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Add Freescale MC44S803 tuner driver

PATCH Superseded Jochen Friedrich 3 participants 5 messages Jan 14, 2009 – Jan 15, 2009 Media (V4L/DVB)

v2 of 5 Superseded Latest is v5 →

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#0 lore raw

PATCH v2 1/1 Add Freescale MC44S803 tuner driver

---

Changes since v1:
- rebase against official linux tree. v1 was based against a local tree and didn't apply cleanly.

 drivers/media/common/tuners/Kconfig         |    8 +
 drivers/media/common/tuners/Makefile        |    1 +
 drivers/media/common/tuners/mc44s803.c      |  366 +++++++++++++++++++++++++++
 drivers/media/common/tuners/mc44s803.h      |   46 ++++
 drivers/media/common/tuners/mc44s803_priv.h |  208 +++++++++++++++
 5 files changed, 629 insertions(+), 0 deletions(-)
 create mode 100644 drivers/media/common/tuners/mc44s803.c
 create mode 100644 drivers/media/common/tuners/mc44s803.h
 create mode 100644 drivers/media/common/tuners/mc44s803_priv.h
drivers/media/common/tuners/Kconfig +8 -0
index 6f92bea..7969b69 100644
@@ -29,6 +29,7 @@ config MEDIA_TUNER
 	select MEDIA_TUNER_TEA5767 if !MEDIA_TUNER_CUSTOMIZE
 	select MEDIA_TUNER_SIMPLE if !MEDIA_TUNER_CUSTOMIZE
 	select MEDIA_TUNER_TDA9887 if !MEDIA_TUNER_CUSTOMIZE
+	select MEDIA_TUNER_MC44S803 if !MEDIA_TUNER_CUSTOMIZE
 
 menuconfig MEDIA_TUNER_CUSTOMIZE
 	bool "Customize analog and hybrid tuner modules to build"
@@ -164,4 +165,11 @@ config MEDIA_TUNER_MXL5007T
 	help
 	  A driver for the silicon tuner MxL5007T from MaxLinear.
 
+config MEDIA_TUNER_MC44S803
+	tristate "Freescale MC44S803 Low Power CMOS Broadband tuners"
+	depends on VIDEO_MEDIA && I2C
+	default m if DVB_FE_CUSTOMISE
+	help
+	  Say Y here to support the Freescale MC44S803 based tuners
+
 endif # MEDIA_TUNER_CUSTOMIZE
drivers/media/common/tuners/Makefile +1 -0
index 4dfbe5b..4132b2b 100644
@@ -22,6 +22,7 @@ obj-$(CONFIG_MEDIA_TUNER_QT1010) += qt1010.o
 obj-$(CONFIG_MEDIA_TUNER_MT2131) += mt2131.o
 obj-$(CONFIG_MEDIA_TUNER_MXL5005S) += mxl5005s.o
 obj-$(CONFIG_MEDIA_TUNER_MXL5007T) += mxl5007t.o
+obj-$(CONFIG_MEDIA_TUNER_MC44S803) += mc44s803.o
 
 EXTRA_CFLAGS += -Idrivers/media/dvb/dvb-core
 EXTRA_CFLAGS += -Idrivers/media/dvb/frontends
drivers/media/common/tuners/mc44s803.c new file +366 -0

366 lines not on this page · raw message

drivers/media/common/tuners/mc44s803.h new file +46 -0

46 lines not on this page · raw message

drivers/media/common/tuners/mc44s803_priv.h new file +208 -0

208 lines not on this page · raw message

Signature · 1 line
1.5.6.5
#1 lore raw

hi Jochen,

Quoted 2 lines · Jochen Friedrich

Changes since v1:
- rebase against official linux tree. v1 was based against a local tree and didn't apply cleanly.

Now it applies cleanly, but didn't compile. Some header file is missing.

Antti

CC [M] /home/crope/linuxtv/code/af9015/81/v4l-dvb/v4l/mxl5007t.o
CC [M] /home/crope/linuxtv/code/af9015/81/v4l-dvb/v4l/mc44s803.o
/home/crope/linuxtv/code/af9015/81/v4l-dvb/v4l/mc44s803.c: In function 'mc44s803_attach':
/home/crope/linuxtv/code/af9015/81/v4l-dvb/v4l/mc44s803.c:339: error: 'KERN_ERROR' undeclared (first use in this function) /home/crope/linuxtv/code/af9015/81/v4l-dvb/v4l/mc44s803.c:339: error: (Each undeclared identifier is reported only once /home/crope/linuxtv/code/af9015/81/v4l-dvb/v4l/mc44s803.c:339: error: for each function it appears in.) /home/crope/linuxtv/code/af9015/81/v4l-dvb/v4l/mc44s803.c:339: error: expected ')' before string constant make[3]: *** [/home/crope/linuxtv/code/af9015/81/v4l-dvb/v4l/mc44s803.o] Error 1
make[2]: *** [_module_/home/crope/linuxtv/code/af9015/81/v4l-dvb/v4l] Error 2
make[2]: Leaving directory `/usr/src/kernels/2.6.27.9-159.fc10.x86_64'
make[1]: *** [default] Error 2
make[1]: Leaving directory `/home/crope/linuxtv/code/af9015/81/v4l-dvb/v4l'
make: *** [all] Error 2
[crope@localhost v4l-dvb]$

Signature · 1 line
http://palosaari.fi/
#2 lore raw

Hi Antti,

Quoted 5 lines

Now it applies cleanly, but didn't compile.

/home/crope/linuxtv/code/af9015/81/v4l-dvb/v4l/mc44s803.c:339: error:
'KERN_ERROR' undeclared (first use in this function)

Ouch, forgot to commit the fix for this typo:

s/KERN_ERROR/KERN_ERR/

v3 will follow.

Thanks,
Jochen

#3 lore raw
In reply to Jochen Friedrich
Quoted 364 lines · Jochen Friedrich

---

Changes since v1:
- rebase against official linux tree. v1 was based against a local tree and didn't apply cleanly.

 drivers/media/common/tuners/Kconfig         |    8 +
 drivers/media/common/tuners/Makefile        |    1 +
 drivers/media/common/tuners/mc44s803.c      |  366 +++++++++++++++++++++++++++
 drivers/media/common/tuners/mc44s803.h      |   46 ++++
 drivers/media/common/tuners/mc44s803_priv.h |  208 +++++++++++++++
 5 files changed, 629 insertions(+), 0 deletions(-)
 create mode 100644 drivers/media/common/tuners/mc44s803.c
 create mode 100644 drivers/media/common/tuners/mc44s803.h
 create mode 100644 drivers/media/common/tuners/mc44s803_priv.h
drivers/media/common/tuners/Kconfig +8 -0
index 6f92bea..7969b69 100644
@@ -29,6 +29,7 @@ config MEDIA_TUNER
       select MEDIA_TUNER_TEA5767 if !MEDIA_TUNER_CUSTOMIZE
       select MEDIA_TUNER_SIMPLE if !MEDIA_TUNER_CUSTOMIZE
       select MEDIA_TUNER_TDA9887 if !MEDIA_TUNER_CUSTOMIZE
+       select MEDIA_TUNER_MC44S803 if !MEDIA_TUNER_CUSTOMIZE
 
 menuconfig MEDIA_TUNER_CUSTOMIZE
       bool "Customize analog and hybrid tuner modules to build"
@@ -164,4 +165,11 @@ config MEDIA_TUNER_MXL5007T
       help
         A driver for the silicon tuner MxL5007T from MaxLinear.
 
+config MEDIA_TUNER_MC44S803
+       tristate "Freescale MC44S803 Low Power CMOS Broadband tuners"
+       depends on VIDEO_MEDIA && I2C
+       default m if DVB_FE_CUSTOMISE
+       help
+         Say Y here to support the Freescale MC44S803 based tuners
+
 endif # MEDIA_TUNER_CUSTOMIZE
drivers/media/common/tuners/Makefile +1 -0
index 4dfbe5b..4132b2b 100644
@@ -22,6 +22,7 @@ obj-$(CONFIG_MEDIA_TUNER_QT1010) += qt1010.o
 obj-$(CONFIG_MEDIA_TUNER_MT2131) += mt2131.o
 obj-$(CONFIG_MEDIA_TUNER_MXL5005S) += mxl5005s.o
 obj-$(CONFIG_MEDIA_TUNER_MXL5007T) += mxl5007t.o
+obj-$(CONFIG_MEDIA_TUNER_MC44S803) += mc44s803.o
 
 EXTRA_CFLAGS += -Idrivers/media/dvb/dvb-core
 EXTRA_CFLAGS += -Idrivers/media/dvb/frontends
drivers/media/common/tuners/mc44s803.c new file +305 -0
new file mode 100644
index 0000000..8fd7fc1
@@ -0,0 +1,366 @@
+/*
+ *  Driver for Freescale MC44S803 Low Power CMOS Broadband Tuner
+ *
+ *  Copyright (c) 2009 Jochen Friedrich <[email protected]>
+ *
+ *  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., 675 Mass Ave, Cambridge, MA 02139, USA.=
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/dvb/frontend.h>
+#include <linux/i2c.h>
+
+#include "dvb_frontend.h"
+
+#include "mc44s803.h"
+#include "mc44s803_priv.h"
+
+/* Writes a single register */
+static int mc44s803_writereg(struct mc44s803_priv *priv, u32 val)
+{
+       u8 buf[3];
+       struct i2c_msg msg = {
+               .addr = priv->cfg->i2c_address, .flags = 0, .buf = buf, .len = 3
+       };
+
+       buf[0] = (val & 0xFF0000) >> 16;
+       buf[1] = (val & 0xFF00) >> 8;
+       buf[2] = (val & 0xFF);
+
+       if (i2c_transfer(priv->i2c, &msg, 1) != 1) {
+               printk(KERN_WARNING "mc44s803 I2C write failed\n");
+               return -EREMOTEIO;
+       }
+       return 0;
+}
+
+/* Reads a single register */
+static int mc44s803_readreg(struct mc44s803_priv *priv, u8 reg, u32 *val)
+{
+       u32 wval;
+       u8 buf[3];
+       u8 ret;
+       struct i2c_msg msg[] = {
+               { .addr = priv->cfg->i2c_address, .flags = I2C_M_RD,
+                 .buf = buf, .len = 3 },
+       };
+
+       wval = MC44S803_REG_SM(MC44S803_REG_DATAREG, MC44S803_ADDR) |
+              MC44S803_REG_SM(reg, MC44S803_D);
+
+       ret = mc44s803_writereg(priv, wval);
+       if (ret)
+               return ret;
+
+       if (i2c_transfer(priv->i2c, msg, 1) != 1) {
+               printk(KERN_WARNING "mc44s803 I2C read failed\n");
+               return -EREMOTEIO;
+       }
+
+       *val = (buf[0] << 16) | (buf[1] << 8) | buf[2];
+
+       return 0;
+}
+
+static int mc44s803_release(struct dvb_frontend *fe)
+{
+       struct mc44s803_priv *priv = fe->tuner_priv;
+
+       fe->tuner_priv = NULL;
+       kfree(priv);
+
+       return 0;
+}
+
+static int mc44s803_init(struct dvb_frontend *fe)
+{
+       struct mc44s803_priv *priv = fe->tuner_priv;
+       u32 val;
+       int err;
+
+       if (fe->ops.i2c_gate_ctrl)
+               fe->ops.i2c_gate_ctrl(fe, 1);
+
+/* Reset chip */
+       val = MC44S803_REG_SM(MC44S803_REG_RESET, MC44S803_ADDR) |
+             MC44S803_REG_SM(1, MC44S803_RS);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+       val = MC44S803_REG_SM(MC44S803_REG_RESET, MC44S803_ADDR);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+/* Power Up and Start Osc */
+
+       val = MC44S803_REG_SM(MC44S803_REG_REFOSC, MC44S803_ADDR) |
+             MC44S803_REG_SM(0xC0, MC44S803_REFOSC) |
+             MC44S803_REG_SM(1, MC44S803_OSCSEL);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+       val = MC44S803_REG_SM(MC44S803_REG_POWER, MC44S803_ADDR) |
+             MC44S803_REG_SM(0x200, MC44S803_POWER);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+       msleep(10);
+
+       val = MC44S803_REG_SM(MC44S803_REG_REFOSC, MC44S803_ADDR) |
+             MC44S803_REG_SM(0x40, MC44S803_REFOSC) |
+             MC44S803_REG_SM(1, MC44S803_OSCSEL);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+       msleep(20);
+
+/* Setup Mixer */
+
+       val = MC44S803_REG_SM(MC44S803_REG_MIXER, MC44S803_ADDR) |
+             MC44S803_REG_SM(1, MC44S803_TRI_STATE) |
+             MC44S803_REG_SM(0x7F, MC44S803_MIXER_RES);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+/* Setup Cirquit Adjust */
+
+       val = MC44S803_REG_SM(MC44S803_REG_CIRCADJ, MC44S803_ADDR) |
+             MC44S803_REG_SM(1, MC44S803_G1) |
+             MC44S803_REG_SM(1, MC44S803_G3) |
+             MC44S803_REG_SM(0x3, MC44S803_CIRCADJ_RES) |
+             MC44S803_REG_SM(1, MC44S803_G6) |
+             MC44S803_REG_SM(priv->cfg->dig_out, MC44S803_S1) |
+             MC44S803_REG_SM(0x3, MC44S803_LP) |
+             MC44S803_REG_SM(1, MC44S803_CLRF) |
+             MC44S803_REG_SM(1, MC44S803_CLIF);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+       val = MC44S803_REG_SM(MC44S803_REG_CIRCADJ, MC44S803_ADDR) |
+             MC44S803_REG_SM(1, MC44S803_G1) |
+             MC44S803_REG_SM(1, MC44S803_G3) |
+             MC44S803_REG_SM(1, MC44S803_G6) |
+             MC44S803_REG_SM(priv->cfg->dig_out, MC44S803_S1) |
+             MC44S803_REG_SM(0x3, MC44S803_LP);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+/* Setup Digtune */
+
+       val = MC44S803_REG_SM(MC44S803_REG_DIGTUNE, MC44S803_ADDR) |
+             MC44S803_REG_SM(3, MC44S803_XOD);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+/* Setup AGC */
+
+       val = MC44S803_REG_SM(MC44S803_REG_LNAAGC, MC44S803_ADDR) |
+             MC44S803_REG_SM(1, MC44S803_AT1) |
+             MC44S803_REG_SM(1, MC44S803_AT2) |
+             MC44S803_REG_SM(1, MC44S803_AGC_AN_DIG) |
+             MC44S803_REG_SM(1, MC44S803_AGC_READ_EN) |
+             MC44S803_REG_SM(1, MC44S803_LNA0);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+       if (fe->ops.i2c_gate_ctrl)
+               fe->ops.i2c_gate_ctrl(fe, 0);
+       return 0;
+
+exit:
+       if (fe->ops.i2c_gate_ctrl)
+               fe->ops.i2c_gate_ctrl(fe, 0);
+
+       printk(KERN_WARNING "mc44s803: I/O Error\n");
+       return err;
+}
+
+static int mc44s803_set_params(struct dvb_frontend *fe,
+                              struct dvb_frontend_parameters *params)
+{
+       struct mc44s803_priv *priv = fe->tuner_priv;
+       u32 r1, r2, n1, n2, lo1, lo2, freq, val;
+       int err;
+
+       priv->frequency = params->frequency;
+
+       r1 = MC44S803_OSC / 1000000;
+       r2 = MC44S803_OSC /  100000;
+
+       n1 = (params->frequency + MC44S803_IF1 + 500000) / 1000000;
+       freq = MC44S803_OSC / r1 * n1;
+       lo1 = ((60 * n1) + (r1 / 2)) / r1;
+       freq = freq - params->frequency;
+
+       n2 = (freq - MC44S803_IF2 + 50000) / 100000;
+       lo2 = ((60 * n2) + (r2 / 2)) / r2;
+
+       if (fe->ops.i2c_gate_ctrl)
+               fe->ops.i2c_gate_ctrl(fe, 1);
+
+       val = MC44S803_REG_SM(MC44S803_REG_REFDIV, MC44S803_ADDR) |
+             MC44S803_REG_SM(r1-1, MC44S803_R1) |
+             MC44S803_REG_SM(r2-1, MC44S803_R2) |
+             MC44S803_REG_SM(1, MC44S803_REFBUF_EN);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+       val = MC44S803_REG_SM(MC44S803_REG_LO1, MC44S803_ADDR) |
+             MC44S803_REG_SM(n1-2, MC44S803_LO1);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+       val = MC44S803_REG_SM(MC44S803_REG_LO2, MC44S803_ADDR) |
+             MC44S803_REG_SM(n2-2, MC44S803_LO2);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+       val = MC44S803_REG_SM(MC44S803_REG_DIGTUNE, MC44S803_ADDR) |
+             MC44S803_REG_SM(1, MC44S803_DA) |
+             MC44S803_REG_SM(lo1, MC44S803_LO_REF) |
+             MC44S803_REG_SM(1, MC44S803_AT);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+       val = MC44S803_REG_SM(MC44S803_REG_DIGTUNE, MC44S803_ADDR) |
+             MC44S803_REG_SM(2, MC44S803_DA) |
+             MC44S803_REG_SM(lo2, MC44S803_LO_REF) |
+             MC44S803_REG_SM(1, MC44S803_AT);
+
+       err = mc44s803_writereg(priv, val);
+       if (err)
+               goto exit;
+
+       if (fe->ops.i2c_gate_ctrl)
+               fe->ops.i2c_gate_ctrl(fe, 0);
+
+       return 0;
+
+exit:
+       if (fe->ops.i2c_gate_ctrl)
+               fe->ops.i2c_gate_ctrl(fe, 0);
+
+       printk(KERN_WARNING "mc44s803: I/O Error\n");
+       return err;
+}
+
+static int mc44s803_get_frequency(struct dvb_frontend *fe, u32 *frequency)
+{
+       struct mc44s803_priv *priv = fe->tuner_priv;
+       *frequency = priv->frequency;
+       return 0;
+}
+
+static const struct dvb_tuner_ops mc44s803_tuner_ops = {
+       .info = {
+               .name           = "Freescale MC44S803",
+               .frequency_min  =   48000000,
+               .frequency_max  = 1000000000,
+               .frequency_step =     100000,
+       },
+
+       .release       = mc44s803_release,
+       .init          = mc44s803_init,

drivers/media/common/tuners/mc44s803.c line 315

Quoted 10 lines
drivers/media/common/tuners/mc44s803.c new file +10 -0
+       .set_params    = mc44s803_set_params,
+       .get_frequency = mc44s803_get_frequency
+};
+
+/* This functions tries to identify a MC44S803 tuner by reading the ID
+   register. This is hasty. */
+struct dvb_frontend *mc44s803_attach(struct dvb_frontend *fe,
+        struct i2c_adapter *i2c, struct mc44s803_config *cfg)
+{
+       struct mc44s803_priv *priv = NULL;

Do you really need *priv set to NULL here ?

drivers/media/common/tuners/mc44s803.c line 323

Quoted 8 lines
drivers/media/common/tuners/mc44s803.c new file +8 -0
+       u32 reg;
+       u8 ret, id;
+
+       reg = 0;
+
+       priv = kzalloc(sizeof(struct mc44s803_priv), GFP_KERNEL);
+       if (priv == NULL)
+               return NULL;

Maybe return -ENOMEM; ? I don't sure about return NULL, may be your variant is right.

Quoted 5 lines
drivers/media/common/tuners/mc44s803.c new file +5 -0
+       priv->cfg = cfg;
+       priv->i2c = i2c;
+       priv->fe  = fe;
+
+       if (fe->ops.i2c_gate_ctrl)

drivers/media/common/tuners/mc44s803.c line 339

Quoted 10 lines
drivers/media/common/tuners/mc44s803.c new file +10 -0
+               fe->ops.i2c_gate_ctrl(fe, 1); /* open i2c_gate */
+
+       ret = mc44s803_readreg(priv, MC44S803_REG_ID, &reg);
+       if (ret)
+               goto error;
+
+       id = MC44S803_REG_MS(reg, MC44S803_ID);
+
+       if (id != 0x14) {
+               printk(KERN_ERROR "MC44S803: unsupported ID "

You pass the name of driver directly to printk messages in few places. Is it better to use such approach:
#define MC44S803_DRIVER_NAME "mc44s803"

printk (KERN_ERR MC44S803_DRIVER_NAME ": something\n");

?
What do you think?

Quoted 11 lines
drivers/media/common/tuners/mc44s803.c new file +11 -0
+                      "(%x should be 0x14)\n", id);
+               goto error;
+       }
+
+       printk(KERN_INFO "MC44S803: successfully identified (ID = %x)\n", id);
+       memcpy(&fe->ops.tuner_ops, &mc44s803_tuner_ops,
+              sizeof(struct dvb_tuner_ops));
+
+       fe->tuner_priv = priv;
+
+       if (fe->ops.i2c_gate_ctrl)

drivers/media/common/tuners/mc44s803.c line 360

Quoted 10 lines
drivers/media/common/tuners/mc44s803.c new file +10 -0
+               fe->ops.i2c_gate_ctrl(fe, 0); /* close i2c_gate */
+
+       return fe;
+
+error:
+       if (fe->ops.i2c_gate_ctrl)
+               fe->ops.i2c_gate_ctrl(fe, 0); /* close i2c_gate */
+
+       kfree(priv);
+       return NULL;

I'm not sure is it right to return NULL here.. May be some negative error number ?

<snip>

Signature · 1 line
Best regards, Klimov Alexey
#4 lore raw

Hi Alexey,

Quoted 8 lines

drivers/media/common/tuners/mc44s803.c line 315

Quoted 6 lines
drivers/media/common/tuners/mc44s803.c new file +6 -0
+/* This functions tries to identify a MC44S803 tuner by reading the ID
+   register. This is hasty. */
+struct dvb_frontend *mc44s803_attach(struct dvb_frontend *fe,
+        struct i2c_adapter *i2c, struct mc44s803_config *cfg)
+{
+       struct mc44s803_priv *priv = NULL;

Do you really need *priv set to NULL here ?

No, it's not needed. Will remove.

Quoted 6 lines

drivers/media/common/tuners/mc44s803.c line 323

Quoted 3 lines
drivers/media/common/tuners/mc44s803.c new file +3 -0
+       priv = kzalloc(sizeof(struct mc44s803_priv), GFP_KERNEL);
+       if (priv == NULL)
+               return NULL;

Maybe return -ENOMEM; ? I don't sure about return NULL, may be your variant is right.

NULL is correct here. All tuners are supposed to return NULL on an error during attach().

Quoted 11 lines

drivers/media/common/tuners/mc44s803.c line 339

Quoted 2 lines
drivers/media/common/tuners/mc44s803.c new file +2 -0
+       if (id != 0x14) {
+               printk(KERN_ERROR "MC44S803: unsupported ID "

You pass the name of driver directly to printk messages in few places. Is it better to use such approach:
#define MC44S803_DRIVER_NAME "mc44s803"

printk (KERN_ERR MC44S803_DRIVER_NAME ": something\n");

?
What do you think?

You're right.

Thanks for your comments.
Jochen