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clk: qcom: Add support for RCGs with shared branches

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Some root clock generators may have child branches that are controlled
by different CPUs. These RCGs require some special operations:
 - some enable bits have to be toggled when we set the rate;
 - if RCG is disabled we only cache the rate and set it later when enabled;
 - when the RCG is disabled, the mux is set to the safe source;

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
[sboyd@codeaurora.org: Simplify recalc_rate implementation]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
This commit is contained in:
Georgi Djakov 2015-09-17 19:39:27 +03:00 committed by Stephen Boyd
parent 93e71695da
commit d042877aa7
2 changed files with 82 additions and 1 deletions
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4
drivers/clk/qcom/clk-rcg.h
View file

@ -153,8 +153,8 @@ extern const struct clk_ops clk_dyn_rcg_ops;
* @hid_width: number of bits in half integer divider
* @parent_map: map from software's parent index to hardware's src_sel field
* @freq_tbl: frequency table
* @current_freq: last cached frequency when using branches with shared RCGs
* @clkr: regmap clock handle
* @lock: register lock
*
*/
struct clk_rcg2 {
@ -163,12 +163,14 @@ struct clk_rcg2 {
u8 hid_width;
const struct parent_map *parent_map;
const struct freq_tbl *freq_tbl;
unsigned long current_freq;
struct clk_regmap clkr;
};
#define to_clk_rcg2(_hw) container_of(to_clk_regmap(_hw), struct clk_rcg2, clkr)
extern const struct clk_ops clk_rcg2_ops;
extern const struct clk_ops clk_rcg2_shared_ops;
extern const struct clk_ops clk_edp_pixel_ops;
extern const struct clk_ops clk_byte_ops;
extern const struct clk_ops clk_byte2_ops;

79
drivers/clk/qcom/clk-rcg2.c
View file

@ -300,6 +300,85 @@ const struct clk_ops clk_rcg2_ops = {
};
EXPORT_SYMBOL_GPL(clk_rcg2_ops);
static int clk_rcg2_shared_force_enable(struct clk_hw *hw, unsigned long rate)
{
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
const char *name = clk_hw_get_name(hw);
int ret, count;
/* force enable RCG */
ret = regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + CMD_REG,
CMD_ROOT_EN, CMD_ROOT_EN);
if (ret)
return ret;
/* wait for RCG to turn ON */
for (count = 500; count > 0; count--) {
ret = clk_rcg2_is_enabled(hw);
if (ret)
break;
udelay(1);
}
if (!count)
pr_err("%s: RCG did not turn on\n", name);
/* set clock rate */
ret = __clk_rcg2_set_rate(hw, rate);
if (ret)
return ret;
/* clear force enable RCG */
return regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + CMD_REG,
CMD_ROOT_EN, 0);
}
static int clk_rcg2_shared_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
/* cache the rate */
rcg->current_freq = rate;
if (!__clk_is_enabled(hw->clk))
return 0;
return clk_rcg2_shared_force_enable(hw, rcg->current_freq);
}
static unsigned long
clk_rcg2_shared_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
{
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
return rcg->current_freq = clk_rcg2_recalc_rate(hw, parent_rate);
}
static int clk_rcg2_shared_enable(struct clk_hw *hw)
{
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
return clk_rcg2_shared_force_enable(hw, rcg->current_freq);
}
static void clk_rcg2_shared_disable(struct clk_hw *hw)
{
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
/* switch to XO, which is the lowest entry in the freq table */
clk_rcg2_shared_set_rate(hw, rcg->freq_tbl[0].freq, 0);
}
const struct clk_ops clk_rcg2_shared_ops = {
.enable = clk_rcg2_shared_enable,
.disable = clk_rcg2_shared_disable,
.get_parent = clk_rcg2_get_parent,
.recalc_rate = clk_rcg2_shared_recalc_rate,
.determine_rate = clk_rcg2_determine_rate,
.set_rate = clk_rcg2_shared_set_rate,
};
EXPORT_SYMBOL_GPL(clk_rcg2_shared_ops);
struct frac_entry {
int num;
int den;