2 * drivers/media/i2c/smiapp/smiapp-regs.c
4 * Generic driver for SMIA/SMIA++ compliant camera modules
6 * Copyright (C) 2011--2012 Nokia Corporation
7 * Contact: Sakari Ailus <sakari.ailus@iki.fi>
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * version 2 as published by the Free Software Foundation.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
25 #include <linux/delay.h>
26 #include <linux/i2c.h>
29 #include "smiapp-regs.h"
31 static uint32_t float_to_u32_mul_1000000(struct i2c_client *client,
37 if (phloat >= 0x80000000) {
38 dev_err(&client->dev, "this is a negative number\n");
42 if (phloat == 0x7f800000)
45 if ((phloat & 0x7f800000) == 0x7f800000) {
46 dev_err(&client->dev, "NaN or other special number\n");
50 /* Valid cases begin here */
52 return 0; /* Valid zero */
54 if (phloat > 0x4f800000)
55 return ~0; /* larger than 4294967295 */
58 * Unbias exponent (note how phloat is now guaranteed to
59 * have 0 in the high bit)
61 exp = ((int32_t)phloat >> 23) - 127;
63 /* Extract mantissa, add missing '1' bit and it's in MHz */
64 man = ((phloat & 0x7fffff) | 0x800000) * 1000000ULL;
71 man >>= 23; /* Remove mantissa bias */
73 return man & 0xffffffff;
78 * Read a 8/16/32-bit i2c register. The value is returned in 'val'.
79 * Returns zero if successful, or non-zero otherwise.
81 static int ____smiapp_read(struct smiapp_sensor *sensor, u16 reg,
84 struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
86 unsigned char data[4];
90 msg.addr = client->addr;
95 /* high byte goes out first */
96 data[0] = (u8) (offset >> 8);
97 data[1] = (u8) offset;
98 r = i2c_transfer(client->adapter, &msg, 1);
106 msg.flags = I2C_M_RD;
107 r = i2c_transfer(client->adapter, &msg, 1);
115 /* high byte comes first */
118 *val = (data[0] << 24) + (data[1] << 16) + (data[2] << 8) +
122 *val = (data[0] << 8) + data[1];
134 dev_err(&client->dev, "read from offset 0x%x error %d\n", offset, r);
139 /* Read a register using 8-bit access only. */
140 static int ____smiapp_read_8only(struct smiapp_sensor *sensor, u16 reg,
148 for (i = 0; i < len; i++) {
151 rval = ____smiapp_read(sensor, reg + i, 1, &val8);
154 *val |= val8 << ((len - i - 1) << 3);
161 * Read a 8/16/32-bit i2c register. The value is returned in 'val'.
162 * Returns zero if successful, or non-zero otherwise.
164 static int __smiapp_read(struct smiapp_sensor *sensor, u32 reg, u32 *val,
167 struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
168 unsigned int len = (u8)(reg >> 16);
171 if (len != SMIA_REG_8BIT && len != SMIA_REG_16BIT
172 && len != SMIA_REG_32BIT)
175 if (smiapp_quirk_reg(sensor, reg, val))
178 if (len == SMIA_REG_8BIT && !only8)
179 rval = ____smiapp_read(sensor, (u16)reg, len, val);
181 rval = ____smiapp_read_8only(sensor, (u16)reg, len, val);
186 if (reg & SMIA_REG_FLAG_FLOAT)
187 *val = float_to_u32_mul_1000000(client, *val);
192 int smiapp_read(struct smiapp_sensor *sensor, u32 reg, u32 *val)
194 return __smiapp_read(
196 smiapp_needs_quirk(sensor,
197 SMIAPP_QUIRK_FLAG_8BIT_READ_ONLY));
200 int smiapp_read_8only(struct smiapp_sensor *sensor, u32 reg, u32 *val)
202 return __smiapp_read(sensor, reg, val, true);
206 * Write to a 8/16-bit register.
207 * Returns zero if successful, or non-zero otherwise.
209 int smiapp_write(struct smiapp_sensor *sensor, u32 reg, u32 val)
211 struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
213 unsigned char data[6];
214 unsigned int retries;
215 unsigned int flags = reg >> 24;
216 unsigned int len = (u8)(reg >> 16);
220 if ((len != SMIA_REG_8BIT && len != SMIA_REG_16BIT &&
221 len != SMIA_REG_32BIT) || flags)
224 msg.addr = client->addr;
225 msg.flags = 0; /* Write */
229 /* high byte goes out first */
230 data[0] = (u8) (reg >> 8);
231 data[1] = (u8) (reg & 0xff);
251 for (retries = 0; retries < 5; retries++) {
253 * Due to unknown reason sensor stops responding. This
254 * loop is a temporaty solution until the root cause
257 r = i2c_transfer(client->adapter, &msg, 1);
260 dev_err(&client->dev,
261 "sensor i2c stall encountered. "
262 "retries: %d\n", retries);
266 usleep_range(2000, 2000);
269 dev_err(&client->dev,
270 "wrote 0x%x to offset 0x%x error %d\n", val, offset, r);