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Date: Fri, 6 Nov 2015 23:19:38 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
Cc: Stephen Boyd <sboyd@...eaurora.org>, Simon <horms@...ge.net.au>,
Michael Turquette <mturquette@...libre.com>,
Magnus <magnus.damm@...il.com>,
Linux-SH <linux-sh@...r.kernel.org>,
Linux-Kernel <linux-kernel@...r.kernel.org>,
linux-clk@...r.kernel.org
Subject: Re: [PATCH v5] clk: add CS2000 Fractional-N driver
On Tue, Oct 20, 2015 at 4:26 AM, Kuninori Morimoto
<kuninori.morimoto.gx@...esas.com> wrote:
> From: Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
Hmm… Something wrong with send-email settings?
> This patch adds CS2000 Fractional-N driver as clock provider.
> +#define CH_SIZE_ERR(ch) ((ch < 0) || (ch >= CH_MAX))
> +#define hw_to_priv(_hw) container_of(_hw, struct cs2000_priv, hw)
> +#define priv_to_client(priv) (priv->client)
to_client()?
> +#define priv_to_dev(priv) (&(priv_to_client(priv)->dev))
to_dev() ?
> +static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)
> +{
> + s32 data;
> +
> + data = cs2000_read(priv, addr);
> + if (data < 0)
> + return data;
> +
> + data &= ~mask;
> + data |= (val & mask);
> +
> + return cs2000_write(priv, addr, data);
> +}
> +
> +static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
> +{
> + u32 val;
> + int ret;
> +
> + val = enable ? ENDEV1 : 0;
Put in expression below?
> + ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1, val);
> + if (ret < 0)
> + return ret;
> +
> + val = enable ? ENDEV2 : 0;
Same.
> + ret = cs2000_bset(priv, GLOBAL_CFG, ENDEV2, val);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,
> + u32 rate_in)
> +{
> + u32 val;
> +
> + if (rate_in >= 32000000 &&
> + rate_in < 56000000)
One line here and below?
> + val = 0x0;
> + else if (rate_in >= 16000000 &&
> + rate_in < 28000000)
> + val = 0x1;
> + else if (rate_in >= 8000000 &&
> + rate_in < 14000000)
> + val = 0x2;
> + else
> + return -EINVAL;
> +
> + return cs2000_bset(priv, FUNC_CFG1, 0x3 << 3, val << 3);
> +}
> +
> +static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
> +{
> + struct device *dev = priv_to_dev(priv);
> + s32 val;
> + unsigned int i;
> +
> + for (i = 0; i < 256; i++) {
> + val = cs2000_read(priv, DEVICE_CTRL);
> + if (val < 0)
> + return val;
> + if (!(val & PLL_UNLOCK))
> + return 0;
> + udelay(1);
> + }
unsigned int i = 256;
do {
val = read();
…
while ((val & PLL_UNLOCK) && --i);
if (!i) {
…
return -EIO;
Actually -ETIMEDOUT ?
}
return 0;
> +
> + dev_err(dev, "pll lock failed\n");
> +
> + return -EIO;
> +}
> +
> +static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
> +{
> + u32 val = enable ? 0 : 0x3;
Redundant variable?
> +
> + /* enable both AUX_OUT, CLK_OUT */
> + return cs2000_write(priv, DEVICE_CTRL, val);
> +}
> +
> +static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
> +{
> + u64 ratio;
> +
> + /*
> + * ratio = rate_out / rate_in * 2^20
> + *
> + * To avoid over flow, rate_out is u64
> + * The result should be u32
> + */
> + ratio = (u64)rate_out << 20;
> + do_div(ratio, rate_in);
> +
> + return (u32)ratio;
No need to do explicit casting.
> +}
> +
> +static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
> +{
> + u64 rate_out;
> +
> + /*
> + * ratio = rate_out / rate_in * 2^20
> + *
> + * To avoid over flow, rate_out is u64
> + * The result should be u32
u32 or unsigned long?
Btw, dots at the end of sentences.
> + */
> +
> + rate_out = (u64)ratio * rate_in;
> + return (unsigned long)(rate_out >> 20);
Same.
> +}
> +
> +static int cs2000_ratio_set(struct cs2000_priv *priv,
> + int ch, u32 rate_in, u32 rate_out)
> +{
> + u32 val;
> + unsigned int i;
> + int ret;
> +
> + if (CH_SIZE_ERR(ch))
> + return -EINVAL;
> +
> + val = cs2000_rate_to_ratio(rate_in, rate_out);
> + for (i = 0; i < 4; i++)
4 is magic, you have define already.
> + ret = cs2000_write(priv,
> + Ratio_Add(ch, i),
> + Ratio_Val(val, i));
> + if (ret < 0)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
> +{
> + u32 tmp, val;
> + unsigned int i;
> +
> + val = 0;
> + for (i = 0; i < 4; i++) {
Same.
> + tmp = cs2000_read(priv,
> + Ratio_Add(ch, i));
One line?
> + if (tmp < 0)
> + return 0;
> +
> + val |= Val_Ratio(tmp, i);
> + }
> +
> + return val;
> +}
> +
> +static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
> +{
> + int ret;
> +
> + if (CH_SIZE_ERR(ch))
> + return -EINVAL;
> +
> + /*
> + * FIXME
> + *
> + * this driver supports static ratio mode only
> + * at this point
> + */
One line?
> + ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
> + if (ret < 0)
> + return ret;
> +
> + ret = cs2000_write(priv, DEVICE_CFG2, 0x0);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + struct cs2000_priv *priv = hw_to_priv(hw);
> + int ch = 0; /* it uses ch0 only at this point */
> + u32 ratio;
> +
> + ratio = cs2000_ratio_get(priv, ch);
> +
> + return cs2000_ratio_to_rate(ratio, parent_rate);
> +}
> +
> +static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long *parent_rate)
> +{
> + u32 ratio;
> +
> + ratio = cs2000_rate_to_ratio(*parent_rate, rate);
> +
> + return cs2000_ratio_to_rate(ratio, *parent_rate);
> +}
> +
> +static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
> + unsigned long rate, unsigned long parent_rate)
> +
> +{
> + int ret;
> +
> + ret = cs2000_clk_in_bound_rate(priv, parent_rate);
> + if (ret < 0)
> + return ret;
> +
> + ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
> + if (ret < 0)
> + return ret;
> +
> + ret = cs2000_ratio_select(priv, ch);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int cs2000_set_rate(struct clk_hw *hw,
> + unsigned long rate, unsigned long parent_rate)
> +{
> + struct cs2000_priv *priv = hw_to_priv(hw);
> + int ch = 0; /* it uses ch0 only at this point */
> +
> + return __cs2000_set_rate(priv, ch, rate, parent_rate);
> +}
> +
> +static int cs2000_enable(struct clk_hw *hw)
> +{
> + struct cs2000_priv *priv = hw_to_priv(hw);
> + int ret;
> +
> + ret = cs2000_enable_dev_config(priv, true);
> + if (ret < 0)
> + return ret;
> +
> + ret = cs2000_clk_out_enable(priv, true);
> + if (ret < 0)
> + return ret;
> +
> + ret = cs2000_wait_pll_lock(priv);
> + if (ret < 0)
> + return ret;
> +
> + return ret;
> +}
> +
> +static void cs2000_disable(struct clk_hw *hw)
> +{
> + struct cs2000_priv *priv = hw_to_priv(hw);
> +
> + cs2000_enable_dev_config(priv, false);
> +
> + cs2000_clk_out_enable(priv, false);
> +}
> +
> +static u8 cs2000_get_parent(struct clk_hw *hw)
> +{
> + /* always return REF_CLK */
> + return REF_CLK;
> +}
> +
> +static const struct clk_ops cs2000_ops = {
> + .get_parent = cs2000_get_parent,
> + .recalc_rate = cs2000_recalc_rate,
> + .round_rate = cs2000_round_rate,
> + .set_rate = cs2000_set_rate,
> + .prepare = cs2000_enable,
> + .unprepare = cs2000_disable,
> +};
> +
> +static int cs2000_clk_get(struct cs2000_priv *priv)
> +{
> + struct i2c_client *client = priv_to_client(priv);
> + struct device *dev = &client->dev;
> + struct clk *clk_in, *ref_clk;
> +
> + clk_in = devm_clk_get(dev, "clk_in");
> + /* not yet provided */
> + if (IS_ERR(clk_in))
> + return -EPROBE_DEFER;
> +
> + ref_clk = devm_clk_get(dev, "ref_clk");
> + /* not yet provided */
> + if (IS_ERR(ref_clk))
> + return -EPROBE_DEFER;
> +
> + priv->clk_in = clk_in;
> + priv->ref_clk = ref_clk;
> +
> + return 0;
> +}
> +
> +static int cs2000_clk_register(struct cs2000_priv *priv)
> +{
> + struct device *dev = priv_to_dev(priv);
> + struct device_node *np = dev->of_node;
> + struct clk_init_data init;
> + const char *name = np->name;
> + struct clk *clk;
> + static const char *parent_names[CLK_MAX];
> + int ch = 0; /* it uses ch0 only at this point */
> + int rate;
> + int ret;
> +
> + of_property_read_string(np, "clock-output-names", &name);
What about device property API?
> +
> + /*
> + * set default rate as 1/1.
> + * otherwise .set_rate which setup ratio
> + * is never called if user requests 1/1 rate
> + */
> + rate = clk_get_rate(priv->ref_clk);
> + ret = __cs2000_set_rate(priv, ch, rate, rate);
> + if (ret < 0)
> + return ret;
> +
> + parent_names[CLK_IN] = __clk_get_name(priv->clk_in);
> + parent_names[REF_CLK] = __clk_get_name(priv->ref_clk);
> +
> + init.name = name;
> + init.ops = &cs2000_ops;
> + init.flags = CLK_SET_RATE_GATE;
> + init.parent_names = parent_names;
> + init.num_parents = ARRAY_SIZE(parent_names);
> +
> + priv->hw.init = &init;
> +
> + clk = clk_register(dev, &priv->hw);
> + if (IS_ERR(clk))
> + return PTR_ERR(clk);
> +
> + ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
> + if (ret < 0) {
> + clk_unregister(clk);
> + return ret;
> + }
> +
> + priv->clk_out = clk;
> +
> + return 0;
> +}
> +
> +static int cs2000_version_print(struct cs2000_priv *priv)
> +{
> + struct i2c_client *client = priv_to_client(priv);
> + struct device *dev = &client->dev;
> + s32 val = cs2000_read(priv, DEVICE_ID);
> + const char *revision;
> +
Move read here to see how val is assigned.
s32 val;
…
val = read();
> + if (val < 0)
> + return val;
> +
> + /* CS2000 should be 0x0 */
> + if (0 != (val >> 3))
if (val >> 3)
> + return -EIO;
> +
> + switch (val & 0x7) {
magic
> + case 0x4:
magic
> + revision = "B2 / B3";
> + break;
> + case 0x6:
magic
> + revision = "C1";
> + break;
> + default:
> + return -EIO;
> + }
> +
> + dev_info(dev, "revision - %s\n", revision);
> +
> + return 0;
> +}
> +
> +static int cs2000_remove(struct i2c_client *client)
> +{
> + struct cs2000_priv *priv = i2c_get_clientdata(client);
> + struct device *dev = &client->dev;
> + struct device_node *np = dev->of_node;
> +
> + of_clk_del_provider(np);
> +
> + clk_unregister(priv->clk_out);
> +
> + return 0;
> +}
> +
> +static int cs2000_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct cs2000_priv *priv;
> + struct device *dev = &client->dev;
> + int ret;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->client = client;
> + i2c_set_clientdata(client, priv);
> +
> + ret = cs2000_clk_get(priv);
> + if (ret < 0)
> + return ret;
> +
> + ret = cs2000_clk_register(priv);
> + if (ret < 0)
> + return ret;
> +
> + ret = cs2000_version_print(priv);
> + if (ret < 0)
> + goto probe_err;
> +
> + return 0;
> +
> +probe_err:
> + cs2000_remove(client);
> +
> + return ret;
> +}
> +
> +static struct i2c_driver cs2000_driver = {
> + .driver = {
> + .name = "cs2000-cp",
> + .of_match_table = cs2000_of_match,
> + },
> + .probe = cs2000_probe,
> + .remove = cs2000_remove,
> + .id_table = cs2000_id,
> +};
> +
> +module_i2c_driver(cs2000_driver);
> +
> +MODULE_DESCRIPTION("CS2000-CP driver");
> +MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>");
> +MODULE_LICENSE("GPL v2");
> --
> 1.9.1
>
> --
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--
With Best Regards,
Andy Shevchenko
--
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