Re: [PATCH] media: dvb-frontends: add LNBH29 LNB supply driver

From: Mauro Carvalho Chehab
Date: Thu Aug 02 2018 - 19:10:41 EST

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Em Thu, 26 Jul 2018 12:35:34 +0900
Katsuhiro Suzuki <suzuki.katsuhiro@xxxxxxxxxxxxx> escreveu:

> Add support for STMicroelectronics LNBH29 LNB supply driver.
>
> Signed-off-by: Katsuhiro Suzuki <suzuki.katsuhiro@xxxxxxxxxxxxx>
> ---
> drivers/media/dvb-frontends/Kconfig | 10 ++
> drivers/media/dvb-frontends/Makefile | 1 +
> drivers/media/dvb-frontends/lnbh29.c | 170 +++++++++++++++++++++++++++
> drivers/media/dvb-frontends/lnbh29.h | 36 ++++++
> 4 files changed, 217 insertions(+)
> create mode 100644 drivers/media/dvb-frontends/lnbh29.c
> create mode 100644 drivers/media/dvb-frontends/lnbh29.h
>
> diff --git a/drivers/media/dvb-frontends/Kconfig b/drivers/media/dvb-frontends/Kconfig
> index 048285134cdf..847da72d1256 100644
> --- a/drivers/media/dvb-frontends/Kconfig
> +++ b/drivers/media/dvb-frontends/Kconfig
> @@ -791,6 +791,16 @@ config DVB_LNBH25
> An SEC control chip.
> Say Y when you want to support this chip.
>
> +config DVB_LNBH29
> + tristate "LNBH29 SEC controller"
> + depends on DVB_CORE && I2C
> + default m if !MEDIA_SUBDRV_AUTOSELECT
> + help
> + LNB power supply and control voltage
> + regulator chip with step-up converter
> + and I2C interface for STMicroelectronics LNBH29.
> + Say Y when you want to support this chip.
> +
> config DVB_LNBP21
> tristate "LNBP21/LNBH24 SEC controllers"
> depends on DVB_CORE && I2C
> diff --git a/drivers/media/dvb-frontends/Makefile b/drivers/media/dvb-frontends/Makefile
> index 779dfd027b24..e9179162658c 100644
> --- a/drivers/media/dvb-frontends/Makefile
> +++ b/drivers/media/dvb-frontends/Makefile
> @@ -58,6 +58,7 @@ obj-$(CONFIG_DVB_LGDT3306A) += lgdt3306a.o
> obj-$(CONFIG_DVB_LG2160) += lg2160.o
> obj-$(CONFIG_DVB_CX24123) += cx24123.o
> obj-$(CONFIG_DVB_LNBH25) += lnbh25.o
> +obj-$(CONFIG_DVB_LNBH29) += lnbh29.o
> obj-$(CONFIG_DVB_LNBP21) += lnbp21.o
> obj-$(CONFIG_DVB_LNBP22) += lnbp22.o
> obj-$(CONFIG_DVB_ISL6405) += isl6405.o
> diff --git a/drivers/media/dvb-frontends/lnbh29.c b/drivers/media/dvb-frontends/lnbh29.c
> new file mode 100644
> index 000000000000..5cc08c70e64a
> --- /dev/null
> +++ b/drivers/media/dvb-frontends/lnbh29.c
> @@ -0,0 +1,170 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +// Driver for LNB supply and control IC STMicroelectronics LNBH29
> +//
> +// Copyright (c) 2018 Socionext Inc.
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/string.h>
> +#include <linux/slab.h>
> +
> +#include <media/dvb_frontend.h>
> +#include "lnbh29.h"
> +
> +/**
> + * struct lnbh29_priv - LNBH29 driver private data
> + * @i2c: Pointer to the I2C adapter structure
> + * @i2c_address: I2C address of LNBH29 chip
> + * @config: Registers configuration
> + * offset 0: 1st register address, always 0x01 (DATA)
> + * offset 1: DATA register value
> + */
> +struct lnbh29_priv {
> + struct i2c_adapter *i2c;
> + u8 i2c_address;
> + u8 config[2];
> +};
> +
> +#define LNBH29_STATUS_OLF BIT(0)
> +#define LNBH29_STATUS_OTF BIT(1)
> +#define LNBH29_STATUS_VMON BIT(2)
> +#define LNBH29_STATUS_PNG BIT(3)
> +#define LNBH29_STATUS_PDO BIT(4)
> +#define LNBH29_VSEL_MASK GENMASK(2, 0)
> +#define LNBH29_VSEL_0 0x00
> +#define LNBH29_VSEL_13 0x03
> +#define LNBH29_VSEL_18 0x07
> +
> +static int lnbh29_read_vmon(struct lnbh29_priv *priv)
> +{
> + u8 addr = 0x00;
> + u8 status[2];
> + int i, ret;
> + struct i2c_msg msg[2] = {
> + {
> + .addr = priv->i2c_address,
> + .flags = 0,
> + .len = 1,
> + .buf = &addr
> + }, {
> + .addr = priv->i2c_address,
> + .flags = I2C_M_RD,
> + .len = sizeof(status),
> + .buf = status
> + }
> + };
> +
> + for (i = 0; i < ARRAY_SIZE(msg); i++) {
> + ret = i2c_transfer(priv->i2c, &msg[i], 1);
> + if (ret >= 0 && ret != 1)
> + ret = -EIO;
> + if (ret < 0) {
> + dev_dbg(&priv->i2c->dev,
> + "LNBH29 I2C transfer %d failed (%d)\n",
> + i, ret);
> + return ret;
> + }
> + }

No, it is not a good idea to issue 2 i2c transfers, as some other driver
(like IR controller or CAM) could issue an I2C transfer in the middle,
causing data mangling.

The best here is to just do:

ret = i2c_transfer(priv->i2c, msg, 2);
if (ret >= 0 && ret != 2)
ret = -EIO;
if (ret < 0) {
dev_dbg(&priv->i2c->dev,
"LNBH29 I2C transfer %d failed (%d)\n",
i, ret);
return ret;
}

in order to let the I2C core to serialize both write and read ops.

> +
> + if (status[0] & (LNBH29_STATUS_OLF | LNBH29_STATUS_VMON)) {
> + dev_err(&priv->i2c->dev,
> + "LNBH29 voltage in failure state, status reg 0x%x\n",
> + status[0]);
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +static int lnbh29_set_voltage(struct dvb_frontend *fe,
> + enum fe_sec_voltage voltage)
> +{
> + struct lnbh29_priv *priv = fe->sec_priv;
> + u8 data_reg;
> + int ret;
> + struct i2c_msg msg = {
> + .addr = priv->i2c_address,
> + .flags = 0,
> + .len = sizeof(priv->config),
> + .buf = priv->config
> + };
> +
> + switch (voltage) {
> + case SEC_VOLTAGE_OFF:
> + data_reg = LNBH29_VSEL_0;
> + break;
> + case SEC_VOLTAGE_13:
> + data_reg = LNBH29_VSEL_13;
> + break;
> + case SEC_VOLTAGE_18:
> + data_reg = LNBH29_VSEL_18;
> + break;
> + default:
> + return -EINVAL;
> + }
> + priv->config[1] &= ~LNBH29_VSEL_MASK;
> + priv->config[1] |= data_reg;
> +
> + ret = i2c_transfer(priv->i2c, &msg, 1);
> + if (ret >= 0 && ret != 1)
> + ret = -EIO;
> + if (ret < 0) {
> + dev_err(&priv->i2c->dev, "LNBH29 I2C transfer error (%d)\n",
> + ret);
> + return ret;
> + }
> +
> + /* Soft-start time (Vout 0V to 18V) is Typ. 6ms. */
> + usleep_range(6000, 20000);
> +
> + if (voltage == SEC_VOLTAGE_OFF)
> + return 0;
> +
> + return lnbh29_read_vmon(priv);
> +}
> +
> +static void lnbh29_release(struct dvb_frontend *fe)
> +{
> + lnbh29_set_voltage(fe, SEC_VOLTAGE_OFF);
> + kfree(fe->sec_priv);
> + fe->sec_priv = NULL;
> +}
> +
> +struct dvb_frontend *lnbh29_attach(struct dvb_frontend *fe,
> + struct lnbh29_config *cfg,
> + struct i2c_adapter *i2c)
> +{
> + struct lnbh29_priv *priv;
> +
> + priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return NULL;
> +
> + priv->i2c_address = (cfg->i2c_address >> 1);
> + priv->i2c = i2c;
> + priv->config[0] = 0x01;
> + priv->config[1] = cfg->data_config;
> + fe->sec_priv = priv;
> +
> + if (lnbh29_set_voltage(fe, SEC_VOLTAGE_OFF)) {
> + dev_err(&i2c->dev, "no LNBH29 found at I2C addr 0x%02x\n",
> + priv->i2c_address);
> + kfree(priv);
> + fe->sec_priv = NULL;
> + return NULL;
> + }
> +
> + fe->ops.release_sec = lnbh29_release;
> + fe->ops.set_voltage = lnbh29_set_voltage;
> +
> + dev_info(&i2c->dev, "LNBH29 attached at I2C addr 0x%02x\n",
> + priv->i2c_address);
> +
> + return fe;
> +}
> +EXPORT_SYMBOL(lnbh29_attach);
> +
> +MODULE_AUTHOR("Katsuhiro Suzuki <suzuki.katsuhiro@xxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("STMicroelectronics LNBH29 driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/media/dvb-frontends/lnbh29.h b/drivers/media/dvb-frontends/lnbh29.h
> new file mode 100644
> index 000000000000..6179921520d9
> --- /dev/null
> +++ b/drivers/media/dvb-frontends/lnbh29.h
> @@ -0,0 +1,36 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Driver for LNB supply and control IC STMicroelectronics LNBH29
> + *
> + * Copyright (c) 2018 Socionext Inc.
> + */
> +
> +#ifndef LNBH29_H
> +#define LNBH29_H
> +
> +#include <linux/i2c.h>
> +#include <linux/dvb/frontend.h>
> +
> +/* Using very low E.S.R. capacitors or ceramic caps */
> +#define LNBH29_DATA_COMP BIT(3)
> +
> +struct lnbh29_config {
> + u8 i2c_address;
> + u8 data_config;
> +};
> +
> +#if IS_REACHABLE(CONFIG_DVB_LNBH29)
> +struct dvb_frontend *lnbh29_attach(struct dvb_frontend *fe,
> + struct lnbh29_config *cfg,
> + struct i2c_adapter *i2c);
> +#else
> +static inline struct dvb_frontend *lnbh29_attach(struct dvb_frontend *fe,
> + struct lnbh29_config *cfg,
> + struct i2c_adapter *i2c)
> +{
> + printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
> + return NULL;
> +}
> +#endif
> +
> +#endif

Thanks,
Mauro

Next message: Atish Patra: "Re: [PATCH 10/11] irqchip: add a SiFive PLIC driver"
Previous message: Dave Hansen: "[PATCH 2/7] mm: allow non-direct-map arguments to free_reserved_area()"
Next in thread: Katsuhiro Suzuki: "Re: [PATCH] media: dvb-frontends: add LNBH29 LNB supply driver"
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