On Tue, Jun 7, 2016 at 1:09 PM, Trent Piepho <tpiepho@xxxxxxxxxxxxxx> wrote:
> Move OF configuration code into new function which can be used by both
> style of chips.
>
> Extend the DT bindings to allow configuring both input and output
> rate, as the DS1337/41 type chips have this ability.
>
> Signed-off-by: Trent Piepho <tpiepho@xxxxxxxxxxxxxx>
> ---
> .../devicetree/bindings/rtc/dallas,ds1307.rst | 18 +-
> drivers/rtc/rtc-ds1307.c | 188 ++++++++++++---------
> 2 files changed, 124 insertions(+), 82 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/rtc/dallas,ds1307.rst b/Documentation/devicetree/bindings/rtc/dallas,ds1307.rst
> index 52787a8..b9e91f1 100644
> --- a/Documentation/devicetree/bindings/rtc/dallas,ds1307.rst
> +++ b/Documentation/devicetree/bindings/rtc/dallas,ds1307.rst
> @@ -2,22 +2,28 @@ Dallas DS1307 I2C Serial Real-Time Clock
> ========================================
>
> Required properties:
> -* ``compatible``: ``dallas,ds1307``, ``dallas,ds1308``, ``dallas,ds1338``
> +* ``compatible``: ``dallas,ds1307``, ``dallas,ds1308``, ``dallas,ds1337``,
> + ``dallas,ds1338``, ``dallas,ds1341``
> "maxim" can be used in place of "dallas"
>
> * ``reg``: I2C address for chip
>
> Optional properties:
> * ``ext-clock-input``: Enable external clock input pin
> -* ``ext-clock-output``: Enable square wave output. The above two
> - properties are mutually exclusive
> +* ``ext-clock-output``: Enable square wave output. On some chips both
> + the above properties can not be enabled at once.
> * ``ext-clock-bb``: Enable external clock on battery power
> -* ``ext-clock-rate``: Expected/Generated rate on external clock pin
> - in Hz. Allowable values are 1, 50, 60, 4096, 8192, and 32768 Hz.
There seem to be a trailing white-space at the end of the line above,
which prevented me from applying the first hunk of the patch since
there was no trailing white-space in the latest "next" source tree.
> +* ``ext-clock-input-rate``: Expected rate on external clock input pin
> + in Hz. Allowable values are 1, 50, 60, 4096, 8192, and 32768 Hz.
> Not all values are valid for all configurations.
> +* ``ext-clock-output-rate``: Rate to generate on square wave output pin
> + in Hz. Allowable values are 1, 50, 60, 4096, 8192, and 32768 Hz.
> + Not all values are valid for all configurations. Some chips do not allow
> + setting both input and output rate. In this case, only the correct property
> + should be set.
>
> The default is ext-clock-input, ext-clock-output, and ext-clock-bb
> -disabled and ext-clock-rate of 1 Hz.
> +disabled and ext-clock-input/output-rate of 1 Hz.
>
> Example::
> ds1307: rtc@68 {
> diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
> index 1526273..b772ca3 100644
> --- a/drivers/rtc/rtc-ds1307.c
> +++ b/drivers/rtc/rtc-ds1307.c
> @@ -92,6 +92,8 @@ enum ds_type {
> #define DS1337_REG_STATUS 0x0f
> # define DS1337_BIT_OSF 0x80
> # define DS1341_BIT_DOSF 0x40
> +# define DS1341_BIT_CLKSEL2 0x10
> +# define DS1341_BIT_CLKSEL1 0x08
> # define DS1341_BIT_ECLK 0x04
> # define DS1337_BIT_A2I 0x02
> # define DS1337_BIT_A1I 0x01
> @@ -293,6 +295,70 @@ static const struct rtc_class_ops ds13xx_rtc_ops = {
> .set_time = ds1307_set_time,
> };
>
> +
> +/* Convert rate in Hz to config bits */
> +static u8 parse_rate(u32 rate)
> +{
> + switch (rate) {
> + default:
> + case 1: return 0;
> + case 50: return DS1307_BIT_RS0;
> + case 60: return DS1307_BIT_RS1;
> + case 4096: return DS1307_BIT_RS0;
> + case 8192: return DS1307_BIT_RS1;
> + case 32768: return DS1307_BIT_RS0|DS1307_BIT_RS1;
> + }
> +}
> +
> +/* Produces a config word with DT settings. This word must be
> + * translated into chip specific bits. The low 8-bit are basically
> + * identical to the ds1307/1308/1338 control reg to make this
> + * translation simpler.
> + *
> + * Word uses these bits:
> + * DS1308_BIT_ECLK enable external clock input
> + * DS1307_BIT_SQWE enable square wave output
> + * DS1308_BIT_BBCLK enable square wave on battery
> + * DS1307_BIT_RS1/0 square wave output frequency
> + * DS1307_BIT_RS1/0 << 8 external clock input frequency
> + *
> + * The rate select bits will be zero if not specified in the device
> + * tree.
> + */
> +static u16 ds1307_config(const struct device_node *np)
> +{
> + u16 control = 0;
> + u32 rate;
> +
> + if (of_property_read_bool(np, "ext-clock-input"))
> + control |= DS1308_BIT_ECLK;
> +
> + if (of_property_read_bool(np, "ext-clock-output"))
> + control |= DS1307_BIT_SQWE;
> +
> + if (of_property_read_bool(np, "ext-clock-bb"))
> + control |= DS1308_BIT_BBCLK;
> +
> + rate = 0;
> + of_property_read_u32(np, "ext-clock-input-rate", &rate);
> + control |= parse_rate(rate);
> +
> + rate = 0;
> + of_property_read_u32(np, "ext-clock-output-rate", &rate);
> + control |= parse_rate(rate) << 8;
> +
> + return control;
> +}
> +
> +static void write_if_changed(struct ds1307 *ds1307, u8 *buf,
> + int reg, u8 value)
> +{
> + if (buf[reg] != value) {
> + buf[reg] = value;
> + i2c_smbus_write_byte_data(ds1307->client, reg, buf[reg]);
> + }
> +}
> +
> static int ds1307_probe(struct device_d *dev)
> {
> struct i2c_client *client = to_i2c_client(dev);
> @@ -343,82 +409,6 @@ read_rtc:
> goto exit;
> }
>
> - if (ds1307->has_alarms) {
> - /*
> - Make sure no alarm interrupts or square wave signals
> - are produced by the chip while we are in
> - bootloader. We do this by configuring the RTC to
> - generate alarm interrupts (thus disabling square
> - wave generation), but disabling each individual
> - alarm interrupt source
> - */
> - buf[DS1337_REG_CONTROL] |= DS1337_BIT_INTCN;
> - buf[DS1337_REG_CONTROL] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
> -
> - i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
> - buf[DS1337_REG_CONTROL]);
> -
> - if (ds1307->type == ds_1341) {
> - /*
> - * For the above to be true, DS1341 also has to have
> - * ECLK bit set to 0
> - */
> - buf[DS1337_REG_STATUS] &= ~DS1341_BIT_ECLK;
> -
> - /*
> - * Let's set additionale RTC bits to
> - * facilitate maximum power saving.
> - */
> - buf[DS1337_REG_STATUS] |= DS1341_BIT_DOSF;
> - buf[DS1337_REG_CONTROL] &= ~DS1341_BIT_EGFIL;
> -
> - i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
> - buf[DS1337_REG_CONTROL]);
> - i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
> - buf[DS1337_REG_STATUS]);
> - }
> -
> - }
> -
> - /* Configure clock using OF data if available */
> - if (IS_ENABLED(CONFIG_OFDEVICE) && np && !ds1307->has_alarms) {
> - u8 control = buf[DS1307_REG_CONTROL];
> - u32 rate = 0;
> -
> - if (of_property_read_bool(np, "ext-clock-input"))
> - control |= DS1308_BIT_ECLK;
> - else
> - control &= ~DS1308_BIT_ECLK;
> -
> - if (of_property_read_bool(np, "ext-clock-output"))
> - control |= DS1307_BIT_SQWE;
> - else
> - control &= ~DS1307_BIT_SQWE;
> -
> - if (of_property_read_bool(np, "ext-clock-bb"))
> - control |= DS1308_BIT_BBCLK;
> - else
> - control &= ~DS1308_BIT_BBCLK;
> -
> - control &= ~(DS1307_BIT_RS1 | DS1307_BIT_RS0);
> - of_property_read_u32(np, "ext-clock-rate", &rate);
> - switch (rate) {
> - default:
> - case 1: control |= 0; break;
> - case 50: control |= 1; break;
> - case 60: control |= 2; break;
> - case 4096: control |= 1; break;
> - case 8192: control |= 2; break;
> - case 32768: control |= 3; break;
> - }
> - dev_dbg(&client->dev, "control reg: 0x%02x\n", control);
> -
> - if (buf[DS1307_REG_CONTROL] != control) {
> - i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL, control);
> - buf[DS1307_REG_CONTROL] = control;
> - }
> - }
> -
> /* Check for clock halted conditions and start clock */
> fault = 0;
>
> @@ -465,6 +455,52 @@ read_rtc:
> goto read_rtc;
> }
>
> + /* Configure clock using OF data if available */
> + if (IS_ENABLED(CONFIG_OFDEVICE) && np) {
> + u16 config = ds1307_config(np);
> + if (ds1307->has_alarms) {
> + u8 creg = buf[DS1337_REG_CONTROL];
> + u8 sreg = buf[DS1337_REG_STATUS];
> +
> + /* Translate bits to the DS1337_REG_CONTROL format */
> + creg &= ~(DS1337_BIT_RS2 | DS1337_BIT_RS1);
> + creg |= (config & 0x003) << 3;
If you swap masking and shifting you should be able to use named
constants instead of magic numbers.
> + sreg &= ~(DS1341_BIT_CLKSEL2 | DS1341_BIT_CLKSEL1);
> + sreg |= (config & 0x300) >> 5;
Ditto.
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