Hi Lee, > Subject: Re: [PATCH v4 1/3] mfd: Add new mfd device TPS68470 > > On Tue, 25 Jul 2017, Mani, Rajmohan wrote: > > > Hi Lee, > > > > > Subject: Re: [PATCH v4 1/3] mfd: Add new mfd device TPS68470 > > > > > > On Fri, 21 Jul 2017, Mani, Rajmohan wrote: > > > > > On Wed, 19 Jul 2017, Rajmohan Mani wrote: > > > > > > > > > > > The TPS68470 device is an advanced power management unit that > > > > > > powers > > > > > a > > > > > > Compact Camera Module (CCM), generates clocks for image > > > > > > sensors, drives a dual LED for Flash and incorporates two LED > > > > > > drivers for general purpose indicators. > > > > > > > > > > > > This patch adds support for TPS68470 mfd device. > > > > > > > > > > > > Signed-off-by: Rajmohan Mani <rajmohan.mani@xxxxxxxxx> > > > > > > --- > > > > > > drivers/mfd/Kconfig | 18 +++++++ > > > > > > drivers/mfd/Makefile | 1 + > > > > > > drivers/mfd/tps68470.c | 110 > > > > > +++++++++++++++++++++++++++++++++++++++++++ > > > > > > include/linux/mfd/tps68470.h | 97 > > > > > > ++++++++++++++++++++++++++++++++++++++ > > > > > > 4 files changed, 226 insertions(+) create mode 100644 > > > > > > drivers/mfd/tps68470.c create mode 100644 > > > > > > include/linux/mfd/tps68470.h > > > > > > [...] > > > > > > > > > +static const struct regmap_config tps68470_regmap_config = { > > > > > > + .reg_bits = 8, > > > > > > + .val_bits = 8, > > > > > > + .max_register = TPS68470_REG_MAX, }; > > > > > > + > > > > > > +static int tps68470_chip_init(struct device *dev, struct > > > > > > +regmap > > > > > > +*regmap) { > > > > > > + unsigned int version; > > > > > > + int ret; > > > > > > + > > > > > > + /* Force software reset */ > > > > > > + ret = regmap_write(regmap, TPS68470_REG_RESET, > > > > > TPS68470_REG_RESET_MASK); > > > > > > + if (ret < 0) > > > > > > > > > > Will 'if (!ret)' do? > > > > > > > > > > > > > We intend to check error conditions and bail out. So, if (ret < 0) > > > > works for > > > this. > > > > > > Yes, 'if (!ret)' does that too. > > > > > > > regmap_write() and regmap_read() functions return 0 on success. Hence > we can not use 'if (!ret)' here, since we check for error conditions. > > Sorry, this was a typo. > > It should be 'if (ret)'. > > What I'm trying to get at is the " < 0" is not required. > Ack > > > > > > + return ret; > > > > > > + > > > > > > + ret = regmap_read(regmap, TPS68470_REG_REVID, > &version); > > > > > > + if (ret < 0) { > > > > > > > > > > Same > > > > > > > > > > > > > We intend to check error conditions and bail out. So, if (ret < 0) > > > > works for > > > this. > > > > > > As above. > > > > > > > Same as above > > > > > > > > + dev_err(dev, "Failed to read revision register: %d\n", > ret); > > > > > > + return ret; > > > > > > + } > > > > > > + > > > > > > + dev_info(dev, "TPS68470 REVID: 0x%x\n", version); > > > > > > + > > > > > > + return 0; > > > > > > +} > > > > > > + > > > > > > +static int tps68470_probe(struct i2c_client *client) { > > > > > > + struct device *dev = &client->dev; > > > > > > + struct regmap *regmap; > > > > > > + int ret; > > > > > > + > > > > > > + regmap = devm_regmap_init_i2c(client, > &tps68470_regmap_config); > > > > > > + if (IS_ERR(regmap)) { > > > > > > + dev_err(dev, "devm_regmap_init_i2c Error %ld\n", > > > > > > + PTR_ERR(regmap)); > > > > > > + return PTR_ERR(regmap); > > > > > > + } > > > > > > + > > > > > > + i2c_set_clientdata(client, regmap); > > > > > > + > > > > > > + ret = tps68470_chip_init(dev, regmap); > > > > > > + if (ret < 0) { > > > > > > > > > > Same > > > > > > > > > > > > > We intend to check error conditions and bail out. So, if (ret < 0) > > > > works for > > > this. > > > > > > As above. > > > > > > > Same as above > > -- > Lee Jones > Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source > software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog ��.n��������+%������w��{.n�����{�����ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f