i2c: axxia: Add I2C driver for AXM55xx
Add I2C bus driver for the controller found in the LSI Axxia family SoCs. The driver implements 10-bit addressing and SMBus transfer modes via emulation (including SMBus block data read). Signed-off-by: Anders Berg <anders.berg@avagotech.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Anders Berg
Wolfram Sang
parent
2374a5399b
commit
08678b850c
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@ -0,0 +1,30 @@
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LSI Axxia I2C
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Required properties :
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- compatible : Must be "lsi,api2c"
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- reg : Offset and length of the register set for the device
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- interrupts : the interrupt specifier
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- #address-cells : Must be <1>;
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- #size-cells : Must be <0>;
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- clock-names : Must contain "i2c".
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- clocks: Must contain an entry for each name in clock-names. See the common
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clock bindings.
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Optional properties :
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- clock-frequency : Desired I2C bus clock frequency in Hz. If not specified,
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the default 100 kHz frequency will be used. As only Normal and Fast modes
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are supported, possible values are 100000 and 400000.
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Example :
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i2c@02010084000 {
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compatible = "lsi,api2c";
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device_type = "i2c";
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#address-cells = <1>;
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#size-cells = <0>;
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reg = <0x20 0x10084000 0x00 0x1000>;
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interrupts = <0 19 4>;
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clocks = <&clk_per>;
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clock-names = "i2c";
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clock-frequency = <400000>;
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};
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@ -337,6 +337,17 @@ config I2C_AU1550
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This driver can also be built as a module. If so, the module
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will be called i2c-au1550.
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config I2C_AXXIA
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tristate "Axxia I2C controller"
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depends on ARCH_AXXIA || COMPILE_TEST
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default ARCH_AXXIA
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help
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Say yes if you want to support the I2C bus on Axxia platforms.
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Please note that this controller is limited to transfers of maximum
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255 bytes in length. Any attempt to to a larger transfer will return
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an error.
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config I2C_BCM2835
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tristate "Broadcom BCM2835 I2C controller"
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depends on ARCH_BCM2835
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@ -31,6 +31,7 @@ obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o
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# Embedded system I2C/SMBus host controller drivers
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obj-$(CONFIG_I2C_AT91) += i2c-at91.o
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obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o
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obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o
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obj-$(CONFIG_I2C_BCM2835) += i2c-bcm2835.o
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obj-$(CONFIG_I2C_BLACKFIN_TWI) += i2c-bfin-twi.o
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obj-$(CONFIG_I2C_CADENCE) += i2c-cadence.o
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@ -0,0 +1,559 @@
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/*
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* This driver implements I2C master functionality using the LSI API2C
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* controller.
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*
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* NOTE: The controller has a limitation in that it can only do transfers of
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* maximum 255 bytes at a time. If a larger transfer is attempted, error code
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* (-EINVAL) is returned.
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*/
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#include <linux/clk.h>
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#include <linux/clkdev.h>
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#include <linux/err.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#define SCL_WAIT_TIMEOUT_NS 25000000
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#define I2C_XFER_TIMEOUT (msecs_to_jiffies(250))
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#define I2C_STOP_TIMEOUT (msecs_to_jiffies(100))
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#define FIFO_SIZE 8
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#define GLOBAL_CONTROL 0x00
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#define GLOBAL_MST_EN BIT(0)
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#define GLOBAL_SLV_EN BIT(1)
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#define GLOBAL_IBML_EN BIT(2)
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#define INTERRUPT_STATUS 0x04
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#define INTERRUPT_ENABLE 0x08
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#define INT_SLV BIT(1)
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#define INT_MST BIT(0)
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#define WAIT_TIMER_CONTROL 0x0c
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#define WT_EN BIT(15)
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#define WT_VALUE(_x) ((_x) & 0x7fff)
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#define IBML_TIMEOUT 0x10
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#define IBML_LOW_MEXT 0x14
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#define IBML_LOW_SEXT 0x18
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#define TIMER_CLOCK_DIV 0x1c
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#define I2C_BUS_MONITOR 0x20
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#define SOFT_RESET 0x24
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#define MST_COMMAND 0x28
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#define CMD_BUSY (1<<3)
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#define CMD_MANUAL (0x00 | CMD_BUSY)
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#define CMD_AUTO (0x01 | CMD_BUSY)
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#define MST_RX_XFER 0x2c
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#define MST_TX_XFER 0x30
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#define MST_ADDR_1 0x34
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#define MST_ADDR_2 0x38
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#define MST_DATA 0x3c
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#define MST_TX_FIFO 0x40
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#define MST_RX_FIFO 0x44
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#define MST_INT_ENABLE 0x48
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#define MST_INT_STATUS 0x4c
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#define MST_STATUS_RFL (1 << 13) /* RX FIFO serivce */
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#define MST_STATUS_TFL (1 << 12) /* TX FIFO service */
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#define MST_STATUS_SNS (1 << 11) /* Manual mode done */
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#define MST_STATUS_SS (1 << 10) /* Automatic mode done */
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#define MST_STATUS_SCC (1 << 9) /* Stop complete */
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#define MST_STATUS_IP (1 << 8) /* Invalid parameter */
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#define MST_STATUS_TSS (1 << 7) /* Timeout */
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#define MST_STATUS_AL (1 << 6) /* Arbitration lost */
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#define MST_STATUS_ND (1 << 5) /* NAK on data phase */
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#define MST_STATUS_NA (1 << 4) /* NAK on address phase */
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#define MST_STATUS_NAK (MST_STATUS_NA | \
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MST_STATUS_ND)
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#define MST_STATUS_ERR (MST_STATUS_NAK | \
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MST_STATUS_AL | \
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MST_STATUS_IP | \
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MST_STATUS_TSS)
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#define MST_TX_BYTES_XFRD 0x50
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#define MST_RX_BYTES_XFRD 0x54
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#define SCL_HIGH_PERIOD 0x80
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#define SCL_LOW_PERIOD 0x84
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#define SPIKE_FLTR_LEN 0x88
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#define SDA_SETUP_TIME 0x8c
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#define SDA_HOLD_TIME 0x90
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/**
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* axxia_i2c_dev - I2C device context
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* @base: pointer to register struct
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* @msg: pointer to current message
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* @msg_xfrd: number of bytes transferred in msg
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* @msg_err: error code for completed message
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* @msg_complete: xfer completion object
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* @dev: device reference
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* @adapter: core i2c abstraction
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* @i2c_clk: clock reference for i2c input clock
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* @bus_clk_rate: current i2c bus clock rate
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*/
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struct axxia_i2c_dev {
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void __iomem *base;
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struct i2c_msg *msg;
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size_t msg_xfrd;
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int msg_err;
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struct completion msg_complete;
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struct device *dev;
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struct i2c_adapter adapter;
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struct clk *i2c_clk;
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u32 bus_clk_rate;
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};
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static void i2c_int_disable(struct axxia_i2c_dev *idev, u32 mask)
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{
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u32 int_en;
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int_en = readl(idev->base + MST_INT_ENABLE);
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writel(int_en & ~mask, idev->base + MST_INT_ENABLE);
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}
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static void i2c_int_enable(struct axxia_i2c_dev *idev, u32 mask)
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{
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u32 int_en;
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int_en = readl(idev->base + MST_INT_ENABLE);
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writel(int_en | mask, idev->base + MST_INT_ENABLE);
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}
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/**
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* ns_to_clk - Convert time (ns) to clock cycles for the given clock frequency.
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*/
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static u32 ns_to_clk(u64 ns, u32 clk_mhz)
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{
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return div_u64(ns * clk_mhz, 1000);
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}
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static int axxia_i2c_init(struct axxia_i2c_dev *idev)
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{
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u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate;
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u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000;
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u32 t_setup;
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u32 t_high, t_low;
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u32 tmo_clk;
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u32 prescale;
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unsigned long timeout;
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dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n",
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idev->bus_clk_rate, clk_mhz, divisor);
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/* Reset controller */
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writel(0x01, idev->base + SOFT_RESET);
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timeout = jiffies + msecs_to_jiffies(100);
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while (readl(idev->base + SOFT_RESET) & 1) {
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if (time_after(jiffies, timeout)) {
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dev_warn(idev->dev, "Soft reset failed\n");
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break;
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}
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}
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/* Enable Master Mode */
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writel(0x1, idev->base + GLOBAL_CONTROL);
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if (idev->bus_clk_rate <= 100000) {
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/* Standard mode SCL 50/50, tSU:DAT = 250 ns */
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t_high = divisor * 1 / 2;
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t_low = divisor * 1 / 2;
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t_setup = ns_to_clk(250, clk_mhz);
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} else {
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/* Fast mode SCL 33/66, tSU:DAT = 100 ns */
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t_high = divisor * 1 / 3;
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t_low = divisor * 2 / 3;
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t_setup = ns_to_clk(100, clk_mhz);
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}
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/* SCL High Time */
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writel(t_high, idev->base + SCL_HIGH_PERIOD);
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/* SCL Low Time */
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writel(t_low, idev->base + SCL_LOW_PERIOD);
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/* SDA Setup Time */
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writel(t_setup, idev->base + SDA_SETUP_TIME);
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/* SDA Hold Time, 300ns */
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writel(ns_to_clk(300, clk_mhz), idev->base + SDA_HOLD_TIME);
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/* Filter <50ns spikes */
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writel(ns_to_clk(50, clk_mhz), idev->base + SPIKE_FLTR_LEN);
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/* Configure Time-Out Registers */
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tmo_clk = ns_to_clk(SCL_WAIT_TIMEOUT_NS, clk_mhz);
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/* Find prescaler value that makes tmo_clk fit in 15-bits counter. */
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for (prescale = 0; prescale < 15; ++prescale) {
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if (tmo_clk <= 0x7fff)
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break;
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tmo_clk >>= 1;
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}
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if (tmo_clk > 0x7fff)
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tmo_clk = 0x7fff;
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/* Prescale divider (log2) */
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writel(prescale, idev->base + TIMER_CLOCK_DIV);
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/* Timeout in divided clocks */
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writel(WT_EN | WT_VALUE(tmo_clk), idev->base + WAIT_TIMER_CONTROL);
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/* Mask all master interrupt bits */
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i2c_int_disable(idev, ~0);
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/* Interrupt enable */
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writel(0x01, idev->base + INTERRUPT_ENABLE);
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return 0;
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}
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static int i2c_m_rd(const struct i2c_msg *msg)
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{
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return (msg->flags & I2C_M_RD) != 0;
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}
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static int i2c_m_ten(const struct i2c_msg *msg)
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{
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return (msg->flags & I2C_M_TEN) != 0;
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}
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static int i2c_m_recv_len(const struct i2c_msg *msg)
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{
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return (msg->flags & I2C_M_RECV_LEN) != 0;
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}
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/**
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* axxia_i2c_empty_rx_fifo - Fetch data from RX FIFO and update SMBus block
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* transfer length if this is the first byte of such a transfer.
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*/
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static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev)
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{
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struct i2c_msg *msg = idev->msg;
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size_t rx_fifo_avail = readl(idev->base + MST_RX_FIFO);
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int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd);
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while (bytes_to_transfer-- > 0) {
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int c = readl(idev->base + MST_DATA);
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if (idev->msg_xfrd == 0 && i2c_m_recv_len(msg)) {
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/*
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* Check length byte for SMBus block read
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*/
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if (c <= 0 || c > I2C_SMBUS_BLOCK_MAX) {
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idev->msg_err = -EPROTO;
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i2c_int_disable(idev, ~0);
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complete(&idev->msg_complete);
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break;
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}
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msg->len = 1 + c;
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writel(msg->len, idev->base + MST_RX_XFER);
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}
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msg->buf[idev->msg_xfrd++] = c;
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}
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return 0;
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}
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/**
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* axxia_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer.
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* @return: Number of bytes left to transfer.
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*/
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static int axxia_i2c_fill_tx_fifo(struct axxia_i2c_dev *idev)
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{
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struct i2c_msg *msg = idev->msg;
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size_t tx_fifo_avail = FIFO_SIZE - readl(idev->base + MST_TX_FIFO);
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int bytes_to_transfer = min(tx_fifo_avail, msg->len - idev->msg_xfrd);
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int ret = msg->len - idev->msg_xfrd - bytes_to_transfer;
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while (bytes_to_transfer-- > 0)
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writel(msg->buf[idev->msg_xfrd++], idev->base + MST_DATA);
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return ret;
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}
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static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
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{
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struct axxia_i2c_dev *idev = _dev;
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u32 status;
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if (!(readl(idev->base + INTERRUPT_STATUS) & INT_MST))
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return IRQ_NONE;
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/* Read interrupt status bits */
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status = readl(idev->base + MST_INT_STATUS);
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if (!idev->msg) {
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dev_warn(idev->dev, "unexpected interrupt\n");
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goto out;
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}
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/* RX FIFO needs service? */
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if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL))
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axxia_i2c_empty_rx_fifo(idev);
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/* TX FIFO needs service? */
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if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) {
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if (axxia_i2c_fill_tx_fifo(idev) == 0)
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i2c_int_disable(idev, MST_STATUS_TFL);
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}
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if (status & MST_STATUS_SCC) {
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/* Stop completed */
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i2c_int_disable(idev, ~0);
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complete(&idev->msg_complete);
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} else if (status & MST_STATUS_SNS) {
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/* Transfer done */
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i2c_int_disable(idev, ~0);
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if (i2c_m_rd(idev->msg) && idev->msg_xfrd < idev->msg->len)
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axxia_i2c_empty_rx_fifo(idev);
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complete(&idev->msg_complete);
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} else if (unlikely(status & MST_STATUS_ERR)) {
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/* Transfer error */
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i2c_int_disable(idev, ~0);
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if (status & MST_STATUS_AL)
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idev->msg_err = -EAGAIN;
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else if (status & MST_STATUS_NAK)
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idev->msg_err = -ENXIO;
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else
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idev->msg_err = -EIO;
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dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u tx=%u/%u\n",
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status,
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idev->msg->addr,
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readl(idev->base + MST_RX_BYTES_XFRD),
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readl(idev->base + MST_RX_XFER),
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readl(idev->base + MST_TX_BYTES_XFRD),
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readl(idev->base + MST_TX_XFER));
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complete(&idev->msg_complete);
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}
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out:
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/* Clear interrupt */
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writel(INT_MST, idev->base + INTERRUPT_STATUS);
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return IRQ_HANDLED;
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}
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static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
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{
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u32 int_mask = MST_STATUS_ERR | MST_STATUS_SNS;
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u32 rx_xfer, tx_xfer;
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u32 addr_1, addr_2;
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int ret;
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if (msg->len > 255) {
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dev_warn(idev->dev, "unsupported length %u\n", msg->len);
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return -EINVAL;
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}
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idev->msg = msg;
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idev->msg_xfrd = 0;
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idev->msg_err = 0;
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reinit_completion(&idev->msg_complete);
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if (i2c_m_ten(msg)) {
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/* 10-bit address
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* addr_1: 5'b11110 | addr[9:8] | (R/nW)
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* addr_2: addr[7:0]
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*/
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addr_1 = 0xF0 | ((msg->addr >> 7) & 0x06);
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addr_2 = msg->addr & 0xFF;
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} else {
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/* 7-bit address
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* addr_1: addr[6:0] | (R/nW)
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* addr_2: dont care
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*/
|
||||
addr_1 = (msg->addr << 1) & 0xFF;
|
||||
addr_2 = 0;
|
||||
}
|
||||
|
||||
if (i2c_m_rd(msg)) {
|
||||
/* I2C read transfer */
|
||||
rx_xfer = i2c_m_recv_len(msg) ? I2C_SMBUS_BLOCK_MAX : msg->len;
|
||||
tx_xfer = 0;
|
||||
addr_1 |= 1; /* Set the R/nW bit of the address */
|
||||
} else {
|
||||
/* I2C write transfer */
|
||||
rx_xfer = 0;
|
||||
tx_xfer = msg->len;
|
||||
}
|
||||
|
||||
writel(rx_xfer, idev->base + MST_RX_XFER);
|
||||
writel(tx_xfer, idev->base + MST_TX_XFER);
|
||||
writel(addr_1, idev->base + MST_ADDR_1);
|
||||
writel(addr_2, idev->base + MST_ADDR_2);
|
||||
|
||||
if (i2c_m_rd(msg))
|
||||
int_mask |= MST_STATUS_RFL;
|
||||
else if (axxia_i2c_fill_tx_fifo(idev) != 0)
|
||||
int_mask |= MST_STATUS_TFL;
|
||||
|
||||
/* Start manual mode */
|
||||
writel(CMD_MANUAL, idev->base + MST_COMMAND);
|
||||
|
||||
i2c_int_enable(idev, int_mask);
|
||||
|
||||
ret = wait_for_completion_timeout(&idev->msg_complete,
|
||||
I2C_XFER_TIMEOUT);
|
||||
|
||||
i2c_int_disable(idev, int_mask);
|
||||
|
||||
if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
|
||||
dev_warn(idev->dev, "busy after xfer\n");
|
||||
|
||||
if (ret == 0)
|
||||
idev->msg_err = -ETIMEDOUT;
|
||||
|
||||
if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO)
|
||||
axxia_i2c_init(idev);
|
||||
|
||||
return idev->msg_err;
|
||||
}
|
||||
|
||||
static int axxia_i2c_stop(struct axxia_i2c_dev *idev)
|
||||
{
|
||||
u32 int_mask = MST_STATUS_ERR | MST_STATUS_SCC;
|
||||
int ret;
|
||||
|
||||
reinit_completion(&idev->msg_complete);
|
||||
|
||||
/* Issue stop */
|
||||
writel(0xb, idev->base + MST_COMMAND);
|
||||
i2c_int_enable(idev, int_mask);
|
||||
ret = wait_for_completion_timeout(&idev->msg_complete,
|
||||
I2C_STOP_TIMEOUT);
|
||||
i2c_int_disable(idev, int_mask);
|
||||
if (ret == 0)
|
||||
return -ETIMEDOUT;
|
||||
|
||||
if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
|
||||
dev_warn(idev->dev, "busy after stop\n");
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int
|
||||
axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
|
||||
{
|
||||
struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
|
||||
int i;
|
||||
int ret = 0;
|
||||
|
||||
for (i = 0; ret == 0 && i < num; ++i)
|
||||
ret = axxia_i2c_xfer_msg(idev, &msgs[i]);
|
||||
|
||||
axxia_i2c_stop(idev);
|
||||
|
||||
return ret ? : i;
|
||||
}
|
||||
|
||||
static u32 axxia_i2c_func(struct i2c_adapter *adap)
|
||||
{
|
||||
u32 caps = (I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
|
||||
I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA);
|
||||
return caps;
|
||||
}
|
||||
|
||||
static const struct i2c_algorithm axxia_i2c_algo = {
|
||||
.master_xfer = axxia_i2c_xfer,
|
||||
.functionality = axxia_i2c_func,
|
||||
};
|
||||
|
||||
static int axxia_i2c_probe(struct platform_device *pdev)
|
||||
{
|
||||
struct device_node *np = pdev->dev.of_node;
|
||||
struct axxia_i2c_dev *idev = NULL;
|
||||
struct resource *res;
|
||||
void __iomem *base;
|
||||
int irq;
|
||||
int ret = 0;
|
||||
|
||||
idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
|
||||
if (!idev)
|
||||
return -ENOMEM;
|
||||
|
||||
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||
base = devm_ioremap_resource(&pdev->dev, res);
|
||||
if (IS_ERR(base))
|
||||
return PTR_ERR(base);
|
||||
|
||||
irq = platform_get_irq(pdev, 0);
|
||||
if (irq < 0) {
|
||||
dev_err(&pdev->dev, "missing interrupt resource\n");
|
||||
return irq;
|
||||
}
|
||||
|
||||
idev->i2c_clk = devm_clk_get(&pdev->dev, "i2c");
|
||||
if (IS_ERR(idev->i2c_clk)) {
|
||||
dev_err(&pdev->dev, "missing clock\n");
|
||||
return PTR_ERR(idev->i2c_clk);
|
||||
}
|
||||
|
||||
idev->base = base;
|
||||
idev->dev = &pdev->dev;
|
||||
init_completion(&idev->msg_complete);
|
||||
|
||||
of_property_read_u32(np, "clock-frequency", &idev->bus_clk_rate);
|
||||
if (idev->bus_clk_rate == 0)
|
||||
idev->bus_clk_rate = 100000; /* default clock rate */
|
||||
|
||||
ret = axxia_i2c_init(idev);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "failed to initialize\n");
|
||||
return ret;
|
||||
}
|
||||
|
||||
ret = devm_request_irq(&pdev->dev, irq, axxia_i2c_isr, 0,
|
||||
pdev->name, idev);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "failed to claim IRQ%d\n", irq);
|
||||
return ret;
|
||||
}
|
||||
|
||||
clk_prepare_enable(idev->i2c_clk);
|
||||
|
||||
i2c_set_adapdata(&idev->adapter, idev);
|
||||
strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
|
||||
idev->adapter.owner = THIS_MODULE;
|
||||
idev->adapter.algo = &axxia_i2c_algo;
|
||||
idev->adapter.dev.parent = &pdev->dev;
|
||||
idev->adapter.dev.of_node = pdev->dev.of_node;
|
||||
|
||||
platform_set_drvdata(pdev, idev);
|
||||
|
||||
ret = i2c_add_adapter(&idev->adapter);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "failed to add adapter\n");
|
||||
return ret;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int axxia_i2c_remove(struct platform_device *pdev)
|
||||
{
|
||||
struct axxia_i2c_dev *idev = platform_get_drvdata(pdev);
|
||||
|
||||
clk_disable_unprepare(idev->i2c_clk);
|
||||
i2c_del_adapter(&idev->adapter);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* Match table for of_platform binding */
|
||||
static const struct of_device_id axxia_i2c_of_match[] = {
|
||||
{ .compatible = "lsi,api2c", },
|
||||
{},
|
||||
};
|
||||
|
||||
MODULE_DEVICE_TABLE(of, axxia_i2c_of_match);
|
||||
|
||||
static struct platform_driver axxia_i2c_driver = {
|
||||
.probe = axxia_i2c_probe,
|
||||
.remove = axxia_i2c_remove,
|
||||
.driver = {
|
||||
.name = "axxia-i2c",
|
||||
.of_match_table = axxia_i2c_of_match,
|
||||
},
|
||||
};
|
||||
|
||||
module_platform_driver(axxia_i2c_driver);
|
||||
|
||||
MODULE_DESCRIPTION("Axxia I2C Bus driver");
|
||||
MODULE_AUTHOR("Anders Berg <anders.berg@lsi.com>");
|
||||
MODULE_LICENSE("GPL v2");
|
||||
Loading…
Reference in New Issue