Re: [PATCH v2 2/9] clk: ralink: add clock and reset driver for MTMIPS SoCs

Sergio Paracuellos
2023-04-14T05:50:10Z

On Thu, Apr 13, 2023 at 8:55 PM Stephen Boyd <sboyd@kernel.org> wrote:
>
> Quoting Sergio Paracuellos (2023-03-20 22:00:27)
> > diff --git a/drivers/clk/ralink/clk-mtmips.c b/drivers/clk/ralink/clk-mtmips.c
> > new file mode 100644
> > index 000000000000..6b4b5ae9384d
> > --- /dev/null
> > +++ b/drivers/clk/ralink/clk-mtmips.c
> > @@ -0,0 +1,985 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * MTMIPS SoCs Clock Driver
> > + * Author: Sergio Paracuellos <sergio.paracuellos@gmail.com>
> > + */
> > +
> > +#include <linux/bitops.h>
> > +#include <linux/clk-provider.h>
> > +#include <linux/clk.h>
>
> Drop unused include.

Sure :)

>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +#include <linux/reset-controller.h>
> > +#include <linux/slab.h>
> > +
> [..]

Will drop this extra empty line.

> > +
> > +/*
> > + * There are drivers for these SoCs that are older than clock driver
> > + * and are not prepared for the clock. We don't want the kernel to
> > + * disable anything so we add CLK_IS_CRITICAL flag here.
> > + */
> > +#define CLK_PERIPH(_name, _parent) { \
> > + .init = &(struct clk_init_data) { \
>
> const?
>
> > + .name = _name, \
> > + .ops = &(const struct clk_ops) { \
>
> Make this into a named variable? Otherwise I suspect the compiler will
> want to duplicate it.

I am not sure if I understand this. What do you mean exactly?

>
> > + .recalc_rate = mtmips_pherip_clk_rate \
> > + }, \
> > + .parent_data = &(const struct clk_parent_data) {\
> > + .name = _parent, \
> > + .fw_name = _parent \
> > + }, \
> > + .num_parents = 1, \
> > + .flags = CLK_SET_RATE_PARENT | CLK_IS_CRITICAL \
>
> Why is everything critical? Put the comment here instead of above the
> macro

Ok, will do.

>
> > + }, \
> > +}
> > +
> [...]
> > +
> > +static int mtmips_register_pherip_clocks(struct device_node *np,
> > + struct clk_hw_onecell_data *clk_data,
> > + struct mtmips_clk_priv *priv)
> > +{
> > + struct clk_hw **hws = clk_data->hws;
> > + struct mtmips_clk *sclk;
> > + int ret, i;
> > +
> > + for (i = 0; i < priv->data->num_clk_periph; i++) {
> > + int idx = (priv->data->num_clk_base - 1) + i;
> > +
> > + sclk = &priv->data->clk_periph[i];
> > + ret = of_clk_hw_register(np, &sclk->hw);
> > + if (ret) {
> > + pr_err("Couldn't register peripheral clock %d\n", idx);
> > + goto err_clk_unreg;
> > + }
> > +
> > + hws[idx] = &sclk->hw;
> > + }
> > +
> > + return 0;
> > +
> > +err_clk_unreg:
> > + while (--i >= 0) {
> > + sclk = &priv->data->clk_periph[i];
> > + clk_hw_unregister(&sclk->hw);
> > + }
> > + return ret;
> > +}
> > +
> > +static inline struct mtmips_clk *to_mtmips_clk(struct clk_hw *hw)
> > +{
> > + return container_of(hw, struct mtmips_clk, hw);
> > +}
> > +
> > +static unsigned long rt5350_xtal_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + u32 val;
> > +
> > + regmap_read(sysc, SYSC_REG_SYSTEM_CONFIG, &val);
> > + if (!(val & RT5350_CLKCFG0_XTAL_SEL))
> > + return 20000000;
> > +
> > + return 40000000;
> > +}
> > +
> > +static unsigned long rt5350_cpu_recalc_rate(struct clk_hw *hw,
> > + unsigned long xtal_clk)
> > +{
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + u32 t;
> > +
> > + regmap_read(sysc, SYSC_REG_SYSTEM_CONFIG, &t);
> > + t = (t >> RT5350_SYSCFG0_CPUCLK_SHIFT) & RT5350_SYSCFG0_CPUCLK_MASK;
> > +
> > + switch (t) {
> > + case RT5350_SYSCFG0_CPUCLK_360:
> > + return 360000000;
> > + case RT5350_SYSCFG0_CPUCLK_320:
> > + return 320000000;
> > + case RT5350_SYSCFG0_CPUCLK_300:
> > + return 300000000;
> > + default:
> > + BUG();
> > + }
> > +}
> > +
> > +static unsigned long rt5350_bus_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + if (parent_rate == 320000000)
> > + return parent_rate / 4;
> > +
> > + return parent_rate / 3;
> > +}
> > +
> > +static unsigned long rt3352_cpu_recalc_rate(struct clk_hw *hw,
> > + unsigned long xtal_clk)
> > +{
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + u32 t;
> > +
> > + regmap_read(sysc, SYSC_REG_SYSTEM_CONFIG, &t);
> > + t = (t >> RT3352_SYSCFG0_CPUCLK_SHIFT) & RT3352_SYSCFG0_CPUCLK_MASK;
> > +
> > + switch (t) {
> > + case RT3352_SYSCFG0_CPUCLK_LOW:
> > + return 384000000;
> > + case RT3352_SYSCFG0_CPUCLK_HIGH:
> > + return 400000000;
> > + default:
> > + BUG();
> > + }
> > +}
> > +
> > +static unsigned long rt3352_periph_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + return 40000000;
> > +}
> > +
> > +static unsigned long rt3352_bus_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + return parent_rate / 3;
> > +}
> > +
> > +static unsigned long rt305x_xtal_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + return 40000000;
> > +}
>
> Register fixed factor and fixed rate clks in software instead of
> duplicating the code here.

All the macros used in current code rely on the fact of having recalc
functions so we can maintain the code shorter just using them. Is
there a real benefit of using a fixed factor and fixed clks here?
If possible I can avoid the duplicate here just using the same
recalc_rate function returning the fixed stuff for both 305x and 3352
SoCs as I am also doing for other functions.

>
> > +
> > +static unsigned long rt305x_cpu_recalc_rate(struct clk_hw *hw,
> > + unsigned long xtal_clk)
> > +{
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + u32 t;
> > +
> > + regmap_read(sysc, SYSC_REG_SYSTEM_CONFIG, &t);
> > + t = (t >> RT305X_SYSCFG_CPUCLK_SHIFT) & RT305X_SYSCFG_CPUCLK_MASK;
> > +
> > + switch (t) {
> > + case RT305X_SYSCFG_CPUCLK_LOW:
> > + return 320000000;
> > + case RT305X_SYSCFG_CPUCLK_HIGH:
> > + return 384000000;
> > + default:
> > + BUG();
> > + }
> > +}
> > +
> > +static unsigned long rt3883_cpu_recalc_rate(struct clk_hw *hw,
> > + unsigned long xtal_clk)
> > +{
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + u32 t;
> > +
> > + regmap_read(sysc, SYSC_REG_SYSTEM_CONFIG, &t);
> > + t = (t >> RT3883_SYSCFG0_CPUCLK_SHIFT) & RT3883_SYSCFG0_CPUCLK_MASK;
> > +
> > + switch (t) {
> > + case RT3883_SYSCFG0_CPUCLK_250:
> > + return 250000000;
> > + case RT3883_SYSCFG0_CPUCLK_384:
> > + return 384000000;
> > + case RT3883_SYSCFG0_CPUCLK_480:
> > + return 480000000;
> > + case RT3883_SYSCFG0_CPUCLK_500:
> > + return 500000000;
> > + default:
> > + BUG();
> > + }
> > +}
> > +
> > +static unsigned long rt3883_bus_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + u32 ddr2;
> > + u32 t;
> > +
> > + regmap_read(sysc, SYSC_REG_SYSTEM_CONFIG, &t);
> > + ddr2 = t & RT3883_SYSCFG0_DRAM_TYPE_DDR2;
> > +
> > + switch (parent_rate) {
> > + case 250000000:
> > + return (ddr2) ? 125000000 : 83000000;
> > + case 384000000:
> > + return (ddr2) ? 128000000 : 96000000;
> > + case 480000000:
> > + return (ddr2) ? 160000000 : 120000000;
> > + case 500000000:
> > + return (ddr2) ? 166000000 : 125000000;
> > + default:
> > + BUG();
>
> Why? Depending on clk registration order 'parent_rate' could be 0, and
> then this will crash the system.

I was maintaining previous code from the arch/mips/ralink folders.
Will drop 'default' then.

>
> > + }
> > +}
> > +
> > +static unsigned long rt2880_cpu_recalc_rate(struct clk_hw *hw,
> > + unsigned long xtal_clk)
> > +{
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + u32 t;
> > +
> > + regmap_read(sysc, SYSC_REG_SYSTEM_CONFIG, &t);
> > + t = (t >> RT2880_CONFIG_CPUCLK_SHIFT) & RT2880_CONFIG_CPUCLK_MASK;
> > +
> > + switch (t) {
> > + case RT2880_CONFIG_CPUCLK_250:
> > + return 250000000;
> > + case RT2880_CONFIG_CPUCLK_266:
> > + return 266000000;
> > + case RT2880_CONFIG_CPUCLK_280:
> > + return 280000000;
> > + case RT2880_CONFIG_CPUCLK_300:
> > + return 300000000;
> > + default:
> > + BUG();
> > + }
> > +}
> > +
> > +static unsigned long rt2880_bus_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + return parent_rate / 2;
> > +}
>
> A fixed factor clk?

As I have said, macros rely on having recalc_rate functions. Also,
having in this way makes pretty clear the relation between the bus
clock and its related parent as it is in the datasheet.

>
> > +
> > +static u32 mt7620_calc_rate(u32 ref_rate, u32 mul, u32 div)
> > +{
> > + u64 t;
> > +
> > + t = ref_rate;
> > + t *= mul;
> > + do_div(t, div);
>
> Do we really need to do 64-bit math? At the least use div_u64().

This is directly extracted from arch/mips/ralink clock code, so I have
maintained it as it is since I don't have an mt7620 SoC based board to
test. However using div_u64 here with t being u64 makes sense.

>
> > +
> > + return t;
> > +}
> > +
> > +static unsigned long mt7620_pll_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + static const u32 clk_divider[] = { 2, 3, 4, 8 };
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + unsigned long cpu_pll;
> > + u32 t;
> > + u32 mul;
> > + u32 div;
> > +
> > + regmap_read(sysc, SYSC_REG_CPLL_CONFIG0, &t);
> > + if (t & CPLL_CFG0_BYPASS_REF_CLK) {
> > + cpu_pll = parent_rate;
> > + } else if ((t & CPLL_CFG0_SW_CFG) == 0) {
> > + cpu_pll = 600000000;
> > + } else {
> > + mul = (t >> CPLL_CFG0_PLL_MULT_RATIO_SHIFT) &
> > + CPLL_CFG0_PLL_MULT_RATIO_MASK;
> > + mul += 24;
> > + if (t & CPLL_CFG0_LC_CURFCK)
> > + mul *= 2;
> > +
> > + div = (t >> CPLL_CFG0_PLL_DIV_RATIO_SHIFT) &
> > + CPLL_CFG0_PLL_DIV_RATIO_MASK;
> > +
> > + WARN_ON(div >= ARRAY_SIZE(clk_divider));
>
> WARN_ON_ONCE() so that this doesn't spam the system.

Sure.

>
> > +
> > + cpu_pll = mt7620_calc_rate(parent_rate, mul, clk_divider[div]);
> > + }
> > +
> > + regmap_read(sysc, SYSC_REG_CPLL_CONFIG1, &t);
> > + if (t & CPLL_CFG1_CPU_AUX1)
> > + return parent_rate;
> > +
> > + if (t & CPLL_CFG1_CPU_AUX0)
> > + return 480000000;
> > +
> > + return cpu_pll;
> > +}
> > +
> > +static unsigned long mt7620_cpu_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + u32 t;
> > + u32 mul;
> > + u32 div;
> > +
> > + regmap_read(sysc, SYSC_REG_CPU_SYS_CLKCFG, &t);
> > + mul = t & CPU_SYS_CLKCFG_CPU_FFRAC_MASK;
> > + div = (t >> CPU_SYS_CLKCFG_CPU_FDIV_SHIFT) &
> > + CPU_SYS_CLKCFG_CPU_FDIV_MASK;
> > +
> > + return mt7620_calc_rate(parent_rate, mul, div);
> > +}
> > +
> > +static unsigned long mt7620_bus_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + static const u32 ocp_dividers[16] = {
> > + [CPU_SYS_CLKCFG_OCP_RATIO_2] = 2,
> > + [CPU_SYS_CLKCFG_OCP_RATIO_3] = 3,
> > + [CPU_SYS_CLKCFG_OCP_RATIO_4] = 4,
> > + [CPU_SYS_CLKCFG_OCP_RATIO_5] = 5,
> > + [CPU_SYS_CLKCFG_OCP_RATIO_10] = 10,
> > + };
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + u32 t;
> > + u32 ocp_ratio;
> > + u32 div;
> > +
> > + if (IS_ENABLED(CONFIG_USB)) {
> > + /*
> > + * When the CPU goes into sleep mode, the BUS
> > + * clock will be too low for USB to function properly.
> > + * Adjust the busses fractional divider to fix this
> > + */
> > + regmap_read(sysc, SYSC_REG_CPU_SYS_CLKCFG, &t);
> > + t &= ~(CLKCFG_FDIV_MASK | CLKCFG_FFRAC_MASK);
> > + t |= CLKCFG_FDIV_USB_VAL | CLKCFG_FFRAC_USB_VAL;
> > + regmap_write(sysc, SYSC_REG_CPU_SYS_CLKCFG, t);
>
> Why can't we do this unconditionally? And recalc_rate() shouldn't be
> writing registers. It should be calculating the frequency of the clk
> based on 'parent_rate' and whatever the hardware is configured for.

This code is with IS_ENABLED(CONFIG_USB) guard in the original code so
I have maintained it as it is. Where should it be moved into instead
of doing the register writes in this recalc function?

>
> > + }
> > +
> > + regmap_read(sysc, SYSC_REG_CPU_SYS_CLKCFG, &t);
> > + ocp_ratio = (t >> CPU_SYS_CLKCFG_OCP_RATIO_SHIFT) &
> > + CPU_SYS_CLKCFG_OCP_RATIO_MASK;
> > +
> > + if (WARN_ON(ocp_ratio >= ARRAY_SIZE(ocp_dividers)))
> > + return parent_rate;
> > +
> > + div = ocp_dividers[ocp_ratio];
> > + if (WARN(!div, "invalid divider for OCP ratio %u", ocp_ratio))
>
> Missing newline.

Will add it.

>
> > + return parent_rate;
> > +
> > + return parent_rate / div;
> > +}
> > +
> > +static unsigned long mt7620_periph_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + u32 t;
> > +
> > + regmap_read(sysc, SYSC_REG_CLKCFG0, &t);
> > + if (t & CLKCFG0_PERI_CLK_SEL)
> > + return parent_rate;
> > +
> > + return 40000000;
> > +}
> > +
> > +static unsigned long mt76x8_xtal_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + struct mtmips_clk *clk = to_mtmips_clk(hw);
> > + struct regmap *sysc = clk->priv->sysc;
> > + u32 t;
> > +
> > + regmap_read(sysc, SYSC_REG_SYSTEM_CONFIG, &t);
> > + if (t & MT7620_XTAL_FREQ_SEL)
> > + return 40000000;
> > +
> > + return 20000000;
> > +}
> > +
> > +static unsigned long mt76x8_cpu_recalc_rate(struct clk_hw *hw,
> > + unsigned long xtal_clk)
> > +{
> > + if (xtal_clk == 40000000)
> > + return 580000000;
> > +
> > + return 575000000;
> > +}
> > +
> > +static unsigned long mt76x8_pcmi2s_recalc_rate(struct clk_hw *hw,
> > + unsigned long xtal_clk)
> > +{
> > + return 480000000;
> > +}
>
> Use fixed rate clk.

See my previous comments about this, please.

>
> > +
> > +#define CLK_BASE(_name, _parent, _recalc) { \
> > + .init = &(struct clk_init_data) { \
>
> const

Sure.

>
> > + .name = _name, \
> > + .ops = &(const struct clk_ops) { \
> > + .recalc_rate = _recalc, \
> > + }, \
> > + .parent_data = &(const struct clk_parent_data) { \
> > + .name = _parent, \
> > + .fw_name = _parent \
> > + }, \
> > + .num_parents = _parent ? 1 : 0 \
> > + }, \
> > +}
> > +
> [...]

Will drop the extra line here.

> > +
> > +static void __init mtmips_clk_init(struct device_node *node)
> > +{
> > + const struct of_device_id *match;
> > + const struct mtmips_clk_data *data;
> > + struct mtmips_clk_priv *priv;
> > + struct clk_hw_onecell_data *clk_data;
> > + int ret, i, count;
> > +
> > + if (!of_find_property(node, "#clock-cells", NULL)) {
> > + pr_err("No '#clock-cells' property found\n");
>
> We don't need to validate the bindings in the driver.

Sure, will drop this check, then.

>
> > + return;
> > + }
> > +
> > + priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return;
> > +
> > + priv->sysc = syscon_node_to_regmap(node);
> > + if (IS_ERR(priv->sysc)) {
> > + pr_err("Could not get sysc syscon regmap\n");
> > + goto free_clk_priv;
> > + }
> > +
> > + match = of_match_node(mtmips_of_match, node);
> > + if (WARN_ON(!match))
> > + return;
> > +
> > + data = match->data;
> > + priv->data = data;
> > + count = priv->data->num_clk_base + priv->data->num_clk_periph;
> > + clk_data = kzalloc(struct_size(clk_data, hws, count), GFP_KERNEL);
> > + if (!clk_data)
> > + goto free_clk_priv;
> > +
> > + ret = mtmips_register_clocks(node, clk_data, priv);
> > + if (ret) {
> > + pr_err("Couldn't register top clocks\n");
> > + goto free_clk_data;
> > + }
> > +
> > + ret = mtmips_register_pherip_clocks(node, clk_data, priv);
> > + if (ret) {
> > + pr_err("Couldn't register peripheral clocks\n");
> > + goto unreg_clk_top;
> > + }
> > +
> > + clk_data->num = count;
> > +
> > + ret = of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
> > + if (ret) {
> > + pr_err("Couldn't add clk hw provider\n");
> > + goto unreg_clk_periph;
> > + }
> > +
> > + return;
> > +
> > +unreg_clk_periph:
> > + for (i = 0; i < priv->data->num_clk_periph; i++) {
> > + struct mtmips_clk *sclk = &priv->data->clk_periph[i];
> > +
> > + clk_hw_unregister(&sclk->hw);
> > + }
> > +
> > +unreg_clk_top:
> > + for (i = 0; i < priv->data->num_clk_base; i++) {
> > + struct mtmips_clk *sclk = &priv->data->clk_base[i];
> > +
> > + clk_hw_unregister(&sclk->hw);
> > + }
> > +
> > +free_clk_data:
> > + kfree(clk_data);
> > +
> > +free_clk_priv:
> > + kfree(priv);
> > +}
> > +CLK_OF_DECLARE_DRIVER(rt2880_clk, "ralink,rt2880-sysc", mtmips_clk_init);
> > +CLK_OF_DECLARE_DRIVER(rt3050_clk, "ralink,rt3050-sysc", mtmips_clk_init);
> > +CLK_OF_DECLARE_DRIVER(rt3052_clk, "ralink,rt3052-sysc", mtmips_clk_init);
> > +CLK_OF_DECLARE_DRIVER(rt3352_clk, "ralink,rt3352-sysc", mtmips_clk_init);
> > +CLK_OF_DECLARE_DRIVER(rt3883_clk, "ralink,rt3883-sysc", mtmips_clk_init);
> > +CLK_OF_DECLARE_DRIVER(rt5350_clk, "ralink,rt5350-sysc", mtmips_clk_init);
> > +CLK_OF_DECLARE_DRIVER(mt7620_clk, "ralink,mt7620-sysc", mtmips_clk_init);
> > +CLK_OF_DECLARE_DRIVER(mt7620a_clk, "ralink,mt7620a-sysc", mtmips_clk_init);
> > +CLK_OF_DECLARE_DRIVER(mt7628_clk, "ralink,mt7628-sysc", mtmips_clk_init);
> > +CLK_OF_DECLARE_DRIVER(mt7688_clk, "ralink,mt7688-sysc", mtmips_clk_init);
>
> Is there any reason why these can't be platform drivers?

The ralink system uses a performance counter as the default clocksource.
Then, mips_hpt_frequency should be figured out when doing plat_time_init(),
And mips_hpt_frequency depends on CPU clock.
So these clocks should be initialized as early as possible.
It's too late for being a platform device driver.

>
> > +
> [..]
> > +
> > +static int mtmips_clk_probe(struct platform_device *pdev)
> > +{
> > + struct device_node *np = pdev->dev.of_node;
> > + struct device *dev = &pdev->dev;
> > + struct mtmips_clk_priv *priv;
> > + int ret;
> > +
> > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return -ENOMEM;
> > +
> > + priv->sysc = syscon_node_to_regmap(np);
> > + if (IS_ERR(priv->sysc)) {
> > + ret = PTR_ERR(priv->sysc);
> > + dev_err(dev, "Could not get sysc syscon regmap\n");
>
> Use dev_err_probe()?

Sure, will change to use this.

>
> > + return ret;
> > + }
> > +
> > + ret = mtmips_reset_init(dev, priv->sysc);
> > + if (ret) {
> > + dev_err(dev, "Could not init reset controller\n");
>
> Use dev_err_probe()?

Ditto.

>
> > + return ret;
> > + }
> > +
> > + return 0;
> > +}
> > +

Thanks,
Sergio Paracuellos