mirror of https://gitee.com/openkylin/linux.git
i2c/nuc900: add i2c driver support for nuc900
This patch is to add i2c driver support for nuc900. Signed-off-by: Wan ZongShun <mcuos.com@gmail.org> Reviewed-by: Marek Vasut <marek.vasut@gmail.com> Reviewed-by: Baruch Siach <baruch@tkos.co.il> Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Wan ZongShun
Ben Dooks
parent
45d7f32c7a
commit
ededad3e6f
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@ -0,0 +1,9 @@
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#ifndef __ASM_ARCH_NUC900_I2C_H
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#define __ASM_ARCH_NUC900_I2C_H
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struct nuc900_platform_i2c {
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int bus_num;
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unsigned long bus_freq;
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};
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#endif /* __ASM_ARCH_NUC900_I2C_H */
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@ -448,6 +448,13 @@ config I2C_NOMADIK
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If you say yes to this option, support will be included for the
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I2C interface from ST-Ericsson's Nomadik and Ux500 architectures.
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config I2C_NUC900
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tristate "NUC900 I2C Driver"
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depends on ARCH_W90X900
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help
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Say Y here to include support for I2C controller in the
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Winbond/Nuvoton NUC900 based System-on-Chip devices.
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config I2C_OCORES
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tristate "OpenCores I2C Controller"
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depends on EXPERIMENTAL
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@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_IXP2000) += i2c-ixp2000.o
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obj-$(CONFIG_I2C_MPC) += i2c-mpc.o
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obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o
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obj-$(CONFIG_I2C_NOMADIK) += i2c-nomadik.o
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obj-$(CONFIG_I2C_NUC900) += i2c-nuc900.o
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obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o
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obj-$(CONFIG_I2C_OMAP) += i2c-omap.o
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obj-$(CONFIG_I2C_PASEMI) += i2c-pasemi.o
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@ -0,0 +1,709 @@
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/*
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* linux/drivers/i2c/busses/i2c-nuc900.c
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*
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* Copyright (c) 2010 Nuvoton technology corporation.
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*
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* This driver based on S3C2410 I2C driver of Ben Dooks <ben-Y5A6D6n0/KfQXOPxS62xeg@public.gmane.org>.
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* Written by Wan ZongShun <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation;version 2 of the License.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/i2c-id.h>
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#include <linux/init.h>
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#include <linux/time.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/errno.h>
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#include <linux/err.h>
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#include <linux/platform_device.h>
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#include <linux/clk.h>
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#include <linux/cpufreq.h>
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#include <linux/slab.h>
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#include <linux/io.h>
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#include <mach/mfp.h>
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#include <mach/i2c.h>
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/* nuc900 i2c registers offset */
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#define CSR 0x00
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#define DIVIDER 0x04
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#define CMDR 0x08
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#define SWR 0x0C
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#define RXR 0x10
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#define TXR 0x14
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/* nuc900 i2c CSR register bits */
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#define IRQEN 0x003
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#define I2CBUSY 0x400
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#define I2CSTART 0x018
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#define IRQFLAG 0x004
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#define ARBIT_LOST 0x200
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#define SLAVE_ACK 0x800
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/* nuc900 i2c CMDR register bits */
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#define I2C_CMD_START 0x10
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#define I2C_CMD_STOP 0x08
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#define I2C_CMD_READ 0x04
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#define I2C_CMD_WRITE 0x02
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#define I2C_CMD_NACK 0x01
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/* i2c controller state */
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enum nuc900_i2c_state {
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STATE_IDLE,
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STATE_START,
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STATE_READ,
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STATE_WRITE,
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STATE_STOP
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};
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/* i2c controller private data */
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struct nuc900_i2c {
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spinlock_t lock;
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wait_queue_head_t wait;
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struct i2c_msg *msg;
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unsigned int msg_num;
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unsigned int msg_idx;
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unsigned int msg_ptr;
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unsigned int irq;
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enum nuc900_i2c_state state;
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void __iomem *regs;
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struct clk *clk;
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struct device *dev;
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struct resource *ioarea;
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struct i2c_adapter adap;
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};
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/* nuc900_i2c_master_complete
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*
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* complete the message and wake up the caller, using the given return code,
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* or zero to mean ok.
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*/
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static inline void nuc900_i2c_master_complete(struct nuc900_i2c *i2c, int ret)
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{
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dev_dbg(i2c->dev, "master_complete %d\n", ret);
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i2c->msg_ptr = 0;
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i2c->msg = NULL;
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i2c->msg_idx++;
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i2c->msg_num = 0;
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if (ret)
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i2c->msg_idx = ret;
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wake_up(&i2c->wait);
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}
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/* irq enable/disable functions */
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static inline void nuc900_i2c_disable_irq(struct nuc900_i2c *i2c)
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{
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unsigned long tmp;
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tmp = readl(i2c->regs + CSR);
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writel(tmp & ~IRQEN, i2c->regs + CSR);
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}
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static inline void nuc900_i2c_enable_irq(struct nuc900_i2c *i2c)
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{
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unsigned long tmp;
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tmp = readl(i2c->regs + CSR);
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writel(tmp | IRQEN, i2c->regs + CSR);
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}
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/* nuc900_i2c_message_start
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*
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* put the start of a message onto the bus
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*/
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static void nuc900_i2c_message_start(struct nuc900_i2c *i2c,
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struct i2c_msg *msg)
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{
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unsigned int addr = (msg->addr & 0x7f) << 1;
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if (msg->flags & I2C_M_RD)
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addr |= 0x1;
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writel(addr & 0xff, i2c->regs + TXR);
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writel(I2C_CMD_START | I2C_CMD_WRITE, i2c->regs + CMDR);
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}
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static inline void nuc900_i2c_stop(struct nuc900_i2c *i2c, int ret)
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{
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dev_dbg(i2c->dev, "STOP\n");
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/* stop the transfer */
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i2c->state = STATE_STOP;
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writel(I2C_CMD_STOP, i2c->regs + CMDR);
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nuc900_i2c_master_complete(i2c, ret);
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nuc900_i2c_disable_irq(i2c);
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}
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/* helper functions to determine the current state in the set of
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* messages we are sending
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*/
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/* is_lastmsg()
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*
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* returns TRUE if the current message is the last in the set
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*/
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static inline int is_lastmsg(struct nuc900_i2c *i2c)
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{
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return i2c->msg_idx >= (i2c->msg_num - 1);
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}
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/* is_msglast
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*
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* returns TRUE if we this is the last byte in the current message
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*/
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static inline int is_msglast(struct nuc900_i2c *i2c)
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{
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return i2c->msg_ptr == i2c->msg->len-1;
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}
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/* is_msgend
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*
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* returns TRUE if we reached the end of the current message
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*/
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static inline int is_msgend(struct nuc900_i2c *i2c)
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{
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return i2c->msg_ptr >= i2c->msg->len;
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}
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/* i2c_nuc900_irq_nextbyte
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*
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* process an interrupt and work out what to do
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*/
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static void i2c_nuc900_irq_nextbyte(struct nuc900_i2c *i2c,
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unsigned long iicstat)
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{
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unsigned char byte;
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switch (i2c->state) {
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case STATE_IDLE:
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dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
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break;
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case STATE_STOP:
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dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
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nuc900_i2c_disable_irq(i2c);
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break;
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case STATE_START:
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/* last thing we did was send a start condition on the
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* bus, or started a new i2c message
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*/
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if (iicstat & SLAVE_ACK &&
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!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
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/* ack was not received... */
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dev_dbg(i2c->dev, "ack was not received\n");
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nuc900_i2c_stop(i2c, -ENXIO);
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break;
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}
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if (i2c->msg->flags & I2C_M_RD)
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i2c->state = STATE_READ;
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else
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i2c->state = STATE_WRITE;
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/* terminate the transfer if there is nothing to do
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* as this is used by the i2c probe to find devices.
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*/
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if (is_lastmsg(i2c) && i2c->msg->len == 0) {
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nuc900_i2c_stop(i2c, 0);
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break;
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}
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if (i2c->state == STATE_READ)
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goto prepare_read;
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/* fall through to the write state, as we will need to
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* send a byte as well
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*/
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case STATE_WRITE:
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/* we are writing data to the device... check for the
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* end of the message, and if so, work out what to do
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*/
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if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
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if (iicstat & SLAVE_ACK) {
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dev_dbg(i2c->dev, "WRITE: No Ack\n");
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nuc900_i2c_stop(i2c, -ECONNREFUSED);
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break;
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}
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}
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retry_write:
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if (!is_msgend(i2c)) {
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byte = i2c->msg->buf[i2c->msg_ptr++];
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writeb(byte, i2c->regs + TXR);
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writel(I2C_CMD_WRITE, i2c->regs + CMDR);
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} else if (!is_lastmsg(i2c)) {
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/* we need to go to the next i2c message */
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dev_dbg(i2c->dev, "WRITE: Next Message\n");
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i2c->msg_ptr = 0;
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i2c->msg_idx++;
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i2c->msg++;
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/* check to see if we need to do another message */
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if (i2c->msg->flags & I2C_M_NOSTART) {
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if (i2c->msg->flags & I2C_M_RD) {
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/* cannot do this, the controller
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* forces us to send a new START
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* when we change direction
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*/
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nuc900_i2c_stop(i2c, -EINVAL);
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}
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goto retry_write;
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} else {
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/* send the new start */
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nuc900_i2c_message_start(i2c, i2c->msg);
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i2c->state = STATE_START;
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}
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} else {
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/* send stop */
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nuc900_i2c_stop(i2c, 0);
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}
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break;
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case STATE_READ:
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/* we have a byte of data in the data register, do
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* something with it, and then work out wether we are
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* going to do any more read/write
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*/
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byte = readb(i2c->regs + RXR);
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i2c->msg->buf[i2c->msg_ptr++] = byte;
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prepare_read:
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if (is_msglast(i2c)) {
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/* last byte of buffer */
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if (is_lastmsg(i2c))
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writel(I2C_CMD_READ | I2C_CMD_NACK,
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i2c->regs + CMDR);
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} else if (is_msgend(i2c)) {
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/* ok, we've read the entire buffer, see if there
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* is anything else we need to do
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*/
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if (is_lastmsg(i2c)) {
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/* last message, send stop and complete */
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dev_dbg(i2c->dev, "READ: Send Stop\n");
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nuc900_i2c_stop(i2c, 0);
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} else {
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/* go to the next transfer */
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dev_dbg(i2c->dev, "READ: Next Transfer\n");
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i2c->msg_ptr = 0;
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i2c->msg_idx++;
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i2c->msg++;
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writel(I2C_CMD_READ, i2c->regs + CMDR);
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}
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} else {
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writel(I2C_CMD_READ, i2c->regs + CMDR);
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}
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break;
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}
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}
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/* nuc900_i2c_irq
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*
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* top level IRQ servicing routine
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*/
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static irqreturn_t nuc900_i2c_irq(int irqno, void *dev_id)
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{
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struct nuc900_i2c *i2c = dev_id;
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unsigned long status;
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status = readl(i2c->regs + CSR);
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writel(status | IRQFLAG, i2c->regs + CSR);
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if (status & ARBIT_LOST) {
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/* deal with arbitration loss */
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dev_err(i2c->dev, "deal with arbitration loss\n");
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goto out;
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}
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if (i2c->state == STATE_IDLE) {
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dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
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goto out;
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}
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/* pretty much this leaves us with the fact that we've
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* transmitted or received whatever byte we last sent
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*/
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i2c_nuc900_irq_nextbyte(i2c, status);
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out:
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return IRQ_HANDLED;
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}
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/* nuc900_i2c_set_master
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*
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* get the i2c bus for a master transaction
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*/
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static int nuc900_i2c_set_master(struct nuc900_i2c *i2c)
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{
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int timeout = 400;
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while (timeout-- > 0) {
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if (((readl(i2c->regs + SWR) & I2CSTART) == I2CSTART) &&
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((readl(i2c->regs + CSR) & I2CBUSY) == 0)) {
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return 0;
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}
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msleep(1);
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}
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return -ETIMEDOUT;
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}
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/* nuc900_i2c_doxfer
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*
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* this starts an i2c transfer
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*/
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static int nuc900_i2c_doxfer(struct nuc900_i2c *i2c,
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struct i2c_msg *msgs, int num)
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{
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unsigned long iicstat, timeout;
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int spins = 20;
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int ret;
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ret = nuc900_i2c_set_master(i2c);
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if (ret != 0) {
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dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
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ret = -EAGAIN;
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goto out;
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}
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spin_lock_irq(&i2c->lock);
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i2c->msg = msgs;
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i2c->msg_num = num;
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i2c->msg_ptr = 0;
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i2c->msg_idx = 0;
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i2c->state = STATE_START;
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nuc900_i2c_message_start(i2c, msgs);
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spin_unlock_irq(&i2c->lock);
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timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
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ret = i2c->msg_idx;
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/* having these next two as dev_err() makes life very
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* noisy when doing an i2cdetect
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*/
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if (timeout == 0)
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dev_dbg(i2c->dev, "timeout\n");
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else if (ret != num)
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dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
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/* ensure the stop has been through the bus */
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dev_dbg(i2c->dev, "waiting for bus idle\n");
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/* first, try busy waiting briefly */
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do {
|
||||
iicstat = readl(i2c->regs + CSR);
|
||||
} while ((iicstat & I2CBUSY) && --spins);
|
||||
|
||||
/* if that timed out sleep */
|
||||
if (!spins) {
|
||||
msleep(1);
|
||||
iicstat = readl(i2c->regs + CSR);
|
||||
}
|
||||
|
||||
if (iicstat & I2CBUSY)
|
||||
dev_warn(i2c->dev, "timeout waiting for bus idle\n");
|
||||
|
||||
out:
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* nuc900_i2c_xfer
|
||||
*
|
||||
* first port of call from the i2c bus code when an message needs
|
||||
* transferring across the i2c bus.
|
||||
*/
|
||||
|
||||
static int nuc900_i2c_xfer(struct i2c_adapter *adap,
|
||||
struct i2c_msg *msgs, int num)
|
||||
{
|
||||
struct nuc900_i2c *i2c = (struct nuc900_i2c *)adap->algo_data;
|
||||
int retry;
|
||||
int ret;
|
||||
|
||||
nuc900_i2c_enable_irq(i2c);
|
||||
|
||||
for (retry = 0; retry < adap->retries; retry++) {
|
||||
|
||||
ret = nuc900_i2c_doxfer(i2c, msgs, num);
|
||||
|
||||
if (ret != -EAGAIN)
|
||||
return ret;
|
||||
|
||||
dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
|
||||
|
||||
udelay(100);
|
||||
}
|
||||
|
||||
return -EREMOTEIO;
|
||||
}
|
||||
|
||||
/* declare our i2c functionality */
|
||||
static u32 nuc900_i2c_func(struct i2c_adapter *adap)
|
||||
{
|
||||
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
|
||||
}
|
||||
|
||||
/* i2c bus registration info */
|
||||
|
||||
static const struct i2c_algorithm nuc900_i2c_algorithm = {
|
||||
.master_xfer = nuc900_i2c_xfer,
|
||||
.functionality = nuc900_i2c_func,
|
||||
};
|
||||
|
||||
/* nuc900_i2c_probe
|
||||
*
|
||||
* called by the bus driver when a suitable device is found
|
||||
*/
|
||||
|
||||
static int __devinit nuc900_i2c_probe(struct platform_device *pdev)
|
||||
{
|
||||
struct nuc900_i2c *i2c;
|
||||
struct nuc900_platform_i2c *pdata;
|
||||
struct resource *res;
|
||||
int ret;
|
||||
|
||||
pdata = pdev->dev.platform_data;
|
||||
if (!pdata) {
|
||||
dev_err(&pdev->dev, "no platform data\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
i2c = kzalloc(sizeof(struct nuc900_i2c), GFP_KERNEL);
|
||||
if (!i2c) {
|
||||
dev_err(&pdev->dev, "no memory for state\n");
|
||||
return -ENOMEM;
|
||||
}
|
||||
|
||||
strlcpy(i2c->adap.name, "nuc900-i2c0", sizeof(i2c->adap.name));
|
||||
i2c->adap.owner = THIS_MODULE;
|
||||
i2c->adap.algo = &nuc900_i2c_algorithm;
|
||||
i2c->adap.retries = 2;
|
||||
i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
|
||||
|
||||
spin_lock_init(&i2c->lock);
|
||||
init_waitqueue_head(&i2c->wait);
|
||||
|
||||
/* find the clock and enable it */
|
||||
|
||||
i2c->dev = &pdev->dev;
|
||||
i2c->clk = clk_get(&pdev->dev, NULL);
|
||||
if (IS_ERR(i2c->clk)) {
|
||||
dev_err(&pdev->dev, "cannot get clock\n");
|
||||
ret = -ENOENT;
|
||||
goto err_noclk;
|
||||
}
|
||||
|
||||
dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
|
||||
|
||||
clk_enable(i2c->clk);
|
||||
|
||||
/* map the registers */
|
||||
|
||||
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||
if (res == NULL) {
|
||||
dev_err(&pdev->dev, "cannot find IO resource\n");
|
||||
ret = -ENOENT;
|
||||
goto err_clk;
|
||||
}
|
||||
|
||||
i2c->ioarea = request_mem_region(res->start, resource_size(res),
|
||||
pdev->name);
|
||||
|
||||
if (i2c->ioarea == NULL) {
|
||||
dev_err(&pdev->dev, "cannot request IO\n");
|
||||
ret = -ENXIO;
|
||||
goto err_clk;
|
||||
}
|
||||
|
||||
i2c->regs = ioremap(res->start, resource_size(res));
|
||||
|
||||
if (i2c->regs == NULL) {
|
||||
dev_err(&pdev->dev, "cannot map IO\n");
|
||||
ret = -ENXIO;
|
||||
goto err_ioarea;
|
||||
}
|
||||
|
||||
dev_dbg(&pdev->dev, "registers %p (%p, %p)\n",
|
||||
i2c->regs, i2c->ioarea, res);
|
||||
|
||||
/* setup info block for the i2c core */
|
||||
|
||||
i2c->adap.algo_data = i2c;
|
||||
i2c->adap.dev.parent = &pdev->dev;
|
||||
|
||||
mfp_set_groupg(&pdev->dev);
|
||||
|
||||
clk_get_rate(i2c->clk);
|
||||
|
||||
ret = (i2c->clk.apbfreq)/(pdata->bus_freq * 5) - 1;
|
||||
writel(ret & 0xffff, i2c->regs + DIVIDER);
|
||||
|
||||
/* find the IRQ for this unit (note, this relies on the init call to
|
||||
* ensure no current IRQs pending
|
||||
*/
|
||||
|
||||
i2c->irq = ret = platform_get_irq(pdev, 0);
|
||||
if (ret <= 0) {
|
||||
dev_err(&pdev->dev, "cannot find IRQ\n");
|
||||
goto err_iomap;
|
||||
}
|
||||
|
||||
ret = request_irq(i2c->irq, nuc900_i2c_irq, IRQF_DISABLED | IRQF_SHARED,
|
||||
dev_name(&pdev->dev), i2c);
|
||||
|
||||
if (ret != 0) {
|
||||
dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
|
||||
goto err_iomap;
|
||||
}
|
||||
|
||||
/* Note, previous versions of the driver used i2c_add_adapter()
|
||||
* to add the bus at any number. We now pass the bus number via
|
||||
* the platform data, so if unset it will now default to always
|
||||
* being bus 0.
|
||||
*/
|
||||
|
||||
i2c->adap.nr = pdata->bus_num;
|
||||
|
||||
ret = i2c_add_numbered_adapter(&i2c->adap);
|
||||
if (ret < 0) {
|
||||
dev_err(&pdev->dev, "failed to add bus to i2c core\n");
|
||||
goto err_irq;
|
||||
}
|
||||
|
||||
platform_set_drvdata(pdev, i2c);
|
||||
|
||||
dev_info(&pdev->dev, "%s: NUC900 I2C adapter\n",
|
||||
dev_name(&i2c->adap.dev));
|
||||
return 0;
|
||||
|
||||
err_irq:
|
||||
free_irq(i2c->irq, i2c);
|
||||
|
||||
err_iomap:
|
||||
iounmap(i2c->regs);
|
||||
|
||||
err_ioarea:
|
||||
release_resource(i2c->ioarea);
|
||||
kfree(i2c->ioarea);
|
||||
|
||||
err_clk:
|
||||
clk_disable(i2c->clk);
|
||||
clk_put(i2c->clk);
|
||||
|
||||
err_noclk:
|
||||
kfree(i2c);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* nuc900_i2c_remove
|
||||
*
|
||||
* called when device is removed from the bus
|
||||
*/
|
||||
|
||||
static int __devexit nuc900_i2c_remove(struct platform_device *pdev)
|
||||
{
|
||||
struct nuc900_i2c *i2c = platform_get_drvdata(pdev);
|
||||
|
||||
i2c_del_adapter(&i2c->adap);
|
||||
free_irq(i2c->irq, i2c);
|
||||
|
||||
clk_disable(i2c->clk);
|
||||
clk_put(i2c->clk);
|
||||
|
||||
iounmap(i2c->regs);
|
||||
|
||||
release_resource(i2c->ioarea);
|
||||
kfree(i2c->ioarea);
|
||||
kfree(i2c);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static struct platform_driver nuc900_i2c_driver = {
|
||||
.probe = nuc900_i2c_probe,
|
||||
.remove = __devexit_p(nuc900_i2c_remove),
|
||||
.driver = {
|
||||
.owner = THIS_MODULE,
|
||||
.name = "nuc900-i2c0",
|
||||
},
|
||||
};
|
||||
|
||||
static int __init i2c_adap_nuc900_init(void)
|
||||
{
|
||||
return platform_driver_register(&nuc900_i2c_driver);
|
||||
}
|
||||
|
||||
static void __exit i2c_adap_nuc900_exit(void)
|
||||
{
|
||||
platform_driver_unregister(&nuc900_i2c_driver);
|
||||
}
|
||||
subsys_initcall(i2c_adap_nuc900_init);
|
||||
module_exit(i2c_adap_nuc900_exit);
|
||||
|
||||
MODULE_DESCRIPTION("NUC900 I2C Bus driver");
|
||||
MODULE_AUTHOR("Wan ZongShun, <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>");
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_ALIAS("platform:nuc900-i2c0");
|
||||
Loading…
Reference in New Issue