP(div, 2);
+
+ i2c_writel(i2c, (div << 16) | (div & 0xffff), REG_CLKDIV);
+}
+
+/**
+ * Setup I2C registers for an I2C operation specified by msgs, num.
+ *
+ * Must be called with i2c->lock held.
+ *
+ * @msgs: I2C msgs to process
+ * @num: Number of msgs
+ *
+ * returns: Number of I2C msgs processed or negative in case of error
+ */
+static int rk3x_i2c_setup(struct rk3x_i2c *i2c, struct i2c_msg *msgs, int num)
+{
+ u32 addr = (msgs[0].addr & 0x7f) << 1;
+ int ret = 0;
+
+ /*
+ * The I2C adapter can issue a small (len < 4) write packet before
+ * reading. This speeds up SMBus-style register reads.
+ * The MRXADDR/MRXRADDR hold the slave address and the slave register
+ * address in this case.
+ */
+
+ if (num >= 2 && msgs[0].len < 4
+ && !(msgs[0].flags & I2C_M_RD)
+ && (msgs[1].flags & I2C_M_RD)) {
+ u32 reg_addr = 0;
+ int i;
+
+ dev_dbg(i2c->dev, "Combined write/read from addr 0x%x\n",
+ addr >> 1);
+
+ /* Fill MRXRADDR with the register address(es) */
+ for (i = 0; i < msgs[0].len; ++i) {
+ reg_addr |= msgs[0].buf[i] << (i * 8);
+ reg_addr |= REG_MRXADDR_VALID(i);
+ }
+
+ /* msgs[0] is handled by hw. */
+ i2c->msg = &msgs[1];
+
+ i2c->mode = REG_CON_MOD_REGISTER_TX;
+
+ i2c_writel(i2c, addr | REG_MRXADDR_VALID(0), REG_MRXADDR);
+ i2c_writel(i2c, reg_addr, REG_MRXRADDR);
+
+ ret = 2;
+ } else {
+ /*
+ * We'll have to do it the boring way and process the msgs
+ * one-by-one.
+ */
+
+ if (msgs[0].flags & I2C_M_RD) {
+ addr |= 1; /* set read bit */
+
+ /*
+ * We have to transmit the slave addr first. Use
+ * MOD_REGISTER_TX for that purpose.
+ */
+ i2c->mode = REG_CON_MOD_REGISTER_TX;
+ i2c_writel(i2c, addr | REG_MRXADDR_VALID(0),
+ REG_MRXADDR);
+ i2c_writel(i2c, 0, REG_MRXRADDR);
+ } else {
+ i2c->mode = REG_CON_MOD_TX;
+ }
+
+ i2c->msg = &msgs[0];
+
+ ret = 1;
+ }
+
+ i2c->addr = msgs[0].addr;
+ i2c->busy = true;
+ i2c->state = STATE_START;
+ i2c->processed = 0;
+ i2c->error = 0;
+
+ rk3x_i2c_clean_ipd(i2c);
+
+ return ret;
+}
+
+static int rk3x_i2c_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs, int num)
+{
+ struct rk3x_i2c *i2c = (struct rk3x_i2c *)adap->algo_data;
+ unsigned long timeout, flags;
+ int ret = 0;
+ int i;
+
+ spin_lock_irqsave(&i2c->lock, flags);
+
+ clk_enable(i2c->clk);
+
+ /* The clock rate might have changed, so setup the divider again */
+ rk3x_i2c_set_scl_rate(i2c, i2c->scl_frequency);
+
+ i2c->is_last_msg = false;
+
+ /*
+ * Process msgs. We can handle more than one message at once (see
+ * rk3x_i2c_setup()).
+ */
+ for (i = 0; i < num; i += ret) {
+ ret = rk3x_i2c_setup(i2c, msgs + i, num - i);
+
+ if (ret < 0) {
+ dev_err(i2c->dev, "rk3x_i2c_setup() failed\n");
+ break;
+ }
+
+ if (i + ret >= num)
+ i2c->is_last_msg = true;
+
+ spin_unlock_irqrestore(&i2c->lock, flags);
+
+ rk3x_i2c_start(i2c);
+
+ timeout = wait_event_timeout(i2c->wait, !i2c->busy,
+ msecs_to_jiffies(WAIT_TIMEOUT));
+
+ spin_lock_irqsave(&i2c->lock, flags);
+
+ if (timeout == 0) {
+ dev_err(i2c->dev, "timeout, ipd: 0x%02x, state: %d\n",
+ i2c_readl(i2c, REG_IPD), i2c->state);
+
+ /* Force a STOP condition without interrupt */
+ i2c_writel(i2c, 0, REG_IEN);
+ i2c_writel(i2c, REG_CON_EN | REG_CON_STOP, REG_CON);
+
+ i2c->state = STATE_IDLE;
+
+ ret = -ETIMEDOUT;
+ break;
+ }
+
+ if (i2c->error) {
+ ret = i2c->error;
+ break;
+ }
+ }
+
+ clk_disable(i2c->clk);
+ spin_unlock_irqrestore(&i2c->lock, flags);
+
+ return ret;
+}
+
+static u32 rk3x_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
+}
+
+static const struct i2c_algorithm rk3x_i2c_algorithm = {
+ .master_xfer = rk3x_i2c_xfer,
+ .functionality = rk3x_i2c_func,
+};
+
+static struct rk3x_i2c_soc_data soc_data[3] = {
+ { .grf_offset = 0x154 }, /* rk3066 */
+ { .grf_offset = 0x0a4 }, /* rk3188 */
+ { .grf_offset = -1 }, /* no I2C switching needed */
+};
+
+static const struct of_device_id rk3x_i2c_match[] = {
+ { .compatible = "rockchip,rk3066-i2c", .data = (void *)&soc_data[0] },
+ { .compatible = "rockchip,rk3188-i2c", .data = (void *)&soc_data[1] },
+ { .compatible = "rockchip,rk3288-i2c", .data = (void *)&soc_data[2] },
+};
+
+static int rk3x_i2c_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ const struct of_device_id *match;
+ struct rk3x_i2c *i2c;
+ struct resource *mem;
+ int ret = 0;
+ int bus_nr;
+ u32 value;
+ int irq;
+
+ i2c = devm_kzalloc(&pdev->dev, sizeof(struct rk3x_i2c), GFP_KERNEL);
+ if (!i2c)
+ return -ENOMEM;
+
+ match = of_match_node(rk3x_i2c_match, np);
+ i2c->soc_data = (struct rk3x_i2c_soc_data *)match->data;
+
+ if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
+ &i2c->scl_frequency)) {
+ dev_info(&pdev->dev, "using default SCL frequency: %d\n",
+ DEFAULT_SCL_RATE);
+ i2c->scl_frequency = DEFAULT_SCL_RATE;
+ }
+
+ if (i2c->scl_frequency == 0 || i2c->scl_frequency > 400 * 1000) {
+ dev_warn(&pdev->dev, "invalid SCL frequency specified.\n");
+ dev_warn(&pdev->dev, "using default SCL frequency: %d\n",
+ DEFAULT_SCL_RATE);
+ i2c->scl_frequency = DEFAULT_SCL_RATE;
+ }
+
+ strlcpy(i2c->adap.name, "rk3x-i2c", sizeof(i2c->adap.name));
+ i2c->adap.owner = THIS_MODULE;
+ i2c->adap.algo = &rk3x_i2c_algorithm;
+ i2c->adap.retries = 3;
+ i2c->adap.dev.of_node = np;
+ i2c->adap.algo_data = i2c;
+ i2c->adap.dev.parent = &pdev->dev;
+
+ i2c->dev = &pdev->dev;
+
+ spin_lock_init(&i2c->lock);
+ init_waitqueue_head(&i2c->wait);
+
+ i2c->clk = devm_clk_get(&pdev->dev, 0);
+ if (IS_ERR(i2c->clk)) {
+ dev_err(&pdev->dev, "cannot get clock\n");
+ return PTR_ERR(i2c->clk);
+ }
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ i2c->regs = devm_ioremap_resource(&pdev->dev, mem);
+ if (IS_ERR(i2c->regs))
+ return PTR_ERR(i2c->regs);
+
+ /* Try to set the I2C adapter number from dt */
+ bus_nr = of_alias_get_id(np, "i2c");
+
+ /*
+ * Switch to new interface if the SoC also offers the old one.
+ * The control bit is located in the GRF register space.
+ */
+ if (i2c->soc_data->grf_offset >= 0) {
+ struct regmap *grf;
+
+ grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
+ if (IS_ERR(grf)) {
+ dev_err(&pdev->dev,
+ "rk3x-i2c needs 'rockchip,grf' property\n");
+ return PTR_ERR(grf);
+ }
+
+ if (bus_nr < 0) {
+ dev_err(&pdev->dev, "rk3x-i2c needs i2cX alias");
+ return -EINVAL;
+ }
+
+ /* 27+i: write mask, 11+i: value */
+ value = BIT(27 + bus_nr) | BIT(11 + bus_nr);
+
+ ret = regmap_write(grf, i2c->soc_data->grf_offset, value);
+ if (ret != 0) {
+ dev_err(i2c->dev, "Could not write to GRF: %d\n", ret);
+ return ret;
+ }
+ }
+
+ /* IRQ setup */
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "cannot find rk3x IRQ\n");
+ return irq;
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq, rk3x_i2c_irq,
+ 0, dev_name(&pdev->dev), i2c);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "cannot request IRQ\n");
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, i2c);
+
+ ret = clk_prepare(i2c->clk);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Could not prepare clock\n");
+ return ret;
+ }
+
+ ret = i2c_add_adapter(&i2c->adap);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Could not register adapter\n");
+ goto err_clk;
+ }
+
+ dev_info(&pdev->dev, "Initialized RK3xxx I2C bus at 0x%08x\n",
+ (unsigned int)i2c->regs);
+
+ return 0;
+
+err_clk:
+ clk_unprepare(i2c->clk);
+ return ret;
+}
+
+static int rk3x_i2c_remove(struct platform_device *pdev)
+{
+ struct rk3x_i2c *i2c = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&i2c->adap);
+ clk_unprepare(i2c->clk);
+
+ return 0;
+}
+
+static struct platform_driver rk3x_i2c_driver = {
+ .probe = rk3x_i2c_probe,
+ .remove = rk3x_i2c_remove,
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "rk3x-i2c",
+ .of_match_table = rk3x_i2c_match,
+ },
+};
+
+module_platform_driver(rk3x_i2c_driver);
+
+MODULE_DESCRIPTION("Rockchip RK3xxx I2C Bus driver");
+MODULE_AUTHOR("Max Schwarz <max.schwarz@xxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
--
1.9.1


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/