[PATCH v2 2/2] i2c: uniphier_f: add UniPhier FIFO-builtin I2C driver

From: Masahiro Yamada
Date: Fri Oct 23 2015 - 06:53:21 EST

Add support for on-chip I2C controller used on newer UniPhier SoCs
such as PH1-Pro4, PH1-Pro5, etc. This adapter is equipped with
8-depth TX/RX FIFOs.

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
---

Changes in v2:
- Delete if-block after platform_get_resource()
- Add I2C_FUNC_SMBUS_EMUL to functionality
- Add bindings document
- Fix a typo in a comment block

.../devicetree/bindings/i2c/i2c-uniphier-f.txt | 25 +
drivers/i2c/busses/Kconfig | 8 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-uniphier-f.c | 584 +++++++++++++++++++++
4 files changed, 618 insertions(+)
create mode 100644 Documentation/devicetree/bindings/i2c/i2c-uniphier-f.txt
create mode 100644 drivers/i2c/busses/i2c-uniphier-f.c

diff --git a/Documentation/devicetree/bindings/i2c/i2c-uniphier-f.txt b/Documentation/devicetree/bindings/i2c/i2c-uniphier-f.txt
new file mode 100644
index 0000000..27fc6f8
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-uniphier-f.txt
@@ -0,0 +1,25 @@
+UniPhier I2C controller (FIFO-builtin)
+
+Required properties:
+- compatible: should be "socionext,uniphier-fi2c".
+- #address-cells: should be 1.
+- #size-cells: should be 0.
+- reg: offset and length of the register set for the device.
+- interrupts: a single interrupt specifier.
+- clocks: phandle to the input clock.
+
+Optional properties:
+- clock-frequency: desired I2C bus frequency in Hz. The maximum supported
+ value is 400000. Defaults to 100000 if not specified.
+
+Examples:
+
+ i2c0: i2c@58780000 {
+ compatible = "socionext,uniphier-fi2c";
+ reg = <0x58780000 0x80>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ interrupts = <0 41 4>;
+ clocks = <&i2c_clk>;
+ clock-frequency = <100000>;
+ };
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 2a176b0..0111219 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -910,6 +910,14 @@ config I2C_UNIPHIER
the UniPhier FIFO-less I2C interface embedded in PH1-LD4, PH1-sLD8,
or older UniPhier SoCs.

+config I2C_UNIPHIER_F
+ tristate "UniPhier FIFO-builtin I2C controller"
+ depends on ARCH_UNIPHIER
+ help
+ If you say yes to this option, support will be included for
+ the UniPhier FIFO-builtin I2C interface embedded in PH1-Pro4,
+ PH1-Pro5, or newer UniPhier SoCs.
+
config I2C_VERSATILE
tristate "ARM Versatile/Realview I2C bus support"
depends on ARCH_VERSATILE || ARCH_REALVIEW || ARCH_VEXPRESS
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index f9f0902..37f2819 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -88,6 +88,7 @@ obj-$(CONFIG_I2C_STU300) += i2c-stu300.o
obj-$(CONFIG_I2C_SUN6I_P2WI) += i2c-sun6i-p2wi.o
obj-$(CONFIG_I2C_TEGRA) += i2c-tegra.o
obj-$(CONFIG_I2C_UNIPHIER) += i2c-uniphier.o
+obj-$(CONFIG_I2C_UNIPHIER_F) += i2c-uniphier-f.o
obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o
obj-$(CONFIG_I2C_WMT) += i2c-wmt.o
obj-$(CONFIG_I2C_OCTEON) += i2c-octeon.o
diff --git a/drivers/i2c/busses/i2c-uniphier-f.c b/drivers/i2c/busses/i2c-uniphier-f.c
new file mode 100644
index 0000000..e8d03bc
--- /dev/null
+++ b/drivers/i2c/busses/i2c-uniphier-f.c
@@ -0,0 +1,584 @@
+/*
+ * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
+ *
+ * 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define UNIPHIER_FI2C_CR 0x00 /* control register */
+#define UNIPHIER_FI2C_CR_MST BIT(3) /* master mode */
+#define UNIPHIER_FI2C_CR_STA BIT(2) /* start condition */
+#define UNIPHIER_FI2C_CR_STO BIT(1) /* stop condition */
+#define UNIPHIER_FI2C_CR_NACK BIT(0) /* do not return ACK */
+#define UNIPHIER_FI2C_DTTX 0x04 /* TX FIFO */
+#define UNIPHIER_FI2C_DTTX_CMD BIT(8) /* send command (slave addr) */
+#define UNIPHIER_FI2C_DTTX_RD BIT(0) /* read transaction */
+#define UNIPHIER_FI2C_DTRX 0x04 /* RX FIFO */
+#define UNIPHIER_FI2C_SLAD 0x0c /* slave address */
+#define UNIPHIER_FI2C_CYC 0x10 /* clock cycle control */
+#define UNIPHIER_FI2C_LCTL 0x14 /* clock low period control */
+#define UNIPHIER_FI2C_SSUT 0x18 /* restart/stop setup time control */
+#define UNIPHIER_FI2C_DSUT 0x1c /* data setup time control */
+#define UNIPHIER_FI2C_INT 0x20 /* interrupt status */
+#define UNIPHIER_FI2C_IE 0x24 /* interrupt enable */
+#define UNIPHIER_FI2C_IC 0x28 /* interrupt clear */
+#define UNIPHIER_FI2C_INT_TE BIT(9) /* TX FIFO empty */
+#define UNIPHIER_FI2C_INT_RF BIT(8) /* RX FIFO full */
+#define UNIPHIER_FI2C_INT_TC BIT(7) /* send complete (STOP) */
+#define UNIPHIER_FI2C_INT_RC BIT(6) /* receive complete (STOP) */
+#define UNIPHIER_FI2C_INT_TB BIT(5) /* sent specified bytes */
+#define UNIPHIER_FI2C_INT_RB BIT(4) /* received specified bytes */
+#define UNIPHIER_FI2C_INT_NA BIT(2) /* no ACK */
+#define UNIPHIER_FI2C_INT_AL BIT(1) /* arbitration lost */
+#define UNIPHIER_FI2C_SR 0x2c /* status register */
+#define UNIPHIER_FI2C_SR_DB BIT(12) /* device busy */
+#define UNIPHIER_FI2C_SR_STS BIT(11) /* stop condition detected */
+#define UNIPHIER_FI2C_SR_BB BIT(8) /* bus busy */
+#define UNIPHIER_FI2C_SR_RFF BIT(3) /* RX FIFO full */
+#define UNIPHIER_FI2C_SR_RNE BIT(2) /* RX FIFO not empty */
+#define UNIPHIER_FI2C_SR_TNF BIT(1) /* TX FIFO not full */
+#define UNIPHIER_FI2C_SR_TFE BIT(0) /* TX FIFO empty */
+#define UNIPHIER_FI2C_RST 0x34 /* reset control */
+#define UNIPHIER_FI2C_RST_TBRST BIT(2) /* clear TX FIFO */
+#define UNIPHIER_FI2C_RST_RBRST BIT(1) /* clear RX FIFO */
+#define UNIPHIER_FI2C_RST_RST BIT(0) /* forcible bus reset */
+#define UNIPHIER_FI2C_BM 0x38 /* bus monitor */
+#define UNIPHIER_FI2C_BM_SDAO BIT(3) /* output for SDA line */
+#define UNIPHIER_FI2C_BM_SDAS BIT(2) /* readback of SDA line */
+#define UNIPHIER_FI2C_BM_SCLO BIT(1) /* output for SCL line */
+#define UNIPHIER_FI2C_BM_SCLS BIT(0) /* readback of SCL line */
+#define UNIPHIER_FI2C_NOISE 0x3c /* noise filter control */
+#define UNIPHIER_FI2C_TBC 0x40 /* TX byte count setting */
+#define UNIPHIER_FI2C_RBC 0x44 /* RX byte count setting */
+#define UNIPHIER_FI2C_TBCM 0x48 /* TX byte count monitor */
+#define UNIPHIER_FI2C_RBCM 0x4c /* RX byte count monitor */
+#define UNIPHIER_FI2C_BRST 0x50 /* bus reset */
+#define UNIPHIER_FI2C_BRST_FOEN BIT(1) /* normal operation */
+#define UNIPHIER_FI2C_BRST_RSCL BIT(0) /* release SCL */
+
+#define UNIPHIER_FI2C_INT_FAULTS \
+ (UNIPHIER_FI2C_INT_NA | UNIPHIER_FI2C_INT_AL)
+#define UNIPHIER_FI2C_INT_STOP \
+ (UNIPHIER_FI2C_INT_TC | UNIPHIER_FI2C_INT_RC)
+
+#define UNIPHIER_FI2C_RD BIT(0)
+#define UNIPHIER_FI2C_STOP BIT(1)
+#define UNIPHIER_FI2C_MANUAL_NACK BIT(2)
+#define UNIPHIER_FI2C_BYTE_WISE BIT(3)
+#define UNIPHIER_FI2C_DEFER_STOP_COMP BIT(4)
+
+#define UNIPHIER_FI2C_DEFAULT_SPEED 100000
+#define UNIPHIER_FI2C_MAX_SPEED 400000
+#define UNIPHIER_FI2C_FIFO_SIZE 8
+
+struct uniphier_fi2c_priv {
+ struct completion comp;
+ struct i2c_adapter adap;
+ void __iomem *membase;
+ struct clk *clk;
+ unsigned int len;
+ u8 *buf;
+ u32 enabled_irqs;
+ int error;
+ unsigned int flags;
+ unsigned int busy_cnt;
+};
+
+static void uniphier_fi2c_fill_txfifo(struct uniphier_fi2c_priv *priv,
+ bool first)
+{
+ int fifo_space = UNIPHIER_FI2C_FIFO_SIZE;
+
+ /*
+ * TX-FIFO stores slave address in it for the first access.
+ * Decrement the counter.
+ */
+ if (first)
+ fifo_space--;
+
+ while (priv->len) {
+ if (fifo_space-- <= 0)
+ break;
+
+ dev_dbg(&priv->adap.dev, "write data: %02x\n", *priv->buf);
+ writel(*priv->buf++, priv->membase + UNIPHIER_FI2C_DTTX);
+ priv->len--;
+ }
+}
+
+static void uniphier_fi2c_drain_rxfifo(struct uniphier_fi2c_priv *priv)
+{
+ int fifo_left = priv->flags & UNIPHIER_FI2C_BYTE_WISE ?
+ 1 : UNIPHIER_FI2C_FIFO_SIZE;
+
+ while (priv->len) {
+ if (fifo_left-- <= 0)
+ break;
+
+ *priv->buf++ = readl(priv->membase + UNIPHIER_FI2C_DTRX);
+ dev_dbg(&priv->adap.dev, "read data: %02x\n", priv->buf[-1]);
+ priv->len--;
+ }
+}
+
+static void uniphier_fi2c_set_irqs(struct uniphier_fi2c_priv *priv)
+{
+ writel(priv->enabled_irqs, priv->membase + UNIPHIER_FI2C_IE);
+}
+
+static void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv)
+{
+ writel(-1, priv->membase + UNIPHIER_FI2C_IC);
+}
+
+static void uniphier_fi2c_stop(struct uniphier_fi2c_priv *priv)
+{
+ dev_dbg(&priv->adap.dev, "stop condition\n");
+
+ priv->enabled_irqs |= UNIPHIER_FI2C_INT_STOP;
+ uniphier_fi2c_set_irqs(priv);
+ writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STO,
+ priv->membase + UNIPHIER_FI2C_CR);
+}
+
+static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id)
+{
+ struct uniphier_fi2c_priv *priv = dev_id;
+ u32 irq_status;
+
+ irq_status = readl(priv->membase + UNIPHIER_FI2C_INT);
+
+ dev_dbg(&priv->adap.dev,
+ "interrupt: enabled_irqs=%04x, irq_status=%04x\n",
+ priv->enabled_irqs, irq_status);
+
+ if (irq_status & UNIPHIER_FI2C_INT_STOP)
+ goto complete;
+
+ if (unlikely(irq_status & UNIPHIER_FI2C_INT_AL)) {
+ dev_dbg(&priv->adap.dev, "arbitration lost\n");
+ priv->error = -EAGAIN;
+ goto complete;
+ }
+
+ if (unlikely(irq_status & UNIPHIER_FI2C_INT_NA)) {
+ dev_dbg(&priv->adap.dev, "could not get ACK\n");
+ priv->error = -ENXIO;
+ if (priv->flags & UNIPHIER_FI2C_RD) {
+ /*
+ * work around a hardware bug:
+ * The receive-completed interrupt is never set even if
+ * STOP condition is detected after the address phase
+ * of read transaction fails to get ACK.
+ * To avoid time-out error, we issue STOP here,
+ * but do not wait for its completion.
+ * It should be checked after exiting this handler.
+ */
+ uniphier_fi2c_stop(priv);
+ priv->flags |= UNIPHIER_FI2C_DEFER_STOP_COMP;
+ goto complete;
+ }
+ goto stop;
+ }
+
+ if (irq_status & UNIPHIER_FI2C_INT_TE) {
+ if (!priv->len)
+ goto data_done;
+
+ uniphier_fi2c_fill_txfifo(priv, false);
+ goto handled;
+ }
+
+ if (irq_status & (UNIPHIER_FI2C_INT_RF | UNIPHIER_FI2C_INT_RB)) {
+ uniphier_fi2c_drain_rxfifo(priv);
+ if (!priv->len)
+ goto data_done;
+
+ if (unlikely(priv->flags & UNIPHIER_FI2C_MANUAL_NACK)) {
+ if (priv->len <= UNIPHIER_FI2C_FIFO_SIZE &&
+ !(priv->flags & UNIPHIER_FI2C_BYTE_WISE)) {
+ dev_dbg(&priv->adap.dev,
+ "enable read byte count IRQ\n");
+ priv->enabled_irqs |= UNIPHIER_FI2C_INT_RB;
+ uniphier_fi2c_set_irqs(priv);
+ priv->flags |= UNIPHIER_FI2C_BYTE_WISE;
+ }
+ if (priv->len <= 1) {
+ dev_dbg(&priv->adap.dev, "set NACK\n");
+ writel(UNIPHIER_FI2C_CR_MST |
+ UNIPHIER_FI2C_CR_NACK,
+ priv->membase + UNIPHIER_FI2C_CR);
+ }
+ }
+
+ goto handled;
+ }
+
+ return IRQ_NONE;
+
+data_done:
+ if (priv->flags & UNIPHIER_FI2C_STOP) {
+stop:
+ uniphier_fi2c_stop(priv);
+ } else {
+complete:
+ priv->enabled_irqs = 0;
+ uniphier_fi2c_set_irqs(priv);
+ complete(&priv->comp);
+ }
+
+handled:
+ uniphier_fi2c_clear_irqs(priv);
+
+ return IRQ_HANDLED;
+}
+
+static void uniphier_fi2c_tx_init(struct uniphier_fi2c_priv *priv, u16 addr)
+{
+ priv->enabled_irqs |= UNIPHIER_FI2C_INT_TE;
+ /* do not use TX byte counter */
+ writel(0, priv->membase + UNIPHIER_FI2C_TBC);
+ /* set slave address */
+ writel(UNIPHIER_FI2C_DTTX_CMD | addr << 1,
+ priv->membase + UNIPHIER_FI2C_DTTX);
+ /* first chunk of data */
+ uniphier_fi2c_fill_txfifo(priv, true);
+}
+
+static void uniphier_fi2c_rx_init(struct uniphier_fi2c_priv *priv, u16 addr)
+{
+ priv->flags |= UNIPHIER_FI2C_RD;
+
+ if (likely(priv->len < 256)) {
+ /*
+ * If possible, use RX byte counter.
+ * It can automatically handle NACK for the last byte.
+ */
+ writel(priv->len, priv->membase + UNIPHIER_FI2C_RBC);
+ priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF |
+ UNIPHIER_FI2C_INT_RB;
+ } else {
+ /*
+ * The byte counter can not count over 256. In this case,
+ * do not use it at all. Drain data when FIFO gets full,
+ * but treat the last portion as a special case.
+ */
+ writel(0, priv->membase + UNIPHIER_FI2C_RBC);
+ priv->flags |= UNIPHIER_FI2C_MANUAL_NACK;
+ priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF;
+ }
+
+ /* set slave address with RD bit */
+ writel(UNIPHIER_FI2C_DTTX_CMD | UNIPHIER_FI2C_DTTX_RD | addr << 1,
+ priv->membase + UNIPHIER_FI2C_DTTX);
+}
+
+static void uniphier_fi2c_reset(struct uniphier_fi2c_priv *priv)
+{
+ writel(UNIPHIER_FI2C_RST_RST, priv->membase + UNIPHIER_FI2C_RST);
+}
+
+static void uniphier_fi2c_prepare_operation(struct uniphier_fi2c_priv *priv)
+{
+ writel(UNIPHIER_FI2C_BRST_FOEN | UNIPHIER_FI2C_BRST_RSCL,
+ priv->membase + UNIPHIER_FI2C_BRST);
+}
+
+static void uniphier_fi2c_recover(struct uniphier_fi2c_priv *priv)
+{
+ uniphier_fi2c_reset(priv);
+ i2c_recover_bus(&priv->adap);
+}
+
+static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
+ struct i2c_msg *msg, bool stop)
+{
+ struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
+ bool is_read = msg->flags & I2C_M_RD;
+ unsigned long time_left;
+
+ dev_dbg(&adap->dev, "%s: addr=0x%02x, len=%d, stop=%d\n",
+ is_read ? "receive" : "transmit", msg->addr, msg->len, stop);
+
+ priv->len = msg->len;
+ priv->buf = msg->buf;
+ priv->enabled_irqs = UNIPHIER_FI2C_INT_FAULTS;
+ priv->error = 0;
+ priv->flags = 0;
+
+ if (stop)
+ priv->flags |= UNIPHIER_FI2C_STOP;
+
+ reinit_completion(&priv->comp);
+ uniphier_fi2c_clear_irqs(priv);
+ writel(UNIPHIER_FI2C_RST_TBRST | UNIPHIER_FI2C_RST_RBRST,
+ priv->membase + UNIPHIER_FI2C_RST); /* reset TX/RX FIFO */
+
+ if (is_read)
+ uniphier_fi2c_rx_init(priv, msg->addr);
+ else
+ uniphier_fi2c_tx_init(priv, msg->addr);
+
+ uniphier_fi2c_set_irqs(priv);
+
+ dev_dbg(&adap->dev, "start condition\n");
+ writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STA,
+ priv->membase + UNIPHIER_FI2C_CR);
+
+ time_left = wait_for_completion_timeout(&priv->comp, adap->timeout);
+ if (!time_left) {
+ dev_err(&adap->dev, "transaction timeout.\n");
+ uniphier_fi2c_recover(priv);
+ return -ETIMEDOUT;
+ }
+ dev_dbg(&adap->dev, "complete\n");
+
+ if (unlikely(priv->flags & UNIPHIER_FI2C_DEFER_STOP_COMP)) {
+ u32 status = readl(priv->membase + UNIPHIER_FI2C_SR);
+
+ if (!(status & UNIPHIER_FI2C_SR_STS) ||
+ status & UNIPHIER_FI2C_SR_BB) {
+ dev_err(&adap->dev,
+ "stop condition was not completed.\n");
+ uniphier_fi2c_recover(priv);
+ return -EBUSY;
+ }
+ }
+
+ return priv->error;
+}
+
+static int uniphier_fi2c_check_bus_busy(struct i2c_adapter *adap)
+{
+ struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
+
+ if (readl(priv->membase + UNIPHIER_FI2C_SR) & UNIPHIER_FI2C_SR_DB) {
+ if (priv->busy_cnt++ > 3) {
+ /*
+ * If bus busy continues too long, it is probably
+ * in a wrong state. Try bus recovery.
+ */
+ uniphier_fi2c_recover(priv);
+ priv->busy_cnt = 0;
+ }
+
+ return -EAGAIN;
+ }
+
+ priv->busy_cnt = 0;
+ return 0;
+}
+
+static int uniphier_fi2c_master_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs, int num)
+{
+ struct i2c_msg *msg, *emsg = msgs + num;
+ int ret;
+
+ ret = uniphier_fi2c_check_bus_busy(adap);
+ if (ret)
+ return ret;
+
+ for (msg = msgs; msg < emsg; msg++) {
+ /* If next message is read, skip the stop condition */
+ bool stop = !(msg + 1 < emsg && msg[1].flags & I2C_M_RD);
+ /* but, force it if I2C_M_STOP is set */
+ if (msg->flags & I2C_M_STOP)
+ stop = true;
+
+ ret = uniphier_fi2c_master_xfer_one(adap, msg, stop);
+ if (ret)
+ return ret;
+ }
+
+ return num;
+}
+
+static u32 uniphier_fi2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm uniphier_fi2c_algo = {
+ .master_xfer = uniphier_fi2c_master_xfer,
+ .functionality = uniphier_fi2c_functionality,
+};
+
+static int uniphier_fi2c_get_scl(struct i2c_adapter *adap)
+{
+ struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
+
+ return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
+ UNIPHIER_FI2C_BM_SCLS);
+}
+
+static void uniphier_fi2c_set_scl(struct i2c_adapter *adap, int val)
+{
+ struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
+
+ writel(val ? UNIPHIER_FI2C_BRST_RSCL : 0,
+ priv->membase + UNIPHIER_FI2C_BRST);
+}
+
+static int uniphier_fi2c_get_sda(struct i2c_adapter *adap)
+{
+ struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
+
+ return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
+ UNIPHIER_FI2C_BM_SDAS);
+}
+
+static void uniphier_fi2c_unprepare_recovery(struct i2c_adapter *adap)
+{
+ uniphier_fi2c_prepare_operation(i2c_get_adapdata(adap));
+}
+
+static struct i2c_bus_recovery_info uniphier_fi2c_bus_recovery_info = {
+ .recover_bus = i2c_generic_scl_recovery,
+ .get_scl = uniphier_fi2c_get_scl,
+ .set_scl = uniphier_fi2c_set_scl,
+ .get_sda = uniphier_fi2c_get_sda,
+ .unprepare_recovery = uniphier_fi2c_unprepare_recovery,
+};
+
+static int uniphier_fi2c_clk_init(struct device *dev,
+ struct uniphier_fi2c_priv *priv)
+{
+ struct device_node *np = dev->of_node;
+ unsigned long clk_rate;
+ u32 bus_speed, clk_count;
+ int ret;
+
+ if (of_property_read_u32(np, "clock-frequency", &bus_speed))
+ bus_speed = UNIPHIER_FI2C_DEFAULT_SPEED;
+
+ if (bus_speed > UNIPHIER_FI2C_MAX_SPEED)
+ bus_speed = UNIPHIER_FI2C_MAX_SPEED;
+
+ /* Get input clk rate through clk driver */
+ priv->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(priv->clk)) {
+ dev_err(dev, "failed to get clock\n");
+ return PTR_ERR(priv->clk);
+ }
+
+ ret = clk_prepare_enable(priv->clk);
+ if (ret)
+ return ret;
+
+ clk_rate = clk_get_rate(priv->clk);
+
+ uniphier_fi2c_reset(priv);
+
+ clk_count = clk_rate / bus_speed;
+
+ writel(clk_count, priv->membase + UNIPHIER_FI2C_CYC);
+ writel(clk_count / 2, priv->membase + UNIPHIER_FI2C_LCTL);
+ writel(clk_count / 2, priv->membase + UNIPHIER_FI2C_SSUT);
+ writel(clk_count / 16, priv->membase + UNIPHIER_FI2C_DSUT);
+
+ uniphier_fi2c_prepare_operation(priv);
+
+ return 0;
+}
+
+static int uniphier_fi2c_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct uniphier_fi2c_priv *priv;
+ struct resource *regs;
+ int irq;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ priv->membase = devm_ioremap_resource(dev, regs);
+ if (IS_ERR(priv->membase))
+ return PTR_ERR(priv->membase);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(dev, "failed to get IRQ number");
+ return irq;
+ }
+
+ init_completion(&priv->comp);
+ priv->adap.owner = THIS_MODULE;
+ priv->adap.algo = &uniphier_fi2c_algo;
+ priv->adap.dev.parent = dev;
+ priv->adap.dev.of_node = dev->of_node;
+ strlcpy(priv->adap.name, "UniPhier FI2C", sizeof(priv->adap.name));
+ priv->adap.bus_recovery_info = &uniphier_fi2c_bus_recovery_info;
+ i2c_set_adapdata(&priv->adap, priv);
+ platform_set_drvdata(pdev, priv);
+
+ ret = uniphier_fi2c_clk_init(dev, priv);
+ if (ret)
+ return ret;
+
+ ret = devm_request_irq(dev, irq, uniphier_fi2c_interrupt, 0,
+ pdev->name, priv);
+ if (ret) {
+ dev_err(dev, "failed to request irq %d\n", irq);
+ goto err;
+ }
+
+ ret = i2c_add_adapter(&priv->adap);
+ if (ret) {
+ dev_err(dev, "failed to add I2C adapter\n");
+ goto err;
+ }
+
+err:
+ if (ret)
+ clk_disable_unprepare(priv->clk);
+
+ return ret;
+}
+
+static int uniphier_fi2c_remove(struct platform_device *pdev)
+{
+ struct uniphier_fi2c_priv *priv = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&priv->adap);
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static const struct of_device_id uniphier_fi2c_match[] = {
+ { .compatible = "socionext,uniphier-fi2c" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, uniphier_fi2c_match);
+
+static struct platform_driver uniphier_fi2c_drv = {
+ .probe = uniphier_fi2c_probe,
+ .remove = uniphier_fi2c_remove,
+ .driver = {
+ .name = "uniphier-fi2c",
+ .of_match_table = uniphier_fi2c_match,
+ },
+};
+module_platform_driver(uniphier_fi2c_drv);
+
+MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("UniPhier FIFO-builtin I2C bus driver");
+MODULE_LICENSE("GPL");
--
1.9.1

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