[PATCH v3 0/2] Qualcomm Universal Peripheral (QUP) I2C controller

[PATCH v3 0/2] Qualcomm Universal Peripheral (QUP) I2C controller

[Bjorn Andersson]

Continuing on Ivans i2c-qup series.

Changes from v2:
 - Removed unused variables and includes
 - Corrected read logic in irq handler
 - Made the polling loop in qup_i2c_poll_state() less arbitrary
 - Only building suspend/resume if CONFIG_PM_SLEEP

Changes from v1:
 - Cleaned up device tree binding example.
 - Refrased device tree bindings.
 - Following changes in the i2c framework.
 - Use the core clock to calculate divider for the bus clock, instead of
   explicitly setting it.
 - Remove explicit pinctrl settting.
 - Split/renamed qup_i2c_enable(bool) into enable/disable functions.
 - Return value was overwritten on error in write_one/read_one.
 - Initialize the i2c core every time, so that we actually can execute
   more than 1 transmission per xfer.

Ivan T. Ivanov (2):
  i2c: qup: Add device tree bindings information
  i2c: New bus driver for the QUP I2C controller

 .../devicetree/bindings/i2c/qcom,i2c-qup.txt       |  41 +
 drivers/i2c/busses/Kconfig                         |  10 +
 drivers/i2c/busses/Makefile                        |   1 +
 drivers/i2c/busses/i2c-qup.c                       | 894 +++++++++++++++++++++
 4 files changed, 946 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
 create mode 100644 drivers/i2c/busses/i2c-qup.c

-- 
1.8.2.2

[PATCH v3 1/2] i2c: qup: Add device tree bindings information

[Bjorn Andersson]

From: "Ivan T. Ivanov" <iivanov@mm-sol.com>

The Qualcomm Universal Peripherial (QUP) wraps I2C mini-core and
provide input and output FIFO's for it. I2C controller can operate
as master with supported bus speeds of 100Kbps and 400Kbps.

Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
[bjorn: reformulated part of binding description and cleaned up example]
Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
---
 .../devicetree/bindings/i2c/qcom,i2c-qup.txt       | 41 ++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt

diff --git a/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
new file mode 100644
index 0000000..a99711b
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
@@ -0,0 +1,41 @@
+Qualcomm Universal Peripheral (QUP) I2C controller
+
+Required properties:
+ - compatible: Should be "qcom,i2c-qup".
+ - reg: Should contain QUP register address and length.
+ - interrupts: Should contain I2C interrupt.
+
+ - clocks: Should contain the core clock and the AHB clock.
+ - clock-names: Should be "core" for the core clock and "iface" for the
+                AHB clock.
+
+ - #address-cells: Should be <1> Address cells for i2c device address
+ - #size-cells: Should be <0> as i2c addresses have no size component
+
+Optional properties:
+ - clock-frequency: Should specify the desired i2c bus clock frequency in Hz,
+                    default is 100kHz if omitted.
+
+Child nodes should conform to i2c bus binding.
+
+Example:
+
+ i2c2: i2c@f9924000 {
+ 	compatible = "qcom,i2c-qup";
+ 	reg = <0xf9924000 0x1000>;
+ 	interrupts = <0 96 0>;
+
+ 	clocks = <&gcc_blsp1_qup2_i2c_apps_clk>, <&gcc_blsp1_ahb_clk>;
+ 	clock-names = "core", "iface";
+
+ 	clock-frequency = <355000>;
+
+ 	#address-cells = <1>;
+ 	#size-cells = <0>;
+
+ 	dummy@60 {
+ 		compatible = "dummy";
+ 		reg = <0x60>;
+ 	};
+ };
+
-- 
1.8.2.2

[PATCH v3 2/2] i2c: New bus driver for the QUP I2C controller

[Bjorn Andersson]

From: "Ivan T. Ivanov" <iivanov@mm-sol.com>

This bus driver supports the QUP i2c hardware controller in the Qualcomm
MSM SOCs.  The Qualcomm Universal Peripheral Engine (QUP) is a general
purpose data path engine with input/output FIFOs and an embedded i2c
mini-core. The driver supports FIFO mode (for low bandwidth	applications)
and block mode (interrupt generated for each block-size data transfer).
The driver currently does not support DMA transfers.

Shamelessly based on codeaurora version of the driver.

Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
[bjorn: updated to reflect i2c framework changes
        splited up qup_i2c_enable() in enable/disable
        don't overwrite ret value on error in xfer functions
        initilize core for each transfer
        remove explicit pinctrl selection
        use existing clock instead of setting new core clock]
Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
---
 drivers/i2c/busses/Kconfig   |  10 +
 drivers/i2c/busses/Makefile  |   1 +
 drivers/i2c/busses/i2c-qup.c | 894 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 905 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-qup.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 3b26129..4eaded0 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -648,6 +648,16 @@ config I2C_PXA_SLAVE
 	  is necessary for systems where the PXA may be a target on the
 	  I2C bus.
 
+config I2C_QUP
+	tristate "Qualcomm QUP based I2C controller"
+	depends on ARCH_MSM
+	help
+	  If you say yes to this option, support will be included for the
+	  built-in I2C interface on the MSM family processors.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-qup.
+
 config HAVE_S3C2410_I2C
 	bool
 	help
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index c73eb0e..c93f593 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -63,6 +63,7 @@ obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o
 obj-$(CONFIG_I2C_PUV3)		+= i2c-puv3.o
 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_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-qup.c b/drivers/i2c/busses/i2c-qup.c
new file mode 100644
index 0000000..2e0020e
--- /dev/null
+++ b/drivers/i2c/busses/i2c-qup.c
@@ -0,0 +1,894 @@
+/* Copyright (c) 2009-2013, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 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.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+/* QUP Registers */
+#define QUP_CONFIG		0x000
+#define QUP_STATE		0x004
+#define QUP_IO_MODE		0x008
+#define QUP_SW_RESET		0x00c
+#define QUP_OPERATIONAL		0x018
+#define QUP_ERROR_FLAGS		0x01c
+#define QUP_ERROR_FLAGS_EN	0x020
+#define QUP_HW_VERSION		0x030
+#define QUP_MX_OUTPUT_CNT	0x100
+#define QUP_OUT_FIFO_BASE	0x110
+#define QUP_MX_WRITE_CNT	0x150
+#define QUP_MX_INPUT_CNT	0x200
+#define QUP_MX_READ_CNT		0x208
+#define QUP_IN_FIFO_BASE	0x218
+#define QUP_I2C_CLK_CTL		0x400
+#define QUP_I2C_STATUS		0x404
+
+/* QUP States and reset values */
+#define QUP_RESET_STATE		0
+#define QUP_RUN_STATE		1
+#define QUP_PAUSE_STATE		3
+#define QUP_STATE_MASK		3
+
+#define QUP_STATE_VALID		BIT(2)
+#define QUP_I2C_MAST_GEN	BIT(4)
+
+#define QUP_OPERATIONAL_RESET	0x000ff0
+#define QUP_I2C_STATUS_RESET	0xfffffc
+
+/* QUP OPERATIONAL FLAGS */
+#define QUP_OUT_SVC_FLAG	BIT(8)
+#define QUP_IN_SVC_FLAG		BIT(9)
+#define QUP_MX_INPUT_DONE	BIT(11)
+
+/* I2C mini core related values */
+#define I2C_MINI_CORE		(2 << 8)
+#define I2C_N_VAL		15
+/* Most significant word offset in FIFO port */
+#define QUP_MSW_SHIFT		(I2C_N_VAL + 1)
+#define QUP_CLOCK_AUTO_GATE	BIT(13)
+
+/* Packing/Unpacking words in FIFOs, and IO modes */
+#define QUP_UNPACK_EN		BIT(14)
+#define QUP_PACK_EN		BIT(15)
+#define QUP_OUTPUT_BLK_MODE	BIT(10)
+#define QUP_INPUT_BLK_MODE	BIT(12)
+
+#define QUP_REPACK_EN		(QUP_UNPACK_EN | QUP_PACK_EN)
+
+#define QUP_OUTPUT_BLOCK_SIZE(x)(((x) & (0x03 << 0)) >> 0)
+#define QUP_OUTPUT_FIFO_SIZE(x)	(((x) & (0x07 << 2)) >> 2)
+#define QUP_INPUT_BLOCK_SIZE(x)	(((x) & (0x03 << 5)) >> 5)
+#define QUP_INPUT_FIFO_SIZE(x)	(((x) & (0x07 << 7)) >> 7)
+
+/* QUP tags */
+#define QUP_OUT_NOP		(0 << 8)
+#define QUP_OUT_START		(1 << 8)
+#define QUP_OUT_DATA		(2 << 8)
+#define QUP_OUT_STOP		(3 << 8)
+#define QUP_OUT_REC		(4 << 8)
+#define QUP_IN_DATA		(5 << 8)
+#define QUP_IN_STOP		(6 << 8)
+#define QUP_IN_NACK		(7 << 8)
+
+/* Status, Error flags */
+#define I2C_STATUS_WR_BUFFER_FULL	BIT(0)
+#define I2C_STATUS_BUS_ACTIVE		BIT(8)
+#define I2C_STATUS_BUS_MASTER		BIT(9)
+#define I2C_STATUS_ERROR_MASK		0x38000fc
+#define QUP_I2C_NACK_FLAG		BIT(3)
+#define QUP_IN_NOT_EMPTY		BIT(5)
+#define QUP_STATUS_ERROR_FLAGS		0x7c
+
+/* Master bus_err clock states */
+#define I2C_CLK_RESET_BUSIDLE_STATE	0
+#define I2C_CLK_FORCED_LOW_STATE	5
+
+#define QUP_MAX_CLK_STATE_RETRIES	300
+#define QUP_MAX_QUP_STATE_RETRIES	100
+#define I2C_STATUS_CLK_STATE		13
+#define QUP_OUT_FIFO_NOT_EMPTY		0x10
+#define QUP_READ_LIMIT			256
+
+struct qup_i2c_dev {
+	struct device		*dev;
+	void __iomem		*base;
+	int			irq;
+	struct clk		*clk;
+	struct clk		*pclk;
+	struct i2c_adapter	adap;
+
+	int			clk_ctl;
+	int			one_bit_t;
+	int			out_fifo_sz;
+	int			in_fifo_sz;
+	int			out_blk_sz;
+	int			in_blk_sz;
+	unsigned long		xfer_time;
+	unsigned long		wait_idle;
+
+	struct i2c_msg		*msg;
+	/* Current posion in user message buffer */
+	int			pos;
+	/* Keep number of bytes left to be transmitted */
+	int			cnt;
+	/* I2C protocol errors */
+	u32			bus_err;
+	/* QUP core errors */
+	u32			qup_err;
+	/*
+	 * Maximum bytes that could be send (per iteration). Could be
+	 * equal of fifo size or block size (in block mode)
+	 */
+	int			chunk_sz;
+	struct completion	xfer;
+};
+
+static irqreturn_t qup_i2c_interrupt(int irq, void *dev)
+{
+	struct qup_i2c_dev *qup = dev;
+	u32 bus_err;
+	u32 qup_err;
+	u32 opflags;
+
+	bus_err = readl(qup->base + QUP_I2C_STATUS);
+	qup_err = readl(qup->base + QUP_ERROR_FLAGS);
+	opflags = readl(qup->base + QUP_OPERATIONAL);
+
+	if (!qup->msg) {
+		/* Clear Error interrupt */
+		writel(QUP_RESET_STATE, qup->base + QUP_STATE);
+		return IRQ_HANDLED;
+	}
+
+	bus_err &= I2C_STATUS_ERROR_MASK;
+	qup_err &= QUP_STATUS_ERROR_FLAGS;
+
+	if (qup_err) {
+		/* Clear Error interrupt */
+		writel(qup_err & QUP_STATUS_ERROR_FLAGS,
+			qup->base + QUP_ERROR_FLAGS);
+		goto done;
+	}
+
+	if (bus_err) {
+		/* Clear Error interrupt */
+		writel(QUP_RESET_STATE, qup->base + QUP_STATE);
+		goto done;
+	}
+
+	if (opflags & QUP_OUT_SVC_FLAG)
+		writel(QUP_OUT_SVC_FLAG, qup->base + QUP_OPERATIONAL);
+
+	if (qup->msg->flags == I2C_M_RD) {
+		if ((opflags & QUP_MX_INPUT_DONE) || (opflags & QUP_IN_SVC_FLAG))
+			writel(QUP_IN_SVC_FLAG, qup->base + QUP_OPERATIONAL);
+		else
+			return IRQ_HANDLED;
+	}
+
+done:
+	qup->qup_err = qup_err;
+	qup->bus_err = bus_err;
+	complete(&qup->xfer);
+	return IRQ_HANDLED;
+}
+
+static int
+qup_i2c_poll_state(struct qup_i2c_dev *qup, u32 req_state, bool only_valid)
+{
+	int retries = 0;
+	u32 state;
+
+	do {
+		state = readl(qup->base + QUP_STATE);
+
+		/*
+		 * If only valid bit needs to be checked, requested state is
+		 * 'don't care'
+		 */
+		if (state & QUP_STATE_VALID) {
+			if (only_valid)
+				return 0;
+			if ((req_state & QUP_I2C_MAST_GEN)
+			    && (state & QUP_I2C_MAST_GEN))
+				return 0;
+			if ((state & QUP_STATE_MASK) == req_state)
+				return 0;
+		}
+
+		udelay(1);
+	} while (retries++ != QUP_MAX_QUP_STATE_RETRIES);
+
+	return -ETIMEDOUT;
+}
+
+static int qup_i2c_change_state(struct qup_i2c_dev *qup, u32 state)
+{
+	if (qup_i2c_poll_state(qup, 0, true) != 0)
+		return -EIO;
+
+	writel(state, qup->base + QUP_STATE);
+
+	if (qup_i2c_poll_state(qup, state, false) != 0)
+		return -EIO;
+	return 0;
+}
+
+static void qup_i2c_enable_clocks(struct qup_i2c_dev *qup)
+{
+	clk_prepare_enable(qup->clk);
+	clk_prepare_enable(qup->pclk);
+}
+
+static void qup_i2c_disable_clocks(struct qup_i2c_dev *qup)
+{
+	u32 config;
+
+	qup_i2c_change_state(qup, QUP_RESET_STATE);
+	clk_disable_unprepare(qup->clk);
+	config = readl(qup->base + QUP_CONFIG);
+	config |= QUP_CLOCK_AUTO_GATE;
+	writel(config, qup->base + QUP_CONFIG);
+	clk_disable_unprepare(qup->pclk);
+}
+
+static int qup_i2c_wait_idle(struct qup_i2c_dev *qup, struct i2c_msg *msg)
+{
+	bool buf_full, bus_active;
+	int retries = 0;
+	u32 status;
+
+	do {
+		status = readl(qup->base + QUP_I2C_STATUS);
+		buf_full = status & I2C_STATUS_WR_BUFFER_FULL;
+		bus_active = status & I2C_STATUS_BUS_ACTIVE;
+
+		if (!buf_full) {
+			if ((msg->flags & I2C_M_RD) && !bus_active)
+				return 0;
+			else if (msg->flags == 0)
+				return 0;
+			else /* 1-bit delay before we check for bus busy */
+				udelay(qup->one_bit_t);
+		}
+
+		if (retries++ == 1000)
+			usleep_range(qup->wait_idle, qup->wait_idle + 10);
+
+	} while (retries != 2000);
+
+	dev_err(qup->dev, "Timeout waiting bus idle\n");
+	return -ETIMEDOUT;
+}
+
+static void qup_i2c_wait_clock_ready(struct qup_i2c_dev *qup)
+{
+	u32 have_data, clk_state, bus_state;
+	int retries = 0;
+
+	/*
+	 * Wait for the clock state to transition to either IDLE or FORCED
+	 * LOW. This will usually happen within one cycle of the i2c clock.
+	 */
+	do {
+		bus_state = readl(qup->base + QUP_I2C_STATUS);
+		clk_state = (bus_state >> I2C_STATUS_CLK_STATE) & 0x7;
+
+		have_data = readl(qup->base + QUP_OPERATIONAL);
+		have_data &= QUP_OUT_FIFO_NOT_EMPTY;
+
+		/*
+		 * In very corner case when slave do clock stretching and
+		 * output fifo will have 1 block of data space have_data at
+		 * the same time.  So i2c dev will get output service
+		 * interrupt and as it doesn't have more data to be written.
+		 * This can lead to issue where output fifo is not have_data.
+		 */
+		if (!have_data &&
+		    (clk_state == I2C_CLK_RESET_BUSIDLE_STATE ||
+		    clk_state == I2C_CLK_FORCED_LOW_STATE)) {
+			return;
+		}
+
+		/* 1-bit delay before we check again */
+		udelay(qup->one_bit_t);
+	} while (retries++ < QUP_MAX_CLK_STATE_RETRIES);
+
+	dev_warn(qup->dev, "Timeout clk_state: %x buffer %sempty\n", clk_state,
+		 have_data ? "not-" : "");
+}
+
+static void qup_i2c_set_read_mode(struct qup_i2c_dev *qup)
+{
+	/*
+	 * QUP limit QUP_READ_LIMIT bytes per read. By HW design, 0 in the
+	 * 8-bit field is treated as QUP_READ_LIMIT byte read.
+	 */
+	u16 len = (qup->cnt >= QUP_READ_LIMIT) ? QUP_READ_LIMIT : qup->cnt;
+
+	if (len <= qup->in_fifo_sz) {
+		/* FIFO mode */
+		writel(QUP_REPACK_EN, qup->base + QUP_IO_MODE);
+		writel(len, qup->base + QUP_MX_READ_CNT);
+	} else {
+		/* BLOCK mode (transfer data on chunks) */
+		writel(QUP_INPUT_BLK_MODE | QUP_REPACK_EN,
+				qup->base + QUP_IO_MODE);
+		writel(len, qup->base + QUP_MX_INPUT_CNT);
+	}
+}
+
+static void qup_i2c_issue_read(struct qup_i2c_dev *qup, struct i2c_msg *msg)
+{
+	u32 addr = (msg->addr << 1) | 1;
+	/*
+	 * QUP limit 256 bytes per read. By HW design, 0 in the
+	 * 8-bit field is treated as 256 byte read.
+	 */
+	u32 len = (qup->cnt >= QUP_READ_LIMIT) ? 0 : qup->cnt;
+	u32 val;
+
+	val = ((QUP_OUT_REC | len) << QUP_MSW_SHIFT) | QUP_OUT_START | addr;
+
+	writel(val, qup->base + QUP_OUT_FIFO_BASE);
+}
+
+
+static void qup_i2c_read_fifo(struct qup_i2c_dev *qup, struct i2c_msg *msg)
+{
+	u32 val, stat;
+	int idx;
+
+	val = 0;
+	for (idx = 0; qup->pos < msg->len; idx++, qup->pos++, qup->cnt--) {
+		if ((idx & 1) == 0) {
+			/* Check that FIFO have_data */
+			stat = readl(qup->base + QUP_OPERATIONAL);
+			if ((stat & QUP_IN_NOT_EMPTY) == 0)
+				break;
+
+			/* Reading 2 words at time */
+			val = readl(qup->base + QUP_IN_FIFO_BASE);
+
+			msg->buf[qup->pos] = val & 0xFF;
+		} else {
+			msg->buf[qup->pos] = val >> QUP_MSW_SHIFT;
+		}
+	}
+}
+
+static bool
+qup_i2c_set_write_mode(struct qup_i2c_dev *qup, struct i2c_msg *msg)
+{
+	bool block = false;
+	int total;
+
+	if (msg->len <= qup->out_fifo_sz) {
+		/* FIFO mode */
+		writel(QUP_REPACK_EN, qup->base + QUP_IO_MODE);
+	} else {
+		/* BLOCK mode (transfer data on chunks) */
+		total = msg->len + 1 + (msg->len / (qup->out_blk_sz - 1));
+		writel(QUP_OUTPUT_BLK_MODE | QUP_REPACK_EN,
+				qup->base + QUP_IO_MODE);
+		writel(total, qup->base + QUP_MX_OUTPUT_CNT);
+		block = true;
+	}
+
+	return block;
+}
+
+static void qup_i2c_issue_write(struct qup_i2c_dev *qup, struct i2c_msg *msg)
+{
+	u32 addr = msg->addr << 1;
+	u32 val, qup_tag;
+	int idx, entries;
+
+	if (qup->pos == 0) {
+		val = QUP_OUT_START | addr;
+	} else {
+		/*
+		 * Avoid setup time issue by adding 1 NOP when number of bytes
+		 * are more than FIFO/BLOCK size. setup time issue can't appear
+		 * otherwise since next byte to be written will always be ready
+		 */
+		val = (QUP_OUT_NOP | 1);
+	}
+
+	entries = qup->cnt + 1;
+
+	if (entries > qup->chunk_sz)
+		entries = qup->chunk_sz;
+
+	qup_tag = QUP_OUT_DATA;
+
+	/* Reserve one entry for STOP */
+	for (idx = 1; idx < entries - 1; idx++, qup->pos++) {
+
+		if (idx & 1) {
+			val |= (qup_tag | msg->buf[qup->pos]) << QUP_MSW_SHIFT;
+			writel(val, qup->base + QUP_OUT_FIFO_BASE);
+		} else {
+			val = qup_tag | msg->buf[qup->pos];
+		}
+	}
+
+	if (qup->pos == (msg->len - 1))
+		qup_tag = QUP_OUT_STOP;
+
+	if (idx & 1)
+		val |= (qup_tag | msg->buf[qup->pos]) << QUP_MSW_SHIFT;
+	else
+		val = qup_tag | msg->buf[qup->pos];
+
+	writel(val, qup->base + QUP_OUT_FIFO_BASE);
+
+	qup->pos++;
+	qup->cnt = msg->len - qup->pos;
+}
+
+static int qup_i2c_write_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
+{
+	unsigned long left;
+	bool block;
+	int ret;
+	int tmp;
+
+	if (!msg->len)
+		return -EINVAL;
+
+	qup->msg = msg;
+	qup->cnt = msg->len;
+
+	qup->chunk_sz = qup->out_fifo_sz;
+	qup->bus_err = 0;
+	qup->qup_err = 0;
+	qup->pos = 0;
+
+	enable_irq(qup->irq);
+
+	block = qup_i2c_set_write_mode(qup, msg);
+
+	reinit_completion(&qup->xfer);
+	ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
+	if (ret < 0)
+		goto err;
+
+	writel(qup->clk_ctl, qup->base + QUP_I2C_CLK_CTL);
+
+	if (block) {
+		/* Don't fill block till we get interrupt */
+		qup->chunk_sz = qup->out_blk_sz;
+		left = wait_for_completion_timeout(&qup->xfer, qup->xfer_time);
+		if (!left) {
+			writel(1, qup->base + QUP_SW_RESET);
+			ret = -ETIMEDOUT;
+			goto err;
+		}
+	}
+
+	do {
+		/* Note: transition to PAUSE state only possible from RUN */
+		ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
+		if (ret < 0)
+			goto err;
+
+		qup_i2c_issue_write(qup, msg);
+
+		reinit_completion(&qup->xfer);
+		ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
+		if (ret < 0)
+			goto err;
+
+		left = wait_for_completion_timeout(&qup->xfer, qup->xfer_time);
+		if (!left) {
+			writel(1, qup->base + QUP_SW_RESET);
+			ret = -ETIMEDOUT;
+			goto err;
+		}
+
+		if (qup->bus_err || qup->qup_err) {
+			if (qup->bus_err & QUP_I2C_NACK_FLAG)
+				dev_err(qup->dev, "NACK from %x\n", msg->addr);
+			ret = -EIO;
+			goto err;
+		}
+	} while (qup->cnt > 0);
+
+ err:
+	disable_irq(qup->irq);
+	qup->msg = NULL;
+
+	qup_i2c_wait_clock_ready(qup);
+
+	tmp = qup_i2c_change_state(qup, QUP_RESET_STATE);
+	if (!tmp)
+		tmp = qup_i2c_wait_idle(qup, msg);
+	if (!ret)
+		ret = tmp;
+
+	return ret;
+}
+
+static int qup_i2c_read_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
+{
+	unsigned long left;
+	int ret;
+	int tmp;
+
+	if (!msg->len)
+		return -EINVAL;
+
+	qup->cnt = msg->len;
+	qup->msg = msg;
+
+	qup->chunk_sz = qup->in_fifo_sz;
+	qup->bus_err = 0;
+	qup->qup_err = 0;
+	qup->pos  = 0;
+
+	enable_irq(qup->irq);
+
+	do {
+		qup_i2c_set_read_mode(qup);
+
+		reinit_completion(&qup->xfer);
+		ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
+		if (ret < 0)
+			goto err;
+
+		writel(qup->clk_ctl, qup->base + QUP_I2C_CLK_CTL);
+
+		/* Note: transition to PAUSE state only possible from RUN */
+		ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
+		if (ret < 0)
+			goto err;
+
+		/*
+		 * HW limits READ up to QUP_READ_LIMIT bytes in 1
+		 * read without stop
+		 */
+		qup_i2c_issue_read(qup, msg);
+
+		ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
+		if (ret < 0)
+			goto err;
+
+		left = wait_for_completion_timeout(&qup->xfer, qup->xfer_time);
+		if (!left) {
+			writel(1, qup->base + QUP_SW_RESET);
+			ret = -ETIMEDOUT;
+			goto err;
+		}
+
+		if (qup->bus_err || qup->qup_err) {
+			if (qup->bus_err & QUP_I2C_NACK_FLAG)
+				dev_err(qup->dev, "NACK from %x\n", msg->addr);
+			ret = -EIO;
+			goto err;
+		}
+
+		qup_i2c_read_fifo(qup, msg);
+	} while (qup->cnt > 0);
+
+ err:
+	disable_irq(qup->irq);
+	qup->msg = NULL;
+
+	tmp = qup_i2c_change_state(qup, QUP_RESET_STATE);
+	if (!tmp)
+		tmp = qup_i2c_wait_idle(qup, msg);
+	if (!ret)
+		ret = tmp;
+
+	return ret;
+}
+
+/*
+ * Prepare controller for a transaction and call omap_i2c_xfer_msg
+ * to do the work during IRQ processing.
+ */
+static int
+qup_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+	struct qup_i2c_dev *qup = i2c_get_adapdata(adap);
+	int ret, idx;
+
+	ret = pm_runtime_get_sync(qup->dev);
+	if (IS_ERR_VALUE(ret))
+		goto out;
+
+	writel(1, qup->base + QUP_SW_RESET);
+	ret = qup_i2c_poll_state(qup, QUP_RESET_STATE, false);
+	if (ret) {
+		dev_err(qup->dev, "cannot goto reset state\n");
+		goto out;
+	}
+
+	for (idx = 0; idx < num; idx++) {
+		/* Initialize QUP registers */
+		writel(0, qup->base + QUP_CONFIG);
+		writel(QUP_OPERATIONAL_RESET, qup->base + QUP_OPERATIONAL);
+		writel(QUP_STATUS_ERROR_FLAGS, qup->base + QUP_ERROR_FLAGS_EN);
+		writel(I2C_MINI_CORE | I2C_N_VAL, qup->base + QUP_CONFIG);
+
+		/* Initialize I2C mini core registers */
+		writel(0, qup->base + QUP_I2C_CLK_CTL);
+		writel(QUP_I2C_STATUS_RESET, qup->base + QUP_I2C_STATUS);
+
+		if (qup_i2c_poll_state(qup, QUP_I2C_MAST_GEN, false) != 0) {
+			ret = -EIO;
+			goto out;
+		}
+
+		if (msgs[idx].flags & I2C_M_RD)
+			ret = qup_i2c_read_one(qup, &msgs[idx]);
+		else
+			ret = qup_i2c_write_one(qup, &msgs[idx]);
+
+		if (ret)
+			break;
+	}
+
+	if (ret == 0)
+		ret = num;
+out:
+	pm_runtime_mark_last_busy(qup->dev);
+	pm_runtime_put_autosuspend(qup->dev);
+	return ret;
+}
+
+static u32 qup_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+}
+
+static const struct i2c_algorithm qup_i2c_algo = {
+	.master_xfer	= qup_i2c_xfer,
+	.functionality	= qup_i2c_func,
+};
+
+static int qup_i2c_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct qup_i2c_dev *qup;
+	struct resource *res;
+	u32 val, io_mode, hw_ver, size;
+	int ret, fs_div, hs_div;
+	int src_clk_freq;
+	int clk_freq;
+
+	qup = devm_kzalloc(&pdev->dev, sizeof(*qup), GFP_KERNEL);
+	if (!qup)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, qup);
+
+	ret = of_alias_get_id(node, "i2c");
+	if (ret >= 0)
+		pdev->id = ret;
+
+	qup->dev = &pdev->dev;
+
+	clk_freq = 100000;
+	if (!of_property_read_u32(node, "clock-frequency", &val))
+		clk_freq = val;
+
+	/* We support frequencies up to FAST Mode(400KHz) */
+	if (clk_freq <= 0 || clk_freq > 400000) {
+		dev_err(qup->dev, "clock frequency not supported %d\n",
+			clk_freq);
+		return -EIO;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	qup->base = devm_ioremap_resource(qup->dev, res);
+	if (IS_ERR(qup->base))
+		return PTR_ERR(qup->base);
+
+	qup->irq = platform_get_irq(pdev, 0);
+	if (qup->irq < 0) {
+		dev_err(qup->dev, "No IRQ defined\n");
+		return qup->irq;
+	}
+
+	qup->clk = devm_clk_get(qup->dev, "core");
+	if (IS_ERR(qup->clk)) {
+		dev_err(qup->dev, "Could not get core clock\n");
+		return PTR_ERR(qup->clk);
+	}
+
+	qup->pclk = devm_clk_get(qup->dev, "iface");
+	if (IS_ERR(qup->pclk)) {
+		dev_err(qup->dev, "Could not get iface clock\n");
+		return PTR_ERR(qup->pclk);
+	}
+
+	init_completion(&qup->xfer);
+
+	qup_i2c_enable_clocks(qup);
+
+	/*
+	 * Bootloaders might leave a pending interrupt on certain QUP's,
+	 * so we reset the core before registering for interrupts.
+	 */
+	writel(1, qup->base + QUP_SW_RESET);
+	ret = qup_i2c_poll_state(qup, 0, true);
+	if (ret)
+		goto fail;
+
+	ret = devm_request_irq(qup->dev, qup->irq, qup_i2c_interrupt,
+			       IRQF_TRIGGER_HIGH, "i2c_qup", qup);
+	if (ret) {
+		dev_err(qup->dev, "Request %d IRQ failed\n", qup->irq);
+		goto fail;
+	}
+	disable_irq(qup->irq);
+
+	hw_ver = readl(qup->base + QUP_HW_VERSION);
+	dev_dbg(qup->dev, "%d Revision %x\n", pdev->id, hw_ver);
+
+	src_clk_freq = clk_get_rate(qup->clk);
+	fs_div = ((src_clk_freq / clk_freq) / 2) - 3;
+	hs_div = 3;
+	qup->clk_ctl = (hs_div << 8) | (fs_div & 0xff);
+	qup->one_bit_t = (USEC_PER_SEC / clk_freq) + 1;
+
+	io_mode = readl(qup->base + QUP_IO_MODE);
+
+	size = QUP_OUTPUT_BLOCK_SIZE(io_mode);
+	if (size)
+		qup->out_blk_sz = size * 16;
+	else
+		qup->out_blk_sz = 16;
+
+	size = QUP_INPUT_BLOCK_SIZE(io_mode);
+	if (size)
+		qup->in_blk_sz = size * 16;
+	else
+		qup->in_blk_sz = 16;
+
+	qup->xfer_time = msecs_to_jiffies(qup->out_fifo_sz);
+
+	/*
+	 * The block/fifo size w.r.t. 'actual data' is 1/2 due to 'tag'
+	 * associated with each byte written/received
+	 */
+	qup->out_blk_sz /= 2;
+	qup->in_blk_sz /= 2;
+
+	size = QUP_OUTPUT_FIFO_SIZE(io_mode);
+	qup->out_fifo_sz = qup->out_blk_sz * (2 << size);
+
+	size = QUP_INPUT_FIFO_SIZE(io_mode);
+	qup->in_fifo_sz = qup->in_blk_sz * (2 << size);
+
+	/*
+	 * Wait for FIFO number of bytes to be absolutely sure
+	 * that I2C write state machine is not idle. Each byte
+	 * takes 9 clock cycles. (8 bits + 1 ack)
+	 */
+	qup->wait_idle = qup->one_bit_t * 9;
+	qup->wait_idle *= qup->out_fifo_sz;
+
+	dev_info(qup->dev, "IN:block:%d, fifo:%d, OUT:block:%d, fifo:%d\n",
+		qup->in_blk_sz, qup->in_fifo_sz,
+		qup->out_blk_sz, qup->out_fifo_sz);
+
+	i2c_set_adapdata(&qup->adap, qup);
+	qup->adap.algo = &qup_i2c_algo;
+	qup->adap.nr = pdev->id;
+	qup->adap.dev.parent = qup->dev;
+	qup->adap.dev.of_node = pdev->dev.of_node;
+	strlcpy(qup->adap.name, "QUP I2C adapter", sizeof(qup->adap.name));
+
+	ret = i2c_add_numbered_adapter(&qup->adap);
+	if (!ret) {
+		pm_runtime_set_autosuspend_delay(qup->dev, MSEC_PER_SEC);
+		pm_runtime_use_autosuspend(qup->dev);
+		pm_runtime_enable(qup->dev);
+		return 0;
+	}
+fail:
+	qup_i2c_disable_clocks(qup);
+	return ret;
+}
+
+static int qup_i2c_remove(struct platform_device *pdev)
+{
+	struct qup_i2c_dev *qup = platform_get_drvdata(pdev);
+
+	disable_irq(qup->irq);
+	qup_i2c_disable_clocks(qup);
+	i2c_del_adapter(&qup->adap);
+	pm_runtime_disable(qup->dev);
+	pm_runtime_set_suspended(qup->dev);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int qup_i2c_pm_suspend_runtime(struct device *device)
+{
+	struct qup_i2c_dev *qup = dev_get_drvdata(device);
+
+	dev_dbg(device, "pm_runtime: suspending...\n");
+	qup_i2c_disable_clocks(qup);
+	return 0;
+}
+
+static int qup_i2c_pm_resume_runtime(struct device *device)
+{
+	struct qup_i2c_dev *qup = dev_get_drvdata(device);
+
+	dev_dbg(device, "pm_runtime: resuming...\n");
+	qup_i2c_enable_clocks(qup);
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_PM_SLEEP
+static int qup_i2c_suspend(struct device *device)
+{
+	dev_dbg(device, "system suspend");
+	qup_i2c_pm_suspend_runtime(device);
+	return 0;
+}
+
+static int qup_i2c_resume(struct device *device)
+{
+	dev_dbg(device, "system resume");
+	qup_i2c_pm_resume_runtime(device);
+	pm_runtime_mark_last_busy(device);
+	pm_request_autosuspend(device);
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops qup_i2c_qup_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(
+		qup_i2c_suspend,
+		qup_i2c_resume)
+	SET_RUNTIME_PM_OPS(
+		qup_i2c_pm_suspend_runtime,
+		qup_i2c_pm_resume_runtime,
+		NULL)
+};
+
+static const struct of_device_id qup_i2c_dt_match[] = {
+	{.compatible = "qcom,i2c-qup"},
+	{}
+};
+MODULE_DEVICE_TABLE(of, qup_i2c_dt_match);
+
+static struct platform_driver qup_i2c_driver = {
+	.probe  = qup_i2c_probe,
+	.remove = qup_i2c_remove,
+	.driver = {
+		.name = "i2c_qup",
+		.owner = THIS_MODULE,
+		.pm = &qup_i2c_qup_pm_ops,
+		.of_match_table = qup_i2c_dt_match,
+	},
+};
+
+module_platform_driver(qup_i2c_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:i2c_qup");
-- 
1.8.2.2

Re: [PATCH v3 1/2] i2c: qup: Add device tree bindings information

[Rob Herring]

On Fri, Jan 17, 2014 at 5:03 PM, Bjorn Andersson
<bjorn.andersson@sonymobile.com> wrote:
> From: "Ivan T. Ivanov" <iivanov@mm-sol.com>
>
> The Qualcomm Universal Peripherial (QUP) wraps I2C mini-core and
> provide input and output FIFO's for it. I2C controller can operate
> as master with supported bus speeds of 100Kbps and 400Kbps.
>
> Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
> [bjorn: reformulated part of binding description and cleaned up example]
> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> ---

Patch history?

>  .../devicetree/bindings/i2c/qcom,i2c-qup.txt       | 41 ++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
>
> diff --git a/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
> new file mode 100644
> index 0000000..a99711b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
> @@ -0,0 +1,41 @@
> +Qualcomm Universal Peripheral (QUP) I2C controller
> +
> +Required properties:
> + - compatible: Should be "qcom,i2c-qup".

Seems a bit generic. All versions of the IP are exactly the same?
"qcom,<chip>-i2c-qup" would be better.

> + - reg: Should contain QUP register address and length.
> + - interrupts: Should contain I2C interrupt.
> +
> + - clocks: Should contain the core clock and the AHB clock.
> + - clock-names: Should be "core" for the core clock and "iface" for the
> +                AHB clock.
> +
> + - #address-cells: Should be <1> Address cells for i2c device address
> + - #size-cells: Should be <0> as i2c addresses have no size component
> +
> +Optional properties:
> + - clock-frequency: Should specify the desired i2c bus clock frequency in Hz,
> +                    default is 100kHz if omitted.
> +
> +Child nodes should conform to i2c bus binding.
> +
> +Example:
> +
> + i2c2: i2c@f9924000 {
> +       compatible = "qcom,i2c-qup";
> +       reg = <0xf9924000 0x1000>;
> +       interrupts = <0 96 0>;
> +
> +       clocks = <&gcc_blsp1_qup2_i2c_apps_clk>, <&gcc_blsp1_ahb_clk>;
> +       clock-names = "core", "iface";
> +
> +       clock-frequency = <355000>;
> +
> +       #address-cells = <1>;
> +       #size-cells = <0>;
> +
> +       dummy@60 {
> +               compatible = "dummy";
> +               reg = <0x60>;
> +       };
> + };
> +
> --
> 1.8.2.2
>
> --
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> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v3 2/2] i2c: New bus driver for the QUP I2C controller

[Stephen Boyd]

On 01/17, Bjorn Andersson wrote:
> diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
> new file mode 100644
> index 0000000..2e0020e
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-qup.c
> @@ -0,0 +1,894 @@
> +/* Copyright (c) 2009-2013, The Linux Foundation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 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.
> + *
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +
> +/* QUP Registers */
> +#define QUP_CONFIG		0x000
> +#define QUP_STATE		0x004
> +#define QUP_IO_MODE		0x008
> +#define QUP_SW_RESET		0x00c
> +#define QUP_OPERATIONAL		0x018
> +#define QUP_ERROR_FLAGS		0x01c
> +#define QUP_ERROR_FLAGS_EN	0x020
> +#define QUP_HW_VERSION		0x030
> +#define QUP_MX_OUTPUT_CNT	0x100
> +#define QUP_OUT_FIFO_BASE	0x110
> +#define QUP_MX_WRITE_CNT	0x150
> +#define QUP_MX_INPUT_CNT	0x200
> +#define QUP_MX_READ_CNT		0x208
> +#define QUP_IN_FIFO_BASE	0x218
> +#define QUP_I2C_CLK_CTL		0x400
> +#define QUP_I2C_STATUS		0x404
> +
> +/* QUP States and reset values */
> +#define QUP_RESET_STATE		0
> +#define QUP_RUN_STATE		1
> +#define QUP_PAUSE_STATE		3
> +#define QUP_STATE_MASK		3
> +
> +#define QUP_STATE_VALID		BIT(2)
> +#define QUP_I2C_MAST_GEN	BIT(4)
> +
> +#define QUP_OPERATIONAL_RESET	0x000ff0
> +#define QUP_I2C_STATUS_RESET	0xfffffc
> +
> +/* QUP OPERATIONAL FLAGS */
> +#define QUP_OUT_SVC_FLAG	BIT(8)
> +#define QUP_IN_SVC_FLAG		BIT(9)
> +#define QUP_MX_INPUT_DONE	BIT(11)
> +
> +/* I2C mini core related values */
> +#define I2C_MINI_CORE		(2 << 8)
> +#define I2C_N_VAL		15
> +/* Most significant word offset in FIFO port */
> +#define QUP_MSW_SHIFT		(I2C_N_VAL + 1)
> +#define QUP_CLOCK_AUTO_GATE	BIT(13)
> +
> +/* Packing/Unpacking words in FIFOs, and IO modes */
> +#define QUP_UNPACK_EN		BIT(14)
> +#define QUP_PACK_EN		BIT(15)
> +#define QUP_OUTPUT_BLK_MODE	BIT(10)
> +#define QUP_INPUT_BLK_MODE	BIT(12)
> +
> +#define QUP_REPACK_EN		(QUP_UNPACK_EN | QUP_PACK_EN)
> +
> +#define QUP_OUTPUT_BLOCK_SIZE(x)(((x) & (0x03 << 0)) >> 0)
> +#define QUP_OUTPUT_FIFO_SIZE(x)	(((x) & (0x07 << 2)) >> 2)
> +#define QUP_INPUT_BLOCK_SIZE(x)	(((x) & (0x03 << 5)) >> 5)
> +#define QUP_INPUT_FIFO_SIZE(x)	(((x) & (0x07 << 7)) >> 7)
> +
> +/* QUP tags */
> +#define QUP_OUT_NOP		(0 << 8)
> +#define QUP_OUT_START		(1 << 8)
> +#define QUP_OUT_DATA		(2 << 8)
> +#define QUP_OUT_STOP		(3 << 8)
> +#define QUP_OUT_REC		(4 << 8)
> +#define QUP_IN_DATA		(5 << 8)
> +#define QUP_IN_STOP		(6 << 8)
> +#define QUP_IN_NACK		(7 << 8)
> +
> +/* Status, Error flags */
> +#define I2C_STATUS_WR_BUFFER_FULL	BIT(0)
> +#define I2C_STATUS_BUS_ACTIVE		BIT(8)
> +#define I2C_STATUS_BUS_MASTER		BIT(9)
> +#define I2C_STATUS_ERROR_MASK		0x38000fc
> +#define QUP_I2C_NACK_FLAG		BIT(3)
> +#define QUP_IN_NOT_EMPTY		BIT(5)
> +#define QUP_STATUS_ERROR_FLAGS		0x7c
> +
> +/* Master bus_err clock states */
> +#define I2C_CLK_RESET_BUSIDLE_STATE	0
> +#define I2C_CLK_FORCED_LOW_STATE	5
> +
> +#define QUP_MAX_CLK_STATE_RETRIES	300
> +#define QUP_MAX_QUP_STATE_RETRIES	100
> +#define I2C_STATUS_CLK_STATE		13
> +#define QUP_OUT_FIFO_NOT_EMPTY		0x10
> +#define QUP_READ_LIMIT			256
> +
> +struct qup_i2c_dev {
> +	struct device		*dev;
> +	void __iomem		*base;
> +	int			irq;
> +	struct clk		*clk;
> +	struct clk		*pclk;
> +	struct i2c_adapter	adap;
> +
> +	int			clk_ctl;
> +	int			one_bit_t;
> +	int			out_fifo_sz;
> +	int			in_fifo_sz;
> +	int			out_blk_sz;
> +	int			in_blk_sz;
> +	unsigned long		xfer_time;
> +	unsigned long		wait_idle;
> +
> +	struct i2c_msg		*msg;
> +	/* Current posion in user message buffer */

s/posion/position/

> +	int			pos;
> +	/* Keep number of bytes left to be transmitted */
> +	int			cnt;
> +	/* I2C protocol errors */
> +	u32			bus_err;
> +	/* QUP core errors */
> +	u32			qup_err;
> +	/*
> +	 * Maximum bytes that could be send (per iteration). Could be
> +	 * equal of fifo size or block size (in block mode)
> +	 */
> +	int			chunk_sz;
> +	struct completion	xfer;
> +};
[...]
> +
> +static int
> +qup_i2c_poll_state(struct qup_i2c_dev *qup, u32 req_state, bool only_valid)
> +{
> +	int retries = 0;
> +	u32 state;
> +
> +	do {
> +		state = readl(qup->base + QUP_STATE);
> +
> +		/*
> +		 * If only valid bit needs to be checked, requested state is
> +		 * 'don't care'
> +		 */
> +		if (state & QUP_STATE_VALID) {
> +			if (only_valid)
> +				return 0;
> +			if ((req_state & QUP_I2C_MAST_GEN)
> +			    && (state & QUP_I2C_MAST_GEN))
> +				return 0;
> +			if ((state & QUP_STATE_MASK) == req_state)
> +				return 0;
> +		}
> +
> +		udelay(1);
> +	} while (retries++ != QUP_MAX_QUP_STATE_RETRIES);
> +
> +	return -ETIMEDOUT;
> +}
> +

This is what I was suggesting. Don't know if it's any clearer,
but it saves us a whopping 3 lines!

---8<----
 drivers/i2c/busses/i2c-qup.c | 43 ++++++++++++++++++++-----------------------
 1 file changed, 20 insertions(+), 23 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index 2e0020e829ae..431de13f6281 100644
--- a/drivers/i2c/busses/i2c-qup.c
+++ b/drivers/i2c/busses/i2c-qup.c
@@ -47,7 +47,7 @@
 #define QUP_STATE_MASK		3
 
 #define QUP_STATE_VALID		BIT(2)
-#define QUP_I2C_MAST_GEN	BIT(4)
+#define QUP_I2C_MAST_GEN	(QUP_STATE_VALID | BIT(4))
 
 #define QUP_OPERATIONAL_RESET	0x000ff0
 #define QUP_I2C_STATUS_RESET	0xfffffc
@@ -190,43 +190,40 @@ done:
 	return IRQ_HANDLED;
 }
 
-static int
-qup_i2c_poll_state(struct qup_i2c_dev *qup, u32 req_state, bool only_valid)
+static int __qup_i2c_poll_state(struct qup_i2c_dev *qup, u32 mask, u32 value)
 {
 	int retries = 0;
 	u32 state;
 
 	do {
 		state = readl(qup->base + QUP_STATE);
-
-		/*
-		 * If only valid bit needs to be checked, requested state is
-		 * 'don't care'
-		 */
-		if (state & QUP_STATE_VALID) {
-			if (only_valid)
-				return 0;
-			if ((req_state & QUP_I2C_MAST_GEN)
-			    && (state & QUP_I2C_MAST_GEN))
-				return 0;
-			if ((state & QUP_STATE_MASK) == req_state)
-				return 0;
-		}
-
+		if ((state & mask) == value)
+			return 0;
 		udelay(1);
 	} while (retries++ != QUP_MAX_QUP_STATE_RETRIES);
 
 	return -ETIMEDOUT;
 }
 
+static int qup_i2c_poll_state_bit(struct qup_i2c_dev *qup, u32 mask)
+{
+	return __qup_i2c_poll_state(qup, mask, mask);
+}
+
+static int qup_i2c_poll_state(struct qup_i2c_dev *qup, u32 state)
+{
+	return __qup_i2c_poll_state(qup, QUP_STATE_VALID | QUP_STATE_MASK,
+					 QUP_STATE_VALID | state);
+}
+
 static int qup_i2c_change_state(struct qup_i2c_dev *qup, u32 state)
 {
-	if (qup_i2c_poll_state(qup, 0, true) != 0)
+	if (qup_i2c_poll_state_bit(qup, QUP_STATE_VALID) != 0)
 		return -EIO;
 
 	writel(state, qup->base + QUP_STATE);
 
-	if (qup_i2c_poll_state(qup, state, false) != 0)
+	if (qup_i2c_poll_state(qup, state) != 0)
 		return -EIO;
 	return 0;
 }
@@ -616,7 +613,7 @@ qup_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 		goto out;
 
 	writel(1, qup->base + QUP_SW_RESET);
-	ret = qup_i2c_poll_state(qup, QUP_RESET_STATE, false);
+	ret = qup_i2c_poll_state(qup, QUP_RESET_STATE);
 	if (ret) {
 		dev_err(qup->dev, "cannot goto reset state\n");
 		goto out;
@@ -633,7 +630,7 @@ qup_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 		writel(0, qup->base + QUP_I2C_CLK_CTL);
 		writel(QUP_I2C_STATUS_RESET, qup->base + QUP_I2C_STATUS);
 
-		if (qup_i2c_poll_state(qup, QUP_I2C_MAST_GEN, false) != 0) {
+		if (qup_i2c_poll_state_bit(qup, QUP_I2C_MAST_GEN) != 0) {
 			ret = -EIO;
 			goto out;
 		}
@@ -730,7 +727,7 @@ static int qup_i2c_probe(struct platform_device *pdev)
 	 * so we reset the core before registering for interrupts.
 	 */
 	writel(1, qup->base + QUP_SW_RESET);
-	ret = qup_i2c_poll_state(qup, 0, true);
+	ret = qup_i2c_poll_state(qup, QUP_STATE_VALID);
 	if (ret)
 		goto fail;
 

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Re: [PATCH v3 1/2] i2c: qup: Add device tree bindings information

[Stephen Boyd]

On 01/20, Rob Herring wrote:
> On Fri, Jan 17, 2014 at 5:03 PM, Bjorn Andersson
> <bjorn.andersson@sonymobile.com> wrote:
> 
> >  .../devicetree/bindings/i2c/qcom,i2c-qup.txt       | 41 ++++++++++++++++++++++
> >  1 file changed, 41 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
> >
> > diff --git a/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
> > new file mode 100644
> > index 0000000..a99711b
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
> > @@ -0,0 +1,41 @@
> > +Qualcomm Universal Peripheral (QUP) I2C controller
> > +
> > +Required properties:
> > + - compatible: Should be "qcom,i2c-qup".
> 
> Seems a bit generic. All versions of the IP are exactly the same?
> "qcom,<chip>-i2c-qup" would be better.
> 

There are different versions of the IP in different SoCs. The
versions for platforms supported upstream are:

	1.1.1 (MSM8660, MSM8960)
	2.2.1 (MSM8974v2)

so how about one of "qcom,i2c-qup-v1.1.1" or
"qcom,i2c-qup-v2.2.1" should be specified as more specific
compatible strings in addition to "qcom,i2c-qup"?

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hosted by The Linux Foundation

Re: [PATCH v3 1/2] i2c: qup: Add device tree bindings information

[Matthew Locke]

Rob,

On Jan 20, 2014, at 8:10 AM, Rob Herring wrote:

> On Fri, Jan 17, 2014 at 5:03 PM, Bjorn Andersson
> <bjorn.andersson@sonymobile.com> wrote:
>> From: "Ivan T. Ivanov" <iivanov@mm-sol.com>
>> 
>> The Qualcomm Universal Peripherial (QUP) wraps I2C mini-core and
>> provide input and output FIFO's for it. I2C controller can operate
>> as master with supported bus speeds of 100Kbps and 400Kbps.
>> 
>> Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
>> [bjorn: reformulated part of binding description and cleaned up example]
>> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
>> ---
> 
> Patch history?
> 
>> .../devicetree/bindings/i2c/qcom,i2c-qup.txt       | 41 ++++++++++++++++++++++
>> 1 file changed, 41 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
>> 
>> diff --git a/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
>> new file mode 100644
>> index 0000000..a99711b
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
>> @@ -0,0 +1,41 @@
>> +Qualcomm Universal Peripheral (QUP) I2C controller
>> +
>> +Required properties:
>> + - compatible: Should be "qcom,i2c-qup".
> 
> Seems a bit generic. All versions of the IP are exactly the same?
> "qcom,<chip>-i2c-qup" would be better.

The QUP IP block is the same across chips.  Its possible there could be different versions of the IP block but its pretty stable now. 

> 
>> + - reg: Should contain QUP register address and length.
>> + - interrupts: Should contain I2C interrupt.
>> +
>> + - clocks: Should contain the core clock and the AHB clock.
>> + - clock-names: Should be "core" for the core clock and "iface" for the
>> +                AHB clock.
>> +
>> + - #address-cells: Should be <1> Address cells for i2c device address
>> + - #size-cells: Should be <0> as i2c addresses have no size component
>> +
>> +Optional properties:
>> + - clock-frequency: Should specify the desired i2c bus clock frequency in Hz,
>> +                    default is 100kHz if omitted.
>> +
>> +Child nodes should conform to i2c bus binding.
>> +
>> +Example:
>> +
>> + i2c2: i2c@f9924000 {
>> +       compatible = "qcom,i2c-qup";
>> +       reg = <0xf9924000 0x1000>;
>> +       interrupts = <0 96 0>;
>> +
>> +       clocks = <&gcc_blsp1_qup2_i2c_apps_clk>, <&gcc_blsp1_ahb_clk>;
>> +       clock-names = "core", "iface";
>> +
>> +       clock-frequency = <355000>;
>> +
>> +       #address-cells = <1>;
>> +       #size-cells = <0>;
>> +
>> +       dummy@60 {
>> +               compatible = "dummy";
>> +               reg = <0x60>;
>> +       };
>> + };
>> +
>> --
>> 1.8.2.2
>> 
>> --
>> To unsubscribe from this list: send the line "unsubscribe devicetree" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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Re: [PATCH v3 1/2] i2c: qup: Add device tree bindings information

[Arnd Bergmann]

On Thursday 23 January 2014, Matthew Locke wrote:
> The QUP IP block is the same across chips.  Its possible there could be different versions of the IP block but its pretty stable now. 

Do you know the version numbers of the IP block? That would be the ideal case. We just
fall back to using the SoC name in most cases because that's all that is publically
known.

	Arnd

Re: [PATCH v3 1/2] i2c: qup: Add device tree bindings information

[Bjorn Andersson]

On Thu, Jan 23, 2014 at 11:11 AM, Matthew Locke <mlocke@codeaurora.org> wrote:
> Rob,
>
> On Jan 20, 2014, at 8:10 AM, Rob Herring wrote:
>
>> On Fri, Jan 17, 2014 at 5:03 PM, Bjorn Andersson
[...]
>>> +Required properties:
>>> + - compatible: Should be "qcom,i2c-qup".
>>
>> Seems a bit generic. All versions of the IP are exactly the same?
>> "qcom,<chip>-i2c-qup" would be better.
>
> The QUP IP block is the same across chips.  Its possible there could be different versions of the IP block but its pretty stable now.

I have not been able to find any differences in this block between
8960 and 8074 and I have successfully tested the driver on both
platforms.

So the reason for making it more specific would be to handle any
future crazyness. Not sure what to do about this though, I have never
heard about the version numbers Stephen gave us and I can't find them
in the documentation available to us, so I wouldn't know which of the
two to select...

Regards,
Bjorn

Re: [PATCH v3 2/2] i2c: New bus driver for the QUP I2C controller

[Philip Elcan]

On 01/17/2014 06:03 PM, Bjorn Andersson wrote:
> From: "Ivan T. Ivanov" <iivanov@mm-sol.com>
> 
> This bus driver supports the QUP i2c hardware controller in the Qualcomm
> MSM SOCs.  The Qualcomm Universal Peripheral Engine (QUP) is a general
> purpose data path engine with input/output FIFOs and an embedded i2c
> mini-core. The driver supports FIFO mode (for low bandwidth	applications)
> and block mode (interrupt generated for each block-size data transfer).
> The driver currently does not support DMA transfers.
> 
> Shamelessly based on codeaurora version of the driver.
> 
> Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
> [bjorn: updated to reflect i2c framework changes
>         splited up qup_i2c_enable() in enable/disable
>         don't overwrite ret value on error in xfer functions
>         initilize core for each transfer
>         remove explicit pinctrl selection
>         use existing clock instead of setting new core clock]
> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> ---

<snip>

> +
> +	io_mode = readl(qup->base + QUP_IO_MODE);
> +
> +	size = QUP_OUTPUT_BLOCK_SIZE(io_mode);
> +	if (size)
> +		qup->out_blk_sz = size * 16;
> +	else
> +		qup->out_blk_sz = 16;
> +
> +	size = QUP_INPUT_BLOCK_SIZE(io_mode);
> +	if (size)
> +		qup->in_blk_sz = size * 16;
> +	else
> +		qup->in_blk_sz = 16;
> +
> +	qup->xfer_time = msecs_to_jiffies(qup->out_fifo_sz);

qup->xfer_time should be set after you calculate qup->out_fifo_sz below.

> +
> +	/*
> +	 * The block/fifo size w.r.t. 'actual data' is 1/2 due to 'tag'
> +	 * associated with each byte written/received
> +	 */
> +	qup->out_blk_sz /= 2;
> +	qup->in_blk_sz /= 2;
> +
> +	size = QUP_OUTPUT_FIFO_SIZE(io_mode);
> +	qup->out_fifo_sz = qup->out_blk_sz * (2 << size);
> +
> +	size = QUP_INPUT_FIFO_SIZE(io_mode);
> +	qup->in_fifo_sz = qup->in_blk_sz * (2 << size);
> +
> +	/*
> +	 * Wait for FIFO number of bytes to be absolutely sure
> +	 * that I2C write state machine is not idle. Each byte
> +	 * takes 9 clock cycles. (8 bits + 1 ack)
> +	 */
> +	qup->wait_idle = qup->one_bit_t * 9;
> +	qup->wait_idle *= qup->out_fifo_sz;
> +
> +	dev_info(qup->dev, "IN:block:%d, fifo:%d, OUT:block:%d, fifo:%d\n",
> +		qup->in_blk_sz, qup->in_fifo_sz,
> +		qup->out_blk_sz, qup->out_fifo_sz);
> +
> +	i2c_set_adapdata(&qup->adap, qup);
> +	qup->adap.algo = &qup_i2c_algo;
> +	qup->adap.nr = pdev->id;
> +	qup->adap.dev.parent = qup->dev;
> +	qup->adap.dev.of_node = pdev->dev.of_node;
> +	strlcpy(qup->adap.name, "QUP I2C adapter", sizeof(qup->adap.name));
> +
> +	ret = i2c_add_numbered_adapter(&qup->adap);
> +	if (!ret) {
> +		pm_runtime_set_autosuspend_delay(qup->dev, MSEC_PER_SEC);
> +		pm_runtime_use_autosuspend(qup->dev);
> +		pm_runtime_enable(qup->dev);
> +		return 0;
> +	}
> +fail:
> +	qup_i2c_disable_clocks(qup);
> +	return ret;
> +}
> +
> +static int qup_i2c_remove(struct platform_device *pdev)
> +{
> +	struct qup_i2c_dev *qup = platform_get_drvdata(pdev);
> +
> +	disable_irq(qup->irq);
> +	qup_i2c_disable_clocks(qup);
> +	i2c_del_adapter(&qup->adap);
> +	pm_runtime_disable(qup->dev);
> +	pm_runtime_set_suspended(qup->dev);
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int qup_i2c_pm_suspend_runtime(struct device *device)
> +{
> +	struct qup_i2c_dev *qup = dev_get_drvdata(device);
> +
> +	dev_dbg(device, "pm_runtime: suspending...\n");
> +	qup_i2c_disable_clocks(qup);
> +	return 0;
> +}
> +
> +static int qup_i2c_pm_resume_runtime(struct device *device)
> +{
> +	struct qup_i2c_dev *qup = dev_get_drvdata(device);
> +
> +	dev_dbg(device, "pm_runtime: resuming...\n");
> +	qup_i2c_enable_clocks(qup);
> +	return 0;
> +}
> +#endif
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int qup_i2c_suspend(struct device *device)
> +{
> +	dev_dbg(device, "system suspend");
> +	qup_i2c_pm_suspend_runtime(device);
> +	return 0;
> +}
> +
> +static int qup_i2c_resume(struct device *device)
> +{
> +	dev_dbg(device, "system resume");
> +	qup_i2c_pm_resume_runtime(device);
> +	pm_runtime_mark_last_busy(device);
> +	pm_request_autosuspend(device);
> +	return 0;
> +}
> +#endif
> +
> +static const struct dev_pm_ops qup_i2c_qup_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(
> +		qup_i2c_suspend,
> +		qup_i2c_resume)
> +	SET_RUNTIME_PM_OPS(
> +		qup_i2c_pm_suspend_runtime,
> +		qup_i2c_pm_resume_runtime,
> +		NULL)
> +};
> +
> +static const struct of_device_id qup_i2c_dt_match[] = {
> +	{.compatible = "qcom,i2c-qup"},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, qup_i2c_dt_match);
> +
> +static struct platform_driver qup_i2c_driver = {
> +	.probe  = qup_i2c_probe,
> +	.remove = qup_i2c_remove,
> +	.driver = {
> +		.name = "i2c_qup",
> +		.owner = THIS_MODULE,
> +		.pm = &qup_i2c_qup_pm_ops,
> +		.of_match_table = qup_i2c_dt_match,
> +	},
> +};
> +
> +module_platform_driver(qup_i2c_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:i2c_qup");
> 


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Re: [PATCH v3 1/2] i2c: qup: Add device tree bindings information

[Andy Gross]

On Mon, Jan 20, 2014 at 06:40:07PM -0800, Stephen Boyd wrote:
> On 01/20, Rob Herring wrote:
> > On Fri, Jan 17, 2014 at 5:03 PM, Bjorn Andersson
> > <bjorn.andersson@sonymobile.com> wrote:
> > 
> > >  .../devicetree/bindings/i2c/qcom,i2c-qup.txt       | 41 ++++++++++++++++++++++
> > >  1 file changed, 41 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
> > >
> > > diff --git a/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
> > > new file mode 100644
> > > index 0000000..a99711b
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/i2c/qcom,i2c-qup.txt
> > > @@ -0,0 +1,41 @@
> > > +Qualcomm Universal Peripheral (QUP) I2C controller
> > > +
> > > +Required properties:
> > > + - compatible: Should be "qcom,i2c-qup".
> > 
> > Seems a bit generic. All versions of the IP are exactly the same?
> > "qcom,<chip>-i2c-qup" would be better.
> > 
> 
> There are different versions of the IP in different SoCs. The
> versions for platforms supported upstream are:
> 
> 	1.1.1 (MSM8660, MSM8960)
> 	2.2.1 (MSM8974v2)
> 
> so how about one of "qcom,i2c-qup-v1.1.1" or
> "qcom,i2c-qup-v2.2.1" should be specified as more specific
> compatible strings in addition to "qcom,i2c-qup"?
> 

This definitely needs two compatible tags.  The v1.1.1 supports the FIFO, block,
and data mover modes.  The v2.2.1 supports FIFO, block, and BAM DMA.

The BAM patches are currently in review and ideally BAM support can be added to
the I2C.  We'll need a way to differentiate so BAM can be used.

Otherwise, the register interfaces are interchangeable except for BAM specific
fields in the registers.


> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

-- 
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Re: [PATCH v3 0/2] Qualcomm Universal Peripheral (QUP) I2C controller

[Ivan T. Ivanov]

Hi Bjorn,

On Fri, 2014-01-17 at 15:03 -0800, Bjorn Andersson wrote: 
> Continuing on Ivans i2c-qup series.
> 

Do you plan to send v4 of this driver? I would like to address
the remaining errors and suggestions and send a new version.

Regards,
Ivan

Re: [PATCH v3 0/2] Qualcomm Universal Peripheral (QUP) I2C controller

[Bjorn Andersson]

On Wed, Jan 29, 2014 at 12:14 AM, Ivan T. Ivanov <iivanov@mm-sol.com> wrote:
>
> Hi Bjorn,
>
> On Fri, 2014-01-17 at 15:03 -0800, Bjorn Andersson wrote:
>> Continuing on Ivans i2c-qup series.
>>
>
> Do you plan to send v4 of this driver? I would like to address
> the remaining errors and suggestions and send a new version.
>
Hi Ivan,

Yes I'm planning to send out a new revision of the patch set.

I've incorporated fixes from the review comments here and my colleague
concluded through some testing that block read did not work, so we've
fixed that as well.

What have been holding me from submitting a new patchset is the 3
functions that does polling of state and status updates;
* qup_i2c_poll_state() reads the state register up to 1000 times,
hoping we reach the expected state, will delay 100uS and then continue
with 1000 more retries.
  According to the data sheet a state transition is supposed to take
up to 2 bus cycles. Only time I can see that this would take longer
time are all error states, but the data sheet is not very clear
regarding this.

* qup_i2c_wait_idle() reads the status register up to 1000 times,
hoping the fifo gets drained and the bus go idle, if that fails it
sleeps for the time we expect it to take to drain a full fifo and then
loops another 1000 times. This waits for the fifo to have drained and
the bus to go idle. On a read we get to this state if we issue the
write and then hit the error state, so we would reset the entire
block. On write we will only wait for the buffer not to be full before
returning.

* qup_i2c_wait_clock_ready() waits up to 300 bus-clocks for the i2c
bus to go idle or forced low, I don't know why it retries 300 times.
This is called at the end of a write, possibly to wait for the fifo to
drain.


All three loops are in line with how it's been in codeaurora since the
beginning of time, but I at least need to figure out some good names
for those "magic numbers".

Regards,
Bjorn

Re: [PATCH v3 0/2] Qualcomm Universal Peripheral (QUP) I2C controller

[Ivan T. Ivanov]

Hi Bjorn,

On Wed, 2014-01-29 at 08:32 -0800, Bjorn Andersson wrote: 
> On Wed, Jan 29, 2014 at 12:14 AM, Ivan T. Ivanov <iivanov@mm-sol.com> wrote:
> >
> > Hi Bjorn,
> >
> > On Fri, 2014-01-17 at 15:03 -0800, Bjorn Andersson wrote:
> >> Continuing on Ivans i2c-qup series.
> >>
> >
> > Do you plan to send v4 of this driver? I would like to address
> > the remaining errors and suggestions and send a new version.
> >
> Hi Ivan,
> 
> Yes I'm planning to send out a new revision of the patch set.
> 
> I've incorporated fixes from the review comments here and my colleague
> concluded through some testing that block read did not work, so we've
> fixed that as well.

Busted. I have not test it.

> 
> What have been holding me from submitting a new patchset is the 3
> functions that does polling of state and status updates;
> * qup_i2c_poll_state() reads the state register up to 1000 times,
> hoping we reach the expected state, will delay 100uS and then continue
> with 1000 more retries.
>   According to the data sheet a state transition is supposed to take
> up to 2 bus cycles. Only time I can see that this would take longer
> time are all error states, but the data sheet is not very clear
> regarding this.
> 
> * qup_i2c_wait_idle() reads the status register up to 1000 times,
> hoping the fifo gets drained and the bus go idle, if that fails it
> sleeps for the time we expect it to take to drain a full fifo and then
> loops another 1000 times. This waits for the fifo to have drained and
> the bus to go idle. On a read we get to this state if we issue the
> write and then hit the error state, so we would reset the entire
> block. On write we will only wait for the buffer not to be full before
> returning.
> 
> * qup_i2c_wait_clock_ready() waits up to 300 bus-clocks for the i2c
> bus to go idle or forced low, I don't know why it retries 300 times.
> This is called at the end of a write, possibly to wait for the fifo to
> drain.
> 
> 
> All three loops are in line with how it's been in codeaurora since the
> beginning of time, but I at least need to figure out some good names
> for those "magic numbers".


Sure. I have keep them this way, just because I don't have information
for internal trickery of the block.

Thanks, 
Ivan


> 
> Regards,
> Bjorn

Re: [PATCH v3 0/2] Qualcomm Universal Peripheral (QUP) I2C controller

[Bjorn Andersson]

On Thu, Jan 30, 2014 at 7:30 AM, Ivan T. Ivanov <iivanov@mm-sol.com> wrote:
>
> Hi Bjorn,
>
> On Wed, 2014-01-29 at 08:32 -0800, Bjorn Andersson wrote:
>> On Wed, Jan 29, 2014 at 12:14 AM, Ivan T. Ivanov <iivanov@mm-sol.com> wrote:
>> >
>> > Hi Bjorn,
>> >
>> > On Fri, 2014-01-17 at 15:03 -0800, Bjorn Andersson wrote:
>> >> Continuing on Ivans i2c-qup series.
>> >>
>> >
>> > Do you plan to send v4 of this driver? I would like to address
>> > the remaining errors and suggestions and send a new version.
>> >
>> Hi Ivan,
>>
>> Yes I'm planning to send out a new revision of the patch set.
>>
>> I've incorporated fixes from the review comments here and my colleague
>> concluded through some testing that block read did not work, so we've
>> fixed that as well.
>
> Busted. I have not test it.

No worries, I'm glad you did the major cleanup from codeaurora!

>
>>
>> What have been holding me from submitting a new patchset is the 3
>> functions that does polling of state and status updates;
>> * qup_i2c_poll_state() reads the state register up to 1000 times,
>> hoping we reach the expected state, will delay 100uS and then continue
>> with 1000 more retries.
>>   According to the data sheet a state transition is supposed to take
>> up to 2 bus cycles. Only time I can see that this would take longer
>> time are all error states, but the data sheet is not very clear
>> regarding this.
>>
>> * qup_i2c_wait_idle() reads the status register up to 1000 times,
>> hoping the fifo gets drained and the bus go idle, if that fails it
>> sleeps for the time we expect it to take to drain a full fifo and then
>> loops another 1000 times. This waits for the fifo to have drained and
>> the bus to go idle. On a read we get to this state if we issue the
>> write and then hit the error state, so we would reset the entire
>> block. On write we will only wait for the buffer not to be full before
>> returning.
>>
>> * qup_i2c_wait_clock_ready() waits up to 300 bus-clocks for the i2c
>> bus to go idle or forced low, I don't know why it retries 300 times.
>> This is called at the end of a write, possibly to wait for the fifo to
>> drain.
>>
>>
>> All three loops are in line with how it's been in codeaurora since the
>> beginning of time, but I at least need to figure out some good names
>> for those "magic numbers".
>
>
> Sure. I have keep them this way, just because I don't have information
> for internal trickery of the block.

I'll continue to talk to the Qualcomm guys to see if we can figure out
anything regarding the expected timings of those operations and I'll
send out a new version when we have something saner.

Regards,
Bjorn