[PATCH v14 2/3] i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver

Tali Perry
2020-05-27T20:12:17Z

Add Nuvoton NPCM BMC I2C controller driver.

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/i2c/busses/Kconfig | 9 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-npcm7xx.c | 1736 ++++++++++++++++++++++++++++++
3 files changed, 1746 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-npcm7xx.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 2ddca08f8a76..a2cfc555c284 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -791,6 +791,15 @@ config I2C_NOMADIK
I2C interface from ST-Ericsson's Nomadik and Ux500 architectures,
as well as the STA2X11 PCIe I/O HUB.

+config I2C_NPCM7XX
+ tristate "Nuvoton I2C Controller"
+ depends on ARCH_NPCM7XX || COMPILE_TEST
+ help
+ If you say yes to this option, support will be included for the
+ Nuvoton I2C controller, which is available on the NPCM7xx BMC
+ controller.
+ Driver can also support slave mode (select I2C_SLAVE).
+
config I2C_OCORES
tristate "OpenCores I2C Controller"
help
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 25d60889713c..8f3dfd376bec 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_I2C_MT7621) += i2c-mt7621.o
obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o
obj-$(CONFIG_I2C_MXS) += i2c-mxs.o
obj-$(CONFIG_I2C_NOMADIK) += i2c-nomadik.o
+obj-$(CONFIG_I2C_NPCM7XX) += i2c-npcm7xx.o
obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o
obj-$(CONFIG_I2C_OMAP) += i2c-omap.o
obj-$(CONFIG_I2C_OWL) += i2c-owl.o
diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
new file mode 100644
index 000000000000..018abf8dda7e
--- /dev/null
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -0,0 +1,1736 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NPCM7xx I2C Controller driver
+ *
+ * Copyright (C) 2020 Nuvoton Technologies tali.perry@nuvoton.com
+ */
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/debugfs.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/iopoll.h>
+#include <linux/irq.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+enum i2c_mode {
+ I2C_MASTER,
+ I2C_SLAVE,
+};
+
+/*
+ * External I2C Interface driver xfer indication values, which indicate status
+ * of the bus.
+ */
+enum i2c_state_ind {
+ I2C_NO_STATUS_IND = 0,
+ I2C_SLAVE_RCV_IND,
+ I2C_SLAVE_XMIT_IND,
+ I2C_SLAVE_XMIT_MISSING_DATA_IND,
+ I2C_SLAVE_RESTART_IND,
+ I2C_SLAVE_DONE_IND,
+ I2C_MASTER_DONE_IND,
+ I2C_NACK_IND,
+ I2C_BUS_ERR_IND,
+ I2C_WAKE_UP_IND,
+ I2C_BLOCK_BYTES_ERR_IND,
+ I2C_SLAVE_RCV_MISSING_DATA_IND,
+};
+
+/*
+ * Operation type values (used to define the operation currently running)
+ * module is interrupt driven, on each interrupt the current operation is
+ * checked to see if the module is currently reading or writing.
+ */
+enum i2c_oper {
+ I2C_NO_OPER = 0,
+ I2C_WRITE_OPER,
+ I2C_READ_OPER,
+};
+
+/* I2C Bank (module had 2 banks of registers) */
+enum i2c_bank {
+ I2C_BANK_0 = 0,
+ I2C_BANK_1,
+};
+
+/* Internal I2C states values (for the I2C module state machine). */
+enum i2c_state {
+ I2C_DISABLE = 0,
+ I2C_IDLE,
+ I2C_MASTER_START,
+ I2C_SLAVE_MATCH,
+ I2C_OPER_STARTED,
+ I2C_STOP_PENDING,
+};
+
+/* init register and default value required to enable module */
+#define NPCM_I2CSEGCTL 0xE4
+#define NPCM_I2CSEGCTL_INIT_VAL 0x0333F000
+
+/* Common regs */
+#define NPCM_I2CSDA 0x00
+#define NPCM_I2CST 0x02
+#define NPCM_I2CCST 0x04
+#define NPCM_I2CCTL1 0x06
+#define NPCM_I2CADDR1 0x08
+#define NPCM_I2CCTL2 0x0A
+#define NPCM_I2CADDR2 0x0C
+#define NPCM_I2CCTL3 0x0E
+#define NPCM_I2CCST2 0x18
+#define NPCM_I2CCST3 0x19
+#define I2C_VER 0x1F
+
+/*BANK0 regs*/
+#define NPCM_I2CADDR3 0x10
+#define NPCM_I2CADDR7 0x11
+#define NPCM_I2CADDR4 0x12
+#define NPCM_I2CADDR8 0x13
+#define NPCM_I2CADDR5 0x14
+#define NPCM_I2CADDR9 0x15
+#define NPCM_I2CADDR6 0x16
+#define NPCM_I2CADDR10 0x17
+
+#define NPCM_I2CCTL4 0x1A
+#define NPCM_I2CCTL5 0x1B
+#define NPCM_I2CSCLLT 0x1C /* SCL Low Time */
+#define NPCM_I2CFIF_CTL 0x1D /* FIFO Control */
+#define NPCM_I2CSCLHT 0x1E /* SCL High Time */
+
+/* BANK 1 regs */
+#define NPCM_I2CFIF_CTS 0x10 /* Both FIFOs Control and Status */
+#define NPCM_I2CTXF_CTL 0x12 /* Tx-FIFO Control */
+#define NPCM_I2CT_OUT 0x14 /* Bus T.O. */
+#define NPCM_I2CPEC 0x16 /* PEC Data */
+#define NPCM_I2CTXF_STS 0x1A /* Tx-FIFO Status */
+#define NPCM_I2CRXF_STS 0x1C /* Rx-FIFO Status */
+#define NPCM_I2CRXF_CTL 0x1E /* Rx-FIFO Control */
+
+/* NPCM_I2CST reg fields */
+#define NPCM_I2CST_XMIT BIT(0)
+#define NPCM_I2CST_MASTER BIT(1)
+#define NPCM_I2CST_NMATCH BIT(2)
+#define NPCM_I2CST_STASTR BIT(3)
+#define NPCM_I2CST_NEGACK BIT(4)
+#define NPCM_I2CST_BER BIT(5)
+#define NPCM_I2CST_SDAST BIT(6)
+#define NPCM_I2CST_SLVSTP BIT(7)
+
+/* NPCM_I2CCST reg fields */
+#define NPCM_I2CCST_BUSY BIT(0)
+#define NPCM_I2CCST_BB BIT(1)
+#define NPCM_I2CCST_MATCH BIT(2)
+#define NPCM_I2CCST_GCMATCH BIT(3)
+#define NPCM_I2CCST_TSDA BIT(4)
+#define NPCM_I2CCST_TGSCL BIT(5)
+#define NPCM_I2CCST_MATCHAF BIT(6)
+#define NPCM_I2CCST_ARPMATCH BIT(7)
+
+/* NPCM_I2CCTL1 reg fields */
+#define NPCM_I2CCTL1_START BIT(0)
+#define NPCM_I2CCTL1_STOP BIT(1)
+#define NPCM_I2CCTL1_INTEN BIT(2)
+#define NPCM_I2CCTL1_EOBINTE BIT(3)
+#define NPCM_I2CCTL1_ACK BIT(4)
+#define NPCM_I2CCTL1_GCMEN BIT(5)
+#define NPCM_I2CCTL1_NMINTE BIT(6)
+#define NPCM_I2CCTL1_STASTRE BIT(7)
+
+/* RW1S fields (inside a RW reg): */
+#define NPCM_I2CCTL1_RWS \
+ (NPCM_I2CCTL1_START | NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_ACK)
+
+/* npcm_i2caddr reg fields */
+#define NPCM_I2CADDR_A GENMASK(6, 0)
+#define NPCM_I2CADDR_SAEN BIT(7)
+
+/* NPCM_I2CCTL2 reg fields */
+#define I2CCTL2_ENABLE BIT(0)
+#define I2CCTL2_SCLFRQ6_0 GENMASK(7, 1)
+
+/* NPCM_I2CCTL3 reg fields */
+#define I2CCTL3_SCLFRQ8_7 GENMASK(1, 0)
+#define I2CCTL3_ARPMEN BIT(2)
+#define I2CCTL3_IDL_START BIT(3)
+#define I2CCTL3_400K_MODE BIT(4)
+#define I2CCTL3_BNK_SEL BIT(5)
+#define I2CCTL3_SDA_LVL BIT(6)
+#define I2CCTL3_SCL_LVL BIT(7)
+
+/* NPCM_I2CCST2 reg fields */
+#define NPCM_I2CCST2_MATCHA1F BIT(0)
+#define NPCM_I2CCST2_MATCHA2F BIT(1)
+#define NPCM_I2CCST2_MATCHA3F BIT(2)
+#define NPCM_I2CCST2_MATCHA4F BIT(3)
+#define NPCM_I2CCST2_MATCHA5F BIT(4)
+#define NPCM_I2CCST2_MATCHA6F BIT(5)
+#define NPCM_I2CCST2_MATCHA7F BIT(5)
+#define NPCM_I2CCST2_INTSTS BIT(7)
+
+/* NPCM_I2CCST3 reg fields */
+#define NPCM_I2CCST3_MATCHA8F BIT(0)
+#define NPCM_I2CCST3_MATCHA9F BIT(1)
+#define NPCM_I2CCST3_MATCHA10F BIT(2)
+#define NPCM_I2CCST3_EO_BUSY BIT(7)
+
+/* NPCM_I2CCTL4 reg fields */
+#define I2CCTL4_HLDT GENMASK(5, 0)
+#define I2CCTL4_LVL_WE BIT(7)
+
+/* NPCM_I2CCTL5 reg fields */
+#define I2CCTL5_DBNCT GENMASK(3, 0)
+
+/* NPCM_I2CFIF_CTS reg fields */
+#define NPCM_I2CFIF_CTS_RXF_TXE BIT(1)
+#define NPCM_I2CFIF_CTS_RFTE_IE BIT(3)
+#define NPCM_I2CFIF_CTS_CLR_FIFO BIT(6)
+#define NPCM_I2CFIF_CTS_SLVRSTR BIT(7)
+
+/* NPCM_I2CTXF_CTL reg fields */
+#define NPCM_I2CTXF_CTL_TX_THR GENMASK(4, 0)
+#define NPCM_I2CTXF_CTL_THR_TXIE BIT(6)
+
+/* NPCM_I2CT_OUT reg fields */
+#define NPCM_I2CT_OUT_TO_CKDIV GENMASK(5, 0)
+#define NPCM_I2CT_OUT_T_OUTIE BIT(6)
+#define NPCM_I2CT_OUT_T_OUTST BIT(7)
+
+/* NPCM_I2CTXF_STS reg fields */
+#define NPCM_I2CTXF_STS_TX_BYTES GENMASK(4, 0)
+#define NPCM_I2CTXF_STS_TX_THST BIT(6)
+
+/* NPCM_I2CRXF_STS reg fields */
+#define NPCM_I2CRXF_STS_RX_BYTES GENMASK(4, 0)
+#define NPCM_I2CRXF_STS_RX_THST BIT(6)
+
+/* NPCM_I2CFIF_CTL reg fields */
+#define NPCM_I2CFIF_CTL_FIFO_EN BIT(4)
+
+/* NPCM_I2CRXF_CTL reg fields */
+#define NPCM_I2CRXF_CTL_RX_THR GENMASK(4, 0)
+#define NPCM_I2CRXF_CTL_LAST_PEC BIT(5)
+#define NPCM_I2CRXF_CTL_THR_RXIE BIT(6)
+
+#define I2C_HW_FIFO_SIZE 16
+
+/* I2C_VER reg fields */
+#define I2C_VER_VERSION GENMASK(6, 0)
+#define I2C_VER_FIFO_EN BIT(7)
+
+/* stall/stuck timeout in us */
+#define DEFAULT_STALL_COUNT 25
+
+/* SCLFRQ field position */
+#define SCLFRQ_0_TO_6 GENMASK(6, 0)
+#define SCLFRQ_7_TO_8 GENMASK(8, 7)
+
+/* supported clk settings. values in Hz. */
+#define I2C_FREQ_MIN_HZ 10000
+#define I2C_FREQ_MAX_HZ I2C_MAX_FAST_MODE_PLUS_FREQ
+
+/* Status of one I2C module */
+struct npcm_i2c {
+ struct i2c_adapter adap;
+ struct device *dev;
+ unsigned char __iomem *reg;
+ spinlock_t lock; /* IRQ synchronization */
+ struct completion cmd_complete;
+ int cmd_err;
+ struct i2c_msg *msgs;
+ int msgs_num;
+ int num;
+ u32 apb_clk;
+ struct i2c_bus_recovery_info rinfo;
+ enum i2c_state state;
+ enum i2c_oper operation;
+ enum i2c_mode master_or_slave;
+ enum i2c_state_ind stop_ind;
+ u8 dest_addr;
+ u8 *rd_buf;
+ u16 rd_size;
+ u16 rd_ind;
+ u8 *wr_buf;
+ u16 wr_size;
+ u16 wr_ind;
+ bool fifo_use;
+ u16 PEC_mask; /* PEC bit mask per slave address */
+ bool PEC_use;
+ bool read_block_use;
+ unsigned long int_time_stamp;
+ unsigned long bus_freq; /* in Hz */
+ struct dentry *debugfs; /* debugfs device directory */
+ u64 ber_cnt;
+ u64 rec_succ_cnt;
+ u64 rec_fail_cnt;
+ u64 nack_cnt;
+ u64 timeout_cnt;
+};
+
+static inline void npcm_i2c_select_bank(struct npcm_i2c *bus,
+ enum i2c_bank bank)
+{
+ u8 i2cctl3 = ioread8(bus->reg + NPCM_I2CCTL3);
+
+ if (bank == I2C_BANK_0)
+ i2cctl3 = i2cctl3 & ~I2CCTL3_BNK_SEL;
+ else
+ i2cctl3 = i2cctl3 | I2CCTL3_BNK_SEL;
+ iowrite8(i2cctl3, bus->reg + NPCM_I2CCTL3);
+}
+
+static void npcm_i2c_init_params(struct npcm_i2c *bus)
+{
+ bus->stop_ind = I2C_NO_STATUS_IND;
+ bus->rd_size = 0;
+ bus->wr_size = 0;
+ bus->rd_ind = 0;
+ bus->wr_ind = 0;
+ bus->read_block_use = false;
+ bus->int_time_stamp = 0;
+ bus->PEC_use = false;
+ bus->PEC_mask = 0;
+}
+
+static inline void npcm_i2c_wr_byte(struct npcm_i2c *bus, u8 data)
+{
+ iowrite8(data, bus->reg + NPCM_I2CSDA);
+}
+
+static inline u8 npcm_i2c_rd_byte(struct npcm_i2c *bus)
+{
+ return ioread8(bus->reg + NPCM_I2CSDA);
+}
+
+static int npcm_i2c_get_SCL(struct i2c_adapter *_adap)
+{
+ struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap);
+
+ return !!(I2CCTL3_SCL_LVL & ioread32(bus->reg + NPCM_I2CCTL3));
+}
+
+static int npcm_i2c_get_SDA(struct i2c_adapter *_adap)
+{
+ struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap);
+
+ return !!(I2CCTL3_SDA_LVL & ioread32(bus->reg + NPCM_I2CCTL3));
+}
+
+static inline u16 npcm_i2c_get_index(struct npcm_i2c *bus)
+{
+ if (bus->operation == I2C_READ_OPER)
+ return bus->rd_ind;
+ if (bus->operation == I2C_WRITE_OPER)
+ return bus->wr_ind;
+ return 0;
+}
+
+/* quick protocol (just address) */
+static inline bool npcm_i2c_is_quick(struct npcm_i2c *bus)
+{
+ return bus->wr_size == 0 && bus->rd_size == 0;
+}
+
+static void npcm_i2c_disable(struct npcm_i2c *bus)
+{
+ u8 i2cctl2;
+
+ /* Disable module */
+ i2cctl2 = ioread8(bus->reg + NPCM_I2CCTL2);
+ i2cctl2 = i2cctl2 & ~I2CCTL2_ENABLE;
+ iowrite8(i2cctl2, bus->reg + NPCM_I2CCTL2);
+
+ bus->state = I2C_DISABLE;
+}
+
+static void npcm_i2c_enable(struct npcm_i2c *bus)
+{
+ u8 i2cctl2 = ioread8(bus->reg + NPCM_I2CCTL2);
+
+ i2cctl2 = i2cctl2 | I2CCTL2_ENABLE;
+ iowrite8(i2cctl2, bus->reg + NPCM_I2CCTL2);
+ bus->state = I2C_IDLE;
+}
+
+/* enable\disable end of busy (EOB) interrupts */
+static inline void npcm_i2c_eob_int(struct npcm_i2c *bus, bool enable)
+{
+ u8 val;
+
+ /* Clear EO_BUSY pending bit: */
+ val = ioread8(bus->reg + NPCM_I2CCST3);
+ val = val | NPCM_I2CCST3_EO_BUSY;
+ iowrite8(val, bus->reg + NPCM_I2CCST3);
+
+ val = ioread8(bus->reg + NPCM_I2CCTL1);
+ val &= ~NPCM_I2CCTL1_RWS;
+ if (enable)
+ val |= NPCM_I2CCTL1_EOBINTE;
+ else
+ val &= ~NPCM_I2CCTL1_EOBINTE;
+ iowrite8(val, bus->reg + NPCM_I2CCTL1);
+}
+
+static inline bool npcm_i2c_tx_fifo_empty(struct npcm_i2c *bus)
+{
+ u8 tx_fifo_sts;
+
+ tx_fifo_sts = ioread8(bus->reg + NPCM_I2CTXF_STS);
+ /* check if TX FIFO is not empty */
+ if ((tx_fifo_sts & NPCM_I2CTXF_STS_TX_BYTES) == 0)
+ return false;
+
+ /* check if TX FIFO status bit is set: */
+ return !!FIELD_GET(NPCM_I2CTXF_STS_TX_THST, tx_fifo_sts);
+}
+
+static inline bool npcm_i2c_rx_fifo_full(struct npcm_i2c *bus)
+{
+ u8 rx_fifo_sts;
+
+ rx_fifo_sts = ioread8(bus->reg + NPCM_I2CRXF_STS);
+ /* check if RX FIFO is not empty: */
+ if ((rx_fifo_sts & NPCM_I2CRXF_STS_RX_BYTES) == 0)
+ return false;
+
+ /* check if rx fifo full status is set: */
+ return !!FIELD_GET(NPCM_I2CRXF_STS_RX_THST, rx_fifo_sts);
+}
+
+static inline void npcm_i2c_clear_fifo_int(struct npcm_i2c *bus)
+{
+ u8 val;
+
+ val = ioread8(bus->reg + NPCM_I2CFIF_CTS);
+ val = (val & NPCM_I2CFIF_CTS_SLVRSTR) | NPCM_I2CFIF_CTS_RXF_TXE;
+ iowrite8(val, bus->reg + NPCM_I2CFIF_CTS);
+}
+
+static inline void npcm_i2c_clear_tx_fifo(struct npcm_i2c *bus)
+{
+ u8 val;
+
+ val = ioread8(bus->reg + NPCM_I2CTXF_STS);
+ val = val | NPCM_I2CTXF_STS_TX_THST;
+ iowrite8(val, bus->reg + NPCM_I2CTXF_STS);
+}
+
+static inline void npcm_i2c_clear_rx_fifo(struct npcm_i2c *bus)
+{
+ u8 val;
+
+ val = ioread8(bus->reg + NPCM_I2CRXF_STS);
+ val = val | NPCM_I2CRXF_STS_RX_THST;
+ iowrite8(val, bus->reg + NPCM_I2CRXF_STS);
+}
+
+static void npcm_i2c_int_enable(struct npcm_i2c *bus, bool enable)
+{
+ u8 val;
+
+ val = ioread8(bus->reg + NPCM_I2CCTL1);
+ val &= ~NPCM_I2CCTL1_RWS;
+ if (enable)
+ val |= NPCM_I2CCTL1_INTEN;
+ else
+ val &= ~NPCM_I2CCTL1_INTEN;
+ iowrite8(val, bus->reg + NPCM_I2CCTL1);
+}
+
+static inline void npcm_i2c_master_start(struct npcm_i2c *bus)
+{
+ u8 val;
+
+ val = ioread8(bus->reg + NPCM_I2CCTL1);
+ val &= ~(NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_ACK);
+ val |= NPCM_I2CCTL1_START;
+ iowrite8(val, bus->reg + NPCM_I2CCTL1);
+}
+
+static inline void npcm_i2c_master_stop(struct npcm_i2c *bus)
+{
+ u8 val;
+
+ /*
+ * override HW issue: I2C may fail to supply stop condition in Master
+ * Write operation.
+ * Need to delay at least 5 us from the last int, before issueing a stop
+ */
+ udelay(10); /* function called from interrupt, can't sleep */
+ val = ioread8(bus->reg + NPCM_I2CCTL1);
+ val &= ~(NPCM_I2CCTL1_START | NPCM_I2CCTL1_ACK);
+ val |= NPCM_I2CCTL1_STOP;
+ iowrite8(val, bus->reg + NPCM_I2CCTL1);
+
+ if (!bus->fifo_use)
+ return;
+
+ npcm_i2c_select_bank(bus, I2C_BANK_1);
+
+ if (bus->operation == I2C_READ_OPER)
+ npcm_i2c_clear_rx_fifo(bus);
+ else
+ npcm_i2c_clear_tx_fifo(bus);
+ npcm_i2c_clear_fifo_int(bus);
+ iowrite8(0, bus->reg + NPCM_I2CTXF_CTL);
+}
+
+static inline void npcm_i2c_stall_after_start(struct npcm_i2c *bus, bool stall)
+{
+ u8 val;
+
+ val = ioread8(bus->reg + NPCM_I2CCTL1);
+ val &= ~NPCM_I2CCTL1_RWS;
+ if (stall)
+ val |= NPCM_I2CCTL1_STASTRE;
+ else
+ val &= ~NPCM_I2CCTL1_STASTRE;
+ iowrite8(val, bus->reg + NPCM_I2CCTL1);
+}
+
+static inline void npcm_i2c_nack(struct npcm_i2c *bus)
+{
+ u8 val;
+
+ val = ioread8(bus->reg + NPCM_I2CCTL1);
+ val &= ~(NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_START);
+ val |= NPCM_I2CCTL1_ACK;
+ iowrite8(val, bus->reg + NPCM_I2CCTL1);
+}
+
+static void npcm_i2c_reset(struct npcm_i2c *bus)
+{
+ /*
+ * Save I2CCTL1 relevant bits. It is being cleared when the module
+ * is disabled.
+ */
+ u8 i2cctl1;
+
+ i2cctl1 = ioread8(bus->reg + NPCM_I2CCTL1);
+
+ npcm_i2c_disable(bus);
+ npcm_i2c_enable(bus);
+
+ /* Restore NPCM_I2CCTL1 Status */
+ i2cctl1 &= ~NPCM_I2CCTL1_RWS;
+ iowrite8(i2cctl1, bus->reg + NPCM_I2CCTL1);
+
+ /* Clear BB (BUS BUSY) bit */
+ iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST);
+ iowrite8(0xFF, bus->reg + NPCM_I2CST);
+
+ /* Clear EOB bit */
+ iowrite8(NPCM_I2CCST3_EO_BUSY, bus->reg + NPCM_I2CCST3);
+
+ /* Clear all fifo bits: */
+ iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, bus->reg + NPCM_I2CFIF_CTS);
+
+ bus->state = I2C_IDLE;
+}
+
+static inline bool npcm_i2c_is_master(struct npcm_i2c *bus)
+{
+ return !!FIELD_GET(NPCM_I2CST_MASTER, ioread8(bus->reg + NPCM_I2CST));
+}
+
+static void npcm_i2c_callback(struct npcm_i2c *bus,
+ enum i2c_state_ind op_status, u16 info)
+{
+ struct i2c_msg *msgs;
+ int msgs_num;
+
+ msgs = bus->msgs;
+ msgs_num = bus->msgs_num;
+ /*
+ * check that transaction was not timed-out, and msgs still
+ * holds a valid value.
+ */
+ if (!msgs)
+ return;
+
+ if (completion_done(&bus->cmd_complete))
+ return;
+
+ switch (op_status) {
+ case I2C_MASTER_DONE_IND:
+ bus->cmd_err = bus->msgs_num;
+ fallthrough;
+ case I2C_BLOCK_BYTES_ERR_IND:
+ /* Master tx finished and all transmit bytes were sent */
+ if (bus->msgs) {
+ if (msgs[0].flags & I2C_M_RD)
+ msgs[0].len = info;
+ else if (msgs_num == 2 &&
+ msgs[1].flags & I2C_M_RD)
+ msgs[1].len = info;
+ }
+ if (completion_done(&bus->cmd_complete) == false)
+ complete(&bus->cmd_complete);
+ break;
+
+ case I2C_NACK_IND:
+ /* MASTER transmit got a NACK before tx all bytes */
+ bus->cmd_err = -ENXIO;
+ if (bus->master_or_slave == I2C_MASTER)
+ complete(&bus->cmd_complete);
+
+ break;
+ case I2C_BUS_ERR_IND:
+ /* Bus error */
+ bus->cmd_err = -EAGAIN;
+ if (bus->master_or_slave == I2C_MASTER)
+ complete(&bus->cmd_complete);
+
+ break;
+ case I2C_WAKE_UP_IND:
+ /* I2C wake up */
+ break;
+ default:
+ break;
+ }
+
+ bus->operation = I2C_NO_OPER;
+}
+
+static u8 npcm_i2c_fifo_usage(struct npcm_i2c *bus)
+{
+ if (bus->operation == I2C_WRITE_OPER)
+ return FIELD_GET(NPCM_I2CTXF_STS_TX_BYTES,
+ ioread8(bus->reg + NPCM_I2CTXF_STS));
+ if (bus->operation == I2C_READ_OPER)
+ return FIELD_GET(NPCM_I2CRXF_STS_RX_BYTES,
+ ioread8(bus->reg + NPCM_I2CRXF_STS));
+ return 0;
+}
+
+static void npcm_i2c_write_to_fifo_master(struct npcm_i2c *bus, u16 max_bytes)
+{
+ u8 size_free_fifo;
+
+ /*
+ * Fill the FIFO, while the FIFO is not full and there are more bytes
+ * to write
+ */
+ size_free_fifo = I2C_HW_FIFO_SIZE - npcm_i2c_fifo_usage(bus);
+ while (max_bytes-- && size_free_fifo) {
+ if (bus->wr_ind < bus->wr_size)
+ npcm_i2c_wr_byte(bus, bus->wr_buf[bus->wr_ind++]);
+ else
+ npcm_i2c_wr_byte(bus, 0xFF);
+ size_free_fifo = I2C_HW_FIFO_SIZE - npcm_i2c_fifo_usage(bus);
+ }
+}
+
+/*
+ * npcm_i2c_set_fifo:
+ * configure the FIFO before using it. If nread is -1 RX FIFO will not be
+ * configured. same for nwrite
+ */
+static void npcm_i2c_set_fifo(struct npcm_i2c *bus, int nread, int nwrite)
+{
+ u8 rxf_ctl = 0;
+
+ if (!bus->fifo_use)
+ return;
+ npcm_i2c_select_bank(bus, I2C_BANK_1);
+ npcm_i2c_clear_tx_fifo(bus);
+ npcm_i2c_clear_rx_fifo(bus);
+
+ /* configure RX FIFO */
+ if (nread > 0) {
+ rxf_ctl = min_t(int, nread, I2C_HW_FIFO_SIZE);
+
+ /* set LAST bit. if LAST is set next FIFO packet is nacked */
+ if (nread <= I2C_HW_FIFO_SIZE)
+ rxf_ctl |= NPCM_I2CRXF_CTL_LAST_PEC;
+
+ /*
+ * if we are about to read the first byte in blk rd mode,
+ * don't NACK it. If slave returns zero size HW can't NACK
+ * it immidiattly, it will read extra byte and then NACK.
+ */
+ if (bus->rd_ind == 0 && bus->read_block_use) {
+ /* set fifo to read one byte, no last: */
+ rxf_ctl = 1;
+ }
+
+ /* set fifo size: */
+ iowrite8(rxf_ctl, bus->reg + NPCM_I2CRXF_CTL);
+ }
+
+ /* configure TX FIFO */
+ if (nwrite > 0) {
+ if (nwrite > I2C_HW_FIFO_SIZE)
+ /* data to send is more then FIFO size. */
+ iowrite8(I2C_HW_FIFO_SIZE, bus->reg + NPCM_I2CTXF_CTL);
+ else
+ iowrite8(nwrite, bus->reg + NPCM_I2CTXF_CTL);
+
+ npcm_i2c_clear_tx_fifo(bus);
+ }
+}
+
+static void npcm_i2c_read_fifo(struct npcm_i2c *bus, u8 bytes_in_fifo)
+{
+ u8 data;
+
+ while (bytes_in_fifo--) {
+ data = npcm_i2c_rd_byte(bus);
+ if (bus->rd_ind < bus->rd_size)
+ bus->rd_buf[bus->rd_ind++] = data;
+ }
+}
+
+static inline void npcm_i2c_clear_master_status(struct npcm_i2c *bus)
+{
+ u8 val;
+
+ /* Clear NEGACK, STASTR and BER bits */
+ val = NPCM_I2CST_BER | NPCM_I2CST_NEGACK | NPCM_I2CST_STASTR;
+ iowrite8(val, bus->reg + NPCM_I2CST);
+}
+
+static void npcm_i2c_master_abort(struct npcm_i2c *bus)
+{
+ /* Only current master is allowed to issue a stop condition */
+ if (!npcm_i2c_is_master(bus))
+ return;
+
+ npcm_i2c_eob_int(bus, true);
+ npcm_i2c_master_stop(bus);
+ npcm_i2c_clear_master_status(bus);
+}
+
+static void npcm_i2c_master_fifo_read(struct npcm_i2c *bus)
+{
+ int rcount;
+ int fifo_bytes;
+ enum i2c_state_ind ind = I2C_MASTER_DONE_IND;
+
+ fifo_bytes = npcm_i2c_fifo_usage(bus);
+ rcount = bus->rd_size - bus->rd_ind;
+
+ /*
+ * In order not to change the RX_TRH during transaction (we found that
+ * this might be problematic if it takes too much time to read the FIFO)
+ * we read the data in the following way. If the number of bytes to
+ * read == FIFO Size + C (where C < FIFO Size)then first read C bytes
+ * and in the next int we read rest of the data.
+ */
+ if (rcount < (2 * I2C_HW_FIFO_SIZE) && rcount > I2C_HW_FIFO_SIZE)
+ fifo_bytes = rcount - I2C_HW_FIFO_SIZE;
+
+ if (rcount <= fifo_bytes) {
+ /* last bytes are about to be read - end of tx */
+ bus->state = I2C_STOP_PENDING;
+ bus->stop_ind = ind;
+ npcm_i2c_eob_int(bus, true);
+ /* Stop should be set before reading last byte. */
+ npcm_i2c_master_stop(bus);
+ npcm_i2c_read_fifo(bus, fifo_bytes);
+ } else {
+ npcm_i2c_read_fifo(bus, fifo_bytes);
+ rcount = bus->rd_size - bus->rd_ind;
+ npcm_i2c_set_fifo(bus, rcount, -1);
+ }
+}
+
+static void npcm_i2c_irq_master_handler_write(struct npcm_i2c *bus)
+{
+ u16 wcount;
+
+ if (bus->fifo_use)
+ npcm_i2c_clear_tx_fifo(bus); /* clear the TX fifo status bit */
+
+ /* Master write operation - last byte handling */
+ if (bus->wr_ind == bus->wr_size) {
+ if (bus->fifo_use && npcm_i2c_fifo_usage(bus) > 0)
+ /*
+ * No more bytes to send (to add to the FIFO),
+ * however the FIFO is not empty yet. It is
+ * still in the middle of tx. Currently there's nothing
+ * to do except for waiting to the end of the tx
+ * We will get an int when the FIFO will get empty.
+ */
+ return;
+
+ if (bus->rd_size == 0) {
+ /* all bytes have been written, in wr only operation */
+ npcm_i2c_eob_int(bus, true);
+ bus->state = I2C_STOP_PENDING;
+ bus->stop_ind = I2C_MASTER_DONE_IND;
+ npcm_i2c_master_stop(bus);
+ /* Clear SDA Status bit (by writing dummy byte) */
+ npcm_i2c_wr_byte(bus, 0xFF);
+
+ } else {
+ /* last write-byte written on previous int - restart */
+ npcm_i2c_set_fifo(bus, bus->rd_size, -1);
+ /* Generate repeated start upon next write to SDA */
+ npcm_i2c_master_start(bus);
+
+ /*
+ * Receiving one byte only - stall after successful
+ * completion of send address byte. If we NACK here, and
+ * slave doesn't ACK the address, we might
+ * unintentionally NACK the next multi-byte read.
+ */
+ if (bus->rd_size == 1)
+ npcm_i2c_stall_after_start(bus, true);
+
+ /* Next int will occur on read */
+ bus->operation = I2C_READ_OPER;
+ /* send the slave address in read direction */
+ npcm_i2c_wr_byte(bus, bus->dest_addr | 0x1);
+ }
+ } else {
+ /* write next byte not last byte and not slave address */
+ if (!bus->fifo_use || bus->wr_size == 1) {
+ npcm_i2c_wr_byte(bus, bus->wr_buf[bus->wr_ind++]);
+ } else {
+ wcount = bus->wr_size - bus->wr_ind;
+ npcm_i2c_set_fifo(bus, -1, wcount);
+ if (wcount)
+ npcm_i2c_write_to_fifo_master(bus, wcount);
+ }
+ }
+}
+
+static void npcm_i2c_irq_master_handler_read(struct npcm_i2c *bus)
+{
+ u16 block_extra_bytes_size;
+ u8 data;
+
+ /* added bytes to the packet: */
+ block_extra_bytes_size = bus->read_block_use + bus->PEC_use;
+
+ /*
+ * Perform master read, distinguishing between last byte and the rest of
+ * the bytes. The last byte should be read when the clock is stopped
+ */
+ if (bus->rd_ind == 0) { /* first byte handling: */
+ if (bus->read_block_use) {
+ /* first byte in block protocol is the size: */
+ data = npcm_i2c_rd_byte(bus);
+ data = clamp_val(data, 1, I2C_SMBUS_BLOCK_MAX);
+ bus->rd_size = data + block_extra_bytes_size;
+ bus->rd_buf[bus->rd_ind++] = data;
+
+ /* clear RX FIFO interrupt status: */
+ if (bus->fifo_use) {
+ data = ioread8(bus->reg + NPCM_I2CFIF_CTS);
+ data = data | NPCM_I2CFIF_CTS_RXF_TXE;
+ iowrite8(data, bus->reg + NPCM_I2CFIF_CTS);
+ }
+
+ npcm_i2c_set_fifo(bus, bus->rd_size - 1, -1);
+ npcm_i2c_stall_after_start(bus, false);
+ } else {
+ npcm_i2c_clear_tx_fifo(bus);
+ npcm_i2c_master_fifo_read(bus);
+ }
+ } else {
+ if (bus->rd_size == block_extra_bytes_size &&
+ bus->read_block_use) {
+ bus->state = I2C_STOP_PENDING;
+ bus->stop_ind = I2C_BLOCK_BYTES_ERR_IND;
+ bus->cmd_err = -EIO;
+ npcm_i2c_eob_int(bus, true);
+ npcm_i2c_master_stop(bus);
+ npcm_i2c_read_fifo(bus, npcm_i2c_fifo_usage(bus));
+ } else {
+ npcm_i2c_master_fifo_read(bus);
+ }
+ }
+}
+
+static void npcm_i2c_irq_handle_nmatch(struct npcm_i2c *bus)
+{
+ iowrite8(NPCM_I2CST_NMATCH, bus->reg + NPCM_I2CST);
+ npcm_i2c_nack(bus);
+ bus->stop_ind = I2C_BUS_ERR_IND;
+ npcm_i2c_callback(bus, bus->stop_ind, npcm_i2c_get_index(bus));
+}
+
+/* A NACK has occurred */
+static void npcm_i2c_irq_handle_nack(struct npcm_i2c *bus)
+{
+ u8 val;
+
+ if (bus->nack_cnt < ULLONG_MAX)
+ bus->nack_cnt++;
+
+ if (bus->fifo_use) {
+ /*
+ * if there are still untransmitted bytes in TX FIFO
+ * reduce them from wr_ind
+ */
+ if (bus->operation == I2C_WRITE_OPER)
+ bus->wr_ind -= npcm_i2c_fifo_usage(bus);
+
+ /* clear the FIFO */
+ iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, bus->reg + NPCM_I2CFIF_CTS);
+ }
+
+ /* In master write operation, got unexpected NACK */
+ bus->stop_ind = I2C_NACK_IND;
+ /* Only current master is allowed to issue Stop Condition */
+ if (npcm_i2c_is_master(bus)) {
+ /* stopping in the middle */
+ npcm_i2c_eob_int(bus, false);
+ npcm_i2c_master_stop(bus);
+
+ /*
+ * The bus is released from stall only after the SW clears
+ * NEGACK bit. Then a Stop condition is sent.
+ */
+ npcm_i2c_clear_master_status(bus);
+ readx_poll_timeout_atomic(ioread8, bus->reg + NPCM_I2CCST, val,
+ !(val & NPCM_I2CCST_BUSY), 10, 200);
+ }
+ bus->state = I2C_IDLE;
+
+ /*
+ * In Master mode, NACK should be cleared only after STOP.
+ * In such case, the bus is released from stall only after the
+ * software clears NACK bit. Then a Stop condition is sent.
+ */
+ npcm_i2c_callback(bus, bus->stop_ind, bus->wr_ind);
+}
+
+ /* Master mode: a Bus Error has been identified */
+static void npcm_i2c_irq_handle_ber(struct npcm_i2c *bus)
+{
+ if (bus->ber_cnt < ULLONG_MAX)
+ bus->ber_cnt++;
+ bus->stop_ind = I2C_BUS_ERR_IND;
+ if (npcm_i2c_is_master(bus)) {
+ npcm_i2c_master_abort(bus);
+ } else {
+ npcm_i2c_clear_master_status(bus);
+
+ /* Clear BB (BUS BUSY) bit */
+ iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST);
+
+ bus->cmd_err = -EAGAIN;
+ npcm_i2c_callback(bus, bus->stop_ind, npcm_i2c_get_index(bus));
+ }
+ bus->state = I2C_IDLE;
+}
+
+ /* EOB: a master End Of Busy (meaning STOP completed) */
+static void npcm_i2c_irq_handle_eob(struct npcm_i2c *bus)
+{
+ npcm_i2c_eob_int(bus, false);
+ bus->state = I2C_IDLE;
+ npcm_i2c_callback(bus, bus->stop_ind, bus->rd_ind);
+}
+
+/* Address sent and requested stall occurred (Master mode) */
+static void npcm_i2c_irq_handle_stall_after_start(struct npcm_i2c *bus)
+{
+ if (npcm_i2c_is_quick(bus)) {
+ bus->state = I2C_STOP_PENDING;
+ bus->stop_ind = I2C_MASTER_DONE_IND;
+ npcm_i2c_eob_int(bus, true);
+ npcm_i2c_master_stop(bus);
+ } else if ((bus->rd_size == 1) && !bus->read_block_use) {
+ /*
+ * Receiving one byte only - set NACK after ensuring
+ * slave ACKed the address byte.
+ */
+ npcm_i2c_nack(bus);
+ }
+
+ /* Reset stall-after-address-byte */
+ npcm_i2c_stall_after_start(bus, false);
+
+ /* Clear stall only after setting STOP */
+ iowrite8(NPCM_I2CST_STASTR, bus->reg + NPCM_I2CST);
+}
+
+/* SDA status is set - TX or RX, master */
+static void npcm_i2c_irq_handle_sda(struct npcm_i2c *bus, u8 i2cst)
+{
+ u8 fif_cts;
+
+ if (!npcm_i2c_is_master(bus))
+ return;
+
+ if (bus->state == I2C_IDLE) {
+ bus->stop_ind = I2C_WAKE_UP_IND;
+
+ if (npcm_i2c_is_quick(bus) || bus->read_block_use)
+ /*
+ * Need to stall after successful
+ * completion of sending address byte
+ */
+ npcm_i2c_stall_after_start(bus, true);
+ else
+ npcm_i2c_stall_after_start(bus, false);
+
+ /*
+ * Receiving one byte only - stall after successful completion
+ * of sending address byte If we NACK here, and slave doesn't
+ * ACK the address, we might unintentionally NACK the next
+ * multi-byte read
+ */
+ if (bus->wr_size == 0 && bus->rd_size == 1)
+ npcm_i2c_stall_after_start(bus, true);
+
+ /* Initiate I2C master tx */
+
+ /* select bank 1 for FIFO regs */
+ npcm_i2c_select_bank(bus, I2C_BANK_1);
+
+ fif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS);
+ fif_cts = fif_cts & ~NPCM_I2CFIF_CTS_SLVRSTR;
+
+ /* clear FIFO and relevant status bits. */
+ fif_cts = fif_cts | NPCM_I2CFIF_CTS_CLR_FIFO;
+ iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS);
+
+ /* re-enable */
+ fif_cts = fif_cts | NPCM_I2CFIF_CTS_RXF_TXE;
+ iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS);
+
+ /*
+ * Configure the FIFO threshold:
+ * according to the needed # of bytes to read.
+ * Note: due to HW limitation can't config the rx fifo before it
+ * got and ACK on the restart. LAST bit will not be reset unless
+ * RX completed. It will stay set on the next tx.
+ */
+ if (bus->wr_size)
+ npcm_i2c_set_fifo(bus, -1, bus->wr_size);
+ else
+ npcm_i2c_set_fifo(bus, bus->rd_size, -1);
+
+ bus->state = I2C_OPER_STARTED;
+
+ if (npcm_i2c_is_quick(bus) || bus->wr_size)
+ npcm_i2c_wr_byte(bus, bus->dest_addr);
+ else
+ npcm_i2c_wr_byte(bus, bus->dest_addr | BIT(0));
+ /* SDA interrupt, after start\restart */
+ } else {
+ if (NPCM_I2CST_XMIT & i2cst) {
+ bus->operation = I2C_WRITE_OPER;
+ npcm_i2c_irq_master_handler_write(bus);
+ } else {
+ bus->operation = I2C_READ_OPER;
+ npcm_i2c_irq_master_handler_read(bus);
+ }
+ }
+}
+
+static int npcm_i2c_int_master_handler(struct npcm_i2c *bus)
+{
+ u8 i2cst;
+ int ret = -EIO;
+
+ i2cst = ioread8(bus->reg + NPCM_I2CST);
+
+ if (FIELD_GET(NPCM_I2CST_NMATCH, i2cst)) {
+ npcm_i2c_irq_handle_nmatch(bus);
+ return 0;
+ }
+ /* A NACK has occurred */
+ if (FIELD_GET(NPCM_I2CST_NEGACK, i2cst)) {
+ npcm_i2c_irq_handle_nack(bus);
+ return 0;
+ }
+
+ /* Master mode: a Bus Error has been identified */
+ if (FIELD_GET(NPCM_I2CST_BER, i2cst)) {
+ npcm_i2c_irq_handle_ber(bus);
+ return 0;
+ }
+
+ /* EOB: a master End Of Busy (meaning STOP completed) */
+ if ((FIELD_GET(NPCM_I2CCTL1_EOBINTE,
+ ioread8(bus->reg + NPCM_I2CCTL1)) == 1) &&
+ (FIELD_GET(NPCM_I2CCST3_EO_BUSY,
+ ioread8(bus->reg + NPCM_I2CCST3)))) {
+ npcm_i2c_irq_handle_eob(bus);
+ return 0;
+ }
+
+ /* Address sent and requested stall occurred (Master mode) */
+ if (FIELD_GET(NPCM_I2CST_STASTR, i2cst)) {
+ npcm_i2c_irq_handle_stall_after_start(bus);
+ ret = 0;
+ }
+
+ /* SDA status is set - TX or RX, master */
+ if (FIELD_GET(NPCM_I2CST_SDAST, i2cst) ||
+ (bus->fifo_use &&
+ (npcm_i2c_tx_fifo_empty(bus) || npcm_i2c_rx_fifo_full(bus)))) {
+ npcm_i2c_irq_handle_sda(bus, i2cst);
+ ret = 0;
+ }
+
+ return ret;
+}
+
+/* recovery using TGCLK functionality of the module */
+static int npcm_i2c_recovery_tgclk(struct i2c_adapter *_adap)
+{
+ u8 val;
+ u8 fif_cts;
+ bool done = false;
+ int status = -ENOTRECOVERABLE;
+ struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap);
+ /* Allow 3 bytes (27 toggles) to be read from the slave: */
+ int iter = 27;
+
+ if ((npcm_i2c_get_SDA(_adap) == 1) && (npcm_i2c_get_SCL(_adap) == 1)) {
+ dev_dbg(bus->dev, "bus%d recovery skipped, bus not stuck",
+ bus->num);
+ npcm_i2c_reset(bus);
+ return status;
+ }
+
+ npcm_i2c_int_enable(bus, false);
+ npcm_i2c_disable(bus);
+ npcm_i2c_enable(bus);
+ iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST);
+ npcm_i2c_clear_tx_fifo(bus);
+ npcm_i2c_clear_rx_fifo(bus);
+ iowrite8(0, bus->reg + NPCM_I2CRXF_CTL);
+ iowrite8(0, bus->reg + NPCM_I2CTXF_CTL);
+ npcm_i2c_stall_after_start(bus, false);
+
+ /* select bank 1 for FIFO regs */
+ npcm_i2c_select_bank(bus, I2C_BANK_1);
+
+ /* clear FIFO and relevant status bits. */
+ fif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS);
+ fif_cts &= ~NPCM_I2CFIF_CTS_SLVRSTR;
+ fif_cts |= NPCM_I2CFIF_CTS_CLR_FIFO;
+ iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS);
+ npcm_i2c_set_fifo(bus, -1, 0);
+
+ /* Repeat the following sequence until SDA is released */
+ do {
+ /* Issue a single SCL toggle */
+ iowrite8(NPCM_I2CCST_TGSCL, bus->reg + NPCM_I2CCST);
+ usleep_range(20, 30);
+ /* If SDA line is inactive (high), stop */
+ if (npcm_i2c_get_SDA(_adap)) {
+ done = true;
+ status = 0;
+ }
+ } while (!done && iter--);
+
+ /* If SDA line is released: send start-addr-stop, to re-sync. */
+ if (npcm_i2c_get_SDA(_adap)) {
+ /* Send an address byte in write direction: */
+ npcm_i2c_wr_byte(bus, bus->dest_addr);
+ npcm_i2c_master_start(bus);
+ /* Wait until START condition is sent */
+ status = readx_poll_timeout(npcm_i2c_get_SCL, _adap, val, !val,
+ 20, 200);
+ /* If START condition was sent */
+ if (npcm_i2c_is_master(bus) > 0) {
+ usleep_range(20, 30);
+ npcm_i2c_master_stop(bus);
+ usleep_range(200, 500);
+ }
+ }
+ npcm_i2c_reset(bus);
+ npcm_i2c_int_enable(bus, true);
+
+ if ((npcm_i2c_get_SDA(_adap) == 1) && (npcm_i2c_get_SCL(_adap) == 1))
+ status = 0;
+ else
+ status = -ENOTRECOVERABLE;
+ if (status) {
+ if (bus->rec_fail_cnt < ULLONG_MAX)
+ bus->rec_fail_cnt++;
+ } else {
+ if (bus->rec_succ_cnt < ULLONG_MAX)
+ bus->rec_succ_cnt++;
+ }
+ return status;
+}
+
+/* recovery using bit banging functionality of the module */
+static void npcm_i2c_recovery_init(struct i2c_adapter *_adap)
+{
+ struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap);
+ struct i2c_bus_recovery_info *rinfo = &bus->rinfo;
+
+ rinfo->recover_bus = npcm_i2c_recovery_tgclk;
+
+ /*
+ * npcm i2c HW allows direct reading of SCL and SDA.
+ * However, it does not support setting SCL and SDA directly.
+ * The recovery function can togle SCL when SDA is low (but not set)
+ * Getter functions used internally, and can be used externaly.
+ */
+ rinfo->get_scl = npcm_i2c_get_SCL;
+ rinfo->get_sda = npcm_i2c_get_SDA;
+ _adap->bus_recovery_info = rinfo;
+}
+
+/* SCLFRQ min/max field values */
+#define SCLFRQ_MIN 10
+#define SCLFRQ_MAX 511
+#define clk_coef(freq, mul) DIV_ROUND_UP((freq) * (mul), 1000000)
+
+/*
+ * npcm_i2c_init_clk: init HW timing parameters.
+ * NPCM7XX i2c module timing parameters are depenent on module core clk (APB)
+ * and bus frequency.
+ * 100kHz bus requires tSCL = 4 * SCLFRQ * tCLK. LT and HT are simetric.
+ * 400kHz bus requires assymetric HT and LT. A different equation is recomended
+ * by the HW designer, given core clock range (equations in comments below).
+ *
+ */
+static int npcm_i2c_init_clk(struct npcm_i2c *bus, u32 bus_freq_hz)
+{
+ u32 k1 = 0;
+ u32 k2 = 0;
+ u8 dbnct = 0;
+ u32 sclfrq = 0;
+ u8 hldt = 7;
+ u8 fast_mode = 0;
+ u32 src_clk_khz;
+ u32 bus_freq_khz;
+
+ src_clk_khz = bus->apb_clk / 1000;
+ bus_freq_khz = bus_freq_hz / 1000;
+ bus->bus_freq = bus_freq_hz;
+
+ /* 100KHz and below: */
+ if (bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ) {
+ sclfrq = src_clk_khz / (bus_freq_khz * 4);
+
+ if (sclfrq < SCLFRQ_MIN || sclfrq > SCLFRQ_MAX)
+ return -EDOM;
+
+ if (src_clk_khz >= 40000)
+ hldt = 17;
+ else if (src_clk_khz >= 12500)
+ hldt = 15;
+ else
+ hldt = 7;
+ }
+
+ /* 400KHz: */
+ else if (bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ) {
+ sclfrq = 0;
+ fast_mode = I2CCTL3_400K_MODE;
+
+ if (src_clk_khz < 7500)
+ /* 400KHZ cannot be supported for core clock < 7.5MHz */
+ return -EDOM;
+
+ else if (src_clk_khz >= 50000) {
+ k1 = 80;
+ k2 = 48;
+ hldt = 12;
+ dbnct = 7;
+ }
+
+ /* Master or Slave with frequency > 25MHz */
+ else if (src_clk_khz > 25000) {
+ hldt = clk_coef(src_clk_khz, 300) + 7;
+ k1 = clk_coef(src_clk_khz, 1600);
+ k2 = clk_coef(src_clk_khz, 900);
+ }
+ }
+
+ /* 1MHz: */
+ else if (bus_freq_hz <= I2C_MAX_FAST_MODE_PLUS_FREQ) {
+ sclfrq = 0;
+ fast_mode = I2CCTL3_400K_MODE;
+
+ /* 1MHZ cannot be supported for core clock < 24 MHz */
+ if (src_clk_khz < 24000)
+ return -EDOM;
+
+ k1 = clk_coef(src_clk_khz, 620);
+ k2 = clk_coef(src_clk_khz, 380);
+
+ /* Core clk > 40 MHz */
+ if (src_clk_khz > 40000) {
+ /*
+ * Set HLDT:
+ * SDA hold time: (HLDT-7) * T(CLK) >= 120
+ * HLDT = 120/T(CLK) + 7 = 120 * FREQ(CLK) + 7
+ */
+ hldt = clk_coef(src_clk_khz, 120) + 7;
+ } else {
+ hldt = 7;
+ dbnct = 2;
+ }
+ }
+
+ /* Frequency larger than 1 MHz is not supported */
+ else
+ return -EINVAL;
+
+ if (bus_freq_hz >= I2C_MAX_FAST_MODE_FREQ) {
+ k1 = round_up(k1, 2);
+ k2 = round_up(k2 + 1, 2);
+ if (k1 < SCLFRQ_MIN || k1 > SCLFRQ_MAX ||
+ k2 < SCLFRQ_MIN || k2 > SCLFRQ_MAX)
+ return -EDOM;
+ }
+
+ /* write sclfrq value. bits [6:0] are in I2CCTL2 reg */
+ iowrite8(FIELD_PREP(I2CCTL2_SCLFRQ6_0, sclfrq & 0x7F),
+ bus->reg + NPCM_I2CCTL2);
+
+ /* bits [8:7] are in I2CCTL3 reg */
+ iowrite8(fast_mode | FIELD_PREP(I2CCTL3_SCLFRQ8_7, (sclfrq >> 7) & 0x3),
+ bus->reg + NPCM_I2CCTL3);
+
+ /* Select Bank 0 to access NPCM_I2CCTL4/NPCM_I2CCTL5 */
+ npcm_i2c_select_bank(bus, I2C_BANK_0);
+
+ if (bus_freq_hz >= I2C_MAX_FAST_MODE_FREQ) {
+ /*
+ * Set SCL Low/High Time:
+ * k1 = 2 * SCLLT7-0 -> Low Time = k1 / 2
+ * k2 = 2 * SCLLT7-0 -> High Time = k2 / 2
+ */
+ iowrite8(k1 / 2, bus->reg + NPCM_I2CSCLLT);
+ iowrite8(k2 / 2, bus->reg + NPCM_I2CSCLHT);
+
+ iowrite8(dbnct, bus->reg + NPCM_I2CCTL5);
+ }
+
+ iowrite8(hldt, bus->reg + NPCM_I2CCTL4);
+
+ /* Return to Bank 1, and stay there by default: */
+ npcm_i2c_select_bank(bus, I2C_BANK_1);
+
+ return 0;
+}
+
+static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
+ u32 bus_freq_hz)
+{
+ u8 val;
+ int ret;
+
+ /* Check whether module already enabled or frequency is out of bounds */
+ if ((bus->state != I2C_DISABLE && bus->state != I2C_IDLE) ||
+ bus_freq_hz < I2C_FREQ_MIN_HZ || bus_freq_hz > I2C_FREQ_MAX_HZ)
+ return -EINVAL;
+
+ npcm_i2c_disable(bus);
+
+ /* Configure FIFO mode : */
+ if (FIELD_GET(I2C_VER_FIFO_EN, ioread8(bus->reg + I2C_VER))) {
+ bus->fifo_use = true;
+ npcm_i2c_select_bank(bus, I2C_BANK_0);
+ val = ioread8(bus->reg + NPCM_I2CFIF_CTL);
+ val |= NPCM_I2CFIF_CTL_FIFO_EN;
+ iowrite8(val, bus->reg + NPCM_I2CFIF_CTL);
+ npcm_i2c_select_bank(bus, I2C_BANK_1);
+ } else {
+ bus->fifo_use = false;
+ }
+
+ /* Configure I2C module clock frequency */
+ ret = npcm_i2c_init_clk(bus, bus_freq_hz);
+ if (ret) {
+ dev_err(bus->dev, "npcm_i2c_init_clk failed\n");
+ return ret;
+ }
+
+ /* Enable module (before configuring CTL1) */
+ npcm_i2c_enable(bus);
+ bus->state = I2C_IDLE;
+ val = ioread8(bus->reg + NPCM_I2CCTL1);
+ val = (val | NPCM_I2CCTL1_NMINTE) & ~NPCM_I2CCTL1_RWS;
+ iowrite8(val, bus->reg + NPCM_I2CCTL1);
+
+ npcm_i2c_int_enable(bus, true);
+
+ npcm_i2c_reset(bus);
+
+ return 0;
+}
+
+static int __npcm_i2c_init(struct npcm_i2c *bus, struct platform_device *pdev)
+{
+ u32 clk_freq_hz;
+ int ret;
+
+ /* Initialize the internal data structures */
+ bus->state = I2C_DISABLE;
+ bus->master_or_slave = I2C_SLAVE;
+ bus->int_time_stamp = 0;
+
+ ret = device_property_read_u32(&pdev->dev, "clock-frequency",
+ &clk_freq_hz);
+ if (ret) {
+ dev_info(&pdev->dev, "Could not read clock-frequency property");
+ clk_freq_hz = I2C_MAX_STANDARD_MODE_FREQ;
+ }
+
+ ret = npcm_i2c_init_module(bus, I2C_MASTER, clk_freq_hz);
+ if (ret) {
+ dev_err(&pdev->dev, "npcm_i2c_init_module failed\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static irqreturn_t npcm_i2c_bus_irq(int irq, void *dev_id)
+{
+ struct npcm_i2c *bus = dev_id;
+
+ if (npcm_i2c_is_master(bus))
+ bus->master_or_slave = I2C_MASTER;
+
+ if (bus->master_or_slave == I2C_MASTER) {
+ bus->int_time_stamp = jiffies;
+ if (!npcm_i2c_int_master_handler(bus))
+ return IRQ_HANDLED;
+ }
+ return IRQ_NONE;
+}
+
+static bool npcm_i2c_master_start_xmit(struct npcm_i2c *bus,
+ u8 slave_addr, u16 nwrite, u16 nread,
+ u8 *write_data, u8 *read_data,
+ bool use_PEC, bool use_read_block)
+{
+ if (bus->state != I2C_IDLE) {
+ bus->cmd_err = -EBUSY;
+ return false;
+ }
+ bus->dest_addr = slave_addr << 1;
+ bus->wr_buf = write_data;
+ bus->wr_size = nwrite;
+ bus->wr_ind = 0;
+ bus->rd_buf = read_data;
+ bus->rd_size = nread;
+ bus->rd_ind = 0;
+ bus->PEC_use = 0;
+
+ /* for tx PEC is appended to buffer from i2c IF. PEC flag is ignored */
+ if (nread)
+ bus->PEC_use = use_PEC;
+
+ bus->read_block_use = use_read_block;
+ if (nread && !nwrite)
+ bus->operation = I2C_READ_OPER;
+ else
+ bus->operation = I2C_WRITE_OPER;
+ if (bus->fifo_use) {
+ u8 i2cfif_cts;
+
+ npcm_i2c_select_bank(bus, I2C_BANK_1);
+ /* clear FIFO and relevant status bits. */
+ i2cfif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS);
+ i2cfif_cts &= ~NPCM_I2CFIF_CTS_SLVRSTR;
+ i2cfif_cts |= NPCM_I2CFIF_CTS_CLR_FIFO;
+ iowrite8(i2cfif_cts, bus->reg + NPCM_I2CFIF_CTS);
+ }
+
+ bus->state = I2C_IDLE;
+ npcm_i2c_stall_after_start(bus, true);
+ npcm_i2c_master_start(bus);
+ return true;
+}
+
+static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+ int num)
+{
+ struct npcm_i2c *bus = container_of(adap, struct npcm_i2c, adap);
+ struct i2c_msg *msg0, *msg1;
+ unsigned long time_left, flags;
+ u16 nwrite, nread;
+ u8 *write_data, *read_data;
+ u8 slave_addr;
+ int timeout;
+ int ret = 0;
+ bool read_block = false;
+ bool read_PEC = false;
+ u8 bus_busy;
+ unsigned long timeout_usec;
+
+ if (bus->state == I2C_DISABLE) {
+ dev_err(bus->dev, "I2C%d module is disabled", bus->num);
+ return -EINVAL;
+ }
+
+ msg0 = &msgs[0];
+ slave_addr = msg0->addr;
+ if (msg0->flags & I2C_M_RD) { /* read */
+ nwrite = 0;
+ write_data = NULL;
+ read_data = msg0->buf;
+ if (msg0->flags & I2C_M_RECV_LEN) {
+ nread = 1;
+ read_block = true;
+ if (msg0->flags & I2C_CLIENT_PEC)
+ read_PEC = true;
+ } else {
+ nread = msg0->len;
+ }
+ } else { /* write */
+ nwrite = msg0->len;
+ write_data = msg0->buf;
+ nread = 0;
+ read_data = NULL;
+ if (num == 2) {
+ msg1 = &msgs[1];
+ read_data = msg1->buf;
+ if (msg1->flags & I2C_M_RECV_LEN) {
+ nread = 1;
+ read_block = true;
+ if (msg1->flags & I2C_CLIENT_PEC)
+ read_PEC = true;
+ } else {
+ nread = msg1->len;
+ read_block = false;
+ }
+ }
+ }
+
+ /* Adaptive TimeOut: astimated time in usec + 100% margin */
+ timeout_usec = (2 * 10000 / bus->bus_freq) * (2 + nread + nwrite);
+ timeout = max(msecs_to_jiffies(35), usecs_to_jiffies(timeout_usec));
+ if (nwrite >= 32 * 1024 || nread >= 32 * 1024) {
+ dev_err(bus->dev, "i2c%d buffer too big\n", bus->num);
+ return -EINVAL;
+ }
+
+ time_left = jiffies + msecs_to_jiffies(DEFAULT_STALL_COUNT) + 1;
+ do {
+ /*
+ * we must clear slave address immediately when the bus is not
+ * busy, so we spinlock it, but we don't keep the lock for the
+ * entire while since it is too long.
+ */
+ spin_lock_irqsave(&bus->lock, flags);
+ bus_busy = ioread8(bus->reg + NPCM_I2CCST) & NPCM_I2CCST_BB;
+ spin_unlock_irqrestore(&bus->lock, flags);
+
+ } while (time_is_after_jiffies(time_left) && bus_busy);
+
+ if (bus_busy) {
+ iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST);
+ npcm_i2c_reset(bus);
+ i2c_recover_bus(adap);
+ return -EAGAIN;
+ }
+
+ npcm_i2c_init_params(bus);
+ bus->dest_addr = slave_addr;
+ bus->msgs = msgs;
+ bus->msgs_num = num;
+ bus->cmd_err = 0;
+ bus->read_block_use = read_block;
+
+ reinit_completion(&bus->cmd_complete);
+ if (!npcm_i2c_master_start_xmit(bus, slave_addr, nwrite, nread,
+ write_data, read_data, read_PEC,
+ read_block))
+ ret = -EBUSY;
+
+ if (ret != -EBUSY) {
+ time_left = wait_for_completion_timeout(&bus->cmd_complete,
+ timeout);
+
+ if (time_left == 0) {
+ if (bus->timeout_cnt < ULLONG_MAX)
+ bus->timeout_cnt++;
+ if (bus->master_or_slave == I2C_MASTER) {
+ i2c_recover_bus(adap);
+ bus->cmd_err = -EIO;
+ bus->state = I2C_IDLE;
+ }
+ }
+ }
+ ret = bus->cmd_err;
+
+ /* if there was BER, check if need to recover the bus: */
+ if (bus->cmd_err == -EAGAIN)
+ ret = i2c_recover_bus(adap);
+
+ return bus->cmd_err;
+}
+
+static u32 npcm_i2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C |
+ I2C_FUNC_SMBUS_EMUL |
+ I2C_FUNC_SMBUS_BLOCK_DATA |
+ I2C_FUNC_SMBUS_PEC;
+}
+
+static const struct i2c_adapter_quirks npcm_i2c_quirks = {
+ .max_read_len = 32768,
+ .max_write_len = 32768,
+ .flags = I2C_AQ_COMB_WRITE_THEN_READ,
+};
+
+static const struct i2c_algorithm npcm_i2c_algo = {
+ .master_xfer = npcm_i2c_master_xfer,
+ .functionality = npcm_i2c_functionality,
+};
+
+/* i2c debugfs directory: used to keep health monitor of i2c devices */
+static struct dentry *npcm_i2c_debugfs_dir;
+
+static void npcm_i2c_init_debugfs(struct platform_device *pdev,
+ struct npcm_i2c *bus)
+{
+ struct dentry *d;
+
+ if (!npcm_i2c_debugfs_dir)
+ return;
+ d = debugfs_create_dir(dev_name(&pdev->dev), npcm_i2c_debugfs_dir);
+ if (IS_ERR_OR_NULL(d))
+ return;
+ debugfs_create_u64("ber_cnt", 0444, d, &bus->ber_cnt);
+ debugfs_create_u64("nack_cnt", 0444, d, &bus->nack_cnt);
+ debugfs_create_u64("rec_succ_cnt", 0444, d, &bus->rec_succ_cnt);
+ debugfs_create_u64("rec_fail_cnt", 0444, d, &bus->rec_fail_cnt);
+ debugfs_create_u64("timeout_cnt", 0444, d, &bus->timeout_cnt);
+
+ bus->debugfs = d;
+}
+
+static int npcm_i2c_probe_bus(struct platform_device *pdev)
+{
+ struct npcm_i2c *bus;
+ struct i2c_adapter *adap;
+ struct clk *i2c_clk;
+ static struct regmap *gcr_regmap;
+ static struct regmap *clk_regmap;
+ int irq;
+ int ret;
+
+ bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
+ if (!bus)
+ return -ENOMEM;
+
+ bus->dev = &pdev->dev;
+
+ bus->num = of_alias_get_id(pdev->dev.of_node, "i2c");
+ /* core clk must be acquired to calculate module timing settings */
+ i2c_clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(i2c_clk))
+ return PTR_ERR(i2c_clk);
+ bus->apb_clk = clk_get_rate(i2c_clk);
+
+ gcr_regmap = syscon_regmap_lookup_by_compatible("nuvoton,npcm750-gcr");
+ if (IS_ERR(gcr_regmap))
+ return IS_ERR(gcr_regmap);
+ regmap_write(gcr_regmap, NPCM_I2CSEGCTL, NPCM_I2CSEGCTL_INIT_VAL);
+
+ clk_regmap = syscon_regmap_lookup_by_compatible("nuvoton,npcm750-clk");
+ if (IS_ERR(clk_regmap))
+ return IS_ERR(clk_regmap);
+
+ bus->reg = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(bus->reg))
+ return PTR_ERR((bus)->reg);
+
+ spin_lock_init(&bus->lock);
+ init_completion(&bus->cmd_complete);
+
+ adap = &bus->adap;
+ adap->owner = THIS_MODULE;
+ adap->retries = 3;
+ adap->timeout = HZ;
+ adap->algo = &npcm_i2c_algo;
+ adap->quirks = &npcm_i2c_quirks;
+ adap->algo_data = bus;
+ adap->dev.parent = &pdev->dev;
+ adap->dev.of_node = pdev->dev.of_node;
+ adap->nr = pdev->id;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ ret = devm_request_irq(bus->dev, irq, npcm_i2c_bus_irq, 0,
+ dev_name(bus->dev), bus);
+ if (ret)
+ return ret;
+
+ ret = __npcm_i2c_init(bus, pdev);
+ if (ret)
+ return ret;
+
+ npcm_i2c_recovery_init(adap);
+
+ i2c_set_adapdata(adap, bus);
+
+ snprintf(bus->adap.name, sizeof(bus->adap.name), "npcm_i2c_%d",
+ bus->num);
+ ret = i2c_add_numbered_adapter(&bus->adap);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, bus);
+ npcm_i2c_init_debugfs(pdev, bus);
+ return 0;
+}
+
+static int npcm_i2c_remove_bus(struct platform_device *pdev)
+{
+ unsigned long lock_flags;
+ struct npcm_i2c *bus = platform_get_drvdata(pdev);
+
+ debugfs_remove_recursive(bus->debugfs);
+ spin_lock_irqsave(&bus->lock, lock_flags);
+ npcm_i2c_disable(bus);
+ spin_unlock_irqrestore(&bus->lock, lock_flags);
+ i2c_del_adapter(&bus->adap);
+ return 0;
+}
+
+static const struct of_device_id npcm_i2c_bus_of_table[] = {
+ { .compatible = "nuvoton,npcm750-i2c", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, npcm_i2c_bus_of_table);
+
+static struct platform_driver npcm_i2c_bus_driver = {
+ .probe = npcm_i2c_probe_bus,
+ .remove = npcm_i2c_remove_bus,
+ .driver = {
+ .name = "nuvoton-i2c",
+ .of_match_table = npcm_i2c_bus_of_table,
+ }
+};
+
+static int __init npcm_i2c_init(void)
+{
+ npcm_i2c_debugfs_dir = debugfs_create_dir("npcm_i2c", NULL);
+ platform_driver_register(&npcm_i2c_bus_driver);
+ return 0;
+}
+module_init(npcm_i2c_init);
+
+static void __exit npcm_i2c_exit(void)
+{
+ platform_driver_unregister(&npcm_i2c_bus_driver);
+ debugfs_remove_recursive(npcm_i2c_debugfs_dir);
+}
+module_exit(npcm_i2c_exit);
+
+MODULE_AUTHOR("Avi Fishman <avi.fishman@gmail.com>");
+MODULE_AUTHOR("Tali Perry <tali.perry@nuvoton.com>");
+MODULE_AUTHOR("Tyrone Ting <kfting@nuvoton.com>");
+MODULE_DESCRIPTION("Nuvoton I2C Bus Driver");
+MODULE_LICENSE("GPL v2");
--
2.22.0