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  • /*
     * drivers/i2c/rcar_i2c.c
     *
     * Copyright (C) 2013 Renesas Electronics Corporation
     * Copyright (C) 2013 Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
     *
     * SPDX-License-Identifier: GPL-2.0
     */
    
    #include <common.h>
    #include <i2c.h>
    #include <asm/io.h>
    
    DECLARE_GLOBAL_DATA_PTR;
    
    struct rcar_i2c {
    	u32 icscr;
    	u32 icmcr;
    	u32 icssr;
    	u32 icmsr;
    	u32 icsier;
    	u32 icmier;
    	u32 icccr;
    	u32 icsar;
    	u32 icmar;
    	u32 icrxdtxd;
    	u32 icccr2;
    	u32 icmpr;
    	u32 ichpr;
    	u32 iclpr;
    };
    
    #define MCR_MDBS	0x80	/* non-fifo mode switch	*/
    #define MCR_FSCL	0x40	/* override SCL pin	*/
    #define MCR_FSDA	0x20	/* override SDA pin	*/
    #define MCR_OBPC	0x10	/* override pins	*/
    #define MCR_MIE		0x08	/* master if enable	*/
    #define MCR_TSBE	0x04
    #define MCR_FSB		0x02	/* force stop bit	*/
    #define MCR_ESG		0x01	/* en startbit gen.	*/
    
    #define MSR_MASK	0x7f
    #define MSR_MNR		0x40	/* nack received	*/
    #define MSR_MAL		0x20	/* arbitration lost	*/
    #define MSR_MST		0x10	/* sent a stop		*/
    #define MSR_MDE		0x08
    #define MSR_MDT		0x04
    #define MSR_MDR		0x02
    #define MSR_MAT		0x01	/* slave addr xfer done	*/
    
    static const struct rcar_i2c *i2c_dev[CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS] = {
    	(struct rcar_i2c *)CONFIG_SYS_RCAR_I2C0_BASE,
    	(struct rcar_i2c *)CONFIG_SYS_RCAR_I2C1_BASE,
    	(struct rcar_i2c *)CONFIG_SYS_RCAR_I2C2_BASE,
    	(struct rcar_i2c *)CONFIG_SYS_RCAR_I2C3_BASE,
    };
    
    static void rcar_i2c_raw_rw_common(struct rcar_i2c *dev, u8 chip, uint addr)
    {
    	/* set slave address */
    	writel(chip << 1, &dev->icmar);
    	/* set register address */
    	writel(addr, &dev->icrxdtxd);
    	/* clear status */
    	writel(0, &dev->icmsr);
    	/* start master send */
    	writel(MCR_MDBS | MCR_MIE | MCR_ESG, &dev->icmcr);
    
    	while ((readl(&dev->icmsr) & (MSR_MAT | MSR_MDE))
    		!= (MSR_MAT | MSR_MDE))
    		udelay(10);
    
    	/* clear ESG */
    	writel(MCR_MDBS | MCR_MIE, &dev->icmcr);
    	/* start SCLclk */
    	writel(~(MSR_MAT | MSR_MDE), &dev->icmsr);
    
    	while (!(readl(&dev->icmsr) & MSR_MDE))
    		udelay(10);
    }
    
    static void rcar_i2c_raw_rw_finish(struct rcar_i2c *dev)
    {
    	while (!(readl(&dev->icmsr) & MSR_MST))
    		udelay(10);
    
    	writel(0, &dev->icmcr);
    }
    
    static int
    rcar_i2c_raw_write(struct rcar_i2c *dev, u8 chip, uint addr, u8 *val, int size)
    {
    	rcar_i2c_raw_rw_common(dev, chip, addr);
    
    	/* set send date */
    	writel(*val, &dev->icrxdtxd);
    	/* start SCLclk */
    	writel(~MSR_MDE, &dev->icmsr);
    
    	while (!(readl(&dev->icmsr) & MSR_MDE))
    		udelay(10);
    
    	/* set stop condition */
    	writel(MCR_MDBS | MCR_MIE | MCR_FSB, &dev->icmcr);
    	/* start SCLclk */
    	writel(~MSR_MDE, &dev->icmsr);
    
    	rcar_i2c_raw_rw_finish(dev);
    
    	return 0;
    }
    
    static u8
    rcar_i2c_raw_read(struct rcar_i2c *dev, u8 chip, uint addr)
    {
    	u8 ret;
    
    	rcar_i2c_raw_rw_common(dev, chip, addr);
    
    	/* set slave address, receive */
    	writel((chip << 1) | 1, &dev->icmar);
    	/* start master receive */
    	writel(MCR_MDBS | MCR_MIE | MCR_ESG, &dev->icmcr);
    
    	while ((readl(&dev->icmsr) & (MSR_MAT | MSR_MDE))
    		!= (MSR_MAT | MSR_MDE))
    		udelay(10);
    
    	/* clear ESG */
    	writel(MCR_MDBS | MCR_MIE, &dev->icmcr);
    	/* prepare stop condition */
    	writel(MCR_MDBS | MCR_MIE | MCR_FSB, &dev->icmcr);
    	/* start SCLclk */
    	writel(~(MSR_MAT | MSR_MDR), &dev->icmsr);
    
    	while (!(readl(&dev->icmsr) & MSR_MDR))
    		udelay(10);
    
    	/* get receive data */
    	ret = (u8)readl(&dev->icrxdtxd);
    	/* start SCLclk */
    	writel(~MSR_MDR, &dev->icmsr);
    
    	rcar_i2c_raw_rw_finish(dev);
    
    	return ret;
    }
    
    /*
     * SCL  = iicck / (20 + SCGD * 8 + F[(ticf + tr + intd) * iicck])
     * iicck  : I2C internal clock < 20 MHz
     * ticf : I2C SCL falling time: 35 ns
     * tr   : I2C SCL rising time:  200 ns
     * intd : LSI internal delay:   I2C0: 50 ns I2C1-3: 5
     * F[n] : n rounded up to an integer
     */
    static u32 rcar_clock_gen(int i2c_no, u32 bus_speed)
    {
    	u32 iicck, f, scl, scgd;
    	u32 intd = 5;
    
    	int bit = 0, cdf_width = 3;
    	for (bit = 0; bit < (1 << cdf_width); bit++) {
    		iicck = CONFIG_HP_CLK_FREQ / (1 + bit);
    		if (iicck < 20000000)
    			break;
    	}
    
    	if (bit > (1 << cdf_width)) {
    		puts("rcar-i2c: Can not get CDF\n");
    		return 0;
    	}
    
    	if (i2c_no == 0)
    		intd = 50;
    
    	f = (35 + 200 + intd) * (iicck / 1000000000);
    
    	for (scgd = 0; scgd < 0x40; scgd++) {
    		scl = iicck / (20 + (scgd * 8) + f);
    		if (scl <= bus_speed)
    			break;
    	}
    
    	if (scgd > 0x40) {
    		puts("rcar-i2c: Can not get SDGB\n");
    		return 0;
    	}
    
    	debug("%s: scl: %d\n", __func__, scl);
    	debug("%s: bit %x\n", __func__, bit);
    	debug("%s: scgd %x\n", __func__, scgd);
    	debug("%s: iccr %x\n", __func__, (scgd << (cdf_width) | bit));
    
    	return scgd << (cdf_width) | bit;
    }
    
    static void
    rcar_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
    {
    	struct rcar_i2c *dev = (struct rcar_i2c *)i2c_dev[adap->hwadapnr];
    	u32 icccr = 0;
    
    	/* No i2c support prior to relocation */
    	if (!(gd->flags & GD_FLG_RELOC))
    		return;
    
    	/*
    	 * reset slave mode.
    	 * slave mode is not used on this driver
    	 */
    	writel(0, &dev->icsier);
    	writel(0, &dev->icsar);
    	writel(0, &dev->icscr);
    	writel(0, &dev->icssr);
    
    	/* reset master mode */
    	writel(0, &dev->icmier);
    	writel(0, &dev->icmcr);
    	writel(0, &dev->icmsr);
    	writel(0, &dev->icmar);
    
    	icccr = rcar_clock_gen(adap->hwadapnr, adap->speed);
    	if (icccr == 0)
    		puts("I2C: Init failed\n");
    	else
    		writel(icccr, &dev->icccr);
    }
    
    static int rcar_i2c_read(struct i2c_adapter *adap, uint8_t chip,
    			uint addr, int alen, u8 *data, int len)
    {
    	struct rcar_i2c *dev = (struct rcar_i2c *)i2c_dev[adap->hwadapnr];
    	int i;
    
    	for (i = 0; i < len; i++)
    		data[i] = rcar_i2c_raw_read(dev, chip, addr + i);
    
    	return 0;
    }
    
    static int rcar_i2c_write(struct i2c_adapter *adap, uint8_t chip, uint addr,
    			int alen, u8 *data, int len)
    {
    	struct rcar_i2c *dev = (struct rcar_i2c *)i2c_dev[adap->hwadapnr];
    	return rcar_i2c_raw_write(dev, chip, addr, data, len);
    }
    
    static int
    rcar_i2c_probe(struct i2c_adapter *adap, u8 dev)
    {
    	return rcar_i2c_read(adap, dev, 0, 0, NULL, 0);
    }
    
    static unsigned int rcar_i2c_set_bus_speed(struct i2c_adapter *adap,
    			unsigned int speed)
    {
    	struct rcar_i2c *dev = (struct rcar_i2c *)i2c_dev[adap->hwadapnr];
    	u32 icccr;
    	int ret = 0;
    
    	rcar_i2c_raw_rw_finish(dev);
    
    	icccr = rcar_clock_gen(adap->hwadapnr, speed);
    	if (icccr == 0) {
    		puts("I2C: Init failed\n");
    		ret = -1;
    	} else {
    		writel(icccr, &dev->icccr);
    	}
    	return ret;
    }
    
    /*
     * Register RCAR i2c adapters
     */
    U_BOOT_I2C_ADAP_COMPLETE(rcar_0, rcar_i2c_init, rcar_i2c_probe, rcar_i2c_read,
    			 rcar_i2c_write, rcar_i2c_set_bus_speed,
    			 CONFIG_SYS_RCAR_I2C0_SPEED, 0, 0)
    U_BOOT_I2C_ADAP_COMPLETE(rcar_1, rcar_i2c_init, rcar_i2c_probe, rcar_i2c_read,
    			 rcar_i2c_write, rcar_i2c_set_bus_speed,
    			 CONFIG_SYS_RCAR_I2C1_SPEED, 0, 1)
    U_BOOT_I2C_ADAP_COMPLETE(rcar_2, rcar_i2c_init, rcar_i2c_probe, rcar_i2c_read,
    			 rcar_i2c_write, rcar_i2c_set_bus_speed,
    			 CONFIG_SYS_RCAR_I2C2_SPEED, 0, 2)
    U_BOOT_I2C_ADAP_COMPLETE(rcar_3, rcar_i2c_init, rcar_i2c_probe, rcar_i2c_read,
    			 rcar_i2c_write, rcar_i2c_set_bus_speed,
    			 CONFIG_SYS_RCAR_I2C3_SPEED, 0, 3)