* [PATCH v2 1/2] i2c: Add Imagination Technologies I2C SCB driver
[not found] ` <1415133430-25355-1-git-send-email-ezequiel.garcia-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>
@ 2014-11-04 20:37 ` Ezequiel Garcia
[not found] ` <1415133430-25355-2-git-send-email-ezequiel.garcia-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>
2014-11-04 20:37 ` [PATCH v2 2/2] DT: i2c: Add binding document for IMG I2C SCB Ezequiel Garcia
1 sibling, 1 reply; 5+ messages in thread
From: Ezequiel Garcia @ 2014-11-04 20:37 UTC (permalink / raw)
To: Wolfram Sang, James Hartley, James Hogan, Andrew Bresticker
Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA, Ezequiel Garcia
From: James Hogan <james.hogan-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>
Add support for the IMG I2C Serial Control Bus (SCB) found on the
Pistachio and TZ1090 SoCs.
Signed-off-by: James Hogan <james.hogan-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>
[Ezequiel: code cleaning and rebasing]
Signed-off-by: Ezequiel Garcia <ezequiel.garcia-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>
---
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-img-scb.c | 1410 ++++++++++++++++++++++++++++++++++++++
3 files changed, 1421 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-img-scb.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 917c358..653f73e 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -523,6 +523,16 @@ config I2C_IBM_IIC
This driver can also be built as a module. If so, the module
will be called i2c-ibm_iic.
+config I2C_IMG
+ tristate "Imagination Technologies I2C SCB Controller"
+ depends on SOC_TZ1090 || COMPILE_TEST
+ help
+ Say Y here if you want to use the IMG I2C SCB controller,
+ available on the TZ1090 SoC.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-img-scb.
+
config I2C_IMX
tristate "IMX I2C interface"
depends on ARCH_MXC
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 78d56c5..84861ea 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -50,6 +50,7 @@ obj-$(CONFIG_I2C_GPIO) += i2c-gpio.o
obj-$(CONFIG_I2C_HIGHLANDER) += i2c-highlander.o
obj-$(CONFIG_I2C_HIX5HD2) += i2c-hix5hd2.o
obj-$(CONFIG_I2C_IBM_IIC) += i2c-ibm_iic.o
+obj-$(CONFIG_I2C_IMG) += i2c-img-scb.o
obj-$(CONFIG_I2C_IMX) += i2c-imx.o
obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o
diff --git a/drivers/i2c/busses/i2c-img-scb.c b/drivers/i2c/busses/i2c-img-scb.c
new file mode 100644
index 0000000..79ad85e
--- /dev/null
+++ b/drivers/i2c/busses/i2c-img-scb.c
@@ -0,0 +1,1410 @@
+/*
+ * I2C adapter for the IMG Serial Control Bus (SCB) IP block.
+ *
+ * Copyright (C) 2009, 2010, 2012, 2014 Imagination Technologies Ltd.
+ *
+ * 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.
+ *
+ * There are three ways that this I2C controller can be driven:
+ *
+ * - Raw control of the SDA and SCK signals.
+ *
+ * This corresponds to MODE_RAW, which takes control of the signals
+ * directly for a certain number of clock cycles (the INT_TIMING
+ * interrupt can be used for timing).
+ *
+ * - Atomic commands. A low level I2C symbol (such as generate
+ * start/stop/ack/nack bit, generate byte, receive byte, and receive
+ * ACK) is given to the hardware, with detection of completion by bits
+ * in the LINESTAT register.
+ *
+ * This mode of operation is used by MODE_ATOMIC, which uses an I2C
+ * state machine in the interrupt handler to compose/react to I2C
+ * transactions using atomic mode commands, and also by MODE_SEQUENCE,
+ * which emits a simple fixed sequence of atomic mode commands.
+ *
+ * Due to software control, the use of atomic commands usually results
+ * in suboptimal use of the bus, with gaps between the I2C symbols while
+ * the driver decides what to do next.
+ *
+ * - Automatic mode. A bus address, and whether to read/write is
+ * specified, and the hardware takes care of the I2C state machine,
+ * using a FIFO to send/receive bytes of data to an I2C slave. The
+ * driver just has to keep the FIFO drained or filled in response to the
+ * appropriate FIFO interrupts.
+ *
+ * This corresponds to MODE_AUTOMATIC, which manages the FIFOs and deals
+ * with control of repeated start bits between I2C messages.
+ *
+ * Use of automatic mode and the FIFO can make much more efficient use
+ * of the bus compared to individual atomic commands, with potentially
+ * no wasted time between I2C symbols or I2C messages.
+ *
+ * In most cases MODE_AUTOMATIC is used, however if any of the messages in
+ * a transaction are zero byte writes (e.g. used by i2cdetect for probing
+ * the bus), MODE_ATOMIC must be used since automatic mode is normally
+ * started by the writing of data into the FIFO.
+ *
+ * The other modes are used in specific circumstances where MODE_ATOMIC and
+ * MODE_AUTOMATIC aren't appropriate. MODE_RAW is used to implement a bus
+ * recovery routine. MODE_SEQUENCE is used to reset the bus and make sure
+ * it is in a sane state.
+ *
+ * Notice that the driver implements a timer-based timeout mechanism.
+ * This is done to avoid slave events interrupts in automatic mode,
+ * given the driver gets a slave event and transaction done interrupts
+ * for each atomic mode command (start, data, ack, stop, etc) that gets
+ * completed, none of which are of interest when using automatic mode
+ * since those atomic mode commands are managed automatically by hardware
+ * rather than by the I2C state machine in the interrupt handler.
+ *
+ * In practice, normal I2C transactions will be complete well before you
+ * get the timer interrupt, as the timer is re-scheduled during FIFO
+ * maintenance and disabled after the transaction is complete.
+ *
+ * In this way normal automatic mode operation isn't impacted by
+ * unnecessary interrupts, but the exceptional abort condition can still be
+ * detected (with a slight delay).
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/timer.h>
+
+/* Register offsets */
+
+#define SCB_STATUS_REG 0x00
+#define SCB_OVERRIDE_REG 0x04
+#define SCB_READ_ADDR_REG 0x08
+#define SCB_READ_COUNT_REG 0x0c
+#define SCB_WRITE_ADDR_REG 0x10
+#define SCB_READ_DATA_REG 0x14
+#define SCB_WRITE_DATA_REG 0x18
+#define SCB_FIFO_STATUS_REG 0x1c
+#define SCB_CONTROL_SOFT_RESET 0x1f
+#define SCB_CLK_SET_REG 0x3c
+#define SCB_INT_STATUS_REG 0x40
+#define SCB_INT_CLEAR_REG 0x44
+#define SCB_INT_MASK_REG 0x48
+#define SCB_CONTROL_REG 0x4c
+#define SCB_TIME_TPL_REG 0x50
+#define SCB_TIME_TPH_REG 0x54
+#define SCB_TIME_TP2S_REG 0x58
+#define SCB_TIME_TBI_REG 0x60
+#define SCB_TIME_TSL_REG 0x64
+#define SCB_TIME_TDL_REG 0x68
+#define SCB_TIME_TSDL_REG 0x6c
+#define SCB_TIME_TSDH_REG 0x70
+#define SCB_READ_XADDR_REG 0x74
+#define SCB_WRITE_XADDR_REG 0x78
+#define SCB_WRITE_COUNT_REG 0x7c
+#define SCB_CORE_REV_REG 0x80
+#define SCB_TIME_TCKH_REG 0x84
+#define SCB_TIME_TCKL_REG 0x88
+#define SCB_FIFO_FLUSH_REG 0x8c
+#define SCB_READ_FIFO_REG 0x94
+#define SCB_CLEAR_REG 0x98
+
+/* SCB_CONTROL_REG bits */
+
+#define SCB_CONTROL_CLK_ENABLE 0x1e0
+#define SCB_CONTROL_TRANSACTION_HALT 0x200
+
+#define FIFO_READ_FULL BIT(0)
+#define FIFO_READ_EMPTY BIT(1)
+#define FIFO_WRITE_FULL BIT(2)
+#define FIFO_WRITE_EMPTY BIT(3)
+
+/* SCB_CLK_SET_REG bits */
+#define SCB_FILT_DISABLE BIT(31)
+#define SCB_FILT_BYPASS BIT(30)
+#define SCB_FILT_INC_MASK 0x7f
+#define SCB_FILT_INC_SHIFT 16
+#define SCB_INC_MASK 0x7f
+#define SCB_INC_SHIFT 8
+
+/* SCB_INT_*_REG bits */
+
+#define INT_BUS_INACTIVE BIT(0)
+#define INT_UNEXPECTED_START BIT(1)
+#define INT_SCLK_LOW_TIMEOUT BIT(2)
+#define INT_SDAT_LOW_TIMEOUT BIT(3)
+#define INT_WRITE_ACK_ERR BIT(4)
+#define INT_ADDR_ACK_ERR BIT(5)
+#define INT_FIFO_FULL BIT(9)
+#define INT_FIFO_FILLING BIT(10)
+#define INT_FIFO_EMPTY BIT(11)
+#define INT_FIFO_EMPTYING BIT(12)
+#define INT_TRANSACTION_DONE BIT(15)
+#define INT_SLAVE_EVENT BIT(16)
+#define INT_TIMING BIT(18)
+
+#define INT_FIFO_FULL_FILLING (INT_FIFO_FULL | INT_FIFO_FILLING)
+#define INT_FIFO_EMPTY_EMPTYING (INT_FIFO_EMPTY | INT_FIFO_EMPTYING)
+
+/* Level interrupts need clearing after handling instead of before */
+#define INT_LEVEL 0x01e00
+
+/* Don't allow any interrupts while the clock may be off */
+#define INT_ENABLE_MASK_INACTIVE 0x00000
+
+/* Interrupt masks for the different driver modes */
+
+#define INT_ENABLE_MASK_RAW INT_TIMING
+
+#define INT_ENABLE_MASK_ATOMIC (INT_TRANSACTION_DONE | \
+ INT_SLAVE_EVENT | \
+ INT_ADDR_ACK_ERR | \
+ INT_WRITE_ACK_ERR)
+
+#define INT_ENABLE_MASK_AUTOMATIC (INT_SCLK_LOW_TIMEOUT | \
+ INT_ADDR_ACK_ERR | \
+ INT_WRITE_ACK_ERR | \
+ INT_FIFO_FULL | \
+ INT_FIFO_FILLING | \
+ INT_FIFO_EMPTY | \
+ INT_FIFO_EMPTYING)
+
+
+#define INT_ENABLE_MASK_WAITSTOP (INT_SLAVE_EVENT | \
+ INT_ADDR_ACK_ERR | \
+ INT_WRITE_ACK_ERR)
+
+/* SCB_STATUS_REG fields */
+
+#define LINESTAT_SCLK_LINE_STATUS BIT(0)
+#define LINESTAT_SCLK_EN BIT(1)
+#define LINESTAT_SDAT_LINE_STATUS BIT(2)
+#define LINESTAT_SDAT_EN BIT(3)
+#define LINESTAT_DET_START_STATUS BIT(4)
+#define LINESTAT_DET_STOP_STATUS BIT(5)
+#define LINESTAT_DET_ACK_STATUS BIT(6)
+#define LINESTAT_DET_NACK_STATUS BIT(7)
+#define LINESTAT_BUS_IDLE BIT(8)
+#define LINESTAT_T_DONE_STATUS BIT(9)
+#define LINESTAT_SCLK_OUT_STATUS BIT(10)
+#define LINESTAT_SDAT_OUT_STATUS BIT(11)
+#define LINESTAT_GEN_LINE_MASK_STATUS BIT(12)
+#define LINESTAT_START_BIT_DET BIT(13)
+#define LINESTAT_STOP_BIT_DET BIT(14)
+#define LINESTAT_ACK_DET BIT(15)
+#define LINESTAT_NACK_DET BIT(16)
+#define LINESTAT_INPUT_HELD_V BIT(17)
+#define LINESTAT_ABORT_DET BIT(18)
+#define LINESTAT_ACK_OR_NACK_DET (LINESTAT_ACK_DET | LINESTAT_NACK_DET)
+#define LINESTAT_INPUT_DATA 0xff000000
+#define LINESTAT_INPUT_DATA_SHIFT 24
+
+#define LINESTAT_CLEAR_SHIFT 13
+#define LINESTAT_LATCHED (0x3f << LINESTAT_CLEAR_SHIFT)
+
+/* SCB_OVERRIDE_REG fields */
+
+#define OVERRIDE_SCLK_OVR BIT(0)
+#define OVERRIDE_SCLKEN_OVR BIT(1)
+#define OVERRIDE_SDAT_OVR BIT(2)
+#define OVERRIDE_SDATEN_OVR BIT(3)
+#define OVERRIDE_MASTER BIT(9)
+#define OVERRIDE_LINE_OVR_EN BIT(10)
+#define OVERRIDE_DIRECT BIT(11)
+#define OVERRIDE_CMD_SHIFT 4
+#define OVERRIDE_CMD_MASK 0x1f
+#define OVERRIDE_DATA_SHIFT 24
+
+#define OVERRIDE_SCLK_DOWN (OVERRIDE_LINE_OVR_EN | \
+ OVERRIDE_SCLKEN_OVR)
+#define OVERRIDE_SCLK_UP (OVERRIDE_LINE_OVR_EN | \
+ OVERRIDE_SCLKEN_OVR | \
+ OVERRIDE_SCLK_OVR)
+#define OVERRIDE_SDAT_DOWN (OVERRIDE_LINE_OVR_EN | \
+ OVERRIDE_SDATEN_OVR)
+#define OVERRIDE_SDAT_UP (OVERRIDE_LINE_OVR_EN | \
+ OVERRIDE_SDATEN_OVR | \
+ OVERRIDE_SDAT_OVR)
+
+/* OVERRIDE_CMD values */
+
+#define CMD_PAUSE 0x00
+#define CMD_GEN_DATA 0x01
+#define CMD_GEN_START 0x02
+#define CMD_GEN_STOP 0x03
+#define CMD_GEN_ACK 0x04
+#define CMD_GEN_NACK 0x05
+#define CMD_RET_DATA 0x08
+#define CMD_RET_ACK 0x09
+
+/* Fixed timing values */
+
+#define TIMEOUT_TBI 0x0
+#define TIMEOUT_TSL 0xffff
+#define TIMEOUT_TDL 0x0
+
+/* Transaction timeout */
+
+#define IMG_I2C_TOUT (msecs_to_jiffies(1000))
+
+/*
+ * Worst incs are 1 (innacurate) and 16*256 (irregular).
+ * So a sensible inc is the logarithmic mean: 64 (2^6), which is
+ * in the middle of the valid range (0-127).
+ */
+#define SCB_OPT_INC 64
+
+/*
+ * Bits to return from interrupt handler functions for different modes.
+ * This delays completion until we've finished with the registers, so that the
+ * function waiting for completion can safely disable the clock to save power.
+ */
+#define ISR_COMPLETE_M BIT(31)
+#define ISR_FATAL_M BIT(30)
+#define ISR_WAITSTOP BIT(29)
+#define ISR_STATUS_M 0x0000ffff /* contains +ve errno */
+#define ISR_COMPLETE(err) (ISR_COMPLETE_M | (ISR_STATUS_M & (err)))
+#define ISR_FATAL(err) (ISR_COMPLETE(err) | ISR_FATAL_M)
+
+#define REL_SOC_IP_SCB_2_2_1 0x00020201
+
+enum img_i2c_mode {
+ MODE_INACTIVE,
+ MODE_RAW,
+ MODE_ATOMIC,
+ MODE_AUTOMATIC,
+ MODE_SEQUENCE,
+ MODE_FATAL,
+ MODE_WAITSTOP,
+ MODE_SUSPEND,
+};
+
+/* Timing parameters for i2c modes (in ns) */
+struct img_i2c_timings {
+ const char *name;
+ unsigned int max_bitrate;
+ unsigned int tckh, tckl, tsdh, tsdl;
+ unsigned int tp2s, tpl, tph;
+};
+
+/* The timings array must be ordered from slower to faster */
+static struct img_i2c_timings timings[] = {
+ /* Standard mode */
+ {
+ .name = "standard",
+ .max_bitrate = 100000,
+ .tckh = 4000,
+ .tckl = 4700,
+ .tsdh = 4700,
+ .tsdl = 8700,
+ .tp2s = 4700,
+ .tpl = 4700,
+ .tph = 4000,
+ },
+ /* Fast mode */
+ {
+ .name = "fast",
+ .max_bitrate = 400000,
+ .tckh = 600,
+ .tckl = 1300,
+ .tsdh = 600,
+ .tsdl = 1200,
+ .tp2s = 1300,
+ .tpl = 600,
+ .tph = 600,
+ },
+};
+
+/* Reset dance */
+static u8 img_i2c_reset_seq[] = { CMD_GEN_START,
+ CMD_GEN_DATA, 0xff,
+ CMD_RET_ACK,
+ CMD_GEN_START,
+ CMD_GEN_STOP,
+ 0 };
+/* Just issue a stop (after an abort condition) */
+static u8 img_i2c_stop_seq[] = { CMD_GEN_STOP,
+ 0 };
+
+/* We're interested in different interrupts depending on the mode */
+static unsigned int img_i2c_int_enable_by_mode[] = {
+ [MODE_INACTIVE] = INT_ENABLE_MASK_INACTIVE,
+ [MODE_RAW] = INT_ENABLE_MASK_RAW,
+ [MODE_ATOMIC] = INT_ENABLE_MASK_ATOMIC,
+ [MODE_AUTOMATIC] = INT_ENABLE_MASK_AUTOMATIC,
+ [MODE_SEQUENCE] = INT_ENABLE_MASK_ATOMIC,
+ [MODE_FATAL] = 0,
+ [MODE_WAITSTOP] = INT_ENABLE_MASK_WAITSTOP,
+ [MODE_SUSPEND] = 0,
+};
+
+/* Atomic command names */
+static const char * const img_i2c_atomic_cmd_names[] = {
+ [CMD_PAUSE] = "PAUSE",
+ [CMD_GEN_DATA] = "GEN_DATA",
+ [CMD_GEN_START] = "GEN_START",
+ [CMD_GEN_STOP] = "GEN_STOP",
+ [CMD_GEN_ACK] = "GEN_ACK",
+ [CMD_GEN_NACK] = "GEN_NACK",
+ [CMD_RET_DATA] = "RET_DATA",
+ [CMD_RET_ACK] = "RET_ACK",
+};
+
+struct img_i2c {
+ struct i2c_adapter adap;
+
+ void __iomem *base;
+
+ /*
+ * The scb core clock is used to get the input frequency, and to disable
+ * it after every set of transactions to save some power.
+ */
+ struct clk *scb_clk, *sys_clk;
+ unsigned int bitrate;
+ unsigned int busdelay;
+ bool need_wr_rd_fence;
+
+ /* state */
+ struct completion msg_complete;
+ spinlock_t lock; /* lock before doing anything with the state */
+ struct i2c_msg msg;
+
+ /* After the last transaction, wait for a stop bit */
+ bool last_msg;
+ int msg_status;
+
+ enum img_i2c_mode mode;
+ u32 int_enable; /* depends on mode */
+ u32 line_status; /* line status over command */
+
+ /*
+ * To avoid slave event interrupts in automatic mode, use a timer to
+ * poll the abort condition if we don't get an interrupt for too long.
+ */
+ struct timer_list check_timer;
+ bool t_halt;
+
+ /* atomic mode state */
+ bool at_t_done;
+ bool at_slave_event;
+ int at_cur_cmd;
+ u8 at_cur_data;
+
+ /* Sequence: either reset or stop. See img_i2c_sequence. */
+ u8 *seq;
+
+ /* raw mode */
+ unsigned int raw_timeout;
+};
+
+static void img_i2c_writel(struct img_i2c *i2c, u32 offset, u32 value)
+{
+ writel(value, i2c->base + offset);
+}
+
+static u32 img_i2c_readl(struct img_i2c *i2c, u32 offset)
+{
+ return readl(i2c->base + offset);
+}
+
+/*
+ * The code to read from the master read fifo, and write to the master
+ * write fifo, checks a bit in an SCB register before every byte to
+ * ensure that the fifo is not full (write fifo) or empty (read fifo).
+ * Due to clock domain crossing inside the SCB block the updated value
+ * of this bit is only visible after 2 cycles.
+ *
+ * The scb_wr_rd_fence() function does 2 dummy writes (to the read-only
+ * revision register), and it's called after reading from or writing to the
+ * fifos to ensure that subsequent reads of the fifo status bits do not read
+ * stale values.
+ */
+static void img_i2c_wr_rd_fence(struct img_i2c *i2c)
+{
+ if (i2c->need_wr_rd_fence) {
+ img_i2c_writel(i2c, SCB_CORE_REV_REG, 0);
+ img_i2c_writel(i2c, SCB_CORE_REV_REG, 0);
+ }
+}
+
+static void img_i2c_switch_mode(struct img_i2c *i2c, enum img_i2c_mode mode)
+{
+ i2c->mode = mode;
+ i2c->int_enable = img_i2c_int_enable_by_mode[mode];
+ i2c->line_status = 0;
+}
+
+static void img_i2c_raw_op(struct img_i2c *i2c)
+{
+ i2c->raw_timeout = 0;
+ img_i2c_writel(i2c, SCB_OVERRIDE_REG,
+ OVERRIDE_SCLKEN_OVR |
+ OVERRIDE_SDATEN_OVR |
+ OVERRIDE_MASTER |
+ OVERRIDE_LINE_OVR_EN |
+ OVERRIDE_DIRECT |
+ ((i2c->at_cur_cmd & OVERRIDE_CMD_MASK) << OVERRIDE_CMD_SHIFT) |
+ (i2c->at_cur_data << OVERRIDE_DATA_SHIFT));
+}
+
+static const char *img_i2c_atomic_op_name(unsigned int cmd)
+{
+ if (unlikely(cmd >= ARRAY_SIZE(img_i2c_atomic_cmd_names)))
+ return "UNKNOWN";
+ return img_i2c_atomic_cmd_names[cmd];
+}
+
+/* Send a single atomic mode command to the hardware */
+static void img_i2c_atomic_op(struct img_i2c *i2c, int cmd, u8 data)
+{
+ i2c->at_cur_cmd = cmd;
+ i2c->at_cur_data = data;
+
+ /* work around lack of data setup time when generating data */
+ if (cmd == CMD_GEN_DATA && i2c->mode == MODE_ATOMIC) {
+ u32 line_status = img_i2c_readl(i2c, SCB_STATUS_REG);
+
+ if (line_status & LINESTAT_SDAT_LINE_STATUS && !(data & 0x80)) {
+ /* hold the data line down for a moment */
+ img_i2c_switch_mode(i2c, MODE_RAW);
+ img_i2c_raw_op(i2c);
+ return;
+ }
+ }
+
+ dev_dbg(i2c->adap.dev.parent,
+ "atomic cmd=%s (%d) data=%#x\n",
+ img_i2c_atomic_op_name(cmd), cmd, data);
+ i2c->at_t_done = (cmd == CMD_RET_DATA || cmd == CMD_RET_ACK);
+ i2c->at_slave_event = false;
+ i2c->line_status = 0;
+
+ img_i2c_writel(i2c, SCB_OVERRIDE_REG,
+ ((cmd & OVERRIDE_CMD_MASK) << OVERRIDE_CMD_SHIFT) |
+ OVERRIDE_MASTER |
+ OVERRIDE_DIRECT |
+ (data << OVERRIDE_DATA_SHIFT));
+}
+
+/* Start a transaction in atomic mode */
+static void img_i2c_atomic_start(struct img_i2c *i2c)
+{
+ img_i2c_switch_mode(i2c, MODE_ATOMIC);
+ img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
+ img_i2c_atomic_op(i2c, CMD_GEN_START, 0x00);
+}
+
+static void img_i2c_soft_reset(struct img_i2c *i2c)
+{
+ i2c->t_halt = 0;
+ img_i2c_writel(i2c, SCB_CONTROL_REG, 0);
+ img_i2c_writel(i2c, SCB_CONTROL_REG,
+ SCB_CONTROL_CLK_ENABLE | SCB_CONTROL_SOFT_RESET);
+}
+
+/* enable or release transaction halt for control of repeated starts */
+static void img_i2c_transaction_halt(struct img_i2c *i2c, bool t_halt)
+{
+ u32 val;
+
+ if (i2c->t_halt == t_halt)
+ return;
+ i2c->t_halt = t_halt;
+ val = img_i2c_readl(i2c, SCB_CONTROL_REG);
+ if (t_halt)
+ val |= SCB_CONTROL_TRANSACTION_HALT;
+ else
+ val &= ~SCB_CONTROL_TRANSACTION_HALT;
+ img_i2c_writel(i2c, SCB_CONTROL_REG, val);
+}
+
+/* Drain data from the FIFO into the buffer (automatic mode) */
+static void img_i2c_read_fifo(struct img_i2c *i2c)
+{
+ while (i2c->msg.len) {
+ u32 fifo_status;
+ u8 data;
+
+ fifo_status = img_i2c_readl(i2c, SCB_FIFO_STATUS_REG);
+ if (fifo_status & FIFO_READ_EMPTY)
+ break;
+
+ data = img_i2c_readl(i2c, SCB_READ_DATA_REG);
+ *i2c->msg.buf = data;
+
+ img_i2c_writel(i2c, SCB_READ_FIFO_REG, 0xff);
+ img_i2c_wr_rd_fence(i2c);
+ i2c->msg.len--;
+ i2c->msg.buf++;
+ }
+}
+
+/* Fill the FIFO with data from the buffer (automatic mode) */
+static void img_i2c_write_fifo(struct img_i2c *i2c)
+{
+ while (i2c->msg.len) {
+ u32 fifo_status;
+
+ fifo_status = img_i2c_readl(i2c, SCB_FIFO_STATUS_REG);
+ if (fifo_status & FIFO_WRITE_FULL)
+ break;
+
+ img_i2c_writel(i2c, SCB_WRITE_DATA_REG, *i2c->msg.buf);
+ img_i2c_wr_rd_fence(i2c);
+ i2c->msg.len--;
+ i2c->msg.buf++;
+
+ }
+
+ /* Disable fifo emptying interrupt if nothing more to write */
+ if (!i2c->msg.len)
+ i2c->int_enable &= ~INT_FIFO_EMPTYING;
+}
+
+/* Start a read transaction in automatic mode */
+static void img_i2c_read(struct img_i2c *i2c)
+{
+ img_i2c_switch_mode(i2c, MODE_AUTOMATIC);
+ if (!i2c->last_msg)
+ i2c->int_enable |= INT_SLAVE_EVENT;
+
+ img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
+ img_i2c_writel(i2c, SCB_READ_ADDR_REG, i2c->msg.addr);
+ img_i2c_writel(i2c, SCB_READ_COUNT_REG, i2c->msg.len);
+
+ img_i2c_transaction_halt(i2c, false);
+ mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1));
+}
+
+/* Start a write transaction in automatic mode */
+static void img_i2c_write(struct img_i2c *i2c)
+{
+ img_i2c_switch_mode(i2c, MODE_AUTOMATIC);
+ if (!i2c->last_msg)
+ i2c->int_enable |= INT_SLAVE_EVENT;
+
+ img_i2c_writel(i2c, SCB_WRITE_ADDR_REG, i2c->msg.addr);
+ img_i2c_writel(i2c, SCB_WRITE_COUNT_REG, i2c->msg.len);
+
+ img_i2c_transaction_halt(i2c, false);
+ mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1));
+ img_i2c_write_fifo(i2c);
+
+ /* img_i2c_write_fifo() may modify int_enable */
+ img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
+}
+
+/*
+ * Indicate that the transaction is complete. This is called from the
+ * ISR to wake up the waiting thread, after which the ISR must not
+ * access any more SCB registers.
+ */
+static void img_i2c_complete_transaction(struct img_i2c *i2c, int status)
+{
+ img_i2c_switch_mode(i2c, MODE_INACTIVE);
+ if (status) {
+ i2c->msg_status = status;
+ img_i2c_transaction_halt(i2c, false);
+ }
+ complete(&i2c->msg_complete);
+}
+
+static unsigned int img_i2c_raw_atomic_delay_handler(struct img_i2c *i2c,
+ u32 int_status, u32 line_status)
+{
+ /* Stay in raw mode for this, so we don't just loop infinitely */
+ img_i2c_atomic_op(i2c, i2c->at_cur_cmd, i2c->at_cur_data);
+ img_i2c_switch_mode(i2c, MODE_ATOMIC);
+ return 0;
+}
+
+static unsigned int img_i2c_raw(struct img_i2c *i2c, u32 int_status,
+ u32 line_status)
+{
+ if (int_status & INT_TIMING) {
+ if (i2c->raw_timeout == 0)
+ return img_i2c_raw_atomic_delay_handler(i2c,
+ int_status, line_status);
+ --i2c->raw_timeout;
+ }
+ return 0;
+}
+
+static unsigned int img_i2c_sequence(struct img_i2c *i2c, u32 int_status)
+{
+ static const unsigned int continue_bits[] = {
+ [CMD_GEN_START] = LINESTAT_START_BIT_DET,
+ [CMD_GEN_DATA] = LINESTAT_INPUT_HELD_V,
+ [CMD_RET_ACK] = LINESTAT_ACK_DET | LINESTAT_NACK_DET,
+ [CMD_RET_DATA] = LINESTAT_INPUT_HELD_V,
+ [CMD_GEN_STOP] = LINESTAT_STOP_BIT_DET,
+ };
+ int next_cmd = -1;
+ u8 next_data = 0x00;
+
+ if (int_status & INT_SLAVE_EVENT)
+ i2c->at_slave_event = true;
+ if (int_status & INT_TRANSACTION_DONE)
+ i2c->at_t_done = true;
+
+ if (!i2c->at_slave_event || !i2c->at_t_done)
+ return 0;
+
+ /* wait if no continue bits are set */
+ if (i2c->at_cur_cmd >= 0 &&
+ i2c->at_cur_cmd < ARRAY_SIZE(continue_bits)) {
+ unsigned int cont_bits = continue_bits[i2c->at_cur_cmd];
+
+ if (cont_bits) {
+ cont_bits |= LINESTAT_ABORT_DET;
+ if (!(i2c->line_status & cont_bits))
+ return 0;
+ }
+ }
+
+ /* follow the sequence of commands in i2c->seq */
+ next_cmd = *i2c->seq;
+ /* stop on a nil */
+ if (!next_cmd) {
+ img_i2c_writel(i2c, SCB_OVERRIDE_REG, 0);
+ return ISR_COMPLETE(0);
+ }
+ /* when generating data, the next byte is the data */
+ if (next_cmd == CMD_GEN_DATA) {
+ ++i2c->seq;
+ next_data = *i2c->seq;
+ }
+ ++i2c->seq;
+ img_i2c_atomic_op(i2c, next_cmd, next_data);
+
+ return 0;
+}
+
+static void img_i2c_reset_start(struct img_i2c *i2c)
+{
+ /* Initiate the magic dance */
+ img_i2c_switch_mode(i2c, MODE_SEQUENCE);
+ img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
+ i2c->seq = img_i2c_reset_seq;
+ i2c->at_slave_event = true;
+ i2c->at_t_done = true;
+ i2c->at_cur_cmd = -1;
+
+ /* img_i2c_reset_seq isn't empty so the following won't fail */
+ img_i2c_sequence(i2c, 0);
+}
+
+static void img_i2c_stop_start(struct img_i2c *i2c)
+{
+ /* Initiate a stop bit sequence */
+ img_i2c_switch_mode(i2c, MODE_SEQUENCE);
+ img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
+ i2c->seq = img_i2c_stop_seq;
+ i2c->at_slave_event = true;
+ i2c->at_t_done = true;
+ i2c->at_cur_cmd = -1;
+
+ /* img_i2c_stop_seq isn't empty so the following won't fail */
+ img_i2c_sequence(i2c, 0);
+}
+
+static unsigned int img_i2c_atomic(struct img_i2c *i2c,
+ u32 int_status,
+ u32 line_status)
+{
+ int next_cmd = -1;
+ u8 next_data = 0x00;
+
+ if (int_status & INT_SLAVE_EVENT)
+ i2c->at_slave_event = true;
+ if (int_status & INT_TRANSACTION_DONE)
+ i2c->at_t_done = true;
+
+ if (!i2c->at_slave_event || !i2c->at_t_done)
+ goto next_atomic_cmd;
+ if (i2c->line_status & LINESTAT_ABORT_DET) {
+ dev_dbg(i2c->adap.dev.parent, "abort condition detected\n");
+ next_cmd = CMD_GEN_STOP;
+ i2c->msg_status = -EIO;
+ goto next_atomic_cmd;
+ }
+
+ /* i2c->at_cur_cmd may have completed */
+ switch (i2c->at_cur_cmd) {
+ case CMD_GEN_START:
+ next_cmd = CMD_GEN_DATA;
+ next_data = (i2c->msg.addr << 1);
+ if (i2c->msg.flags & I2C_M_RD)
+ next_data |= 0x1;
+ break;
+ case CMD_GEN_DATA:
+ if (i2c->line_status & LINESTAT_INPUT_HELD_V)
+ next_cmd = CMD_RET_ACK;
+ break;
+ case CMD_RET_ACK:
+ if (i2c->line_status & LINESTAT_ACK_DET) {
+ if (i2c->msg.len == 0)
+ next_cmd = CMD_GEN_STOP;
+ else if (i2c->msg.flags & I2C_M_RD)
+ next_cmd = CMD_RET_DATA;
+ else {
+ next_cmd = CMD_GEN_DATA;
+ next_data = *i2c->msg.buf;
+ --i2c->msg.len;
+ ++i2c->msg.buf;
+ }
+ } else if (i2c->line_status & LINESTAT_NACK_DET) {
+ i2c->msg_status = -EIO;
+ next_cmd = CMD_GEN_STOP;
+ }
+ break;
+ case CMD_RET_DATA:
+ if (i2c->line_status & LINESTAT_INPUT_HELD_V) {
+ *i2c->msg.buf = (i2c->line_status &
+ LINESTAT_INPUT_DATA)
+ >> LINESTAT_INPUT_DATA_SHIFT;
+ --i2c->msg.len;
+ ++i2c->msg.buf;
+ if (i2c->msg.len)
+ next_cmd = CMD_GEN_ACK;
+ else
+ next_cmd = CMD_GEN_NACK;
+ }
+ break;
+ case CMD_GEN_ACK:
+ if (i2c->line_status & LINESTAT_ACK_DET) {
+ next_cmd = CMD_RET_DATA;
+ } else {
+ i2c->msg_status = -EIO;
+ next_cmd = CMD_GEN_STOP;
+ }
+ break;
+ case CMD_GEN_NACK:
+ next_cmd = CMD_GEN_STOP;
+ break;
+ case CMD_GEN_STOP:
+ img_i2c_writel(i2c, SCB_OVERRIDE_REG, 0);
+ return ISR_COMPLETE(0);
+ default:
+ dev_err(i2c->adap.dev.parent, "bad atomic command %d\n",
+ i2c->at_cur_cmd);
+ i2c->msg_status = -EIO;
+ next_cmd = CMD_GEN_STOP;
+ break;
+ }
+
+next_atomic_cmd:
+ if (next_cmd != -1) {
+ /* don't actually stop unless we're the last transaction */
+ if (next_cmd == CMD_GEN_STOP && !i2c->msg_status &&
+ !i2c->last_msg)
+ return ISR_COMPLETE(0);
+ img_i2c_atomic_op(i2c, next_cmd, next_data);
+ }
+ return 0;
+}
+
+/*
+ * Timer function to check if something has gone wrong in automatic mode (so we
+ * don't have to handle so many interrupts just to catch an exception).
+ */
+static void img_i2c_check_timer(unsigned long arg)
+{
+ struct img_i2c *i2c = (struct img_i2c *)arg;
+ unsigned long flags;
+ unsigned int line_status;
+
+ spin_lock_irqsave(&i2c->lock, flags);
+ line_status = img_i2c_readl(i2c, SCB_STATUS_REG);
+
+ /* check for an abort condition */
+ if (line_status & LINESTAT_ABORT_DET) {
+ dev_dbg(i2c->adap.dev.parent,
+ "abort condition detected by check timer\n");
+ /* enable slave event interrupt mask to trigger irq */
+ img_i2c_writel(i2c, SCB_INT_MASK_REG,
+ i2c->int_enable | INT_SLAVE_EVENT);
+ }
+
+ spin_unlock_irqrestore(&i2c->lock, flags);
+}
+
+static unsigned int img_i2c_auto(struct img_i2c *i2c,
+ unsigned int int_status,
+ unsigned int line_status)
+{
+ if (int_status & (INT_WRITE_ACK_ERR | INT_ADDR_ACK_ERR))
+ return ISR_COMPLETE(EIO);
+
+ if (line_status & LINESTAT_ABORT_DET) {
+ dev_dbg(i2c->adap.dev.parent, "abort condition detected\n");
+ /* empty the read fifo */
+ if ((i2c->msg.flags & I2C_M_RD) &&
+ (int_status & INT_FIFO_FULL_FILLING))
+ img_i2c_read_fifo(i2c);
+ /* use atomic mode and try to force a stop bit */
+ i2c->msg_status = -EIO;
+ img_i2c_stop_start(i2c);
+ return 0;
+ }
+
+ /* Enable transaction halt on start bit */
+ if (!i2c->last_msg && i2c->line_status & LINESTAT_START_BIT_DET) {
+ img_i2c_transaction_halt(i2c, true);
+ /* we're no longer interested in the slave event */
+ i2c->int_enable &= ~INT_SLAVE_EVENT;
+ }
+
+ mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1));
+
+ if (i2c->msg.flags & I2C_M_RD) {
+ if (int_status & INT_FIFO_FULL_FILLING) {
+ img_i2c_read_fifo(i2c);
+ if (i2c->msg.len == 0)
+ return ISR_WAITSTOP;
+ }
+ } else {
+ if (int_status & INT_FIFO_EMPTY_EMPTYING) {
+ /*
+ * The write fifo empty indicates that we're in the
+ * last byte so it's safe to start a new write
+ * transaction without losing any bytes from the
+ * previous one.
+ * see 2.3.7 Repeated Start Transactions.
+ */
+ if ((int_status & INT_FIFO_EMPTY) &&
+ i2c->msg.len == 0)
+ return ISR_WAITSTOP;
+ img_i2c_write_fifo(i2c);
+ }
+ }
+
+ return 0;
+}
+
+static irqreturn_t img_i2c_isr(int irq, void *dev_id)
+{
+ struct img_i2c *i2c = (struct img_i2c *)dev_id;
+ u32 int_status, line_status;
+ /* We handle transaction completion AFTER accessing registers */
+ unsigned int hret;
+
+ /* Read interrupt status register. */
+ int_status = img_i2c_readl(i2c, SCB_INT_STATUS_REG);
+ /* Clear detected interrupts. */
+ img_i2c_writel(i2c, SCB_INT_CLEAR_REG, int_status);
+
+ /*
+ * Read line status and clear it until it actually is clear. We have
+ * to be careful not to lose any line status bits that get latched.
+ */
+ line_status = img_i2c_readl(i2c, SCB_STATUS_REG);
+ if (line_status & LINESTAT_LATCHED) {
+ img_i2c_writel(i2c, SCB_CLEAR_REG,
+ (line_status & LINESTAT_LATCHED)
+ >> LINESTAT_CLEAR_SHIFT);
+ img_i2c_wr_rd_fence(i2c);
+ }
+
+ spin_lock(&i2c->lock);
+
+ /* Keep track of line status bits received */
+ i2c->line_status &= ~LINESTAT_INPUT_DATA;
+ i2c->line_status |= line_status;
+
+ /*
+ * Certain interrupts indicate that sclk low timeout is not
+ * a problem. If any of these are set, just continue.
+ */
+ if ((int_status & INT_SCLK_LOW_TIMEOUT) &&
+ !(int_status & (INT_SLAVE_EVENT |
+ INT_FIFO_EMPTY |
+ INT_FIFO_FULL))) {
+ dev_crit(i2c->adap.dev.parent,
+ "fatal: clock low timeout occurred %s addr 0x%02x\n",
+ (i2c->msg.flags & I2C_M_RD) ? "reading" : "writing",
+ i2c->msg.addr);
+ hret = ISR_FATAL(EIO);
+ goto out;
+ }
+
+ if (i2c->mode == MODE_ATOMIC)
+ hret = img_i2c_atomic(i2c, int_status, line_status);
+ else if (i2c->mode == MODE_AUTOMATIC)
+ hret = img_i2c_auto(i2c, int_status, line_status);
+ else if (i2c->mode == MODE_SEQUENCE)
+ hret = img_i2c_sequence(i2c, int_status);
+ else if (i2c->mode == MODE_WAITSTOP && (int_status & INT_SLAVE_EVENT) &&
+ (line_status & LINESTAT_STOP_BIT_DET))
+ hret = ISR_COMPLETE(0);
+ else if (i2c->mode == MODE_RAW)
+ hret = img_i2c_raw(i2c, int_status, line_status);
+ else
+ hret = 0;
+
+ /* Clear detected level interrupts. */
+ img_i2c_writel(i2c, SCB_INT_CLEAR_REG, int_status & INT_LEVEL);
+
+out:
+ if (hret & ISR_WAITSTOP) {
+ /*
+ * Only wait for stop on last message.
+ * Also we may already have detected the stop bit.
+ */
+ if (!i2c->last_msg || i2c->line_status & LINESTAT_STOP_BIT_DET)
+ hret = ISR_COMPLETE(0);
+ else
+ img_i2c_switch_mode(i2c, MODE_WAITSTOP);
+ }
+
+ /* now we've finished using regs, handle transaction completion */
+ if (hret & ISR_COMPLETE_M) {
+ int status = -(hret & ISR_STATUS_M);
+
+ img_i2c_complete_transaction(i2c, status);
+ if (hret & ISR_FATAL_M)
+ img_i2c_switch_mode(i2c, MODE_FATAL);
+ }
+
+ /* Enable interrupts (int_enable may be altered by changing mode) */
+ img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
+
+ spin_unlock(&i2c->lock);
+
+ return IRQ_HANDLED;
+}
+
+/* Force a bus reset sequence and wait for it to complete */
+static void img_i2c_reset_bus(struct img_i2c *i2c)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&i2c->lock, flags);
+ reinit_completion(&i2c->msg_complete);
+ img_i2c_reset_start(i2c);
+ spin_unlock_irqrestore(&i2c->lock, flags);
+
+ wait_for_completion_timeout(&i2c->msg_complete, IMG_I2C_TOUT);
+}
+
+static int img_i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
+ int num)
+{
+ struct img_i2c *i2c = i2c_get_adapdata(i2c_adap);
+ bool atomic = false;
+ int i;
+
+ if (i2c->mode == MODE_SUSPEND) {
+ WARN(1, "refusing to service transaction in suspended state\n");
+ return -EIO;
+ }
+
+ if (i2c->mode == MODE_FATAL)
+ return -EIO;
+
+ for (i = 0; i < num; i++) {
+ if (likely(msgs[i].len))
+ continue;
+ /*
+ * 0 byte reads are not possible because the slave could try
+ * and pull the data line low, preventing a stop bit.
+ */
+ if (unlikely(msgs[i].flags & I2C_M_RD))
+ return -EIO;
+ /*
+ * 0 byte writes are possible and used for probing, but we
+ * cannot do them in automatic mode, so use atomic mode
+ * instead.
+ */
+ atomic = true;
+ }
+
+ clk_prepare_enable(i2c->scb_clk);
+
+ for (i = 0; i < num; i++) {
+ struct i2c_msg *msg = &msgs[i];
+ unsigned long flags;
+
+ spin_lock_irqsave(&i2c->lock, flags);
+
+ /*
+ * Make a copy of the message struct. We mustn't modify the
+ * original or we'll confuse drivers and i2c-dev.
+ */
+ i2c->msg = *msg;
+ i2c->msg_status = 0;
+
+ /*
+ * After the last message we must have waited for a stop bit.
+ * Not waiting can cause problems when the clock is disabled
+ * before the stop bit is sent, and the linux I2C interface
+ * requires separate transfers not to joined with repeated
+ * start.
+ */
+ i2c->last_msg = (i == num - 1);
+ reinit_completion(&i2c->msg_complete);
+
+ if (atomic)
+ img_i2c_atomic_start(i2c);
+ else if (msg->flags & I2C_M_RD)
+ img_i2c_read(i2c);
+ else
+ img_i2c_write(i2c);
+ spin_unlock_irqrestore(&i2c->lock, flags);
+
+ wait_for_completion_timeout(&i2c->msg_complete, IMG_I2C_TOUT);
+ del_timer_sync(&i2c->check_timer);
+ if (i2c->msg_status)
+ break;
+ }
+
+ clk_disable_unprepare(i2c->scb_clk);
+
+ return i2c->msg_status ? i2c->msg_status : num;
+}
+
+static u32 img_i2c_func(struct i2c_adapter *i2c_adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm img_i2c_algo = {
+ .master_xfer = img_i2c_xfer,
+ .functionality = img_i2c_func,
+};
+
+static int img_i2c_init(struct img_i2c *i2c)
+{
+ unsigned int clk_khz, bitrate_khz, clk_period, tckh, tckl, tsdh;
+ unsigned int i, ret, data, prescale, inc, int_bitrate;
+ unsigned int filt, filt_disable, filt_bypass;
+ struct img_i2c_timings timing;
+ u32 rev;
+
+ ret = clk_prepare_enable(i2c->scb_clk);
+ if (ret)
+ return ret;
+
+ rev = img_i2c_readl(i2c, SCB_CORE_REV_REG);
+ if ((rev & 0x00ffffff) < 0x00020200) {
+ dev_info(i2c->adap.dev.parent,
+ "Unknown hardware revision (%d.%d.%d.%d)\n",
+ (rev >> 24) & 0xff, (rev >> 16) & 0xff,
+ (rev >> 8) & 0xff, rev & 0xff);
+ clk_disable_unprepare(i2c->scb_clk);
+ return -EINVAL;
+ }
+
+ if (rev == REL_SOC_IP_SCB_2_2_1)
+ i2c->need_wr_rd_fence = true;
+
+ bitrate_khz = i2c->bitrate / 1000;
+ clk_khz = clk_get_rate(i2c->scb_clk) / 1000;
+
+ /* Determine what mode we're in from the bitrate */
+ timing = timings[0];
+ for (i = 0; i < ARRAY_SIZE(timings); i++) {
+ if (i2c->bitrate <= timings[i].max_bitrate) {
+ timing = timings[i];
+ break;
+ }
+ }
+
+ /* Find the prescale that would give us that inc (approx delay = 0) */
+ prescale = SCB_OPT_INC * clk_khz / (256 * 16 * bitrate_khz);
+ prescale = clamp_t(unsigned int, prescale, 1, 8);
+ clk_khz /= prescale;
+
+ /* Setup the clock increment value */
+ inc = ((256 * 16 * bitrate_khz) /
+ (clk_khz - (16 * bitrate_khz * (clk_khz / 1000) *
+ i2c->busdelay) / 10000));
+
+ /* Setup the filter clock value */
+ filt_bypass = 0;
+ filt_disable = 0;
+ filt = 0;
+ if (clk_khz < 20000) {
+ filt_disable = SCB_FILT_DISABLE;
+ } else if (clk_khz < 40000) {
+ filt_bypass = SCB_FILT_BYPASS;
+ } else {
+ /* Calculate filter clock */
+ filt = ((640000) / ((clk_khz / 1000) * (250 - i2c->busdelay)));
+ if ((640000) % ((clk_khz / 1000) * (250 - i2c->busdelay))) {
+ /* Scale up */
+ inc++;
+ }
+ if (filt > SCB_FILT_INC_MASK)
+ filt = SCB_FILT_INC_MASK;
+ }
+ data = filt_disable | filt_bypass |
+ ((filt & SCB_FILT_INC_MASK) << SCB_FILT_INC_SHIFT) |
+ ((inc & SCB_INC_MASK) << SCB_INC_SHIFT) |
+ (prescale - 1);
+ img_i2c_writel(i2c, SCB_CLK_SET_REG, data);
+
+ /* Obtain the clock period of the fx16 clock in ns */
+ clk_period = (256 * 1000000) / (clk_khz * inc) + i2c->busdelay;
+
+ /* Calculate the bitrate in terms of internal clock pulses */
+ int_bitrate = 1000000 / (bitrate_khz * clk_period);
+ if ((1000000 % (bitrate_khz * clk_period)) >=
+ ((bitrate_khz * clk_period) / 2))
+ int_bitrate++;
+
+ /* Setup TCKH value */
+ tckh = timing.tckh / clk_period;
+ if (timing.tckh % clk_period)
+ tckh++;
+
+ if (tckh > 0)
+ data = tckh - 1;
+ else
+ data = 0;
+
+ img_i2c_writel(i2c, SCB_TIME_TCKH_REG, data);
+
+ /* Setup TCKL value */
+ tckl = int_bitrate - tckh;
+
+ if (tckl > 0)
+ data = tckl - 1;
+ else
+ data = 0;
+
+ img_i2c_writel(i2c, SCB_TIME_TCKL_REG, data);
+
+ /* Setup TSDH value */
+ tsdh = timing.tsdh / clk_period;
+ if (timing.tsdh % clk_period)
+ tsdh++;
+
+ if (tsdh > 1)
+ data = tsdh - 1;
+ else
+ data = 0x01;
+ img_i2c_writel(i2c, SCB_TIME_TSDH_REG, data);
+
+ /* This value is used later */
+ tsdh = data;
+
+ /* Setup TPL value */
+ data = timing.tpl / clk_period;
+ if (data > 0)
+ --data;
+ img_i2c_writel(i2c, SCB_TIME_TPL_REG, data);
+
+ /* Setup TPH value */
+ data = timing.tph / clk_period;
+ if (data > 0)
+ --data;
+ img_i2c_writel(i2c, SCB_TIME_TPH_REG, data);
+
+ /* Setup TSDL value to TPL + TSDH + 2 */
+ img_i2c_writel(i2c, SCB_TIME_TSDL_REG, data + tsdh + 2);
+
+ /* Setup TP2S value */
+ data = timing.tp2s / clk_period;
+ if (data > 0)
+ --data;
+ img_i2c_writel(i2c, SCB_TIME_TP2S_REG, data);
+
+ img_i2c_writel(i2c, SCB_TIME_TBI_REG, TIMEOUT_TBI);
+ img_i2c_writel(i2c, SCB_TIME_TSL_REG, TIMEOUT_TSL);
+ img_i2c_writel(i2c, SCB_TIME_TDL_REG, TIMEOUT_TDL);
+
+ /* Take module out of soft reset and enable clocks */
+ img_i2c_soft_reset(i2c);
+
+ /* Disable all interrupts */
+ img_i2c_writel(i2c, SCB_INT_MASK_REG, 0);
+
+ /* Clear all interrupts */
+ img_i2c_writel(i2c, SCB_INT_CLEAR_REG, ~0);
+
+ /* Clear the scb_line_status events */
+ img_i2c_writel(i2c, SCB_CLEAR_REG, ~0);
+
+ /* Enable interrupts */
+ img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable);
+
+ /* Perform a synchronous sequence to reset the bus */
+ img_i2c_reset_bus(i2c);
+
+ clk_disable_unprepare(i2c->scb_clk);
+
+ return 0;
+}
+
+static int img_i2c_probe(struct platform_device *pdev)
+{
+ struct device_node *node = pdev->dev.of_node;
+ struct img_i2c *i2c;
+ struct resource *res;
+ int irq, ret;
+ u32 val;
+
+ i2c = devm_kzalloc(&pdev->dev, sizeof(struct img_i2c), GFP_KERNEL);
+ if (!i2c)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ i2c->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(i2c->base))
+ return PTR_ERR(i2c->base);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "can't get irq number\n");
+ return irq;
+ }
+
+ /*
+ * Get the bus number from the devicetree. Other I2C adapters may be
+ * reserved for non-Linux core. Instead of letting Linux pick any
+ * number, it's useful to fix the bus number so users get a consistent
+ * view.
+ */
+ ret = of_property_read_u32(node, "linux,i2c-index", &val);
+ if (!ret)
+ i2c->adap.nr = val;
+ else
+ i2c->adap.nr = pdev->id;
+
+ snprintf(i2c->adap.name, sizeof(i2c->adap.name),
+ "IMG i2c%d", i2c->adap.nr);
+
+ i2c->sys_clk = devm_clk_get(&pdev->dev, "sys");
+ if (IS_ERR(i2c->sys_clk)) {
+ dev_err(&pdev->dev, "can't get system clock\n");
+ return PTR_ERR(i2c->sys_clk);
+ }
+
+
+ i2c->scb_clk = devm_clk_get(&pdev->dev, "scb");
+ if (IS_ERR(i2c->scb_clk)) {
+ dev_err(&pdev->dev, "can't get core clock\n");
+ return PTR_ERR(i2c->scb_clk);
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq, img_i2c_isr, 0,
+ pdev->name, i2c);
+ if (ret) {
+ dev_err(&pdev->dev, "can't request irq %d\n", irq);
+ return ret;
+ }
+
+ /* Set up the exception check timer */
+ init_timer(&i2c->check_timer);
+ i2c->check_timer.function = img_i2c_check_timer;
+ i2c->check_timer.data = (unsigned long)i2c;
+
+ i2c->bitrate = timings[0].max_bitrate;
+ if (!of_property_read_u32(node, "clock-frequency", &val))
+ i2c->bitrate = val;
+
+ i2c->busdelay = 0;
+ if (!of_property_read_u32(node, "bus-delay", &val))
+ i2c->busdelay = val;
+
+ i2c_set_adapdata(&i2c->adap, i2c);
+ i2c->adap.dev.parent = &pdev->dev;
+ i2c->adap.dev.of_node = node;
+ i2c->adap.owner = THIS_MODULE;
+ i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+ i2c->adap.algo = &img_i2c_algo;
+ i2c->adap.retries = 5;
+
+ img_i2c_switch_mode(i2c, MODE_INACTIVE);
+ spin_lock_init(&i2c->lock);
+ init_completion(&i2c->msg_complete);
+
+ platform_set_drvdata(pdev, i2c);
+
+ ret = clk_prepare_enable(i2c->sys_clk);
+ if (ret)
+ return ret;
+
+ ret = img_i2c_init(i2c);
+ if (ret)
+ goto disable_clk;
+
+ ret = i2c_add_numbered_adapter(&i2c->adap);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to add adapter\n");
+ goto disable_clk;
+ }
+
+ return 0;
+
+disable_clk:
+ clk_disable_unprepare(i2c->sys_clk);
+ return ret;
+}
+
+static int img_i2c_remove(struct platform_device *dev)
+{
+ struct img_i2c *i2c = platform_get_drvdata(dev);
+
+ i2c_del_adapter(&i2c->adap);
+ clk_disable_unprepare(i2c->sys_clk);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int img_i2c_suspend(struct device *dev)
+{
+ struct img_i2c *i2c = dev_get_drvdata(dev);
+
+ img_i2c_switch_mode(i2c, MODE_SUSPEND);
+
+ clk_disable(i2c->sys_clk);
+
+ return 0;
+}
+
+static int img_i2c_resume(struct device *dev)
+{
+ struct img_i2c *i2c = dev_get_drvdata(dev);
+
+ clk_enable(i2c->sys_clk);
+
+ img_i2c_init(i2c);
+
+ return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static SIMPLE_DEV_PM_OPS(img_i2c_pm, img_i2c_suspend, img_i2c_resume);
+
+static const struct of_device_id img_scb_i2c_match[] = {
+ { .compatible = "img,scb-i2c" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, img_scb_i2c_match);
+
+static struct platform_driver img_scb_i2c_driver = {
+ .driver = {
+ .name = "img-i2c-scb",
+ .of_match_table = img_scb_i2c_match,
+ .pm = &img_i2c_pm,
+ },
+ .probe = img_i2c_probe,
+ .remove = img_i2c_remove,
+};
+module_platform_driver(img_scb_i2c_driver);
+
+MODULE_AUTHOR("James Hogan <james.hogan-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>");
+MODULE_DESCRIPTION("IMG host I2C driver");
+MODULE_LICENSE("GPL");
--
2.1.0
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