drivers/clk/aspeed/clk-aspeed.c:682 aspeed_ast2500_cc() warn: mask and shift to zero: expr='val >> 23'

BCC: [email protected]
CC: [email protected]
CC: [email protected]
TO: Ryan Chen <[email protected]>
CC: Stephen Boyd <[email protected]>
CC: Brian Masney <[email protected]>

Hi Ryan,

First bad commit (maybe != root cause):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   0ce37745d4bfbc493f718169c3974898ffec8ee7
commit: 03b3faa12c25140d00f9dca4ed44a6184600d9d8 clk: aspeed: Move the existing ASPEED clk drivers into aspeed subdirectory.
date:   6 months ago
:::::: branch date: 14 hours ago
:::::: commit date: 6 months ago
config: riscv-randconfig-r071-20260723 (https://download.01.org/0day-ci/archive/20260726/[email protected]/config)
compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project 890b11e09e45e9d8b29f2f94f22052be3934e757)
smatch: v0.5.0-9187-g5189e3fb

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Fixes: 03b3faa12c25 ("clk: aspeed: Move the existing ASPEED clk drivers into aspeed subdirectory.")
| Reported-by: kernel test robot <[email protected]>
| Reported-by: Dan Carpenter <[email protected]>
| Closes: https://lore.kernel.org/r/[email protected]/

smatch warnings:
drivers/clk/aspeed/clk-aspeed.c:682 aspeed_ast2500_cc() warn: mask and shift to zero: expr='val >> 23'

vim +682 drivers/clk/aspeed/clk-aspeed.c

99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  650  
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  651  static void __init aspeed_ast2500_cc(struct regmap *map)
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  652  {
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  653  	struct clk_hw *hw;
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  654  	u32 val, freq, div;
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  655  
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  656  	/* CLKIN is the crystal oscillator, 24 or 25MHz selected by strapping */
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  657  	regmap_read(map, ASPEED_STRAP, &val);
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  658  	if (val & CLKIN_25MHZ_EN)
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  659  		freq = 25000000;
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  660  	else
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  661  		freq = 24000000;
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  662  	hw = clk_hw_register_fixed_rate(NULL, "clkin", NULL, 0, freq);
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  663  	pr_debug("clkin @%u MHz\n", freq / 1000000);
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  664  
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  665  	/*
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  666  	 * High-speed PLL clock derived from the crystal. This the CPU clock,
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  667  	 * and we assume that it is enabled
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  668  	 */
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  669  	regmap_read(map, ASPEED_HPLL_PARAM, &val);
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  670  	aspeed_clk_data->hws[ASPEED_CLK_HPLL] = aspeed_ast2500_calc_pll("hpll", val);
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  671  
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  672  	/* Strap bits 11:9 define the AXI/AHB clock frequency ratio (aka HCLK)*/
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  673  	regmap_read(map, ASPEED_STRAP, &val);
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  674  	val = (val >> 9) & 0x7;
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  675  	WARN(val == 0, "strapping is zero: cannot determine ahb clock");
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  676  	div = 2 * (val + 1);
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  677  	hw = clk_hw_register_fixed_factor(NULL, "ahb", "hpll", 0, 1, div);
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  678  	aspeed_clk_data->hws[ASPEED_CLK_AHB] = hw;
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  679  
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  680  	/* APB clock clock selection register SCU08 (aka PCLK) */
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  681  	regmap_read(map, ASPEED_CLK_SELECTION, &val);
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22 @682  	val = (val >> 23) & 0x7;
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  683  	div = 4 * (val + 1);
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  684  	hw = clk_hw_register_fixed_factor(NULL, "apb", "hpll", 0, 1, div);
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  685  	aspeed_clk_data->hws[ASPEED_CLK_APB] = hw;
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  686  };
99d01e0ec34154 drivers/clk/clk-aspeed.c Joel Stanley 2017-12-22  687  

:::::: The code at line 682 was first introduced by commit
:::::: 99d01e0ec3415424210fcd345ebb0c516e4b7fa9 clk: aspeed: Register core clocks

:::::: TO: Joel Stanley <[email protected]>
:::::: CC: Stephen Boyd <[email protected]>

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