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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/i2c/busses/i2c-au1550.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/i2c/busses/i2c-au1550.c')
-rw-r--r-- | drivers/i2c/busses/i2c-au1550.c | 435 |
1 files changed, 435 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-au1550.c b/drivers/i2c/busses/i2c-au1550.c new file mode 100644 index 0000000..75831a20 --- /dev/null +++ b/drivers/i2c/busses/i2c-au1550.c @@ -0,0 +1,435 @@ +/* + * 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. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +#include <linux/config.h> +#include <linux/delay.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/errno.h> +#include <linux/i2c.h> + +#include <asm/mach-au1x00/au1000.h> +#include <asm/mach-pb1x00/pb1550.h> +#include <asm/mach-au1x00/au1xxx_psc.h> + +#include "i2c-au1550.h" + +static int +wait_xfer_done(struct i2c_au1550_data *adap) +{ + u32 stat; + int i; + volatile psc_smb_t *sp; + + sp = (volatile psc_smb_t *)(adap->psc_base); + + /* Wait for Tx FIFO Underflow. + */ + for (i = 0; i < adap->xfer_timeout; i++) { + stat = sp->psc_smbevnt; + au_sync(); + if ((stat & PSC_SMBEVNT_TU) != 0) { + /* Clear it. */ + sp->psc_smbevnt = PSC_SMBEVNT_TU; + au_sync(); + return 0; + } + udelay(1); + } + + return -ETIMEDOUT; +} + +static int +wait_ack(struct i2c_au1550_data *adap) +{ + u32 stat; + volatile psc_smb_t *sp; + + if (wait_xfer_done(adap)) + return -ETIMEDOUT; + + sp = (volatile psc_smb_t *)(adap->psc_base); + + stat = sp->psc_smbevnt; + au_sync(); + + 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) +{ + u32 stat; + int i; + volatile psc_smb_t *sp; + + sp = (volatile psc_smb_t *)(adap->psc_base); + + /* Wait for Master Done. + */ + for (i = 0; i < adap->xfer_timeout; i++) { + stat = sp->psc_smbevnt; + au_sync(); + if ((stat & PSC_SMBEVNT_MD) != 0) + return 0; + udelay(1); + } + + return -ETIMEDOUT; +} + +static int +do_address(struct i2c_au1550_data *adap, unsigned int addr, int rd) +{ + volatile psc_smb_t *sp; + u32 stat; + + sp = (volatile psc_smb_t *)(adap->psc_base); + + /* Reset the FIFOs, clear events. + */ + sp->psc_smbpcr = PSC_SMBPCR_DC; + sp->psc_smbevnt = PSC_SMBEVNT_ALLCLR; + au_sync(); + do { + stat = sp->psc_smbpcr; + au_sync(); + } while ((stat & PSC_SMBPCR_DC) != 0); + + /* Write out the i2c chip address and specify operation + */ + addr <<= 1; + if (rd) + addr |= 1; + + /* Put byte into fifo, start up master. + */ + sp->psc_smbtxrx = addr; + au_sync(); + sp->psc_smbpcr = PSC_SMBPCR_MS; + au_sync(); + if (wait_ack(adap)) + return -EIO; + return 0; +} + +static u32 +wait_for_rx_byte(struct i2c_au1550_data *adap, u32 *ret_data) +{ + int j; + u32 data, stat; + volatile psc_smb_t *sp; + + if (wait_xfer_done(adap)) + return -EIO; + + sp = (volatile psc_smb_t *)(adap->psc_base); + + j = adap->xfer_timeout * 100; + do { + j--; + if (j <= 0) + return -EIO; + + stat = sp->psc_smbstat; + au_sync(); + if ((stat & PSC_SMBSTAT_RE) == 0) + j = 0; + else + udelay(1); + } while (j > 0); + data = sp->psc_smbtxrx; + au_sync(); + *ret_data = data; + + return 0; +} + +static int +i2c_read(struct i2c_au1550_data *adap, unsigned char *buf, + unsigned int len) +{ + int i; + u32 data; + volatile psc_smb_t *sp; + + 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. + */ + + sp = (volatile psc_smb_t *)(adap->psc_base); + + i = 0; + while (i < (len-1)) { + sp->psc_smbtxrx = 0; + au_sync(); + if (wait_for_rx_byte(adap, &data)) + return -EIO; + + buf[i] = data; + i++; + } + + /* The last byte has to indicate transfer done. + */ + sp->psc_smbtxrx = PSC_SMBTXRX_STP; + au_sync(); + if (wait_master_done(adap)) + return -EIO; + + data = sp->psc_smbtxrx; + au_sync(); + buf[i] = data; + return 0; +} + +static int +i2c_write(struct i2c_au1550_data *adap, unsigned char *buf, + unsigned int len) +{ + int i; + u32 data; + volatile psc_smb_t *sp; + + if (len == 0) + return 0; + + sp = (volatile psc_smb_t *)(adap->psc_base); + + i = 0; + while (i < (len-1)) { + data = buf[i]; + sp->psc_smbtxrx = data; + au_sync(); + if (wait_ack(adap)) + return -EIO; + i++; + } + + /* The last byte has to indicate transfer done. + */ + data = buf[i]; + data |= PSC_SMBTXRX_STP; + sp->psc_smbtxrx = data; + au_sync(); + 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; + + for (i = 0; !err && i < num; i++) { + p = &msgs[i]; + err = do_address(adap, p->addr, p->flags & I2C_M_RD); + 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; + return err; +} + +static u32 +au1550_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C; +} + +static struct i2c_algorithm au1550_algo = { + .name = "Au1550 algorithm", + .id = I2C_ALGO_AU1550, + .master_xfer = au1550_xfer, + .functionality = au1550_func, +}; + +/* + * 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. + */ +int +i2c_au1550_add_bus(struct i2c_adapter *i2c_adap) +{ + struct i2c_au1550_data *adap = i2c_adap->algo_data; + volatile psc_smb_t *sp; + u32 stat; + + i2c_adap->algo = &au1550_algo; + + /* Now, set up the PSC for SMBus PIO mode. + */ + sp = (volatile psc_smb_t *)(adap->psc_base); + sp->psc_ctrl = PSC_CTRL_DISABLE; + au_sync(); + sp->psc_sel = PSC_SEL_PS_SMBUSMODE; + sp->psc_smbcfg = 0; + au_sync(); + sp->psc_ctrl = PSC_CTRL_ENABLE; + au_sync(); + do { + stat = sp->psc_smbstat; + au_sync(); + } while ((stat & PSC_SMBSTAT_SR) == 0); + + sp->psc_smbcfg = (PSC_SMBCFG_RT_FIFO8 | PSC_SMBCFG_TT_FIFO8 | + PSC_SMBCFG_DD_DISABLE); + + /* Divide by 8 to get a 6.25 MHz clock. The later protocol + * timings are based on this clock. + */ + sp->psc_smbcfg |= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8); + sp->psc_smbmsk = PSC_SMBMSK_ALLMASK; + au_sync(); + + /* Set the protocol timer values. See Table 71 in the + * Au1550 Data Book for standard timing values. + */ + sp->psc_smbtmr = PSC_SMBTMR_SET_TH(0) | PSC_SMBTMR_SET_PS(15) | \ + PSC_SMBTMR_SET_PU(15) | PSC_SMBTMR_SET_SH(15) | \ + PSC_SMBTMR_SET_SU(15) | PSC_SMBTMR_SET_CL(15) | \ + PSC_SMBTMR_SET_CH(15); + au_sync(); + + sp->psc_smbcfg |= PSC_SMBCFG_DE_ENABLE; + do { + stat = sp->psc_smbstat; + au_sync(); + } while ((stat & PSC_SMBSTAT_DR) == 0); + + return i2c_add_adapter(i2c_adap); +} + + +int +i2c_au1550_del_bus(struct i2c_adapter *adap) +{ + return i2c_del_adapter(adap); +} + +static int +pb1550_reg(struct i2c_client *client) +{ + return 0; +} + +static int +pb1550_unreg(struct i2c_client *client) +{ + return 0; +} + +static struct i2c_au1550_data pb1550_i2c_info = { + SMBUS_PSC_BASE, 200, 200 +}; + +static struct i2c_adapter pb1550_board_adapter = { + name: "pb1550 adapter", + id: I2C_HW_AU1550_PSC, + algo: NULL, + algo_data: &pb1550_i2c_info, + client_register: pb1550_reg, + client_unregister: pb1550_unreg, +}; + +/* BIG hack to support the control interface on the Wolfson WM8731 + * audio codec on the Pb1550 board. We get an address and two data + * bytes to write, create an i2c message, and send it across the + * i2c transfer function. We do this here because we have access to + * the i2c adapter structure. + */ +static struct i2c_msg wm_i2c_msg; /* We don't want this stuff on the stack */ +static u8 i2cbuf[2]; + +int +pb1550_wm_codec_write(u8 addr, u8 reg, u8 val) +{ + wm_i2c_msg.addr = addr; + wm_i2c_msg.flags = 0; + wm_i2c_msg.buf = i2cbuf; + wm_i2c_msg.len = 2; + i2cbuf[0] = reg; + i2cbuf[1] = val; + + return pb1550_board_adapter.algo->master_xfer(&pb1550_board_adapter, &wm_i2c_msg, 1); +} + +static int __init +i2c_au1550_init(void) +{ + printk(KERN_INFO "Au1550 I2C: "); + + /* This is where we would set up a 50MHz clock source + * and routing. On the Pb1550, the SMBus is PSC2, which + * uses a shared clock with USB. This has been already + * configured by Yamon as a 48MHz clock, close enough + * for our work. + */ + if (i2c_au1550_add_bus(&pb1550_board_adapter) < 0) { + printk("failed to initialize.\n"); + return -ENODEV; + } + + printk("initialized.\n"); + return 0; +} + +static void __exit +i2c_au1550_exit(void) +{ + i2c_au1550_del_bus(&pb1550_board_adapter); +} + +MODULE_AUTHOR("Dan Malek, Embedded Edge, LLC."); +MODULE_DESCRIPTION("SMBus adapter Alchemy pb1550"); +MODULE_LICENSE("GPL"); + +module_init (i2c_au1550_init); +module_exit (i2c_au1550_exit); |