// SPDX-License-Identifier: GPL-2.0-or-later /* * STK1160 driver * * Copyright (C) 2012 Ezequiel Garcia * <elezegarcia--a.t--gmail.com> * * Based on Easycap driver by R.M. Thomas * Copyright (C) 2010 R.M. Thomas * <rmthomas--a.t--sciolus.org> */ #include <linux/module.h> #include <linux/usb.h> #include <linux/i2c.h> #include "stk1160.h" #include "stk1160-reg.h" static unsigned int i2c_debug; module_param(i2c_debug, int, 0644); MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]"); #define dprintk_i2c(fmt, args...) \ do { \ if (i2c_debug) \ printk(KERN_DEBUG fmt, ##args); \ } while (0) static int stk1160_i2c_busy_wait(struct stk1160 *dev, u8 wait_bit_mask) { unsigned long end; u8 flag; /* Wait until read/write finish bit is set */ end = jiffies + msecs_to_jiffies(STK1160_I2C_TIMEOUT); while (time_is_after_jiffies(end)) { stk1160_read_reg(dev, STK1160_SICTL+1, &flag); /* read/write done? */ if (flag & wait_bit_mask) goto done; usleep_range(10 * USEC_PER_MSEC, 20 * USEC_PER_MSEC); } return -ETIMEDOUT; done: return 0; } static int stk1160_i2c_write_reg(struct stk1160 *dev, u8 addr, u8 reg, u8 value) { int rc; /* Set serial device address */ rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr); if (rc < 0) return rc; /* Set i2c device register sub-address */ rc = stk1160_write_reg(dev, STK1160_SBUSW_WA, reg); if (rc < 0) return rc; /* Set i2c device register value */ rc = stk1160_write_reg(dev, STK1160_SBUSW_WD, value); if (rc < 0) return rc; /* Start write now */ rc = stk1160_write_reg(dev, STK1160_SICTL, 0x01); if (rc < 0) return rc; rc = stk1160_i2c_busy_wait(dev, 0x04); if (rc < 0) return rc; return 0; } static int stk1160_i2c_read_reg(struct stk1160 *dev, u8 addr, u8 reg, u8 *value) { int rc; /* Set serial device address */ rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr); if (rc < 0) return rc; /* Set i2c device register sub-address */ rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, reg); if (rc < 0) return rc; /* Start read now */ rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20); if (rc < 0) return rc; rc = stk1160_i2c_busy_wait(dev, 0x01); if (rc < 0) return rc; rc = stk1160_read_reg(dev, STK1160_SBUSR_RD, value); if (rc < 0) return rc; return 0; } /* * stk1160_i2c_check_for_device() * check if there is a i2c_device at the supplied address */ static int stk1160_i2c_check_for_device(struct stk1160 *dev, unsigned char addr) { int rc; /* Set serial device address */ rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr); if (rc < 0) return rc; /* Set device sub-address, we'll chip version reg */ rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, 0x00); if (rc < 0) return rc; /* Start read now */ rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20); if (rc < 0) return rc; rc = stk1160_i2c_busy_wait(dev, 0x01); if (rc < 0) return -ENODEV; return 0; } /* * stk1160_i2c_xfer() * the main i2c transfer function */ static int stk1160_i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num) { struct stk1160 *dev = i2c_adap->algo_data; int addr, rc, i; for (i = 0; i < num; i++) { addr = msgs[i].addr << 1; dprintk_i2c("%s: addr=%x", __func__, addr); if (!msgs[i].len) { /* no len: check only for device presence */ rc = stk1160_i2c_check_for_device(dev, addr); if (rc < 0) { dprintk_i2c(" no device\n"); return rc; } } else if (msgs[i].flags & I2C_M_RD) { /* read request without preceding register selection */ dprintk_i2c(" subaddr not selected"); rc = -EOPNOTSUPP; goto err; } else if (i + 1 < num && msgs[i].len <= 2 && (msgs[i + 1].flags & I2C_M_RD) && msgs[i].addr == msgs[i + 1].addr) { if (msgs[i].len != 1 || msgs[i + 1].len != 1) { dprintk_i2c(" len not supported"); rc = -EOPNOTSUPP; goto err; } dprintk_i2c(" subaddr=%x", msgs[i].buf[0]); rc = stk1160_i2c_read_reg(dev, addr, msgs[i].buf[0], msgs[i + 1].buf); dprintk_i2c(" read=%x", *msgs[i + 1].buf); /* consumed two msgs, so we skip one of them */ i++; } else { if (msgs[i].len != 2) { dprintk_i2c(" len not supported"); rc = -EOPNOTSUPP; goto err; } dprintk_i2c(" subaddr=%x write=%x", msgs[i].buf[0], msgs[i].buf[1]); rc = stk1160_i2c_write_reg(dev, addr, msgs[i].buf[0], msgs[i].buf[1]); } if (rc < 0) goto err; dprintk_i2c(" OK\n"); } return num; err: dprintk_i2c(" ERROR: %d\n", rc); return num; } /* * functionality(), what da heck is this? */ static u32 functionality(struct i2c_adapter *adap) { return I2C_FUNC_SMBUS_EMUL; } static const struct i2c_algorithm algo = { .master_xfer = stk1160_i2c_xfer, .functionality = functionality, }; static const struct i2c_adapter adap_template = { .owner = THIS_MODULE, .name = "stk1160", .algo = &algo, }; static const struct i2c_client client_template = { .name = "stk1160 internal", }; /* * stk1160_i2c_register() * register i2c bus */ int stk1160_i2c_register(struct stk1160 *dev) { int rc; dev->i2c_adap = adap_template; dev->i2c_adap.dev.parent = dev->dev; strscpy(dev->i2c_adap.name, "stk1160", sizeof(dev->i2c_adap.name)); dev->i2c_adap.algo_data = dev; i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev); rc = i2c_add_adapter(&dev->i2c_adap); if (rc < 0) { stk1160_err("cannot add i2c adapter (%d)\n", rc); return rc; } dev->i2c_client = client_template; dev->i2c_client.adapter = &dev->i2c_adap; /* Set i2c clock divider device address */ stk1160_write_reg(dev, STK1160_SICTL_CD, 0x0f); /* ??? */ stk1160_write_reg(dev, STK1160_ASIC + 3, 0x00); return 0; } /* * stk1160_i2c_unregister() * unregister i2c_bus */ int stk1160_i2c_unregister(struct stk1160 *dev) { i2c_del_adapter(&dev->i2c_adap); return 0; }