diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/clk/clk-versaclock5.c | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c index 344cd6c61188..3c737742c2a9 100644 --- a/drivers/clk/clk-versaclock5.c +++ b/drivers/clk/clk-versaclock5.c @@ -69,7 +69,10 @@ #define VC5_FEEDBACK_FRAC_DIV(n) (0x19 + (n)) #define VC5_RC_CONTROL0 0x1e #define VC5_RC_CONTROL1 0x1f -/* Register 0x20 is factory reserved */ + +/* These registers are named "Unused Factory Reserved Registers" */ +#define VC5_RESERVED_X0(idx) (0x20 + ((idx) * 0x10)) +#define VC5_RESERVED_X0_BYPASS_SYNC BIT(7) /* bypass_sync<idx> bit */ /* Output divider control for divider 1,2,3,4 */ #define VC5_OUT_DIV_CONTROL(idx) (0x21 + ((idx) * 0x10)) @@ -87,7 +90,6 @@ #define VC5_OUT_DIV_SKEW_INT(idx, n) (0x2b + ((idx) * 0x10) + (n)) #define VC5_OUT_DIV_INT(idx, n) (0x2d + ((idx) * 0x10) + (n)) #define VC5_OUT_DIV_SKEW_FRAC(idx) (0x2f + ((idx) * 0x10)) -/* Registers 0x30, 0x40, 0x50 are factory reserved */ /* Clock control register for clock 1,2 */ #define VC5_CLK_OUTPUT_CFG(idx, n) (0x60 + ((idx) * 0x2) + (n)) @@ -140,6 +142,8 @@ #define VC5_HAS_INTERNAL_XTAL BIT(0) /* chip has PFD requency doubler */ #define VC5_HAS_PFD_FREQ_DBL BIT(1) +/* chip has bits to disable FOD sync */ +#define VC5_HAS_BYPASS_SYNC_BIT BIT(2) /* Supported IDT VC5 models. */ enum vc5_model { @@ -582,6 +586,23 @@ static int vc5_clk_out_prepare(struct clk_hw *hw) int ret; /* + * When enabling a FOD, all currently enabled FODs are briefly + * stopped in order to synchronize all of them. This causes a clock + * disruption to any unrelated chips that might be already using + * other clock outputs. Bypass the sync feature to avoid the issue, + * which is possible on the VersaClock 6E family via reserved + * registers. + */ + if (vc5->chip_info->flags & VC5_HAS_BYPASS_SYNC_BIT) { + ret = regmap_update_bits(vc5->regmap, + VC5_RESERVED_X0(hwdata->num), + VC5_RESERVED_X0_BYPASS_SYNC, + VC5_RESERVED_X0_BYPASS_SYNC); + if (ret) + return ret; + } + + /* * If the input mux is disabled, enable it first and * select source from matching FOD. */ @@ -1166,7 +1187,7 @@ static const struct vc5_chip_info idt_5p49v6965_info = { .model = IDT_VC6_5P49V6965, .clk_fod_cnt = 4, .clk_out_cnt = 5, - .flags = 0, + .flags = VC5_HAS_BYPASS_SYNC_BIT, }; static const struct i2c_device_id vc5_id[] = { |