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-rw-r--r--drivers/i2c/busses/i2c-au1550.c380
1 files changed, 380 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-au1550.c b/drivers/i2c/busses/i2c-au1550.c
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index 0000000000..8e43f25c11
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+++ b/drivers/i2c/busses/i2c-au1550.c
@@ -0,0 +1,380 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * i2c-au1550.c: SMBus (i2c) adapter for Alchemy PSC interface
+ * Copyright (C) 2004 Embedded Edge, LLC <dan@embeddededge.com>
+ *
+ * 2.6 port by Matt Porter <mporter@kernel.crashing.org>
+ *
+ * The documentation describes this as an SMBus controller, but it doesn't
+ * understand any of the SMBus protocol in hardware. It's really an I2C
+ * controller that could emulate most of the SMBus in software.
+ *
+ * This is just a skeleton adapter to use with the Au1550 PSC
+ * algorithm. It was developed for the Pb1550, but will work with
+ * any Au1550 board that has a similar PSC configuration.
+ */
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+
+#include <asm/mach-au1x00/au1000.h>
+#include <asm/mach-au1x00/au1xxx_psc.h>
+
+#define PSC_SEL 0x00
+#define PSC_CTRL 0x04
+#define PSC_SMBCFG 0x08
+#define PSC_SMBMSK 0x0C
+#define PSC_SMBPCR 0x10
+#define PSC_SMBSTAT 0x14
+#define PSC_SMBEVNT 0x18
+#define PSC_SMBTXRX 0x1C
+#define PSC_SMBTMR 0x20
+
+struct i2c_au1550_data {
+ void __iomem *psc_base;
+ int xfer_timeout;
+ struct i2c_adapter adap;
+};
+
+static inline void WR(struct i2c_au1550_data *a, int r, unsigned long v)
+{
+ __raw_writel(v, a->psc_base + r);
+ wmb();
+}
+
+static inline unsigned long RD(struct i2c_au1550_data *a, int r)
+{
+ return __raw_readl(a->psc_base + r);
+}
+
+static int wait_xfer_done(struct i2c_au1550_data *adap)
+{
+ int i;
+
+ /* Wait for Tx Buffer Empty */
+ for (i = 0; i < adap->xfer_timeout; i++) {
+ if (RD(adap, PSC_SMBSTAT) & PSC_SMBSTAT_TE)
+ return 0;
+
+ udelay(1);
+ }
+
+ return -ETIMEDOUT;
+}
+
+static int wait_ack(struct i2c_au1550_data *adap)
+{
+ unsigned long stat;
+
+ if (wait_xfer_done(adap))
+ return -ETIMEDOUT;
+
+ stat = RD(adap, PSC_SMBEVNT);
+ if ((stat & (PSC_SMBEVNT_DN | PSC_SMBEVNT_AN | PSC_SMBEVNT_AL)) != 0)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int wait_master_done(struct i2c_au1550_data *adap)
+{
+ int i;
+
+ /* Wait for Master Done. */
+ for (i = 0; i < 2 * adap->xfer_timeout; i++) {
+ if ((RD(adap, PSC_SMBEVNT) & PSC_SMBEVNT_MD) != 0)
+ return 0;
+ udelay(1);
+ }
+
+ return -ETIMEDOUT;
+}
+
+static int
+do_address(struct i2c_au1550_data *adap, unsigned int addr, int rd, int q)
+{
+ unsigned long stat;
+
+ /* Reset the FIFOs, clear events. */
+ stat = RD(adap, PSC_SMBSTAT);
+ WR(adap, PSC_SMBEVNT, PSC_SMBEVNT_ALLCLR);
+
+ if (!(stat & PSC_SMBSTAT_TE) || !(stat & PSC_SMBSTAT_RE)) {
+ WR(adap, PSC_SMBPCR, PSC_SMBPCR_DC);
+ while ((RD(adap, PSC_SMBPCR) & PSC_SMBPCR_DC) != 0)
+ cpu_relax();
+ udelay(50);
+ }
+
+ /* Write out the i2c chip address and specify operation */
+ addr <<= 1;
+ if (rd)
+ addr |= 1;
+
+ /* zero-byte xfers stop immediately */
+ if (q)
+ addr |= PSC_SMBTXRX_STP;
+
+ /* Put byte into fifo, start up master. */
+ WR(adap, PSC_SMBTXRX, addr);
+ WR(adap, PSC_SMBPCR, PSC_SMBPCR_MS);
+ if (wait_ack(adap))
+ return -EIO;
+ return (q) ? wait_master_done(adap) : 0;
+}
+
+static int wait_for_rx_byte(struct i2c_au1550_data *adap, unsigned char *out)
+{
+ int j;
+
+ if (wait_xfer_done(adap))
+ return -EIO;
+
+ j = adap->xfer_timeout * 100;
+ do {
+ j--;
+ if (j <= 0)
+ return -EIO;
+
+ if ((RD(adap, PSC_SMBSTAT) & PSC_SMBSTAT_RE) == 0)
+ j = 0;
+ else
+ udelay(1);
+ } while (j > 0);
+
+ *out = RD(adap, PSC_SMBTXRX);
+
+ return 0;
+}
+
+static int i2c_read(struct i2c_au1550_data *adap, unsigned char *buf,
+ unsigned int len)
+{
+ int i;
+
+ if (len == 0)
+ return 0;
+
+ /* A read is performed by stuffing the transmit fifo with
+ * zero bytes for timing, waiting for bytes to appear in the
+ * receive fifo, then reading the bytes.
+ */
+ i = 0;
+ while (i < (len - 1)) {
+ WR(adap, PSC_SMBTXRX, 0);
+ if (wait_for_rx_byte(adap, &buf[i]))
+ return -EIO;
+
+ i++;
+ }
+
+ /* The last byte has to indicate transfer done. */
+ WR(adap, PSC_SMBTXRX, PSC_SMBTXRX_STP);
+ if (wait_master_done(adap))
+ return -EIO;
+
+ buf[i] = (unsigned char)(RD(adap, PSC_SMBTXRX) & 0xff);
+ return 0;
+}
+
+static int i2c_write(struct i2c_au1550_data *adap, unsigned char *buf,
+ unsigned int len)
+{
+ int i;
+ unsigned long data;
+
+ if (len == 0)
+ return 0;
+
+ i = 0;
+ while (i < (len-1)) {
+ data = buf[i];
+ WR(adap, PSC_SMBTXRX, data);
+ if (wait_ack(adap))
+ return -EIO;
+ i++;
+ }
+
+ /* The last byte has to indicate transfer done. */
+ data = buf[i];
+ data |= PSC_SMBTXRX_STP;
+ WR(adap, PSC_SMBTXRX, data);
+ if (wait_master_done(adap))
+ return -EIO;
+ return 0;
+}
+
+static int
+au1550_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
+{
+ struct i2c_au1550_data *adap = i2c_adap->algo_data;
+ struct i2c_msg *p;
+ int i, err = 0;
+
+ WR(adap, PSC_CTRL, PSC_CTRL_ENABLE);
+
+ for (i = 0; !err && i < num; i++) {
+ p = &msgs[i];
+ err = do_address(adap, p->addr, p->flags & I2C_M_RD,
+ (p->len == 0));
+ if (err || !p->len)
+ continue;
+ if (p->flags & I2C_M_RD)
+ err = i2c_read(adap, p->buf, p->len);
+ else
+ err = i2c_write(adap, p->buf, p->len);
+ }
+
+ /* Return the number of messages processed, or the error code.
+ */
+ if (err == 0)
+ err = num;
+
+ WR(adap, PSC_CTRL, PSC_CTRL_SUSPEND);
+
+ return err;
+}
+
+static u32 au1550_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm au1550_algo = {
+ .master_xfer = au1550_xfer,
+ .functionality = au1550_func,
+};
+
+static void i2c_au1550_setup(struct i2c_au1550_data *priv)
+{
+ unsigned long cfg;
+
+ WR(priv, PSC_CTRL, PSC_CTRL_DISABLE);
+ WR(priv, PSC_SEL, PSC_SEL_PS_SMBUSMODE);
+ WR(priv, PSC_SMBCFG, 0);
+ WR(priv, PSC_CTRL, PSC_CTRL_ENABLE);
+ while ((RD(priv, PSC_SMBSTAT) & PSC_SMBSTAT_SR) == 0)
+ cpu_relax();
+
+ cfg = PSC_SMBCFG_RT_FIFO8 | PSC_SMBCFG_TT_FIFO8 | PSC_SMBCFG_DD_DISABLE;
+ WR(priv, PSC_SMBCFG, cfg);
+
+ /* Divide by 8 to get a 6.25 MHz clock. The later protocol
+ * timings are based on this clock.
+ */
+ cfg |= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8);
+ WR(priv, PSC_SMBCFG, cfg);
+ WR(priv, PSC_SMBMSK, PSC_SMBMSK_ALLMASK);
+
+ /* Set the protocol timer values. See Table 71 in the
+ * Au1550 Data Book for standard timing values.
+ */
+ WR(priv, PSC_SMBTMR, PSC_SMBTMR_SET_TH(0) | PSC_SMBTMR_SET_PS(20) | \
+ PSC_SMBTMR_SET_PU(20) | PSC_SMBTMR_SET_SH(20) | \
+ PSC_SMBTMR_SET_SU(20) | PSC_SMBTMR_SET_CL(20) | \
+ PSC_SMBTMR_SET_CH(20));
+
+ cfg |= PSC_SMBCFG_DE_ENABLE;
+ WR(priv, PSC_SMBCFG, cfg);
+ while ((RD(priv, PSC_SMBSTAT) & PSC_SMBSTAT_SR) == 0)
+ cpu_relax();
+
+ WR(priv, PSC_CTRL, PSC_CTRL_SUSPEND);
+}
+
+static void i2c_au1550_disable(struct i2c_au1550_data *priv)
+{
+ WR(priv, PSC_SMBCFG, 0);
+ WR(priv, PSC_CTRL, PSC_CTRL_DISABLE);
+}
+
+/*
+ * registering functions to load algorithms at runtime
+ * Prior to calling us, the 50MHz clock frequency and routing
+ * must have been set up for the PSC indicated by the adapter.
+ */
+static int
+i2c_au1550_probe(struct platform_device *pdev)
+{
+ struct i2c_au1550_data *priv;
+ int ret;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(struct i2c_au1550_data),
+ GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->psc_base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
+ if (IS_ERR(priv->psc_base))
+ return PTR_ERR(priv->psc_base);
+
+ priv->xfer_timeout = 200;
+
+ priv->adap.nr = pdev->id;
+ priv->adap.algo = &au1550_algo;
+ priv->adap.algo_data = priv;
+ priv->adap.dev.parent = &pdev->dev;
+ strscpy(priv->adap.name, "Au1xxx PSC I2C", sizeof(priv->adap.name));
+
+ /* Now, set up the PSC for SMBus PIO mode. */
+ i2c_au1550_setup(priv);
+
+ ret = i2c_add_numbered_adapter(&priv->adap);
+ if (ret) {
+ i2c_au1550_disable(priv);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, priv);
+ return 0;
+}
+
+static void i2c_au1550_remove(struct platform_device *pdev)
+{
+ struct i2c_au1550_data *priv = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&priv->adap);
+ i2c_au1550_disable(priv);
+}
+
+static int i2c_au1550_suspend(struct device *dev)
+{
+ struct i2c_au1550_data *priv = dev_get_drvdata(dev);
+
+ i2c_au1550_disable(priv);
+
+ return 0;
+}
+
+static int i2c_au1550_resume(struct device *dev)
+{
+ struct i2c_au1550_data *priv = dev_get_drvdata(dev);
+
+ i2c_au1550_setup(priv);
+
+ return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(i2c_au1550_pmops,
+ i2c_au1550_suspend, i2c_au1550_resume);
+
+static struct platform_driver au1xpsc_smbus_driver = {
+ .driver = {
+ .name = "au1xpsc_smbus",
+ .pm = pm_sleep_ptr(&i2c_au1550_pmops),
+ },
+ .probe = i2c_au1550_probe,
+ .remove_new = i2c_au1550_remove,
+};
+
+module_platform_driver(au1xpsc_smbus_driver);
+
+MODULE_AUTHOR("Dan Malek, Embedded Edge, LLC.");
+MODULE_DESCRIPTION("SMBus adapter Alchemy pb1550");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:au1xpsc_smbus");